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9,200 | [Immune status of patients with cardiac arrhythmias: idiopathic and in primary heart disease]. | A detailed description of immune status abnormalities of adult patients with heart arrhythmia either idiopathic or in combination with primary heart disease such as chronic myocarditis and dilated cardiomyopathy (DCMP).</AbstractText>Eighty two consecutive patients aged 16-57 years admitted to the L.A. Myasnikov Institute of Clinical Cardiology (Moscow) for heart arrhythmia were studied. Among them 35 patients had idiopathic heart arrhythmia (IHA, group 1) with no evidence of any primary heart disease, while other 47 patients (group 2) had heart arrhythmia combined with primary heart disease (chronic myocarditis or DCMP). In group 1 ventricular arrhythmia was recorded in 27 patients (12 cases with ventricular tachyarrhrythmia ?VTA, 15 cases with ventricular extrasystolia- VE). Supraventricular heart arrhythmia was found in 6 patients (3 cases of constantly recurring supraventriccular tachycardia, 2 cases of paroxysmal and 1 with constant atrial fibrillation). The intermittent atrioventricular block of the second-third degree was recorded in 2 patients. The patients of group 2 were divided into subgroups 2a, 2b and 2c. In subgroup 2a (patients with DCMP without signs of heart failure) ventricular arrhythmia was found in 7 patients (VT ? 5, VE ? 2). Supraventricular arrhythmia was recorded in 7 patients 5 of which had constantly recurring supraventricular tachycardia, 1 ? paroxysmal and 1 constant atrial fibrillation. In subgroup 2b (DCMP patients with obvious signs of heart failure) ventricular arrhythmia was recorded in 12 patients, among them 6 had VT and 6 ? VE, 2 ? constant atrial fibrillation). In subgroup 2c (patients with chronic myocarditis) ventricular arrhythmia was in 7 patients (VT ? 5, VE ? 2), constant atrial fibrillation ? in 2, heart conduction abnormalities ? in 3 patients, atrioventricular block of the first or second degree ? in 2, sick sinus syndrome ? in 1. To verify the diagnosis, all the patients have undergone physical examination, blood cell counts and biochemical tests, urine clinical analysis, ECG and ultrasound heart examination as well as 24h ECG monitoring. On demand, bicycle exercise test or treadmill test, coronaroangiography, endomyocardial biopsy and invasive electrophysiological examination were made.</AbstractText>Immune status abnormalities found in patients with heart arrhythmia both idiopathic and combined with primary heart diseases such as chronic myocarditis and DCMO correspond to immune defense response during chronic infection. Activation of different anti-infection defense mechanisms was recorded in patients with idiopathic heart rhythm and conductivity abnormalities. Immune deficiency was found in arrhythmia and conductivity abnormalities combined with primary heart diseases (chronic myocarditis or DCMP). A positive correlation exists between the degree of immune defense failure and reduction of myocardial contractility.</AbstractText>There exists a characteristic pattern of immune status abnormalities in patients with arrhythmia, both idiopathic or combined with primary heart disease (myocarditis, DCMP). The abnormalities depend on severity of arrhythmia, intensity of inflammatory processes in the myocardium and on the degree of left ventricular contractility dysfunction in patients with primary heart diseases.</AbstractText> |
9,201 | Effects of biphasic waveforms on outcomes of cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest. | The effects of two clinically available biphasic waveforms on the success of defibrillation and postresuscitation myocardial dysfunction after prolonged ventricular fibrillation were compared with two newly designed dual-path sequential and simultaneous rectilinear biphasic waveforms. Defibrillation via sequential pulses and encircling, overlapping multiple pathway may depolarize a larger myocardial mass and facilitate transthoracic defibrillation.</AbstractText>Animal study.</AbstractText>Experimental laboratory.</AbstractText>Thirty-two 40 +/- 3 kg pigs.</AbstractText>Ventricular fibrillation was ischemically induced in 32 pigs. After 7 mins of untreated ventricular fibrillation, cardiopulmonary resuscitation was initiated and continued for 5 mins. Animals were then randomized to receive up to three shocks with a) single-path rectilinear biphasic waveform; b) single-path biphasic truncated exponential waveform; c) dual-path rectilinear biphasic sequential defibrillation; or d) dual-path rectilinear biphasic simultaneous defibrillation.</AbstractText>Rectilinear biphasic, dual-path sequential defibrillation, and simultaneous defibrillation had significantly fewer shocks (1.1 +/- 0.4, 1.4 +/- 0.5, 1.3 +/- 0.7, respectively) before restoration of spontaneous circulation than biphasic truncated exponential waveform (2.6 +/- 1.4, p < .005) and less postresuscitation myocardial dysfunction (p < .05). Also, dual-path sequential defibrillation had higher postresuscitation ejection fraction than rectilinear biphasic and dual-path simultaneous defibrillation (p < .005).</AbstractText>The energy requirements for terminating ischemically induced ventricular fibrillation were significantly lower and minimized early postresuscitation myocardial dysfunction in the rectilinear biphasic, dual-path sequential defibrillation, and simultaneous defibrillation than the biphasic truncated exponential waveform. Dual-path sequential defibrillation had less postresuscitation myocardial dysfunction than rectilinear biphasic and dual-path simultaneous defibrillation, but at 72 hrs these differences were no longer significant.</AbstractText> |
9,202 | Atrial-specific drug AVE0118 is free of torsades de pointes in anesthetized dogs with chronic complete atrioventricular block. | The novel compound AVE0118 has been shown to prevent and terminate persistent atrial fibrillation. AVE0118 blocks I(Kur), I(KAch), and I(to), leading to prolongation of atrial repolarization with no change in ventricular repolarization. This finding suggests that AVE0118 may be devoid of proarrhythmic side effects. Experimentally, AVE0118 has been antiarrhythmic against some specific ventricular arrhythmias.</AbstractText>The purpose of this study was to investigate the proarrhythmic and antiarrhythmic effects of AVE0118 in anesthetized dogs with chronic complete AV block, known for a high proclivity for torsades de pointes (TdP).</AbstractText>AVE0118 was administered intravenously as a fast infusion (0.5 mg/kg/5 min) and a slow infusion (3 or 10 mg/kg/60 min). Dofetilide was given to induce TdP. ECG and monophasic action potentials were recorded. Short-term beat-to-beat variability (STV) of the left ventricular monophasic action potential duration (MAPD) was calculated. We examined whether AVE0118 (1) caused ventricular proarrhythmia (both infusions), (2) prevented dofetilide-induced TdP (slow infusion + dofetilide after 30 minutes), and (3) abolished TdP (fast infusion).</AbstractText>At 0.55 +/- 0.10 microg/mL (fast infusion at 10 minutes), AVE0118 did not increase ventricular repolarization or induce TdP; however, right atrial MAPD(50) and MAPD(90) were significantly increased by 26% +/- 9% and 10% +/- 5%, respectively (P <.05 vs baseline). At 1.9 +/- 0.5 microg/mL and 6.1 +/- 1.2 microg/mL (30 minutes of 3 or 10 mg/kg/h), AVE0118 did not induce TdP (0/6 and 0/4) nor prevent dofetilide-induced TdP (6/6 and 2/2). Dofetilide significantly increased all repolarization parameters, including STV from 2.1 +/- 0.4 ms to 4.6 +/- 1.8 ms (P <.05 vs baseline), which were not changed by AVE0118 (to 2.1 +/- 0.3 ms after 30 minutes). Rapid infusion of AVE0118 did not suppress dofetilide-induced TdP.</AbstractText>In the anesthetized chronic complete AV block dog, the atrial-specific drug AVE0118 is free of TdP and has no antiarrhythmic properties against dofetilide-induced torsades de pointes.</AbstractText> |
9,203 | Safe and effective conversion of persistent atrial fibrillation to sinus rhythm by intravenous AZD7009. | Acute drug conversion of persistent atrial fibrillation usually fails.</AbstractText>The purpose of this study was to test the proarrhythmic potential, safety, and efficacy of the novel antiarrhythmic agent AZD7009 in patients with persistent atrial fibrillation (AF) or atrial flutter (mean duration 43 days) scheduled for direct current (DC) cardioversion.</AbstractText>Patients were randomized to AZD7009 (3-hour intravenous infusion; n = 86) or placebo (n = 36). AZD7009 was given in doses intended to produce target pseudo-steady-state plasma levels of 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, or 2.5 micromol/L after 30 minutes of infusion. DC cardioversion was performed if conversion to sinus rhythm (SR) did not occur within 2 hours of infusion.</AbstractText>AZD7009 in a concentration-dependent manner increased the rate of conversion of AF to SR and shortened the time to conversion. At the three highest target concentrations of AZD7009, 45%, 64%, and 70% of AF patients converted after a mean time of 62, 55, and 26 minutes, respectively, whereas no placebo-treated patients converted. SR was maintained for 24 hours in 21 of 22 patients with drug-associated conversion. AZD7009 treatment was associated with QT-interval prolongation; the increase in QT corrected according to Fridericia typically ranged from 40 to 80 ms at targeted pseudo-steady-state plasma concentrations >or=0.75 micromol/L, but a number of outliers with QT corrected according to Fridericia >550 ms were seen in the higher concentration groups, particularly after conversion to SR and prolonged infusion. None of the patients exhibited torsades de pointes according to predefined criteria; however, one patient exhibited a nonsustained, polymorphic ventricular tachycardia of eight beats with torsades de pointes-like features after AZD7009 infusion (asymptomatic and discovered only upon retrospective Holter tape analysis). Clinical adverse events (primarily dizziness, bradycardia, hypotension, and nausea) were significantly more common in the highest target concentration AZD7009 group vs placebo (P <.001).</AbstractText>AZD7009 exhibited dose-dependent effects in converting AF to SR in AF patients and appeared to be associated with a low risk of proarrhythmia despite continued administration during a period of heightened vulnerability.</AbstractText> |
9,204 | [The impact of elevated serum creatinine on the prognosis of acute myocardial infarction]. | To evaluate the clinical features and outcomes in patients suffering from acute myocardial infarction combined with elevated serum creatinine.</AbstractText>We enrolled 340 consecutive patients suffering from acute myocardial infarction admitted into our hospital from 2003.2.1 - 2004.8.31. The patients were divided into the following 2 groups, 269 patients in a group with normal serum creatinine and 71 patients in a group with elevated serum creatinine, according to the normal limit of serum creatinine in our hospital. Outcomes during hospitalization were available in all the patients and one year follow-up data were also available in all the patients. The influence of baseline demographic and clinical variables on mortality at day 30 and one year during the follow-up period was evaluated by Cox proportional hazard regression to determine the independent predictors of late adverse events.</AbstractText>Elevated creatinine at baseline was present in 71 of the 340 patients. Compared with patients with normal creatinine, patients with elevated creatinine were older and more likely to have old myocardial infarction and to present with cardiac shock, heart failure, ventricular fibrillation and complete AVB. Mortality was markedly increased in patients with baseline elevated creatinine as compared with these without at day 30 (32.39% versus 4.83%, P = 0.000), during hospitalization (35.21% versus 5.20%, P = 0.000) and at 1 year (43.66% versus 11.15%, P = 0.000). By Cox regression analysis, elevated creatinine was a powerful independent hazard predictor of 30-day survival (odds ratio 4.591, 95% confidence interval 2.149 to 9.808, P = 0.000) and remained to be associated with reduced survival at 1 year (odds ratio 3.936, 95% confidence interval 2.264 to 6.845, P = 0.000).</AbstractText>Baseline elevated creatinine is associated with a markedly increased risk of 30-day death, death during hospitalization and mortality at one year in patients suffering from acute myocardial infarction and may be an independent risk factor of prognosis of acute myocardial infarction.</AbstractText> |
9,205 | The effects of ropivacaine at clinically relevant doses on myocardial ischemia in pigs. | A major risk associated with bupivacaine during myocardial ischemia is ventricular fibrillation. We investigated the influence of ropivacaine on cardiac contractility and the propensity to ventricular fibrillation before and after myocardial ischemia in a placebo-controlled pig study. Anesthetized domestic pigs were administered 1 mg.kg(-1) of ropivacaine intravenously over 1 min and then 0.03 mg.kg(-1).min(-1) as a 30-min infusion, or saline. The following endpoints were measured before and after ropivacaine administration: (1) the ventricular fibrillation threshold (VFT) before and during myocardial ischemia induced by total transient ligation of the anterior interventricular artery and (2) electrophysiological (sinus heart rate, duration of QRS and QT intervals) and hemodynamic (blood pressure, the time derivative of left ventricular pressure [peak LV dP/dt]) parameters. Ropivacaine induced no changes in sinus heart rate, QRS, and or QT before or during ischemia. In contrast, there was a mild increase in the VFT before ischemia, which was drastically and significantly reduced during ischemia. The reduction of peak LV dP/dt during ischemia was further increased by ropivacaine. We also found that the effect of ropivacaine on the VFT was coronary blood flow-dependent, with a markedly decreased threshold in the presence of ischemia. Similar effects have been observed in humans with several other local anesthetics, as well as with class I antiarrhythmic drugs. The results of this study should be taken into account by anesthesiologists when administering ropivacaine to coronary patients. |
9,206 | CHOP-rituximab with pegylated liposomal doxorubicin for the treatment of elderly patients with diffuse large B-cell lymphoma. | Thirty untreated patients, median age 69 years (range 60 - 75 years), with diffuse large B-cell lymphoma (B-DLCL) were treated with a pegylated liposomal doxorubicin (PL-doxorubicin) modified CHOP-rituximab regimen. PL-doxorubicin 30 mg/m2, was given in combination with standard dosage of prednisone, vincristine, cyclophosphamide, rituximab (according to CHOP-R regimen) every 21 days for six courses. Cardiac toxicity was evaluated by mean of echocardiography for left ventricular ejection fraction (LVEF) evaluations and serum troponin-I levels. Overall response and complete response rates were 76% and 59%. Projected two year event free survival and overall survival are 65.5% and 68.5%. No treatment-related mortality was documented. WHO grade III-IV neutropenia and thrombocytopenia were 86% and 3%. Extra-hematological III-IV toxicity was represented, respectively, by a single case of infection, mucositis, and bleeding. LVEF evaluations and the troponin levels did not show significant changes over the course of the treatment. One patient with a previous history of atrial fibrillation experienced a single episode of arrhythmia. None of the patients developed palmar-plantar erythrodysesthesia. This regimen appears an active regimen for the treatment of elderly patients with B-DLCL. The replacement of conventional doxorubicin with PL-doxorubicin seems to be associated with a negligible incidence of extra-hematological toxicity, in particular cardiac and infectious complications. |
9,207 | Could sustained monomorphic ventricular tachycardia in the early phase of a prime acute myocardial infarction affect patient outcome? | Sustained monomorphic ventricular tachycardia (SMVT) in the course of a prime acute myocardial infarction is not a common arrhythmia and its prognostic significance has not been specifically elucidated. The aim of the study was to estimate the prognostic implications of the occurrence of sustained monomorphic ventricular tachycardia in the early phase (<72 h) of a prime acute myocardial infarction.</AbstractText>We studied 690 consecutive patients admitted to the coronary care unit with a diagnosis of a prime myocardial infarction. SMVT was observed in 18 (2.6%) patients and we followed these patients for establishing the prognostic value of the arrhythmia according to the clinical characteristics.</AbstractText>Patients with SMVT had a more extensive myocardial infarction based on the peak of the CK-MB isoenzyme activity (480+/-290 IU/L, vs 270+/-190 IU/L, P < .01), and higher mortality rate (40% vs 9%, P < .001). The independent predictors of SMVT were CK-MB (odds ratio [OR] 12.4), presence of complex ventricular arrhythmias (OR = 5.7), a wide QRS complex > or =130 milliseconds (OR = 4.8) and Killip class (OR = 4.8). The SMVT was itself an independent predictor of mortality (OR = 5.0). Compared with patients with ventricular fibrillation or polymorphic ventricular tachycardia, those with SMVT had a higher CK-MB activity, higher rate of wide QRS > or =130 milliseconds (33% vs 8%, P < .002), had a worse hemodynamic condition (Killip class >I:58% vs 23%, P < .04) and higher recurrence rate of ischemic events (68% vs 16%, P < .05). During the one year follow-up period, 4 patients (36.3%) of the 11 survivors from those with SMVT died of cardiac related causes.</AbstractText>SMVT during the first 72 h of a prime myocardial infarction is an index of a larger healing myocardium with acute very complexed electrophysiological changes and it is an independent predictor of in-hospital mortality and a prognostic factor of a poor one year outcome.</AbstractText> |
9,208 | Variation in pulmonary vein size during the cardiac cycle: implications for non-electrocardiogram-gated imaging. | Understanding pulmonary vein (PV) anatomy is important for the planning and execution of PV isolation for the treatment of atrial fibrillation, screening for PV stenosis after the procedure, and investigating the pathophysiology of atrial fibrillation. We hypothesized that significant changes in PV size occur during the cardiac cycle and sought to identify the relationship of data obtained with conventional non-electrocardiogram (ECG)-gated methods compared with ECG-gated measures of PV size using cardiovascular magnetic resonance.</AbstractText>A consecutive series of 14 patients in sinus rhythm were evaluated with non-ECG-gated contrast-enhanced magnetic resonance angiography and ECG-gated cine cardiovascular magnetic resonance of the PV. Pulmonary vein diameter, perimeter, and cross-sectional area (CSA) were measured using both methods.</AbstractText>Maximum diameter, perimeter, and CSA occurred simultaneously in all PV. The timing of the maximum size varied but generally occurred in ventricular diastole (101 +/- 112 milliseconds after mitral valve opening). The timing of minimum PV size also varied but generally occurred in ventricular systole (212 +/- 90 milliseconds before mitral valve opening). The difference between the maximum and minimum PV size was 15% +/- 8% for diameter, 15% +/- 7% for perimeter, and 27% +/- 12% for CSA (P < .001 for all). Contrast-enhanced magnetic resonance angiography correlated best with the ECG-gated maximum PV size (R2 > 0.48, P < .001 for all) and was greater than the minimum and average PV sizes (P < .05 for all).</AbstractText>All measures of PV size vary significantly during the cardiac cycle. Contrast-enhanced magnetic resonance angiography PV measurements correlate best with maximum PV size.</AbstractText> |
9,209 | Risks and benefits of combining aspirin with anticoagulant therapy in patients with atrial fibrillation: an exploratory analysis of stroke prevention using an oral thrombin inhibitor in atrial fibrillation (SPORTIF) trials. | Aspirin is used in combination with anticoagulant therapy in patients with atrial fibrillation (AF), but evidence of additional efficacy is not available.</AbstractText>We compared ischemic events and bleeding in the SPORTIF III and IV randomized trials of anticoagulation with warfarin (international normalized ratio 2-3) or fixed-dose ximelagatran. Low-dose aspirin (<100 mg/d) was allowed based on prevailing guidelines.</AbstractText>The 14% of patients receiving aspirin more often had diabetes (27.5% vs 23%, P < .01), coronary artery disease (69% vs 41%, P < .01), previous stroke or transient ischemic attack (26% vs 20%, P < .01), and left ventricular dysfunction (41% vs 36%, P < .01). Addition of aspirin to either warfarin or ximelagatran was associated with no reduction in stroke or systemic embolism. Major bleeding occurred significantly more often with aspirin plus warfarin (3.9% per year) than with warfarin alone (2.3% per year, P < .01), aspirin plus ximelagatran (2.0% per year), or ximelagatran alone (1.9% per year). The rate of myocardial infarction with aspirin and warfarin (0.6% per year) was not significantly different from that with ximelagatran alone (1.0% per year), warfarin alone (1.0% per year), or aspirin and ximelagatran (1.4% per year).</AbstractText>Aspirin combined with anticoagulant therapy was associated with no reduction in stroke, systemic embolism, or myocardial infarction in patients with AF. Aspirin combined with warfarin was associated with an incremental rate of major bleeding of 1.6% per year. No increased major bleeding occurred with aspirin and ximelagatran. These results suggest that the risks associated with addition of aspirin to anticoagulation in patients with AF outweigh the benefit.</AbstractText> |
9,210 | A prospective study of outcome of in-patient paediatric cardiopulmonary arrest. | Few prospective studies of the incidence and outcome of paediatric in-hospital cardiopulmonary arrest have been reported to enable quality assurance comparisons within and between institutions.</AbstractText>All cardiac and respiratory arrests and their management over a 41-month period in children not subject to palliative treatment or to a 'do not resuscitate' order were recorded and analysed using the Utstein template.</AbstractText>Cardiac arrest occurred in a total of 111 of 104,780 admissions (1.06/1000) while respiratory arrest alone occurred in 36 (0.34/1000). Return of spontaneous circulation (ROSC) was achieved in 81 patients (73%) in cardiac arrest but only 40 (36%) were discharged from hospital and 38 (34%) survived for 1 year. The 1-year survival from respiratory arrest alone was 97%. Cardiac arrest was four times more common (89 versus 22) and approximately 90 times the incidence in the intensive care unit compared with wards but 1-year survival was similar (34% versus 36%). The initial heart rhythms were hypotensive-bradycardia in 73 (66%) with 38% survival; asystole in 17 (15%) with 12% survival; ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) in 10 (9%) with 40% survival; pulseless electrical activity (PEA) in 10 (9%) with 30% survival and SVT in 1 with survival. Secondary ventricular fibrillation occurred in 15 children given adrenaline (epinephrine) for treatment of asystole, hypotensive-bradycardia or PEA of whom 11 had received adrenaline in an initial dose of > 15 mcg/kg and 4 had < 15 mcg/kg (P = 0.0013). Eleven of 15 patients (73%) in secondary VF never achieved ROSC.</AbstractText>In-patient paediatric cardiac arrest has a mediocre outcome with a better outlook if the initial rhythm is hypotensive-bradycardia, VF or pulsatile VT. Doses of adrenaline greater than 15 mcg/kg given for non-shockable rhythms may cause secondary VF which has a worse outcome than primary VF.</AbstractText> |
9,211 | Obstructive sleep apnea and plasma natriuretic peptide levels in a community-based sample. | We hypothesized that alterations in cardiac hemodynamics associated with obstructive sleep apnea-hypopnea (OSAH) would be reflected in higher natriuretic peptide levels. We examined the association of OSAH with natriuretic peptides in a community-based sample.</AbstractText>Cross-sectional, retrospective, observational study.</AbstractText>Framingham Heart Study Offspring Cohort and Sleep Heart Health Study.</AbstractText>Community-based sample of 623 individuals.</AbstractText>Full-montage home polysomnography was used to determine apnea-hypopnea index (AHI) and percentage of time with an oxyhemoglobin saturation < 90% (PctLt90). Sensitive immunoradiometric assays were used to measure plasma B-type (BNP) and N-terminal pro-atrial natriuretic peptide (NT-ANP). Multivariable regression was used to examine the relations between natriuretic peptides and indicators of OSAH, adjusting for age, sex, body mass index, and clinical covariates.</AbstractText>No statistically significant relations between OSAH indices and BNP were observed in the multivariable model. Compared with an AHI < 5, relative levels of 1.20, 0.88, and 0.91 were observed forAHI categories 5-15, 15-30, >30 events per hour, respectively. For NT-ANP, no significant relations were seen with AHI in the multivariable model (relative levels of 0.98, 0.91, and 0.90). An inverse association was observed between NT-ANP and PctLt90 in age- and sex-adjusted models (relative levels of 0.93, 0.87, and 0.80), although this association became statistically nonsignificant after adjusting for body mass index.</AbstractText>Lack of association of natriuretic peptides with OSAH indices suggests that undiagnosed OSAH may not be associated with major alterations in left ventricular function, as reflected in morning natriuretic peptide levels.</AbstractText> |
9,212 | Incidence of cross-border emergency care and outcomes of cardiopulmonary resuscitation in a unique European region. | Emergency medical service (EMS) systems in Europe have developed differently due to legal, educational and organisational aspects. The aim of the present study was to compare cardiopulmonary resuscitation (CPR) outcomes and characteristics in three differently organised and staffed EMS systems in close vicinity.</AbstractText>We analysed the charts of patients treated in the EMS systems of the cities of Aachen (Germany), Heerlen (The Netherlands) and Eupen (Belgium), retrospectively. Main outcome measures were the rate of return of spontaneous circulation (ROSC), hospital discharge and cerebral performance after 1 year. Furthermore, factors influencing neurological outcome and the incidence of cross-border emergency assistance were assessed.</AbstractText>Of 852 patients found unresponsive with no palpable pulse and/or the absence of breathing, CPR was performed in 322 patients. The overall rate of ROSC was 44.1 and 13.7% of patients were discharged alive. A good neurological outcome was observed in 95.5% of survivors. The rate of ventricular fibrillation was significantly higher (46.9% versus 21.9 and 21.2%, p < 0.05) and the total amount of epinephrine given during CPR significantly lower (4.5+/-5.2 mg versus 9.8+/-10.8 and 8.4+/-6.2 mg, p < 0.05) in the Dutch system. No significant differences in outcome variables were observed between the systems. Neurological outcome was favourable when the arrest was witnessed, occurred in a public place, the initial rhythm was shockable, a low total amount of adrenaline (epinephrine) was given and the call-response interval was short. In 1.2% of the cases cross-border emergency care was provided.</AbstractText>Despite medical and organisational discrepancies, outcomes of CPR in three neighbouring EMS systems are comparable. Neurological outcome is influenced by demographical, organisational and medical factors. Cross-border emergency assistance for CPR is almost undetectable and needs improvement.</AbstractText> |
9,213 | A case of a concealed type of Brugada syndrome with a J wave and mild ST-segment elevation in the inferolateral leads. | We report a patient with a concealed type of Brugada syndrome. The electrocardiogram in the emergency department revealed atrial fibrillation with an almost normal ST segment. Slight electrocardiogram abnormalities of the J wave and mild ST-segment elevation appeared in the inferolateral leads a few days later. Although the ST segment in the right precordial leads, including that recorded from the high intercostal space recording sites, was completely normal, a drug challenge test using pilsicainide revealed a coved-type ST-segment elevation only in a modified V2 lead placed 1 or 2 intercostal spaces higher. |
9,214 | Cardiovascular changes after naloxone administration in propofol-sedated piglets during opioid overdose. | Naloxone is an opioid receptor antagonist. Even when used in modest doses, it has been associated with serious cardiopulmonary side-effects. In this experimental porcine study, we examined the cardiac effects of naloxone during an opioid overdose.</AbstractText>Cardiac parameters, changes in the left ventricular compliance and the magnitude of catecholamine release were evaluated in eight spontaneously breathing piglets under propofol sedation. Cardiac parameters were recorded every 30 s and transthoracic echocardiography was used for the continuous assessment of cardiac performance. Respiratory arrest was induced by morphine (8 mg/kg). Ten minutes after morphine administration, naloxone (80 microg/kg) was injected intravenously. Every 5 min, arterial blood gases were measured and, every 10 min, a sample for the analysis of plasma catecholamines was drawn.</AbstractText>There were no statistically significant changes in left ventricular ejection fraction and no signs of pulmonary hypertension. There was a statistically significant increase in the mean arterial pressure immediately after naloxone administration and in norepinephrine concentration before naloxone administration. After naloxone administration, the plasma catecholamine levels decreased in all but one animal. Two animals developed cardiac arrest (pulseless electrical activity and ventricular fibrillation) shortly after receiving naloxone. Although they were both administered naloxone prematurely due to hypoxic bradycardia, naloxone could have contributed to the development of ventricular fibrillation.</AbstractText>Naloxone did not cause changes in ejection fraction or mean pulmonary artery pressure in hypoxic and hypercarbic conditions. After naloxone administration, the plasma catecholamine levels returned to baseline in all but one animal, and two animals developed cardiac arrest.</AbstractText> |
9,215 | The effect of cryoinjury on ventricular tachycardia in the swine right ventricle. | This study was performed to assess the influence of the cryoinjury on the dynamics of wavefronts and to determine whether they can convert ventricular fibrillation (VF) to ventricular tachycardia (VT) in fibrillating right ventricular (RV) of swines using an optical mapping system. A cryoinjury with a diameter of 12 mm was created on the epicardium of perfused RV of swines (n = 6) and optical mapping were taken from baseline until 10 minutes after the cryoinjury. Out of 35 cryoinjuries, the images were possible to be interpreted in 32. The optical action potential could not be observed in either the cryoinjury or peri-injury sites at 1 and 3 minutes, was observed in only the cryoinjury site at 5 minutes, and recovered in both sites at 10 minutes. The cycle length of the tachycardia was 135.9 +/- 23.6 msec at baseline, 176.2 +/- 79.3 msec at 1 minute, 187.6 +/- 97.9 msec at 3 minutes, 185.5 +/- 19.2 msec at 5 minutes, and 152.1 +/- 64.1 msec at 10 minutes. The cycle lengths at 1, 3, and 5 minutes after the cryoinjury were significantly more prolonged than that at baseline (p = 0.001, p = 0.006, p = 0.016). After the cryoinjury, the VF changed to VT in 9 (28.0%), and terminated in 2 (6.3%). These changes were observed mainly within 5 minutes after cryoinjury. The cryoinjury had anti-fibrillatory effects on the tissue with VF. This phenomenon was related to a decreasing mass and stabilizing wavefronts. |
9,216 | Glibenclamide attenuates the antiarrhythmic effect of endotoxin with a mechanism not involving K(ATP) channels. | The role of K(ATP) channels in the antiarrhythmic effect of Escherichia coli endotoxin-induced nitric oxide synthase (iNOS) was examined in an anesthetised rat model of myocardial ischemia and reperfusion arrhythmia by using glibenclamide (1 mg kg(-1)), nateglinide (10 mg kg(-1)) and repaglinide (0.5 mg kg(-1)). Endotoxin (1 mg kg(-1)) was administered intraperitoneally 4 h before the occlusion of the left coronary artery and glibenclamide, nateglinide or repaglinide was administered 30 min before coronary artery occlusion. We also evaluated the effects of K(ATP) channel blockers and nonselective K(+) channel blocker tetraethylammonium (TEA) on cardiac action potential configuration in the atria obtained from endotoxemic rats. The mean arterial blood pressure of rats receiving endotoxin was lower during both the occlusion and reperfusion periods. Endotoxin significantly reduced the total number of ectopic beats and the duration of ventricular tachycardia. Glibenclamide, but not nateglinide and repaglinide, prevented the hypotension and antiarrhythmic effects of endotoxin. Atria obtained from endotoxin-treated rats had prolonged action potential duration. This effect was abolished with pretreatment of iNOS inhibitors, l-canavanine and dexamethasone and perfusion of glibenclamide, but not with TEA and non-sulfonylurea drug, nateglinide. We demonstrated that glibenclamide inhibits the antiarrhythmic effect of endotoxin and this effect does not appear to involve K(ATP) channels. |
9,217 | Negative-tension instability of scroll waves and winfree turbulence in the oregonator model. | Excitable media support self-organized scroll waves which can be unstable and give rise to three-dimensional wave chaos. Winfree turbulence of scroll waves results from the negative-tension instability of scroll waves; it plays an important role in the cardiac tissue where it may lead to ventricular fibrillation. By numerical simulations of the Oregonator model, we show that this instability and, thus, the Winfree turbulence may also be observed in the Belousov-Zhabotinsky reaction. The region in the parameter space, where the instability takes place, is determined, and a relationship between the negative-tension instability and the meandering behavior of spiral waves is found. The application of global periodic forcing to control such turbulence in the Oregonator model is discussed. |
9,218 | Increase in rapid defibrillation programmes after publication of guidelines. | . To monitor the implementation of in-hospital resuscitation strategies including (i) rapid defibrillation programmes, (ii) the use of amiodarone for prolonged ventricular fibrillation, and (iii) uniform data collection on resuscitation, all recommended by international guidelines published in 2000 and by Finnish national resuscitation guidelines published in 2002.</AbstractText>In 2004, a questionnaire was sent to the chief anaesthesiologists. The results were compared with those of a previous study performed using similar methods in 2000.</AbstractText>All public hospitals that provide anaesthetic services in Finland.</AbstractText>Number of hospitals allowing nurses to perform defibrillation without the presence of physician and number of hospitals using amiodarone as primary antiarrhythmic drug in resuscitation and performing uniform data collection.</AbstractText>The response rate was 95% (52/55). The proportion of the hospitals with rapid defibrillation programmes on general wards had increased from 15% in 2000 to 67% in 2004, and most (79%) hospitals had obtained automated external defibrillators. Amiodarone was used in 88% of the hospitals. Data collection of resuscitation attempts using definitions provided in the Utstein guidelines was performed only in 22% of the hospitals.</AbstractText>Rapid defibrillation programmes have markedly increased, and the use of amiodarone has been established in Finnish hospitals since the publication of the international and the national resuscitation guidelines.</AbstractText> |
9,219 | Prophylactic amiodarone for prevention of atrial fibrillation after cardiac surgery: a meta-analysis. | Amiodarone has been proposed to decrease atrial fibrillation after cardiac surgery. The literature was systematically reviewed for randomized trials comparing amiodarone with control for prevention of atrial fibrillation. Data were extracted on study characteristics, quality, and incidence of atrial fibrillation, cardiovascular outcomes, and length of hospitalization. Nineteen trials were included. Amiodarone reduced the odds ratio of atrial fibrillation (0.50; 95% confidence interval [CI]: 0.43 to 0.59, p < 0.0001), ventricular tachyarrhythmias (0.39; 95% CI: 0.26 to 0.58, p < 0.0001), and strokes (0.53; 95% CI: 0.30 to 0.92, p = 0.02). Amiodarone reduced hospital stay (0.6 days; 95% CI: 0.4 to 0.8, p < 0.0001). Amiodarone decreased atrial fibrillation, reduced perioperative ventricular tachyarrhythmias and strokes, and reduced duration of hospitalization. The current evidence supports recommending the routine use of perioperative amiodarone for cardiac surgery. |
9,220 | Hemodynamic support with the pulsatile catheter pump in a sheep model of acute heart failure. | This study was aimed to mimic clinical heart failure (HF) conditions and to assess the effect of pulsatile catheter (PUCA) pump support on hemodynamics and tissue perfusion in a sheep model of acute HF. In 14 sheep, HF was induced by partial occluding the middle left circumflex coronary artery combined with pacemaker-induced tachycardia. PUCA pump was then activated to support the HF for 3 h. Hemodynamic parameters were recorded at baseline, HF, and then every 30 min during experiments. Blood samples were taken in carotid artery (CA), pulmonary artery (PA), and coronary sinus (CS) for the determination of oxygen saturation (SO2) and lactate concentration as markers of tissue perfusion. Results showed that HF model was induced successfully in 10 sheep and failed in four sheep due to refractory ventricular fibrillation. PUCA pump support was successful in seven out of 10 sheep for 3 h. Three cases failed due to technical problems. After HF (n = 10), cardiac output (CO) was decreased from 3.7 +/- 0.5 to 2.0 +/- 0.5 L/min (P < 0.001). Mean arterial pressure (MAP) was lowered from 116.1 +/- 14.2 to 68.1 +/- 14.7 mm Hg (P < 0.001). In seven sheep supported with PUCA pump, MAP rose from 68.9 +/- 15.2 to 94.7 +/- 14.7 mm Hg (P = 0.005), systolic blood pressure increased from 86.6 +/- 17.0 to 112.6 +/- 17.1 mm Hg (P = 0.009), and diastolic blood pressure increased from 57.7 +/- 12.6 to 79.9 +/- 13.9 mm Hg (P = 0.011). CO remained at about 2.0 L/min. SO2 in CA, PA, and CS decreased significantly after HF (P < 0.001), with an increase after support (compared with HF, P < 0.001, 0.066 and 0.114, respectively). Lactate concentrations increased gradually in CA, PA, and CS toward the end of experiments without difference among different sampling sites. This HF model in sheep is simple, easy to manipulate, reproducible and reflecting clinical HF conditions. PUCA pump can maintain the hemodynamic status for 3 h in this acute HF model. |
9,221 | [Angiotensin receptor blockers and cardiac rhythm disorders]. | Angiotension Receptor Blockers (ARB) are able to prevent the occurrence of atrial fibrillation (AF) through various mechanisms among them: neurhumoral antagonism and hemodynamic control. This occurs during arterial hypertension and chronic heart failure both diseases known to be associated with left atrial dysfunction. In the CHARM program, candesartan reduced by 20% the incidence of AF and thus also mortality and the incidence of hospitalisation for heart failure related to AF This beneficial effect is also observed with ACE inhibitors but is more important and potentated by ARB. In the Val-Heft study, valsartan on the top of standard treatment including ACE inhibitors, significantly lowered the cases of AF In hypertensive patients, ARB are more powerful than ACE inhibitors for the prevention of AF In the LIFE study, patients in the losartan arm had 33% less AF than patients from the other arm, despite treatment with atenolol and similar blood pressure reduction. Moreover ARB beside their specific effects are also able to increase efficiency of anti-arrhythmic agent; since after cardioversion patients treated with amiodarone plus irbesartan had a lower rate of recurrence of atrial fibrillation than patients treated with amiodarone alone. Finally ARB may reduce the risk of sudden death by ventricular arrhythmias in patients with diabetes mellitus. |
9,222 | Transthoracic incremental monophasic versus biphasic defibrillation by emergency responders (TIMBER): a randomized comparison of monophasic with biphasic waveform ascending energy defibrillation for the resuscitation of out-of-hospital cardiac arrest due to ventricular fibrillation. | Although biphasic, as compared with monophasic, waveform defibrillation for cardiac arrest is increasing in use and popularity, whether it is truly a more lifesaving waveform is unproven.</AbstractText>Consecutive adults with nontraumatic out-of-hospital ventricular fibrillation cardiac arrest were randomly allocated to defibrillation according to the waveform from automated external defibrillators administered by prehospital medical providers. The primary event of interest was admission alive to the hospital. Secondary events included return of rhythm and circulation, survival, and neurological outcome. Providers were blinded to automated defibrillator waveform. Of 168 randomized patients, 80 (48%) and 68 (40%) consistently received only monophasic or biphasic waveform shocks, respectively, throughout resuscitation. The prevalence of ventricular fibrillation, asystole, or organized rhythms at 5, 10, or 20 seconds after each shock did not differ significantly between treatment groups. The proportion of patients admitted alive to the hospital was relatively high: 73% in monophasic and 76% in biphasic treatment groups (P=0.58). Several favorable trends were consistently associated with receipt of biphasic waveform shock, none of which reached statistical significance. Notably, 27 of 80 monophasic shock recipients (34%), compared with 28 of 68 biphasic shock recipients (41%), survived (P=0.35). Neurological outcome was similar in both treatment groups (P=0.4). Earlier administration of shock did not significantly alter the performance of one waveform relative to the other, nor did shock waveform predict any clinical outcome after multivariate adjustment.</AbstractText>No statistically significant differences in outcome could be ascribed to use of one waveform over another when out-of-hospital ventricular fibrillation was treated.</AbstractText> |
9,223 | Mild left ventricular dysfunction is associated with thrombogenicity in cardioembolic stroke. | Transesophageal echocardiography (TEE) has been recognized as a valuable tool for identifying the left cardiac thrombus (LCT) or spontaneous echocardiographic contrast (SEC). We aimed to identify risk groups where TEE should be performed in patients with suspected cardioembolic stroke according to magnetic resonance imaging analysis.</AbstractText>One hundred and forty-six patients (mean age 64.7 +/- 11.8 years, 101 males) with suspected cardioembolic stroke were analyzed. We used TEE for the presence of LCT and/or SEC as indication of thrombogenicity. We evaluated the association between thrombogenicity and demographic features, stroke risk factors and echocardiographic variables.</AbstractText>The study included 40 patients (27.3%) who showed thrombogenicity (10 LCT and 30 SEC). The independent echocardiographic variables of thrombogenicity were atrial fibrillation (OR 7.14; 95% CI 2.62-19.48; p < 0.001) and left ventricular ejection fraction </=50% (OR 4.01; 95% CI 1.40-11.49; p = 0.01).</AbstractText>We recommend that TEE should be considered in patients with mildly reduced left ventricular dysfunction (ejection fraction </=50%) after suspected cardioembolic stroke.</AbstractText>Copyright (c) 2006 S. Karger AG, Basel.</CopyrightInformation> |
9,224 | Multiple failed external defibrillation attempts during robot-assisted internal mammary harvest for myocardial revascularization. | We describe multiple failed external defibrillation attempts via rescue defibrillation pads for ventricular fibrillation that occurred secondary to direct electrical current transmission through the pericardial sac from electrocautery during robot-assisted internal mammary harvest. Only after resumption of two-lung ventilation and decompression of the iatrogenic pneumothorax was the patient successfully defibrillated. Conditions necessary for robotic intrathoracic surgery may make defibrillation and resuscitation difficult if they become necessary. |
9,225 | Ventricular fibrillation induced by ischemia-reperfusion is not prevented by the NPY Y2 receptor antagonist BIIE0246. | Neuropeptide Y is released together with norepinephrine from sympathetic nerve terminals during conditions of increased sympathetic activity. Neuropeptide Y is known to inhibit vagal activity, and accordingly, it might increase the risk for ventricular fibrillation during myocardial ischemia-reperfusion, with concomitant sympathetic stimulation. Counteracting the inhibiting effect of neuropeptide Y by the specific neuropeptide Y2 antagonist, BIIE0246, we expected occurrence of ventricular fibrillation in association with repeated periods of myocardial ischemia-reperfusion to decrease. The midleft anterior descending coronary artery was repeatedly occluded in 16 open-chest pigs. Eight pigs received BIIE0246, and the controls received the vehicle only. Ventricular fibrillation developed in 2 animals of the control group, but in 4 pigs receiving BIIE0246. Occurrence of ventricular fibrillation and ventricular tachycardia did not differ significantly between the 2 groups, and in association with repeated periods of regional myocardial ischemia, did not decline in pigs treated by the specific neuropeptide Y2-receptor antagonist BIIE0246. |
9,226 | Prevalence of systolic impairment in an unselected regional population with hypertrophic cardiomyopathy. | Hypertrophic cardiomyopathy (HC) may transition to a phase characterized by systolic impairment resembling dilated cardiomyopathy. This study retrospectively assessed the incidence of left ventricular (LV) systolic impairment at initial clinical evaluation in 248 consecutive patients with HC (mean age 53 +/- 16 years). HC with systolic impairment was diagnosed if the LV ejection fraction was <50%, calculated by echocardiography. Twenty patients (8%) had HC with LV systolic impairment at initial evaluation. Patients with systolic impairment had a greater incidence of family histories of sudden cardiac death (SCD) than patients with preserved systolic function (25% vs 5.3%, p = 0.006) and more severe functional limitations (New York Heart Association class >or=III, p <0.001). All-cause mortality and cardiovascular mortality did not differ between the 2 groups. The incidence of SCD was 1.7% in patients with normal LV ejection fractions, and no SCD was observed in patients with systolic impairment. The latter group had more frequent major cardiac events (SCD, ventricular fibrillation, aborted cardiac arrest, and first implantable cardioverter-defibrillator discharge; p = 0.03). During follow-up, 2 patients progressed to HC with systolic impairment (annual incidence 0.85%). In conclusion, systolic impairment is not exceptional in patients with HC at initial evaluation and is associated with functional deterioration and major cardiac events. |
9,227 | Torsade-de-pointes in a patient under flecainide treatment, an unusual case of proarrhythmicity. | Flecainide is an antiarrhythmic considered safe in patients who have no structural cardiopathy, and frequently used in the prevention of atrial fibrillation. However, in patients with a history of infarction and/or severe conduction disorders, its proarrhythmicity may be lethal. Torsade-de-pointes type tachycardia is not included as one of these proarrhythmic effects, since the drug's scant action on ventricular repolarization makes this adverse effect very unlikely. We present the case of a patient who, shortly after beginning treatment with flecainide, was admitted because of syncope related to bradyarrhythmias, long QT, and torsade-de-pointes. There have been very few published cases in which one finds such an association between flecainide and this infrequent arrhythmia. |
9,228 | The cost comparison of rhythm and rate control strategies in persistent atrial fibrillation. | Our sub study was designed to analyze the cost effectiveness of two alternative treatment strategies with a view to improved allocation of the limited therapeutic resources. To that effect we conducted detailed analysis of the related costs and other relevant data collected in the course of the HOT CAFE study.</AbstractText>The prospective costs related to 205 patients randomly assigned to rhythm or rate control were traced over a 12 month period. Since, both strategies produced similar clinical outcomes a cost minimization analysis was undertaken. The cost of diagnostic and treatment procedures, including hospitalization, outpatient visits, drugs and physicians consultations were estimated for both groups.</AbstractText>The study population comprised 205 patients (mean age 60.8 year; 35% females). A hundred and one patients were randomly assigned to the rate control group with the pharmacological heart rate frequency optimization treatment combined with Holter monitoring. A hundred and four patients were randomized to sinus rhythm (SR) restoration with its subsequent maintenance with sequential antiarrhythmic drug treatment. There was no significant difference in the composite primary end-point (all-cause mortality, number of thromboembolic and major bleeding events). The hospital admissions rate was significantly higher in the rhythm control than the rate control arm (202 vs. 5, respectively). The conservative strategy involving pharmacological ventricular rate control proved to be less costly than rhythm control (1225 euros vs. 2526 euros; p<0.001). The main cost driver behind the established difference was the cardioversion related hospitalization.</AbstractText>The cost effectiveness appraisal seems to have supported the rate control strategy as less costly due to the lower hospitalization rate as a major cost carrier.</AbstractText> |
9,229 | The cardioprotective effect of isosteviol on rats with heart ischemia-reperfusion injury. | This study was designed to assess the cardioprotective effect of isosteviol on rats with heart ischemia-reperfusion (IR) injury and to explore the mechanism of action of the compound. Sprague Dawley rats were divided into 8 groups (n=10-12): a sham-operated control and 7 ischemia-reperfusion groups (IR control, 3 isosteviol pre-treated (0.5, 1.0 and 2.0 mg kg(-1)), ligustrazine pre-treated, 5-hydroxydecanoate (5-HD) pre-treated and 5-HD+ isosteviol pre-treated groups). IR was produced by occluding the left coronary artery for 30 min followed by re-opening the artery for 90 min. The compounds under investigation were administered intravenously 10 min prior to occluding the artery. Hemodynamic parameters (+/-dp/dt(max), LVSP, LVDevP, MAP), heart rate, ventricular tachycardia (VT) and ventricular fibrillation (VF) were determined during the IR period. The myocardial infarct size, activities of serum lactate dehydrogenase and creatine kinase were determined at the end of the experiment. In the isosteviol pre-treated groups, the hemodynamic parameters were improved and the myocardial infarct size, the activities of serum enzymes, and the incidences of VT and VF were all decreased when compared to the control group. These effects of isosteviol were similar to that of a traditional cardioprotective agent, ligustrazine. The 5-HD+ isosteviol group displayed parameters that were between those in the equivalent isosteviol pre-treated group and the IR control group. In conclusion, damage due to a standard rat heart IR injury was reduced by pretreatment with intravenous isosteviol, and this effect was partly attenuated by a mitochondrial ATP-sensitive potassium channel blocker, 5-HD. |
9,230 | [Polymorphic ventricular tachycardia in acute myocardial infarction without ST elevation in a patient with thrombocytopenia]. | 67-year-old woman with thrombocytopenia (treated with prednisolon and azathiopryn) was admitted because of acute myocardial infarction without ST segment elevation (NSTEMI). From the 2nd day we observed increasing QTc interval from 461 ms with normal potassium level. Suddenly on the 6th day of the so far uncomplicated AMI ventricular fibrillation developed and was successfully treated with DC shock, and amiodarone (150 mg i.v.) was administered because of recurrent NSVT. Potassium level was 2.9 mmol/l. Within the next 2 days in the morning hours we observed episodes of recurrent polymorphic ventricular tachycardia (PMVT), always progressing into ventricular fibrillation (VF). The ECG showed QT interval--520 ms, QTc--602 ms. The patient was given an increasing dose of beta-blocker and lidokaine in i.v. infusion. After this regimen PMVT/VF did not recur and QT was normalized. Additionally successful PCI of LAD with 80% stenosis was performed. The paper discusses the problem of PMVT in the settings of AMI. |
9,231 | [Long QT syndrome due to olanzapine administration]. | A case of a 53 year old female with olanzapine-induced QT interval prolongation and ventricular fibrillation is described. The relationship between neuroleptic drugs and the risk of sudden cardiac death is discussed. |
9,232 | Metabolic risk factors for stroke and transient ischemic attacks in middle-aged men: a community-based study with long-term follow-up. | The impact of lipometabolic and glucometabolic disturbances on stroke incidence remains to be characterized in detail. We investigated relations of a comprehensive panel of baseline lipometabolic and glucometabolic variables to incident fatal and nonfatal stroke or transient ischemic attack (TIA), and stroke subtypes.</AbstractText>A community-based prospective study of 2313 middle-aged men invited to a health survey at age 50.</AbstractText>During a follow-up of up to 32 years, 421 developed stroke or TIA. In Cox proportional hazards analyses adjusting for treatment with cardiovascular drugs at baseline, 1-standard deviation increases in body mass index, systolic and diastolic blood pressures, serum proinsulin, and lipoprotein(a) were associated with 11 to 35% increased risk for subsequent stroke/TIA. Electrocardiographic left ventricular hypertrophy and smoking were also associated with a higher risk for stroke/TIA. Essentially the same variables were related to brain infarction/TIA. Higher proportions of palmitic (16:0), palmitoleic (16:1), and oleic acid (18:1) in cholesterol esters were associated with an increased risk, whereas a higher proportion of linoleic acid (18:2 n-6) was protective against stroke/TIA. Further adjusting all models also for hypertension, diabetes, the metabolic syndrome, serum cholesterol, atrial fibrillation, cardiovascular disease, smoking, and physical activity, essentially the same pattern was observed.</AbstractText>Indices of an unhealthy dietary fat intake and a high serum lipoprotein (a) level predicted fatal and nonfatal stroke/TIA independently of established risk factors in a community-based sample of middle-aged men followed for 32 years.</AbstractText> |
9,233 | Electrical storm in patients with an implantable defibrillator: incidence, features, and preventive therapy: insights from a randomized trial. | The purpose of this study was to assess the incidence, features, and clinical sequelae of 'electrical storm' (ES).</AbstractText>This study is a prospectively designed secondary analysis of SHIELD; a randomized trial of azimilide for suppression of ventricular tachycardia/fibrillation (VT/VF) leading to implanted cardioverter defibrillator (ICD) therapies. Systematic and rigorous follow-up and blinded adjudication of ICD therapy allowed identification of all ESs (>/=3 separate VT/VF episodes leading to ICD therapies within 24 h). Of 633 ICD recipients, 148 (23%) experienced at least one ES over 1-year follow-up. No clinical predictors of ES were identified. Frequent VT episodes accounted for 91% of all ESs, with the remaining being VF alone or both VT plus VF. ES led to a 3.1-fold increase in arrhythmia-related hospitalization (95% CI 2.3-4.3; P<0.0001) compared with patients with isolated VT/VF, and to a 10.2-fold increase (95% CI 6.4-16.3; P<0.0001) compared with patients without VT/VF. Compared with placebo, azimilide (75 and 125 mg/day) reduced the risk of recurrent ES by 37% (HR=0.63, 95% CI 0.35-1.11, P=0.11) and 55% (HR=0.45, 95% CI 0.23-0.87, P=0.018), respectively. However, the reduction in time-to-first ES did not reach statistical significance by both doses (75 and 125 mg) of azimilide (HR=0.82, 95% CI 0.56-1.19, P=0.29 and HR=0.69, 95% CI 0.46-1.04, P=0.07), respectively.</AbstractText>ES is common and unpredictable in ICD recipients and it is a strong predictor of hospitalization.</AbstractText> |
9,234 | Treatment practices in heart failure with preserved left ventricular ejection fraction: a prospective observational study. | Current guidelines for treatment of patients with heart failure (HF) and preserved left ventricular ejection fraction (LVEF) are empirical. One of the objectives of the ETICS study was to evaluate medical treatment at discharge and after 1 year in patients hospitalised for a first episode of HF in 2000. We report the results concerning treatment of patients with preserved LVEF at discharge and at 1 year.</AbstractText>Two hundred and sixty three consecutive patients (75+/-10 years, 47 males) with LVEF >50% hospitalised for a first episode of HF were prospectively included. Mean LVEF was 63+/-8%. The main aetiology was hypertension (61%) followed by ischaemic heart disease (29%). Atrial fibrillation and diabetes were present in 34% and 27% of cases, respectively. Medical treatment records were complete at discharge and at 1 year after discharge.</AbstractText>At discharge, as at 1 year after discharge, diuretics were the drugs most commonly prescribed (81% and 78%), followed by ACE inhibitors (49% and 46%), amiodarone (32% and 28%), beta-blockers (27% and 29%), nitrates (28% and 27%), calcium channel blockers (27% and 26%), spironolactone (21% and 25%), cardiac glycosides (19% and 24%), and angiotensin II receptor antagonists (4% and 6%). Once prescribed at hospital discharge, drug prescription rates and daily doses did not change significantly over time. Age did not influence drug prescription rates at discharge or at 1 year, except for the spironolactone prescription rate, which decreased at 1 year in patients > or =75 years of age. At discharge, ACE inhibitor and beta-blocker daily doses were lower in older patients, while, at 1 year, no differences in daily doses of these drugs were observed between patients above and below the age of 75 years.</AbstractText>Loops diuretics are largely prescribed in HF with preserved LVEF, followed by ACE inhibitors. Future large multicentre trials are required to define the background standard treatment in addition to treatment of aetiological factors.</AbstractText> |
9,235 | [Study on effect of Tiaomaiyin injection on experimental arrhythmia]. | To study the effect of Tiaomaiyin injection on the experimental arrhythmia for analyzing its underlying mechanism in the treatment of cardiovascular disease.</AbstractText>Experimental animals anesthetized with 20% urethane (6 mL x kg(-1)) were evenly randomized into control group, positive control group, low-dose and high-dose Tiaomaiyin group. The rate of ventricular fibrillation (VF) chloroform-induced in mice, and the epoch of ventricular extrasystole (VE), ventricular tachycardia (VT),VF and cardiac arrest (CA), actonitine-induced in rats (1.0 microg x mL(-1) x min(-1)), and vabain-induced in guinea pigs (10 microg x mL(-1) x min(-1)), were detected respectively. The result loas converted into cumulative dosage of actonitine or vabain. In ischemia-reperfusion model in rats, the duration of arrhythmia and activity of superoxide dismutase (SOD) and malondialdehyde (MDA) were detected.</AbstractText>After venous injection of Tiaomaiyin, VF in mice was lower significantly (P < 0.01), VE, VT, VF in rats and VF in guinea pigs were lowered considerably (P <0.05). The duration of arrhythmia in ischemia-reperfusion model was reduced considerably (P < 0.05), and the activity of myocardial SOD was raised significantly (P <0.01).</AbstractText>Tiaomaiyin shows the reduction of experimental arrhythmia and protect effect to ischemia-reperfusion injury of the heart, which indicates that the effect mechanism may have the relationship with inhabition of lipid peroxidation and damnification of the free radical.</AbstractText> |
9,236 | [Advantages of restoration and maintenance of sinus rhythm in middle aged patients with atrial fibrillation and chronic heart failure]. | Patients (n=223, age 47-64 years) with persistent nonvalvular atrial fibrillation and functional class II-III chronic heart failure were treated for 2 years with aims of sinus rhythm control (n=113, strategy 1) or slowing of heart rate (n=110, strategy 2). Strategy 1 compared with strategy 2 was associated with lower total (11.5 and 22.7%; respectively, p<0.05), and cardiovascular (9.7 and 20%, respectively; p<0.05) mortality, as well as ischemic stroke rate (13.3 and 25.5%,respectively; p<0.05). Strategy 1 was also associated with elevation of exercise tolerance, reduction of clinical signs of chronic heart failure, augmentation of left ventricular ejection fraction, and improvement of quality of life. Restoration and maintenance of sinus rhythm in patients aged <65 years with atrial fibrillation and chronic heart failure appears to be justified. However large randomized trial is required for testing of this hypothesis. |
9,237 | Right ventricular pacing can induce ventricular dyssynchrony in patients with atrial fibrillation after atrioventricular node ablation. | This study was designed to assess the effects of long-term right ventricular (RV) pacing on left ventricular (LV) dyssynchrony, LV function, and heart failure symptoms.</AbstractText>Atrioventricular (AV) node ablation and subsequent long-term RV pacing is a well-established treatment option in patients with atrial fibrillation (AF).</AbstractText>In 55 patients with drug-refractory AF, AV node ablation and implantation of a pacemaker was performed. At baseline and after a mean of 3.8 +/- 1.7 years, LV dyssynchrony (by M-mode echocardiography and tissue Doppler imaging), LV function, and volumes and functional status were assessed.</AbstractText>After long-term RV pacing, 27 patients (49%) had developed LV dyssynchrony. Concomitantly, these patients worsened in heart failure symptoms (New York Heart Association functional class increased from 1.8 +/- 0.6 to 2.2 +/- 0.7, p < 0.05), with a decrease in LV ejection fraction (from 48 +/- 7% to 43 +/- 7%, p < 0.05) and an increase in LV end-diastolic volume (from 116 +/- 39 ml to 130 +/- 52 ml, p < 0.05). Conversely, patients without LV dyssynchrony did not deteriorate in heart failure symptoms, LV function, or LV volumes.</AbstractText>Long-term RV pacing can induce LV dyssynchrony in almost 50% of patients treated with AV node ablation for chronic AF. The development of LV dyssynchrony was associated with deterioration in heart failure symptoms, systolic LV function, and LV dilatation.</AbstractText> |
9,238 | Cellular autotransplantation for ischemic and idiopathic dilated cardiomyopathy. Preliminary report. | Heart failure is highly prevalent among patients >65 years old. The incidence increases starting at approximately 45 years of age. Recent therapeutic advances have included stem cell transplantation in the affected areas of the myocardium in order to improve perfusion and myocardial performance.</AbstractText>Between July 13, 2004 and August 31, 2005, 39 procedures were undertaken in 34 male and 5 female patients, with a mean age of 53.6 +/- 9.08 years (range: 35-71 years old), suffering from terminal heart failure and without any other therapeutic alternative. Thirty four cases presented ischemic cardiomyopathy and five presented idiopathic dilated cardiomyopathy. All patients were treated with autologous stem cell transplantation obtained from the peripheral blood supply through hemophoresis and implanted by means of a left anterior thoracotomy via intramyocardial injection. Functional class, ejection fraction and myocardial perfusion were analyzed preoperatively and postoperatively.</AbstractText>Seven patients presented ventricular fibrillation during the procedure, requiring defibrillation. Two patients died due to intractable arrhythmias during the perioperative period; the remaining patients are currently participating in a rehabilitation program with a favorable evolution. A mid-term follow-up has been completed in 27 patients. Preoperatively, the functional class for 26 of these patients was III. Postoperatively, functional classes are II in 5 cases and I in 15 patients at the mid-term evaluation with ejection fraction improvements of 37.7 +/- 14.2 to 42.15 +/- 5.9.</AbstractText>Cell therapy is a safe and useful procedure in selected patients with ischemic and idiopathic dilated cardiomyopathy.</AbstractText> |
9,239 | Verification of pacemaker automatic mode switching for the detection of atrial fibrillation and atrial tachycardia with Holter recording. | Verification of the accuracy of onset, offset, and duration of automatic mode switching (AMS) of pacemakers compared with onset and end of atrial fibrillation (AF) or atrial tachycardia (AT). Correct pacemaker diagnosis of atrial tachyarrhythmias (AA) is indispensable for reliable automatic prevention and intervention algorithms of AA.</AbstractText>Comparison was made of the AMS registration of the pacemaker-stored electrograms (EGMs) and the number and cumulative duration of these episodes with continuous 7-day Holter monitoring. Atrial sensitivity was kept at 0.5 mV and far field R-wave recognition in the atrial channel was excluded by blanking of this signal. Lead types were confined to leads with short-ring tip spacing (10-13.8 mm). During Holter monitoring, 18 of 57 included patients with standard reason for pacemaker implantation showed episodes of AF or AT. Cumulative duration of AF and AT from Holter was correctly interpreted by the pacemaker in 99.9% of the patients. All episodes of AF, as seen on the Holter recording, were recognized by the pacemaker (correlation 99.9%). During AF, multiple episodes of undersensing were detected. The number of AMS episodes was influenced by undersensing during AF. The influence of these short episodes of undersensing on the total duration of AF was trivial (cumulative duration of AF was 99.9% correct). In patients with AT without AF on Holter (n=7) and in contrast to the AF episodes, the cumulative AT duration did not correlate well (63%) with the Holter recordings. The number of AMS episodes in the setting of AT was influenced by the atrial tachycardia detection rate setting and the duration of the post-ventricular atrial blanking interval.</AbstractText>The total duration of AF is correctly represented by the total duration of AMS and can be considered a reliable measure of total AF duration. AT duration was poorly correlated with AMS duration. The number of mode switches does not reflect the number of episodes of AF/AT. Increased memory capacity allowing the storing of all EGMs triggered by the initiation of AF/AT would be the ideal setting with which to optimize the diagnostic performance of pacemakers.</AbstractText> |
9,240 | The assessment of autonomic function in chronic atrial fibrillation: description of a non-invasive technique based on circadian rhythm of atrioventricular nodal functional refractory periods. | Heart rate variability (HRV) parameters can be used to assess autonomic function and to predict outcome, but this has been done exclusively in patients with sinus rhythm. Atrial fibrillation (AF) is the commonest sustained arrhythmia and is particularly prevalent in heart failure. We have developed a simple index to assess autonomic function in patients with chronic AF.</AbstractText>Forty patients with chronic AF (>1 month) and symptoms of heart failure underwent ambulatory 24 h electrocardiography recording as well as evaluation of symptoms, exercise capacity (6 min walk distance), ventricular function (echocardiography and radionuclide ventriculography), and neuroendocrine activation. A number of standard HRV parameters shown to have prognostic significance in sinus rhythm were also determined. A modified in-house HRV statistical programme was used to filter labelled QRS intervals and to compute the 5th percentile RR interval in each hour. This parameter has been shown to approximate the functional refractory period (FRP) of the atrioventricular node (AVN). A cosine curve was fitted to hourly 5th percentile RR intervals for each patient and from this was estimated the diurnal change in hourly 5th percentile RR interval (approximating DeltaFRP of the AVN) and, by inference, diurnal variation in sympathovagal input to the AVN. Digoxin was the sole agent permitted for control of ventricular rate. DeltaFRP of the AVN varied and revealed a significant correlation, on multivariate analysis, with mean RR interval (P<0.001), SDARR (SD of 5-min average RR intervals during 24 h, P<0.001), and NYHA class of heart failure (classes III and IV heart failure vs. classes I and II, P=0.02). SDARR has previously been shown independently to predict mortality in patients with chronic AF and heart failure.</AbstractText>This analysis describes a novel non-invasive method for assessing autonomic function in chronic AF. Whether DeltaFRP in chronic AF patients can independently predict adverse prognosis or sudden death requires further study.</AbstractText> |
9,241 | Analysis of surface electrocardiograms in atrial fibrillation: techniques, research, and clinical applications. | Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy is sufficiently predictable by clinical and echocardiographic parameters. The purpose of this article is to describe technical aspects of novel electrocardiogram (ECG) analysis techniques and to present research and clinical applications of these methods for characterization of both the fibrillatory process and the ventricular response during AF. Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface ECG using digital signal processing (extraction of atrial signals and spectral analysis). This measurement shows large inter-individual variability and correlates well with intra-atrial cycle length, a parameter which appears to have primary importance in AF maintenance and response to therapy. AF with a low fibrillatory rate is more likely to terminate spontaneously and responds better to antiarrhythmic drugs or cardioversion, whereas high-rate AF is more often persistent and refractory to therapy. Ventricular responses during AF can be characterized by a variety of methods, which include analysis of heart rate variability, RR-interval histograms, Lorenz plots, and non-linear dynamics. These methods have all shown a certain degree of usefulness, either in scientific explorations of atrioventricular (AV) nodal function or in selected clinical questions such as predicting response to drugs, cardioversion, or AV nodal modification. The role of the autonomic nervous system for AF sustenance and termination, as well as for ventricular rate responses, can be explored by different ECG analysis methods. In conclusion, non-invasive characterization of atrial fibrillatory activity and ventricular response can be performed from the surface ECG in AF patients. Different signal processing techniques have been suggested for identification of underlying AF pathomechanisms and prediction of therapy efficacy. |
9,242 | Left ventricular outflow tract obstruction after bioprosthetic mitral valve replacement with posterior mitral leaflet preservation. | We present a case of transient left ventricular outflow tract obstruction after mitral valve replacement with a high-profile bioprosthesis; only the posterior native mitral valve leaflet was preserved. A 76-year-old woman was admitted to our institution with pulmonary edema. Two weeks earlier, she had undergone mitral valve replacement at our hospital due to severe mitral stenosis and 2+ mitral regurgitation complicated by cardiac failure and atrial fibrillation. The patient was taking digoxin, furosemide, and warfarin at the time of readmission. Echocardiography showed a narrowed left ventricular outflow tract. Doppler echocardiography revealed a peak 64-mmHg gradient between the septum and the strut of the bioprosthesis. The patient was successfully treated medically. This case indicates that the risk of left ventricular outflow tract obstruction after bioprosthetic mitral valve replacement is not always eliminated by removal of the anterior mitral valve leaflet when the posterior mitral leaflet is preserved. |
9,243 | Circulating levels of cytochrome c after resuscitation from cardiac arrest: a marker of mitochondrial injury and predictor of survival. | Ca(2+) overload and reactive oxygen species can injure mitochondria during ischemia and reperfusion. We hypothesized that mitochondrial injury occurs during cardiac resuscitation, causing release of cytochrome c to the cytosol and bloodstream while activating apoptotic pathways. Plasma cytochrome c was measured using reverse-phase HPLC and Western immunoblotting in rats subjected to 4 or 8 min of untreated ventricular fibrillation and 8 min of closed-chest resuscitation followed by 240 min of postresuscitation hemodynamic observation. A sham group served as control. Plasma cytochrome c rose progressively to levels 10-fold higher than in sham rats 240 min after resuscitation (P < 0.01), despite reversal of whole body ischemia (decreases in arterial lactate). Cytochrome c levels were inversely correlated with left ventricular stroke work (r = -0.40, P = 0.02). Western immunoblotting of left ventricular tissue demonstrated increased levels of 17-kDa cleaved caspase-3 fragments in the cytosol. Plasma cytochrome c was then serially measured in 12 resuscitated rats until the rat died or cytochrome c returned to baseline. In three survivors, cytochrome c rose slightly to <or=2 microg/ml and returned to baseline within 96 h. In nine nonsurvivors, cytochrome c rose progressively to significantly higher maximal levels [4.6 (SD 2.0) vs. 1.6 (SD 0.3) microg/ml, P = 0.029] and at faster rates [0.7 (SD 0.5) vs. 0.1 (SD 0.1) microg.ml(-1).h(-1), P = 0.046] than in survivors. Plasma cytochrome c may represent a novel in vivo marker of mitochondrial injury after resuscitation from cardiac arrest that relates inversely with survival outcome. |
9,244 | Characteristics and outcome amongst young adults suffering from out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation is attempted. | Amongst patients suffering from out-of-hospital cardiac arrest, young adults represent a minority. However, these victims suffer from the catastrophe when they are in a very active phase of life and have a long life expectancy. This survey aims to describe young adults in Sweden who suffer from out-of-hospital cardiac arrest and in whom cardiopulmonary resuscitation (CPR) is attempted in terms of characteristics and outcome.</AbstractText>Prospective and descriptive design.</AbstractText>Young adults (18-35 years) who suffered from out-of-hospital cardiac arrest in whom CPR was attempted and who were included in the Swedish Cardiac Arrest Registry between 1990 and 2004.</AbstractText>Survival to 1 month.</AbstractText>In all, 1105 young adults (3.1% of all the patients in the registry) were included, of which 29% were females, 51% were nonwitnessed and 15% had a cardiac aetiology. Only 17% were found in ventricular fibrillation, 53% received bystander CPR. The overall survival to 1 month was 6.3%. High survival was found amongst patients found in ventricular fibrillation (20.8%) and those with a cardiac aetiology (14.8%). Ventricular fibrillation at the arrival of the rescue team remained an independent predictor of an increased chance of survival (odds ratio: 7.43; 95% confidence interval: 3.44-16.65).</AbstractText>Amongst young adults suffering from out-of-hospital cardiac arrest and in whom CPR was attempted, a minority survived to 1 month. Subgroups with a higher survival could be defined (patients found in ventricular fibrillation and patients in whom there was a cardiac aetiology). However, only one independent predictor of an increased chance of survival could be demonstrated, i.e. ventricular fibrillation at the arrival of the rescue team.</AbstractText> |
9,245 | The management of atrial fibrillation in heart failure. | The development of atrial fibrillation (AF) can greatly complicate the course of heart failure (HF). Although recent trials have indicated the nonsuperiority of a rhythm control strategy in the general population with AF, this may not apply to patients with HF. We feel strongly that AF be treated aggressively in patients with HF, defaulting toward an initial rhythm control strategy, to avoid the hemodynamic detriment of irregular rapid ventricular response and the development of tachycardia-related myopathy. The index episode is treated with cardioversion and antiarrhythmic therapy. If significant benefit is demonstrated, the rhythm control strategy is maintained, to the point of catheter ablation for AF if necessary. If there is no change in cardiac performance or symptoms after cardioversion, strict rate control is enforced, to the point of atrioventricular node ablation and pacing if necessary. |
9,246 | Atrioventricular junction ablation followed by resynchronization therapy in patients with congestive heart failure and atrial fibrillation (AVERT-AF) study design. | Atrial fibrillation (AF) and congestive heart failure (CHF) affect millions of patients in the United States. Several studies suggest that AF and in particular the irregular ventricular response might be contributing to the left ventricular dysfunction. Studies that compared pharmacologic rate control to atrioventricular junction (AVJ) ablation followed by right ventricular pacing which restores a regular ventricular response, failed to show an improvement when compared to pharmacological rare control. These results might be explained by the fact that while AVJ ablation restored a regular ventricular response, it subjected patients to the detrimental effects of RV apical pacing. The AVERT-AF trial (Atrio-VEntricular Junction Ablation Followed by Resynchronization Therapy in patients with CHF and AF) is a prospective, randomized, double-blinded, multicenter trial that will be testing the hypothesis that AVJ ablation followed by biventricular pacing significantly improves exercise capacity and functional status compared to pharmacologic rate control in patients with chronic AF and depressed ejection fraction, regardless of rate or QRS duration. A total of 180 patients will be enrolled to test the primary endpoint, which is exercise duration. Patients_enrollment will begin in summer 2006 and is expected to be completed in 2008. The results of this trial should help define the best treatment option for this common arrhythmia in patients with left ventricular dysfunction. |
9,247 | Transient left ventricular dysfunction (tako-tsubo phenomenon): Findings and potential pathophysiological mechanisms. | Tako-tsubo-like left ventricular dysfunction phenomenon (TTP) is characterized by transient left ventricular apical ballooning associated with symptoms, electrocardiographic changes and minimal cardiac enzyme release in the absence of coronary artery disease. Initially described in Japan, TTP occurs worldwide, predominantly in women and frequently after emotional or physical stress. Symptoms include anginal chest pain, dyspnea and syncope. Electrocardiographic ST elevations may be present only for several hours, and are followed by negative T waves that persist for months. Arterial hypertension is found in up to 76% of TTP patients, hyperlipidemia in up to 57% and diabetes mellitus in up to 12%. Potential pathophysiological mechanisms for TTP include catecholamine-induced myocardial stunning or hyperkinesis of the basal left ventricular segments, coronary vasospasm, plaque rupture, myocarditis and genetic factors. TTP patients should be monitored similarly to myocardial infarction patients because organ failure, cardiogenic shock, ventricular fibrillation or rupture may occur. Beta-blockers are indicated, whereas catecholamines and nitrates should be avoided. The long-term prognosis is unknown.</Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Stöllberger</LastName><ForeName>Claudia</ForeName><Initials>C</Initials><AffiliationInfo><Affiliation>Medical Department, Krankenanstalt Rudolfstiftung, Vienna, Austria. claudia.stoellberger@chello.at</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Finsterer</LastName><ForeName>Josef</ForeName><Initials>J</Initials></Author><Author ValidYN="Y"><LastName>Schneider</LastName><ForeName>Birke</ForeName><Initials>B</Initials></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D016454">Review</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Can J Cardiol</MedlineTA><NlmUniqueID>8510280</NlmUniqueID><ISSNLinking>0828-282X</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D002637" MajorTopicYN="N">Chest Pain</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="N">diagnosis</QualifierName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D002986" MajorTopicYN="N">Clinical Trials as Topic</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D017023" MajorTopicYN="N">Coronary Angiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D003331" MajorTopicYN="N">Coronary Vessels</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D003937" MajorTopicYN="N">Diagnosis, Differential</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004452" MajorTopicYN="N">Echocardiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004562" MajorTopicYN="N">Electrocardiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D018487" MajorTopicYN="N">Ventricular Dysfunction, Left</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="N">diagnosis</QualifierName><QualifierName UI="Q000188" MajorTopicYN="N">drug therapy</QualifierName><QualifierName UI="Q000503" MajorTopicYN="Y">physiopathology</QualifierName></MeshHeading></MeshHeadingList><OtherAbstract Type="Publisher" Language="fre">Le phénomène de dysfonctionnement ventriculaire gauche de type takotsubo (PTT) est caractérisé par un ballonnement apical transitoire du ventricule gauche associé à des symptômes, des changements électrocardiographiques et une libération minimale de l’enzyme cardiaque, en l’absence de coronaropathie. Décrit pour la première fois au Japon, le PTT s’observe partout dans le monde, surtout chez les femmes et souvent après un stress affectif ou physique. Les symptômes sont les douleurs angineuses, une dyspnée et une syncope. À l’électrocardiographie, il se peut que les surélévations du segment ST ne soient visibles que quelques heures, suivies d’ondes T négatives qui persistent pendant des mois. On remarque une hypertension artérielle chez jusqu’à 76 % des patients atteints du PTT, une hyperlipidémie chez jusqu’à 57 % d’entre eux et un diabète sucré chez jusqu’à 12 %. Les mécanismes physiopathologiques potentiels du PTT sont une sidération myocardique induite par la catécholamine ou une hyperkinésie des segments ventriculaires gauches basaux, un vasospasme coronaire, une rupture de plaque, une myocardite et des facteurs génétiques. Les patients atteints du PTT devraient être suivis comme s’ils avaient subi un infarctus du myocarde, en raison du risque d’insuffisance organique, de choc cardiogène et de fibrillation ou de rupture ventriculaire. Les bétabloquants sont indiqués, tandis que les catécholamines et les nitrates sont à éviter. On ne connaît pas le pronostic à long terme de cette maladie. |
9,248 | Timing, setting and incidence of cardiovascular complications in patients with acute myocardial infarction submitted to primary percutaneous coronary intervention. | At the Istituto di Clinica Medica Generale e Cardiologia (Florence, Italy), the widespread use of percutaneous coronary intervention (PCI) has markedly changed the hospital course of patients with acute myocardial infarction (AMI). These patients are typically transferred to the coronary care unit (CCU) only after primary PCI, whereas during the thrombolytic era, patients were first admitted to CCU before reperfusion.</AbstractText>The incidence, timing and setting of complications from symptom onset to hospital discharge in 689 consecutive AMI patients undergoing PCI were evaluated.</AbstractText>Ventricular fibrillation occurred in 11% of patients, and most episodes (94.7%) occurred before or during PCI. Of all patients, 6.3% developed complete atrioventricular block (CAVB), and in 86.3% of these cases, the CAVB occurred before or during PCI; in 94.5%, a CAVB resolution occurred in the catheterization laboratory (CL). Thirty-one patients (4.5%) had impending shock on admission to the CL. Cardiogenic shock developed in 2 9 patients (4.2%), mostly in the prehospital phase or in the CL. Only four patients (less than 1%) developed cardiogenic shock later during their hospital course. Similarly, circulatory and ventilatory support, as well as temporary pacing and cardiac defibrillation, were used mostly in the prehospital phase or in the CL. During the CCU stay, 45 patients (6.5%) had hemorrhagic or vascular complications, and the incidence of post-PCI ischemia and early reocclusion of the culprit vessel were low (2.1% and 0.6%, respectively). Thus, cardiac complications usually associated with AMI were observed mainly before hospital admission or in the CL during the reopening of the target vessel. These complications were rarely observed after a successful PCI.</AbstractText>For AMI patients, the CL is not only the site of PCI, it is also where most life-threatening cardiac complications are observed and treated.</AbstractText> |
9,249 | Early outcomes of out-of-hospital cardiac arrest after early defibrillation: a 24 months retrospective analysis. | Cardiovascular disease remains the most common cause of death in the United States and most other Western nations. Among these deaths, sudden, out-of-hospital cardiac arrest claims approximately 1000 lives each day in the United States alone. Most of these cardiac arrests are due to ventricular fibrillation. Though highly reversible with the rapid application of a defibrillator, ventricular fibrillation is otherwise fatal within minutes, even when cardiopulmonary resuscitation is provided immediately. The overall survival rate in the United States is estimated to be less than 5 percent. Recent developments in automated-external-defibrillator technology have provided a means of increasing the rate of prompt defibrillation after out-of-hospital cardiac arrest. After minimal training, nonmedical personnel (e.g., flight attendants and casino workers) are also able to use defibrillators in the workplace, with lifesaving effects. Nonetheless, such programs have involved designated personnel whose job description includes assisting persons who have had sudden cardiac arrest. Data are still lacking on the success of programs in which automated external defibrillators have been installed in public places to be used by persons who have no specific training or duty to act.</AbstractText>All patients who had an out-of-hospital cardiac arrest between January 2003 and December 2004 and who received early defibrillation for ventricular fibrillation were included. We conducted a 24 months retrospective population-based analysis of the outcome in our population.</AbstractText>Over a 24 month period, 446 people had non-traumatic cardiac arrest, and in all of them it was observed to be ventricular fibrillation. In a very few cases, the defibrillator operators were good Samaritans, acting voluntarily. Eighty-nine patients (about 19%) with ventricular fibrillation were successfully resuscitated, including eighteen who regained consciousness before hospital admission.</AbstractText>Automated external defibrillators deployed in readily accessible, well-marked areas, are really very effective in assisting patients with cardiac arrest. However, it's quite true that, in the cases of survivors, most of our users had good prior training in the use of these devices.</AbstractText> |
9,250 | A rabbit Langendorff heart proarrhythmia model: predictive value for clinical identification of Torsades de Pointes. | The rabbit isolated Langendorff heart model (SCREENIT) was used to investigate the proarrhythmic potential of a range of marketed drugs or drugs intended for market. These data were used to validate the SCREENIT model against clinical outcomes.</AbstractText>Fifty-five drugs, 3 replicates and 2 controls were tested in a blinded manner. Proarrhythmia variables included a 10% change in MAPD(60), triangulation, instability and reverse frequency-dependence of the MAP. Early after-depolarisations, ventricular tachycardia, TdP and ventricular fibrillation were noted. Data are reported at nominal concentrations relative to EFTPC(max). Proarrhythmic scores were assigned to each drug and each drug category.</AbstractText>Category 1 and 2 drugs have the highest number of proarrhythmia variables and overt proarrhythmia while Category 5 drugs have the lowest, at every margin. At 30-fold the EFTPC(max), the mean proarrhythmic scores are: Category 1, 101+/-24; Category 2, 101+/-14; Category 3, 72+/-20; Category 4, 59+/-16 and Category 5, 22+/-9 points. Only drugs in Category 5 have mean proarrhythmic scores, below 30-fold, that remain within the Safety Zone.</AbstractText>A 30-fold margin between effects and EFTPC(max) is sufficiently stringent to provide confidence to proceed with a new chemical entity, without incurring the risk of eliminating potentially beneficial drugs. The model is particularly useful where compounds have small margins between the hERG IC(50) and predicted EFTPC(max). These data suggest this is a robust and reliable assay that can add value to an integrated QT/TdP risk assessment.</AbstractText> |
9,251 | Ru360, a specific mitochondrial calcium uptake inhibitor, improves cardiac post-ischaemic functional recovery in rats in vivo. | The mitochondrial permeability transition pore (mPTP), an energy-dissipating channel activated by calcium, contributes to reperfusion damage by depolarizing the mitochondrial inner membrane potential. As mitochondrial Ca(2+) overload is a main inductor of mPTP opening, we examined the effect of Ru(360), a selective inhibitor of the mitochondrial calcium uptake system against myocardial damage induced by reperfusion in a rat model.</AbstractText>Myocardial reperfusion injury was induced by a 5-min occlusion of the left anterior descending coronary artery, followed by a 5-min reperfusion in anaesthetized open-chest rats. We measured reperfusion-induced arrhythmias and functions indicative of unimpaired mitochondrial integrity to evaluate the effect of Ru(360) treatment.</AbstractText>Reperfusion elicited a high incidence of arrhythmias, haemodynamic dysfunction and loss of mitochondrial integrity. A bolus intravenous injection of Ru(360) (15-50 nmol kg(-1)), given 30-min before ischaemia, significantly improved the above mentioned variables in the ischaemic/reperfused myocardium. Calcium uptake in isolated mitochondria from Ru(360)-treated ventricles was partially diminished, suggesting an interaction of this compound with the calcium uniporter.</AbstractText>We showed that Ru(360) treatment abolishes the incidence of arrhythmias and haemodynamic dysfunction elicited by reperfusion in a whole rat model. Ru(360) administration partially inhibits calcium uptake, preventing mitochondria from depolarization by the opening of the mPTP. We conclude that myocardial damage could be a consequence of failure of the mitochondrial network to maintain the membrane potential at reperfusion. Hence, it is plausible that Ru(360) could be used in reperfusion therapy to prevent the occurrence of arrhythmia.</AbstractText> |
9,252 | Mitochondria, the calcium uniporter, and reperfusion-induced ventricular fibrillation. | The role of the mitochondria, and in particular the calcium (Ca) uniporter, in mediating reperfusion-induced arrhythmias is a novel investigative area. This commentary assesses the importance of a new article on this topic, published in this issue of the journal. Ventricular arrhythmogenesis remains an important area of research in the search of novel targets. The article by García-Rivas et al in this issue represents a possible novel focus for investigation. |
9,253 | Pirfenidone prevents the development of a vulnerable substrate for atrial fibrillation in a canine model of heart failure. | Atrial fibrosis is an important substrate in atrial fibrillation (AF), particularly in the setting of structural heart disease. In a canine model, congestive heart failure (CHF) produces significant atrial fibrosis and the substrate for sustained AF. This atrial remodeling is a potential therapeutic target. The objective of the present study is to evaluate the effects of the antifibrotic drug pirfenidone (PFD) on arrhythmogenic atrial remodeling in a canine CHF model.</AbstractText>We studied 15 canines, divided equally into 3 groups: control, CHF canines not treated with PFD, and CHF canines treated with PFD. CHF was induced by ventricular tachypacing (220 bpm for 3 weeks), and oral PFD was administered for the 3-week pacing period. We performed electrophysiology and AF vulnerability studies, atrial fibrosis measurements, and atrial cytokine expression studies. Only canines in the untreated CHF group developed sustained AF (>30 minutes, 4 of 5 canines; P<0.05). Treatment of CHF canines with PFD resulted in an attenuation of arrhythmogenic left atrial remodeling, with a significant reduction in left atrial conduction heterogeneity index (median [25% to 75% interquartile range] 4.96 [3.53 to 5.64] versus 2.52 [2.11 to 2.82], P<0.01; pacing cycle length 300 ms), left atrial fibrosis (16.0% [13.0% to 17.5%] versus 8.7% [5.7% to 10.6%], P<0.01), and AF duration (1800 [1020 to 1800] seconds versus 6 [5 to 22] seconds, P<0.01). Immunoblotting studies demonstrated the drug's effects on multiple cytokines, including a reduction in transforming growth factor-beta1 expression.</AbstractText>Treatment of CHF canines with PFD results in significantly reduced arrhythmogenic atrial remodeling and AF vulnerability. Pharmacological therapy targeted at the fibrotic substrate itself may play an important role in the management of AF.</AbstractText> |
9,254 | Results from the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) trial on atrial flutter, a multicentric prospective randomized study comparing amiodarone and radiofrequency ablation after the first episode of symptomatic atrial flutter. | There is no published randomized study comparing amiodarone therapy and radiofrequency catheter ablation (RFA) after only 1 episode of symptomatic atrial flutter (AFL). The aim of the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) Trial of Atrial Flutter was 2-fold: (1) to prospectively compare first-line RFA (group I) versus cardioversion and amiodarone therapy (group II) after only 1 AFL episode; and (2) to determine the impact of both treatments on the long-term risk of subsequent atrial fibrillation (AF).</AbstractText>From October 2002 to February 2006, 104 patients (aged 78+/-5 years; 20 women) with AFL were included, with 52 patients in group I and 52 patients in group II. The cumulative risk of AFL or AF was interpreted with the use of Kaplan-Meier curves and compared by the log-rank test. Clinical presentation, echocardiographic data, and follow-up were as follows: age (78.5+/-5 versus 78+/-5 years), history of AF (27% versus 21.6%); structural heart disease (58% versus 65%), left ventricular ejection fraction (56+/-14% versus 54.5+/-14%), left atrial size (43+/-7 versus 43+/-6 mm), mean follow-up (13+/-6 versus 13+/-6 months; P=NS), recurrence of AFL (3.8% versus 29.5%; P<0.0001), and occurrence of significant AF beyond 10 minutes (25% versus 18%; P=0.3). Five complications (10%) were noted in group II (sick sinus syndrome in 2, hyperthyroidism in 1, and hypothyroidism in 2) and none in group I (0%) (P=0.03).</AbstractText>RFA should be considered a first-line therapy even after the first episode of symptomatic AFL. There is a better long-term success rate, the same risk of subsequent AF, and fewer secondary effects.</AbstractText> |
9,255 | Prevalence and prognostic significance of atrial fibrillation in outpatients with heart failure due to left ventricular systolic dysfunction. | Atrial fibrillation (AF) is common in patients with heart failure (HF) due to left ventricular systolic dysfunction (LVSD), with conflicting prognostic data. The aim of our study was to assess the prevalence and incidence of AF in patients with HF and to determine the prognostic impact of baseline AF and the development of new onset AF.</AbstractText>We included 1019 outpatients with HF due to LVSD; follow-up time ranged from 3 to 64 months. At baseline 26.4% of patients had AF. Of the 284 patients with a follow-up ECG and baseline SR, 18.7% developed new onset AF. Patients with AF were older (p<0.001), more often male (p=0.04), and more likely to have a history of stroke (p=0.03), but were less likely to have IHD (p<0.001). Baseline rhythm was independent of LVEF and NYHA-class. Baseline AF was associated with increased all-cause mortality (HR 1.38; CI 1.07-1.78, p=0.01) and all-cause mortality/hospitalisation (HR 1.43; CI 1.22-1.68, p<0.001). When adjusted for baseline covariates, baseline AF was independently associated with an increased risk of experiencing the combined endpoint (HR 1.29; CI 1.05-1.58; p=0.02), but did not predict all-cause mortality. By multivariable analyses, new-onset AF was associated with increased risk of all-cause mortality/hospitalisation (HR 1.45; CI 1.05-2.00; p=0.02).</AbstractText>In outpatients with HF due to LVSD, AF is a common co-morbidity, which adversely affects morbidity and mortality outcomes.</AbstractText> |
9,256 | Atrial fibrillation is associated with increased neurohumoral activation and reduced exercise tolerance in patients with non-ischemic dilated cardiomyopathy. | To assess atrial fibrillation (AF) associated differences in proinflammatory cytokines, natriuretic peptide levels and exercise capacity in patients with heart failure (HF) secondary to non-ischemic dilated cardiomyopathy (NIDC).</AbstractText>We studied 147 NIDC patients, mean age 58.3+/-12.5 years, left ventricular (LV) ejection fraction 27.8+/-10.9% and NYHA class II-III. Neurohumoral activation was assessed by measurement of interleukin IL-1, IL-6, tumor necrosis factor-a (TNF-a), its soluble receptors sTNFR I and II, N-terminal atrial (NT-ANP) and -brain (NT-BNP) natriuretic peptide levels, and functional class was assessed by cardiopulmonary exercise test.</AbstractText>Forty patients (27.5%) had chronic AF and they did not differ in age, LV ejection fraction or HF duration compared to patients in sinus rhythm (SR). AF was associated with increased levels of IL-6 (p=0.001), TNF-a (p=0.002), sTNFRI (p=0.023), NT-ANP (p<0.001) and NT-BNP (p=0.003), decreased exercise duration (p<0.001) and slightly reduced maximal oxygen consumption at peak exercise (p=0.07) compared to SR patients. No significant differences in cytokine and natriuretic peptide levels or exercise tolerance were noted when patients in AF were compared to the subgroup of SR with restrictive LV filling pattern. Multivariate analysis showed that NT-ANP (p=0.003) and IL-6 (p=0.006) plasma levels were independently associated with the presence of AF in our patient population.</AbstractText>AF is associated with increased inflammatory state, natriuretic peptide levels and reduced exercise capacity in patients with HF secondary to NIDC. These findings suggest that the presence of AF in HF represents a more advanced stage of the syndrome.</AbstractText> |
9,257 | Electrocardiographic changes by accidental hypothermia in an urban and a tropical region. | Hypothermia is defined as a condition in which core temperature (rectal, esophageal, or tympanic) reaches values below 35 degrees C. This may be accidental, metabolic, or therapeutic. The accidental form is frequent in cold-climate countries and rare in those with tropical or subtropical climate. The aim of this study was to evaluate electrocardiographic changes of patients with accidental hypothermia.</AbstractText>In 59 patients with hypothermia, the following electrocardiogram parameters were analyzed: rhythm and heart rate (HR), P-wave characteristics, PR-interval duration, QRS-complex duration, presence of J wave and its location characteristics, polarity, voltage, aspect and its correlation with the degree of hypothermia, changes in T wave regarding its polarity and characteristics, duration of the QT interval corrected for HR using both Bazett and Friderica formulas, and possible presence of both supraventricular and ventricular arrhythmias were independently and blindly analyzed in the tracings by experienced cardiologists.</AbstractText>In 6 patients, electrocardiogram was normal. Sinus bradycardia was observed in 52.5% of the patients. J wave was present in 51 patients, and its voltage correlated inversely and was statistically significantly with the core temperature. Changes in T wave were observed in 47.4% of the cases. QT interval, adjusted for HR, was prolonged in 72.8% of the cases. Idioventricular rhythm was found in 6 cases, total atrioventricular block in 3 cases, and junctional rhythm and atrial fibrillation in 2 patients.</AbstractText>Electrocardiogram changes in accidental hypothermia are frequent and characteristic for this entity improving diagnosis in usually unconscious patients, and in many cases, it may be the diagnostic clue in patients with conscience deficit in emergency units, even in patients from a tropical climate where the population at risk may be exposed to temperatures below 20 degrees C.</AbstractText> |
9,258 | Cardiac function, inflammatory mediators and mortality in critical limb ischemia. | Patients with critical limb ischemia (CLI) have a high frequency of concomitant coronary heart disease and congestive heart failure. The aim of the study was to evaluate cardiac function in relation to inflammatory markers and 1-year mortality rate among patients with CLI. The authors investigated 232 consecutive patients with CLI by means of electrocardiogram (ECG), and measurements of endothelin (ET)-1, tumor necrosis factor alpha (TNF)alpha, interleukin (IL)-6, neopterin, CD40 ligand, and 8-epi-prostaglandin (PG)F2alpha in plasma. Echocardiography (echo) was performed in 88 (38%) patients. One-year mortality rate was assessed after prospective follow-up. One hundred and eighty-six (80%) patients had sinus rhythm (SR), 36 (16%) had atrial fibrillation or flutter (AF), and 10 (4%) pacemaker rhythm. Ischemic ECG changes occurred in 143 (62%) patients. Patients with AF showed higher IL-6 (p = 0.0296) and neopterin (p = 0.0494) concentrations. Patients with ischemic ECG changes showed higher ET-1 (p = 0.0303), 8-epi-PGF2alpha (p = 0.0027), neopterin (p = 0.0004) concentrations and 1-year mortality rate (p = 0.0105). The difference in ET-1 remained in logistic regression (p = 0.0152). Internal diameter of the left ventricle on echo correlated with IL-6 (r = 0.345, p = 0.0017), TNFalpha (r = 0.240, p = 0.0273), and neopterin (r = 0.327, p = 0.0028). Internal diameter of the left atrium correlated with TNFalpha (r = 0.384, p = 0.0092) and neopterin (r = 0.526, p = 0.0004), and ejection fraction (EF) correlated inversely with IL-6 (r = -0.380, p = 0.0015) and neopterin (r = -0.346, p = 0.0038). Patients with EF <40% showed higher (p = 0.0462) 1-year mortality rate than patients with EF >40%. In conclusion, in critical limb ischemia, cardiac rhythm disturbances and ischemic ECG changes were related to inflammatory mediators and predicted 1-year mortality rate. The inflammatory mediators correlated with echocardiographic signs of congestive heart failure. |
9,259 | [Public access defibrillation. Limited use by trained first responders and laymen]. | As ventricular fibrillation is the most frequent initial heart rhythm causing out-of-hospital sudden cardiac arrest, defibrillation is of essential significance. Automated external defibrillators (AEDs) have been available for some years and as a result defibrillation can be carried out by individuals other than physicians and healthcare providers such as trained first responders and untrained lay rescuers. This so-called public access defibrillation nourished hope of progress in the treatment of sudden cardiac arrest. However, several limitations exist, such as low frequency of sudden cardiac arrest in public, rare use of publicly placed AEDs, low cost effectiveness, legal requirements and insufficient public willingness to help. Due to these restrictions of public access defibrillation other measures are more promising than the attempt at general distribution of AEDs. These measures are primary or secondary prophylaxis of sudden cardiac arrest, general knowledge of adequate activation of emergency medical services, implementation of first responder teams equipped with AEDs and particularly a better education in and application of the well-established principles of cardiopulmonary resuscitation. |
9,260 | [Time-frequency analysis of ventricular fibrillation. An experimental study]. | The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution.</AbstractText>Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle.</AbstractText>Linear regression analysis showed that there was a good correlation between the dominant frequency obtained using the two signal analysis methods: frequency (spectral analysis) = 1.01 x frequency (time-frequency analysis) -- 0.4 (r=0.9; P< .0001; standard error of the estimate, 2.2 Hz). In all cases except one, the dominant frequency exhibited a significant temporal variation on a short timescale (time-frequency analysis); the coefficient of variation was between 0.19 (0.06) and 0.24 (0.07) (NS). In all cases, there were significant differences between regions. The location at which the frequency was highest varied according to the timepoint considered, though it was predominantly in the apical or anterior zone.</AbstractText>In the absence of external modulating factors, the frequency of ventricular fibrillation exhibits temporal and spatial variations which can be observed at short timescales. In the free wall of the left ventricle, the dominant frequency is highest in the apical and anterior zones, and the maximum frequencies are most often found in these zones.</AbstractText> |
9,261 | Protective effect of simvastatin and VULM 1457 in ischaemic-reperfused myocardium of the diabetic-hypercholesterolemic rats. | This study examined the effects of simvastatin (10 mg/ kg) and VULM 1457 (50 mg/kg), an ACAT inhibitor, in the heart model of 6 min ischemia followed by 10 min reperfusion injury in the diabetic-hypercholesterolaemic (DM-HCH) rats. In the DM-HCH rats, the incidence of ventricular tachycardia (VT) had a tendency to be increased, while ventricular fibrillation (VF) occurred in all diseased rats (p < 0.01). Simvastatin and VULM 1457 with the shown hypolipidemic effect, significantly (p < 0.01) suppressed a formation of VF (38% and 29%; respectively). |
9,262 | Experimental evidence of improved transthoracic defibrillation with electroporation-enhancing pulses. | There is considerable work on defibrillation wave form optimization. This paper determines the impedance changes during defibrillation, then uses that information to derive the optimum defibrillation wave form.</AbstractText>Twelve guinea pigs and six swine were used to measure the current wave form for square voltage pulses of a strength which would defibrillate about 50% of the time. In guinea pigs, electrodes were placed thoracically, abdominally and subcutaneously using two electrode materials (zinc and steel) and two electrode pastes (Core-gel and metallic paste).</AbstractText>The measured current wave form indicated an exponentially increasing conductance over the first 3 ms, consistent with enhanced electroporation or another mechanism of time-dependent conductance. We fit this current with a parallel conductance composed of a time-independent component (g0 = 1.22 +/- 0.28 mS) and a time-dependent component described by g delta (1-e(-t/tau)), where g delta = 0.95 +/- 0.20 mS and tau = 0.82 +/- 0.17 ms in guinea pigs using zinc and Cor-gel. Different electrode placements and materials had no significant effect on this fit. From our fit, we determined the stimulating wave form that would theoretically charge the myocardial membrane to a given threshold using the least energy from the defibrillator. The solution was a very short, high voltage pulse followed immediately by a truncated ascending exponential tail.</AbstractText>The optimized wave forms and similar nonoptimized wave forms were tested for efficacy in 25 additional guinea pigs and six additional swine using methods similar to Part I.</AbstractText>Optimized wave forms were significantly more efficacious than similar nonoptimized wave forms. In swine, a wave form with the short pulse was 41% effective while the same wave form without the short pulse was 8.3% effective (p < 0.03) despite there being only a small difference in energy (111 J versus 116 CONCLUSIONS: We conclude that a short pulse preceding a defibrillation pulse significantly improves efficacy, perhaps by enhancing electroporation.</AbstractText> |
9,263 | In-hospital cardiac arrest: incidence, prognosis and possible measures to improve survival. | Review.</AbstractText>Medical literature on in-hospital cardiac arrest (IHCA) was reviewed to summarise: (a) the incidence of and survival after IHCA, (b) major prognostic factors, (c) possible interventions to improve survival.</AbstractText>The incidence of IHCA is rarely reported in the literature. Values range between 1 and 5 events per 1,000 hospital admissions, or 0.175 events/bed annually. Reported survival to hospital discharge varies from 0% to 42%, the most common range being between 15% and 20%. Pre-arrest prognostic factors: the prognostic value of age is controversial. Among comorbidities, sepsis, cancer, renal failure and homebound lifestyle are significantly associated with poor survival. However, pre-arrest morbidity scores have not yet been prospectively validated as instruments to predict failure to survive after IHCA. Intra-arrest factors: ventricular fibrillation/ventricular tachycardia (VF/VT) as the first recorded rhythm and a shorter interval between IHCA and cardiopulmonary resuscitation or defibrillation are associated with higher survival. However, VF/VT is present in only 25-35% of IHCAs. Short-term survival is also higher in patients resuscitated with chest compression rates above 80/min. Interventions likely to improve survival include: early recognition and stabilisation of patients at risk of IHCA to enable prevention, faster and better in-hospital resuscitation and early defibrillation. Mild therapeutic hypothermia is effective as post-arrest treatment of out-of-hospital cardiac arrest due to VF/VT, but its benefit after IHCA and after cardiac arrest with non-VF/VT rhythms has not been clearly demonstrated.</AbstractText> |
9,264 | Low osmolarity transforms ventricular fibrillation from complex to highly organized, with a dominant high-frequency source. | An osmotic challenge activates volume-regulated chloride currents (I(Cl,vol)), resulting in depolarization of the resting membrane potential and shortening of action potential duration (APD). I(Cl,vol) is activated in ischemia/reperfusion, but the effects of osmotic challenges and I(Cl,vol) on ventricular fibrillation (VF) are unknown.</AbstractText>The purpose of this study was to investigate the influence of hypo-osmotic and hypotonic stress and I(Cl,vol) activation on VF dynamics.</AbstractText>Guinea pig hearts were isolated, stained with di-4 ANEPPS to optically map action potentials (APs) from epicardium using a photodiode array, and perfused with iso-osmotic (low NaCl Ringer plus 45 mM mannitol) or hypo-osmotic (low NaCl Ringer) solution.</AbstractText>Hypo-osmotic solution shortened APDs (143 +/- 5 ms --> 115 +/- 10 ms) and increased APD gradients between right and left ventricles (21 +/- 7 ms --> 41 +/- 10 ms, n = 4). In VF induced by burst stimulation, switching to hypo-osmotic solution increased VF frequencies (15.3 +/- 1.2 Hz to 28.9 +/- 3.6 Hz, n = 11), transforming complex fast Fourier transformation spectra to a single dominant high frequency on the left but not the right ventricle. Perfusion with the I(Cl,vol) blocker indanyloxyacetic acid-94 (10 muM) reversed organized VF to complex VF with lower (13.5 +/- 3.7 Hz in left ventricle) frequencies (n = 8), indicating that I(Cl,vol) underlies the changes in VF dynamics. Consistent with this interpretation, the levels of ClC-3 channel protein were 27% greater on left than right ventricles (n = 10), and computer simulations showed that insertion of I(Cl,vol) transformed complex VF to a stable spiral.</AbstractText>Activation of I(Cl,vol) by decreasing osmolarity (45 mOsm) has a major impact on VF dynamics by transforming random multiple wavelets to a highly organized VF with a single dominant frequency.</AbstractText> |
9,265 | Renal dialysis as a risk factor for appropriate therapies and mortality in implantable cardioverter-defibrillator recipients. | Patients with end-stage renal disease are at increased risk for sudden cardiac death, although the utility of implantable cardioverter-defibrillators (ICDs) in these patients is unknown.</AbstractText>The purpose of this study was to evaluate whether end-stage renal disease is an independent risk factor for appropriate ICD therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF) and to compare the long-term survival of ICD recipients with and without end-stage renal disease.</AbstractText>A retrospective cohort study was performed on ICD recipients at a single center. The primary endpoint was first appropriate ICD therapy for VT/VF. The secondary endpoint was survival.</AbstractText>The study included 585 patients, 19 (3.2%) of whom had end-stage renal disease prior to device implantation. Average follow-up time was 2.2 +/- 2.4 years, during which time 156 patients (26.7%) received appropriate ICD therapy. End-stage renal disease was strongly associated with appropriate ICD therapy (hazard ratio 2.30, 95% confidence interval 1.17-4.54) and remained a significant predictor following adjustment for implant indication, ejection fraction, diabetes, hypertension, and beta-blocker use. Survival was significantly shorter in the end-stage renal disease patients, with a median survival time of 3.2 +/- 0.6 (SEM) years in the dialysis cohort and 7.4 +/- 0.5 (SEM) years in those without end-stage renal disease (log rank P = .009). The majority of deaths in the end-stage renal disease cohort were due to non-device-related infection.</AbstractText>In this cohort, end-stage renal disease was the single greatest predictor of ICD therapies for VT/VF. The survival rate was significantly shorter than that of ICD recipients without end-stage renal disease, suggesting that comorbidities in end-stage renal disease patients meeting current implant indications may reduce the survival benefit of ICD placement in this population.</AbstractText> |
9,266 | Quantitative assessment of ST segment elevation in Brugada patients. | ST segment elevation in the right precordial leads constitutes the electrocardiogram (ECG) hallmark of Brugada syndrome (BS). This pattern is variable and can be concealed, but the magnitude and the cause of ST segment fluctuations have been poorly investigated.</AbstractText>Our goal was to quantify ST changes and to assess rate and autonomic influences on ST level.</AbstractText>A 12-lead ECG was continuously recorded during 24 hours in 20 patients with BS (ages 49 +/- 12) and 10 healthy subjects (ages 32 +/- 7). Using two-dimensional binning we obtained average QRS-T complexes every 30 minutes (time bins) and at different RR intervals (rate bins) for each subject. ST level was measured at five different points located 90, 100, 110, 120, and 140 ms after Q onset (Qo). In BS patients, the highest ST elevation was measured 110 ms after Qo (Qo+110).</AbstractText>ST level changes between time points were significantly greater in patients with BS compared with control subjects: on lead V2, the range of ST level at Qo+110 was 264 +/- 85 microV in BS and 91 +/- 22 microV in control subjects (P <.01). In BS, ST level decreased with heart rate acceleration: the difference in ST level at Qo+110 for RR = 900 and 600 ms was 55 +/- 53 microV (P <.01). HFnu was positively, although weakly, correlated with ST level (R(2) = 0.02, P <.01).</AbstractText>ECG changes observed in patients with BS are related in part to heart rate influences on ST segment level. These spontaneous fluctuations over a 24-hour time period suggest that Holter recordings may improve the ECG diagnosis sensitivity in BS.</AbstractText> |
9,267 | Reduction of atrial tachyarrhythmia episodes during the overdrive pacing period using the post-mode switch overdrive pacing (PMOP) algorithm. | Early recurrences within 10 minutes after termination of an atrial tachyarrhythmia, such as atrial tachycardia (AT), atrial flutter, or atrial fibrillation (AF) episodes, account for a large part of paroxysmal AT/AF episodes. It is unclear whether these arrhythmias can be suppressed by overdrive pacing.</AbstractText>We set out to prove that overdrive pacing is effective in preventing early recurrences of AT/AF.</AbstractText>This AT500 (DDDRP device, Bakken Research Center Medtronic, Maastricht, The Netherlands) post-mode switch overdrive pacing (PMOP) study is a randomized controlled trial designed to test the efficacy of overdrive pacing on the suppression of early recurring AT/AF episodes. With the PMOP feature, overdrive pacing is activated 12 ventricular beats after device-confirmed termination of an AT/AF episode with a programmed duration and rate. If at least four episodes of 1 minute in duration occurred within the run-in period of 1 month, patients were randomized to one of the three settings (PMOP off and PMOP 10 minutes at 90 bpm or 120 bpm) for 2 months. At 2 and 4 months, patients were crossed over to another arm. At 6 months, all patients were programmed with PMOP on at 90 bpm for 30 minutes.</AbstractText>We enrolled 122 and randomized 50 patients. Sixty percent of all stored AT/AF episodes occurred within 10 minutes after a previous episode; 31% occurred after device-determined termination and before the device reached the overdrive rate (17-27 ventricular beats after termination), and 29% of the episodes occurred while the device was pacing at the programmed overdrive rate. Thirty-seven percent of the average percentage of episodes during the overdrive period was prevented by the randomized settings of PMOP 90 bpm/10 min (P = .01, paired t-test, n = 39) and 120 bpm/10 min (P = .03, n = 35). In addition, for the nonrandomized setting of PMOP 90 bpm/30 min, the average number of episodes during the overdrive period was significantly smaller than the percentage of episodes occurring during the corresponding off period of 30 minutes (P = .05, n = 33). No significant differences in burden and episodes were found between the PMOP settings and the corresponding off periods.</AbstractText>This is the first randomized controlled clinical trial to prove that overdrive pacing is effective in preventing early recurrences of AT/AF. However, shortcomings of the PMOP algorithm, such as late activation, need further improvement.</AbstractText> |
9,268 | [The role of permanent pacing in atrial fibrillation]. | Nowadays permanent pacing of the heart helps patients not only with pathological bradycardia or asystole in the tract of the AV blocks (AVB) and sick sinus syndrome (SSS), but is also valuable in the prevention of atrial fibrillation (AF) as well as the stabilization of the rhythm in chronic AF. For this reason patients with AF are often candidates for implantation of a cardiac pacemaker. The basic problem for doctor qualifying patients for pacemaker implantation with AF is the choice of a suitable type of pacing. However, this is not the only problem. New possibilities in the tract of solid and very quick progress in the field of pacing have appeared but there are also new doubts. The present publication presents the possibilities of utilization of types of pacing in this field including the newest solutions (antyarrhythmic algorithms) along with the role of placement of stimulation (dual site right ventricular pacing). Hybrid therapy is also described as the only alternative in special circumstances. All these methods were supported by the data from the latest trial. |
9,269 | [Cardiac stimulations for the treatment of supraventricular arrhythmias]. | Permanent cardiac stimulation in patients with supraventricular tachycardia is used primary for treatment and prevention of atrial fibrillation (AF). Different strategies of stimulation have been design for this purpose. Among the most important are: preferential standard atrial pacing, multisite atrial pacing or septal atrial pacing and pacing algorithms for prevention or treatment. Multicentric, controlled and randomized studies design to explore this therapies have disappointing and controversial results. Current therapy is focused in the implant of physiological pacemakers (AAI, DDD) rather than VVI pacemakers. Right apical ventricular stimulation has deleterious effects in ventricular function by producing a dissincronous ventricular contraction and increasing the incidence of AF, so ventricular pacing must be avoided in patients with intact atrioventricular conduction.</AbstractText>Permanent cardiac pacing in patients without symptomatic bradycardia should not be used to treat supraventricular tachycardias. Physiologic pacing should be used to reduce the incidence of AF. Effort should be made to allow normal atrioventricular conduction in patients with sick sinus disease and normal atrioventricular conduction.</AbstractText> |
9,270 | [Dual chamber pacemakers: common problems and how to treat them]. | In the last ten years the technology in Electrophysiology and Cardiac Parcing has advanced rapidly until the arrive of the implantable cardioverter defibrillator for the prevention of Sudden Death and also to the three chamber pacing for ventricular resinchronization as a treatment for advanced heart failure. In the middle of these we have dual chamber pacemakers. The increasing expectative of life worldwide gives the need and more frequency of implanting dual chamber pacemakers with the exception of the patient with chronic atrial fibrillation. For these reasons, it is important not only to detect the common problems of the dual chamber pacemakers but how to treat them. In this review we will define pacemaker pseudomalfunction: the identification of fusion and pseudofusion beats; the normal pacemaker functions that could be confused with malfunction. About malfunction it will be described the causes and the way for treating oversensing, undersensing, loss of capture, loss of output; how to identify and to treat pacemaker reset, myopotentials stimulation, pacemaker syndrome and finally pacemaker-mediated tachycardia. |
9,271 | [Atrial fibrillation: rhythm vs. rate control]. | The atrial fibrillation treatment has been controversial since almost a century. Several studies have been done and there is not a clear therapeutic strategy despite the new technological advances. The disyuntive persist between sinus rhythm control vs. ventricular rate control. The main studies like AFFIRM, RACE, PIAF, PAF2 and STAF have not shown a definitive strategy treatment. Recently, several subgroups have been stablished and variables like life quality and functional state have been included. New therapeutic strategies have resulted. Heart rate control is recommendable for asymptomatic 65 years old patients and older, whereas rhythm control is better for patients with severe symptoms. |
9,272 | Optical imaging of arrhythmias in tissue culture. | Cardiac cell cultures are becoming an important experimental system of minimal complexity that captures many of the salient features of myocardial tissue function and are simple enough that tissue parameters can be controlled systematically. Fundamental mechanisms that underlie normal and pathological electrophysiology at the tissue level can be studied. Of particular interest are spiral waves, which underlie many tachyarrhythmias and fibrillation.</AbstractText>Methods of patterned growth were used to control tissue structure, and contact fluorescence imaging was used to visualize the spread of electrical waves in confluent monolayers of neonatal rat ventricular cells stained with voltage-sensitive dye.</AbstractText>Work is summarized regarding anisotropy, multiarmed spirals, cocultures of cardiac cells and skeletal myoblasts or mesenchymal stem cells, mechanical excitation, attachment of spiral waves to small anatomical obstacles, perturbation of spiral waves by external electric fields, and structure-based facilitation of spiral wave formation.</AbstractText>The cultured cell monolayer is a contemporary experimental model encompassing great versatility for basic studies of wavefront propagation and cardiac arrhythmias.</AbstractText> |
9,273 | Electrophysiology of the electrocardiographic changes of atrial fibrillation. | The history of atrial fibrillation is described in terms of its electrocardiographic delineation, characteristics and clinical associations. The variant configurations are described and their relationship to rhythm duration and cardioversion success. The inter-relationship of fibrillation with flutter and their diagnostic differences are reviewed. The electrophysiologic basis of atrial remodeling is exemplified, together with its relationship to failure of rate adaptation of the atrial refractory period. Electric countershock causes an acute abbreviation of the atrial refractory period as does the induction of hyperthyroidism in the experimental animal. Current theories of the mechanism of fibrillation and the issue of originating pulmonary venous foci are reviewed. The lack of protection from ventricular fibrillation that exists with preexcitation via an accessory pathway is discussed in terms of the teleological role of orthograde downstream refractory periods. |
9,274 | Interdependence of virtual electrode polarization and conduction velocity during premature stimulation. | Fiber orientation in the heart plays a crucial role in the anisotropic nature of impulse propagation and the formation of virtual electrode polarization (VEP). The relationship between anisotropic conduction velocity and VEP is not fully understood.</AbstractText>We recorded transmembrane potential from the surface of isolated rabbit hearts (N = 7) in the presence of 15 mmol/L of diacetylmonoxime using a video imaging system. We paced each heart at a constant cycle length of 250 milliseconds and delivered a premature stimulus (S2) from the same unipolar electrode. The S2 pulses of either polarity were applied at various coupling intervals (CIs); S2 duration was 10 milliseconds and stimulus amplitude was 40 mA. Impulse propagation at 250 milliseconds occurred via elliptical waves with an anisotropy ratio (AR) of approximately 2.5. Owing to VEP, AR varied dramatically as a function of S2 polarity and CI. At intermediate CIs (approximately 150 milliseconds), AR was decreased by a factor of 3 for anodal stimulation and increased by a factor of 2 for cathodal stimulation. At slightly shorter CIs (approximately 115 milliseconds), impulse propagation was blocked, leading to unidirectional block and the initiation of reentrant arrhythmias. Conduction block always occurred along fibers for anodal stimulation and across fibers for cathodal stimulation.</AbstractText>Fiber orientation plays a prominent role in impulse propagation during premature stimulation such as that which occurs during pacing of ventricular tachycardia and ventricular fibrillation. The interdependence of VEP and conduction velocity acts to dramatically alter AR and arrhythmogenesis.</AbstractText> |
9,275 | Adenosine A2A receptors are expressed in human atrial myocytes and modulate spontaneous sarcoplasmic reticulum calcium release. | Alterations in the cyclic AMP-dependent regulation of the cardiac ryanodine receptor (RyR2) have been proposed to account for increased spontaneous calcium release from the sarcoplasmic reticulum (SR) in patients with heart failure, ventricular tachyarrhythmias and atrial fibrillation. While the adenosine A(2A) receptor (A(2A)R) is known to regulate cyclic AMP levels, expression and function of this receptor in human cardiac myocytes has not been investigated.</AbstractText>PCR, western blotting and immunofluorescence were used to identify the A(2A)R, and functional effects of A(2A)R stimulation were measured with confocal calcium imaging and patch-clamp technique.</AbstractText>The A(2A)R is expressed in the human right atrium and distributed in a banded pattern along the Z-lines, overlapping with the ryanodine receptor. A(2A)R stimulation caused a protein kinase A dependent increase in spontaneous SR calcium release in isolated human atrial myocytes. The A(2A)R agonist CGS21680 increased the frequency of calcium sparks from 0.12+/-0.03 to 0.31+/-0.08 sparks.mum min(-1) (p<0.05) and calcium waves from 0.65+/-0.31 to 5.11+/-1.84 waves.min(-1) (p<0.03). Moreover, spontaneous Na-Ca exchange currents (I(NCX)) increased from 1.19+/-0.17 to 2.50+/-0.42 min(-1) (p<0.001). In contrast, CGS21680 did not alter caffeine inducible calcium release (6.98+/-0.52 vs. 6.82+/-0.57 amol pF(-1), p=0.6) or the spontaneous I(NCX) amplitude (0.32+/-0.05 vs. 0.29+/-0.04 pA pF(-1), p=0.2). Current-voltage relationship and amplitude of the L-type calcium current (1.62+/-0.18 vs. 1.80+/-0.18 pA pF(-1)) were not altered, but calcium release dependent inactivation was faster with CGS21680 (13.4+/-0.7 vs. 15.8+/-1.0 ms, p<0.001).</AbstractText>Adenosine A(2A) receptors are expressed in the human atrial myocardium and modulate the frequency of spontaneous calcium release from the SR.</AbstractText> |
9,276 | Initiation of re-entry in an excitable medium: structural investigation of cardiac tissue using a genetic algorithm. | The detailed mechanisms by which re-entry and ventricular fibrillation are initiated in the heart remain poorly understood because they are difficult to investigate experimentally. We have used a simplified excitable media computational model of action potential propagation to systematically study how re-entry can be produced by diffuse regions of inexcitable tissue. Patterns of excitable and inexcitable tissue were generated using a genetic algorithm. The inexcitable tissue was modeled in two ways: (i) diffusive, electrically connected but inexcitable tissue, or (ii) zero-flux, areas of tissue electrically disconnected in the same way as zero-flux boundary conditions. We were able to evolve patterns of diffuse inexcitable tissue that favored re-entry, but no single structure or pattern emerged. Diffusive inexcitable regions were inherently less arrhythmogenic than zero-flux inexcitable ones. |
9,277 | Phobic anxiety, depression, and risk of ventricular arrhythmias in patients with coronary heart disease. | Findings of an association between phobic anxiety and elevated risks of sudden cardiac death suggest that phobic anxiety may be related to increased risk of ventricular arrhythmias. The purpose of this study was to examine whether phobic anxiety is associated with ventricular arrhythmias in patients with documented coronary artery disease (CAD).</AbstractText>Phobic anxiety level was measured using the Crown-Crisp phobic anxiety scale in 940 patients (660 men, 280 women) hospitalized for diagnostic cardiac catheterization between April 1999 and June 2002. Depressive symptomatology was assessed using the Beck Depression Inventory. Patients were followed for a median follow-up period of 3 years, and the occurrence of ventricular arrhythmias was determined through review of medical records.</AbstractText>Ventricular arrhythmias occurred in 97 patients and were significantly related to higher phobic anxiety after statistical adjustment for established medical and demographic determinants of arrhythmias (odds ratio = 1.40; p = .012). Depressive symptomatology was significantly correlated with phobic anxiety (r = 0.44, p < .001) and was also related to ventricular arrhythmias (odds ratio = 1.40; p = .006). The composite of depression and phobic anxiety predicted ventricular arrhythmias with a larger effect size than either depression or phobic anxiety score alone (odds ratio = 1.6, 95% confidence interval, 1.2-2.1, p = .002).</AbstractText>Both phobic anxiety and depressive symptomatology predict ventricular arrhythmias in patients with CAD and may share a common factor predictive of ventricular arrhythmias.</AbstractText> |
9,278 | Are the American College of Cardiology/Emergency Cardiac Care (ACC/ECC) guidelines useful in triaging patients to telemetry units? | To determine if the ACC/ECC guidelines (1991) properly stratify patients according to risk of arrhythmia, defined as a single event on cardiac monitoring, and benefit, defined as a subsequent management change from a recorded telemetry event.</AbstractText>In 2003, a prospective study of 217 consecutive patients admitted to a 24-bed telemetry unit was conducted for 25 days at a major academic hospital. Patients were categorized per ACC/ECC guidelines as appropriate (class I & II) or inappropriate (class III) based on a non-cardiologist admission diagnosis. A cardiologist-led group then reclassified patients at the time of admission using a brief interview. Continuous telemetry-recorded arrhythmias and resultant management changes were reviewed and recorded daily. Subgroup analysis of patients admitted with a chief complaint of chest pain was also performed. In 2004, after this trial was performed, the American Heart Association released a scientific statement updating practice standards for ECG monitor; however, this paper is based upon the original 1991 ACC/ECC guidelines.</AbstractText>Reclassification significantly decreased the percentage of all class I & II patients from 91% to 71% (P<0.001) and the percentage of class I & II patients with chest pain from 100% to 58% (P<0.001) without increasing the percentage of arrhythmias occurring in class III patients. Class II patients had a statistically significant higher percentage of arrhythmias than class I and III patients before and after reclassification (P<0.001 and P<0.001, respectively). Management changes occurring as a direct result of telemetry events were higher in class II than class I or III patients before and after reclassification (P = 0.01 and P = 0.03). Life-threatening arrhythmias (sustained ventricular tachycardia or ventricular fibrillation) occurred in 1% of the 216 patients enrolled in this study.</AbstractText>(1) Cardiology input using ACC/ECC guidelines and a brief interview at admission safely reduced total admissions primarily by identifying low risk chest pain admissions inappropriate for inpatient telemetry monitoring. (2) Life threatening arrhythmias occurring in patients admitted to telemetry are rare.</AbstractText> |
9,279 | Interference detection in implantable defibrillators induced by therapeutic radiation therapy. | Electromagnetic fields and ionising radiation during radiotherapy can influence the functioning of ICDs. Guidelines for radiotherapy treatment were published in 1994, but only based on experience with pacemakers. Data on the influence of radiotherapy on ICDs is limited.</AbstractText>We determined the risk to ICDs of interference detection induced by radiotherapy.</AbstractText>In our study we irradiated 11 ICDs. The irradiation was performed with a 6 megavolt photon beam. In each individual device test, a total of 20 Gray was delivered in a fractionated fashion. During each irradiation the output stimulation rate was monitored and electrogram storage was activated. In case of interference the test was repeated with the ICD outside and the lead(s) inside and outside the irradiation field.</AbstractText>With the ICD inside the irradiation field, interference detection was observed in all ICDs. This caused pacing inhibition or rapid ventricular pacing. Ventricular tachycardia (VT) or ventricular fibrillation (VF) detection occurred, which would have caused tachycardia-terminating therapy. If the ICD was placed outside the irradiation field, no interference was observed.</AbstractText>Interference by ionising radiation on the ICDs is demonstrated both on bradycardia and tachycardia therapy. This can have consequences for patients. Recommendations for radiotherapy are presented in this article.</AbstractText> |
9,280 | [Genetic background of common arrhythmias]. | Progress in the field of clinical and experimental electrophysiology helps us to elucidate connections between clinical problems and genetic cellular abnormalities. So far four genes have been discovered to be responsible for inherited forms of atrial fibrillation. Several polymorphisms in genes encoding angiotensinogen, connexin 40 and subunits of potassium channels (KCNE1) have been disclosed to correlate with this disease. On the other hand genetic background of preexcitation, atrio-ventricular nodal reentry tachycardia and ventricular tachycardias need further studies. More research is also needed to assess the efficacy of pharmacogenetic treatment methods for atrial fibrillation. |
9,281 | The virtual ventricular wall: a tool for exploring cardiac propagation and arrhythmogenesis. | Methods for the experimental and clinical investigation of cardiac arrhythmias are limited to inferring propagation within the myocardium, from surface measurements, or from electrodes at a few sites within the cardiac wall. Biophysically and anatomically detailed computational models of cardiac tissues offer a powerful way for studying the electrical propagation processes and arrhythmias within the virtual heart. We use virtual tissues to study and visualise the effects of patho- and physiological conditions, and pharmacological interventions on transmural propagation in the virtual ventricular walls. Class III drug actions are quantitatively explained by changes induced in the transmural dispersion of action potential duration. We illustrate the automated construction of a virtual anisotropic ventricle from Diffusion Tensor MRI for individual hearts, and use it to explore mechanisms leading to ventricular fibrillation. The virtual ventricular wall provides an effective tool for exploring, evaluating and visualising processes during the initiation and maintenance of ventricular arrhythmias. |
9,282 | Ventricular fibrillation as the first manifestation of primary hyperaldosteronism. | 50 years old female patient, with history of diabetes mellitus and hypertension, receiving metformin (500 mg BID) and atenolol (50 mg BID), presented to the Emergency Room with asthenia and dizziness. The patient was also receiving alternative medication (Dragon Blanco) which contains no licorice. During the emergency workup she developed syncope and three episodes of ventricular fibrillation. She was electrically defibrillated and treated with amiodarone and potassium replacement. The patient was admitted to the Intensive Care Unit. Physical exam: BP: 160/90 mm Hg, RR: 15, Pulse: 83: Cardiovascular: grade II systolic murmur which irradiated to the neck. The rest of the examination was unremarkable. Labs: Na: 138 meg/dl, K: 1.6 meg/dl, Cl: 84 meg/dl, BUN: 17 mg/dl, Creat.: 1.1 mg/dl, Gluc.: 148 mg/dl, Renin: < 0.15 mcgr/ml, Aldosterone: 20.1 mcg%. Aldosterone-Renin ratio: 133. Chest X-Ray: cardiomegaly. EKG: RBBB, long QT segment and prominent broad "u" waves compatible with severe hypokalemia. A CT SCAN of the Abdomen/Pelvis showed a 3.2 cm right adrenal mass, most likely adenomatous. The patient was discharged with the diagnosis of primary aldosteronism. Due to the diagnosis of diabetes mellitus, hypertension and the three episodes of ventricular fibrillation, surgical treatment was postponed until stress tests and eventual coronary angiographic studies were performed. We found in our review of the medical literature 9 reports of fibrillation associated with hyperaldosteronism. Of those, only two were associated with primary aldosteronism, one of them with a fatal outcome. This case is highly unusual and emphasizes the importance of an adequate diagnosis of secondary hypertension. |
9,283 | Effect of endurance exercise training on heart rate onset and heart rate recovery responses to submaximal exercise in animals susceptible to ventricular fibrillation. | Both a large heart rate (HR) increase at exercise onset and a slow heart rate (HR) recovery following the termination of exercise have been linked to an increased risk for ventricular fibrillation (VF) in patients with coronary artery disease. Endurance exercise training can alter cardiac autonomic regulation. Therefore, it is possible that this intervention could restore a more normal HR regulation in high-risk individuals. To test this hypothesis, HR and HR variability (HRV, 0.24- to 1.04-Hz frequency component; an index of cardiac vagal activity) responses to submaximal exercise were measured 30, 60, and 120 s after exercise onset and 30, 60, and 120 s following the termination of exercise in dogs with healed myocardial infarctions known to be susceptible (n = 19) to VF (induced by a 2-min coronary occlusion during the last minute of a submaximal exercise test). These studies were then repeated after either a 10-wk exercise program (treadmill running, n = 10) or an equivalent sedentary period (n = 9). After 10 wk, the response to exercise was not altered in the sedentary animals. In contrast, endurance exercise increased indexes of cardiac vagal activity such that HR at exercise onset was reduced (30 s after exercise onset: HR pretraining 179 +/- 8.4 vs. posttraining 151.4 +/- 6.6 beats/min; HRV pretraining 4.0 +/- 0.4 vs. posttraining 5.8 +/- 0.4 ln ms(2)), whereas HR recovery 30 s after the termination of exercise increased (HR pretraining 186 +/- 7.8 vs. posttraining 159.4 +/- 7.7 beats/min; HRV pretraining 2.4 +/- 0.3 vs. posttraining 4.0 +/- 0.6 ln ms(2)). Thus endurance exercise training restored a more normal HR regulation in dogs susceptible to VF. |
9,284 | The use of unipolar intracardiac impedance for discrimination of haemodynamically stable and unstable arrhythmias in man. | To determine the feasibility of discriminating haemodynamically stable from unstable arrhythmias using right ventricular (RV) unipolar intracardiac impedance (Z).</AbstractText>A quadrapolar temporary pacing electrode was positioned at the RV apex and unipolar impedance was measured between the tip electrode and a surface patch electrode. Changes in peak-to-peak Z amplitude were measured simultaneously with surface ECG and blood pressure during induced arrhythmias. Haemodynamic instability was defined as a systolic pressure of <90 mmHg. There were 25 episodes of ventricular fibrillation (VF) induced in 15 patients, 18 episodes of ventricular tachycardia in 16 patients, and 33 episodes of supraventricular tachycardia (SVT) in 16 patients. Compared with the baseline rhythm, mean Z amplitude reduced from 51.3+/-7.7 to 11.2+/-7.4 Ohm (P<0.001) during VF, from 52.2+/-6.3 to 21.7+/-10.1 Ohm (P<0.01) during haemodynamically unstable VT, from 55.0+/-6.9 to 39.9+/-11 Ohm (ns) during stable VT, and from 56.4+/-8.4 to 36.9+/-9.3 Ohm during SVT (P<0.001).</AbstractText>Right ventricular unipolar impedance is an adequate sensor for determining mechanical ventricular contraction and acts as a surrogate marker for a fall in arterial blood pressure during VF. However, for ventricular and supraventricular tachycardias, variations between patients did not allow adequate discrimination between stable and unstable arrhythmias.</AbstractText> |
9,285 | [Prevalence of dangerous arrhythmia during pharmacological stress echocardiography]. | Pharmacological stress echocardiography (SE) has become a routine diagnostic and prognostic method in patients with ischemic heart disease. However, all stress tests can provoke undesirable adverse effects including dangerous arrhythmia. The aim of the study was to access the prevalence and types of arrhythmia that can appear during SE.</AbstractText>A retrospective study included the cohort of patients studied using SE in our Department of Cardiology between 1995 and 2002. We followed the data of 836 patients (pts) (615 men, aged 52 +/- 5 yrs). Dobutamine SE was performed in 695 pts (83.2%) and dipyridamole SE in a group of 141 pts (16.8%). Additionally, atropine was administrated to achieve submaximal heart rate in a group of 694 pts (83%). 519 pts (62%) underwent SE was performed according to high dose protocol and in 317 pts (35%)--low dose protocol.</AbstractText>During SE the following arrhythmia events were observed: one persistent ventricular tachycardia (0.12%) and two paroxysmal atrial fibrillation (0.24%) in dobutamine test. The set of unsustained ventricular tachycardia in six patients (0.72%) 5 patients from dobutamine group and 1 from dipyridamole group). Complex forms of ventricular extrasystoles (as bigeminy and trigeminy) in 46 pts (5.5%) 43 in dobutamine SE and 3 in dipyridamole SE. All arrhythmias were mild and withdrew spontaneously or after beta-blockers administration.</AbstractText>The risk of dangerous arrhythmia during either dobutamine SE or dipyridamole SE is small and similar in both groups. Dobutamine SE tends to provoke of mild arrhythmia (p = 0.075) more often.</AbstractText> |
9,286 | Evidence of mechanoelectric feedback in the atria of patients with atrioventricular nodal reentrant tachycardia. | Patients with atrioventricular nodal reentrant tachycardia (AVNRT) could serve as a clinical model to study the effects of mechanical stretch in the electrical properties of atrial myocardium.</AbstractText>We studied 14 patients with AVNRT. Peak, mean and minimal atrial pressures, atrial refractoriness (ERP) in the right atrial appendage and high right atrial lateral wall and monophasic action potential duration at 90% of repolarisation (MAPd90) in the right atrial appendage were assessed during atrial pacing at 500 and 400 ms and after 2 min of pacing at the tachycardia cycle length. Measurements were repeated from the same positions after ventricular pacing at the same cycle lengths and after 2 min of tachycardia. Susceptibility to atrial fibrillation (AF) was assessed by noting whether AF was induced during ERP evaluation.</AbstractText>Atrial pressure showed a statistically significant increase during ventricular pacing compared to baseline. This increase remained substantially unchanged when the tachycardia was induced. A significant reduction in atrial ERP and MAPd90 was also observed during ventricular pacing at all cycle lengths compared to atrial pacing. Two minutes of spontaneous tachycardia were enough to change the atrial ERP and MAPd90 to values significantly lower than those during atrial pacing at the cycle length of tachycardia. During the ERP evaluation AF was induced more often during the tachycardia (28%) than during ventricular (14%) and atrial pacing (0%).</AbstractText>In AVNRT patients, ventricular pacing and reentrant tachycardia significantly increase right atrial pressures and subsequently shorten ERP and MAPd90, leading to an enhanced propensity for AF.</AbstractText> |
9,287 | Incidence, clinical characteristics and outcome of congestive heart failure as the initial presentation in patients with primary hyperthyroidism. | There are limited systematic data on the incidence, clinical characteristics and outcomes of congestive heart failure (CHF) in patients with hyperthyroidism. The aim of this study was to investigate the incidence, clinical characteristics and outcome of CHF as the initial presentation in patients with primary hyperthyroidism.</AbstractText>The prevalence, clinical characteristics and outcome of CHF was studied in 591 consecutive patients (mean (SD) age 45 (1) years, 140 men) who presented with primary hyperthyroidism.</AbstractText>CHF was the presenting condition in 34 patients (5.8%) with hyperthyroidism. The presence of atrial fibrillation at presentation (OR 37.4, 95% CI 9.72 to 144.0, p<0.001) was an independent predictor for the occurrence of CHF. Of the 34 patients with CHF, 16 (47%) had systolic left ventricular dysfunction with left ventricular ejection fraction (LVEF)<50%. They were predominantly male (OR 26.6, 95% CI 2.6 to 272.5, p = 0.006) and had a lower serum thyroxine level (OR 0.93, 95% CI 0.87 to 0.99, p = 0.044) than patients with preserved left ventricular systolic function. In these patients, LVEF (55 (4)% vs 30 (2)%, p<0.001) and New York Heart Association functional class (1.2 (0.1) vs 2.5 (0.2), p<0.001) improved significantly 3 months after achieving euthyroid status. Systolic left ventricular dysfunction (mean (SD) LVEF 38 (4)%) persisted on long-term follow-up in five</AbstractText>no clinical parameter could be identified to predict the occurrence of this persistent cardiomyopathy (p>0.05).</AbstractText>CHF was the initial clinical presentation in approximately 6% of patients with hyperthyroidism, and half of them had left ventricular systolic dysfunction. Symptoms of CHF subsided and LVEF improved after treatment for hyperthyroidism. Nonetheless, one-third of these patients developed persistent dilated cardiomyopathy.</AbstractText> |
9,288 | EuroHeart Failure Survey II (EHFS II): a survey on hospitalized acute heart failure patients: description of population. | The objective of the EuroHeart Failure Survey II (EHFS II) was to assess patient characteristics, aetiology, treatment, and outcome of acute heart failure (AHF) in Europe in relation to the guidelines on the diagnosis and treatment of AHF published by the European Society of Cardiology.</AbstractText>Patients hospitalized for AHF were recruited by 133 centres in 30 European countries. Three thousand five hundred and eighty patients were entered into the database by the end of August 2005. Mean age was 70 years, and 61% of patients were male. New-onset AHF (de novo AHF) was diagnosed in 37%, of which 42% was due to acute coronary syndromes (ACS). Clinical classification according to the guidelines divided AHF patients into (i) decompensated HF (65%), (ii) pulmonary oedema (16%), (iii) HF and hypertension (11%), (iv) cardiogenic shock (4%), and (v) right HF (3%). Coronary heart disease, hypertension, and atrial fibrillation were the most common underlying conditions. Arrhythmias, valvular dysfunction, and ACS were each present as precipitating factor in one-third of cases. Preserved left ventricular ejection fraction (> or =45%) was observed in 34%. Valvular disorders were common, especially mitral regurgitation (MR) which was reported on echocardiography in 80% of patients. Median length of stay was 9 days, and in-hospital mortality 6.7%. At discharge, 80% of patients were on angiotensin-converting enzyme-inhibitors or angiotensin receptor blockers, whereas 61% were taking beta-blocker medication.</AbstractText>Decompensated HF is the most common clinical presentation of AHF patients. More than one-third of AHF patients do not have a previous history of HF, and new-onset HF is often caused by ACS. Preserved systolic function is found in a substantial proportion of the patients. The prevalence of valvular dysfunction is strikingly high and contributes to the clinical presentation. The EHFS II on AHF verified that the use of evidence-based HF medication was well adopted to clinical practice.</AbstractText> |
9,289 | Outcome of cardiopulmonary resuscitation in the intensive care units of a university hospital. | The purpose of this study is to evaluate the demographic characteristics of patients who suffered cardiac arrest in our ICUs and to identify those factors influencing outcome after resuscitation following cardiac arrest. We reviewed the records of all patients who underwent CPR in the two ICUs at the Georg-August University Hospital Goettingen, Germany from 1 January, 1999 to 31 December, 2003. During the study period 169 patients underwent CPR and 80 of the 169 patients survived to hospital discharge, giving a survival to hospital discharge rate of 47.3%. The initial monitored rhythm recorded at the time of arrest was asystole in 99 (58.6%) patients, ventricular tachycardia/fibrillation in 59 (34.9%) and pulseless electrical activity in 7 (4.1%) patients. The respective survival rates were 46 (54.8%), 31 (36.9%) and 5 (6.0%) to hospital discharge. Of the 80 patients that survived to hospital discharge 75 (93.8%) achieved good cerebral recovery (CPC 1 or 2) and were alert and fully oriented on discharge; 4 patients (5.0%) were severely disabled (CPC 3), while 1 (1.2%) remained unconscious and was reported dead five days after discharged to another local hospital. Illness severity as assessed by SAPS II score on admission was 38.8 +/- 16.0. None of our patients with > 40 SAPS II score 24 hours after CPR survived to be discharged from the ICU. Our study showed that nearly half the patients that had cardiac arrest in our hospital ICUs had a favourable outcome despite initial rhythms that are traditionally associated with a poor outcome. This confirms that good results are achievable in these groups of patients. |
9,290 | Feasibility of basic emergency medical technicians to perform selected advanced life support interventions. | Emergency medical technician-basic (EMT-B) providers often provide the initial care to victims of out-of-hospital cardiac arrest. While automated external defibrillators enable EMT-B providers to deliver rescue shocks, patients in cardiac arrest may require additional interventions that EMT-B providers may not presently deliver. We sought to evaluate the feasibility of training EMT-B providers to provide additional cardiac resuscitation procedures using the laryngeal mask airway (LMA) and intraosseous (IO) access.</AbstractText>In this prospective observational study, we trained 18 EMT-B providers to use the LMA and IO drill (EZ-IO) in a three-hour educational session. Working in two-person teams, the rescuers performed a simulated ventricular fibrillation resuscitation. We evaluated placement success as well as elapsed time to placement of the LMA and EZ-IO.</AbstractText>EMT-B providers successfully placed the LMA in 14 of 18 scenarios (78%; 95% confidence interval, 52% to 94%), with a mean of two attempts for placement. Subjects successfully placed the EZ-IO in 17 of 18 scenarios (94%; 95% confidence interval, 73% to 100%), all on the first attempt. The median time to LMA placement following the third shock was 109 seconds (interquartile range, 58-158) and the median time to EZ-IO placement was 72 seconds (interquartile range, 50-93) after LMA placement.</AbstractText>EMT-B providers demonstrated moderate success in performing advanced-level cardiac resuscitation interventions. These observations suggest potential for expanding the role of basic-level rescuers in cardiopulmonary resuscitation.</AbstractText> |
9,291 | Prognostic implications of preoperative atrial fibrillation in patients undergoing aortic valve replacement: is there an argument for concomitant arrhythmia surgery? | The prognostic significance of preoperative atrial fibrillation (AF) at the time of aortic valve replacement is unknown, as is the potential role for concomitant arrhythmia surgery.</AbstractText>We performed a cohort comparison of patients with preoperative AF (n = 129) and preoperative sinus rhythm (SR, n = 252) undergoing aortic valve surgery between 1993 and 2002; patients were matched for age, gender, and left ventricular ejection fraction. Follow-up (mean interval, 4.5 years) was 98% complete. Primary endpoints were late cardiac and all-cause mortality, as well as major adverse cardiac or cerebrovascular event.</AbstractText>Patients with preoperative AF presented with more severe congestive heart failure (p = 0.03) and more often had significant tricuspid regurgitation (p = 0.01) preoperatively. They also had worse late survival (risk ratio [RR] for death = 1.5, p = 0.03) with 1-, 5-, and 7-year survival rates substantially reduced at 94%, 87%, and 50%, respectively, for those in AF versus 98%, 90%, and 61% for patients in sinus rhythm preoperatively. Individuals in AF had a greater probability of subsequent rhythm-related intervention (RR = 4.7, p = 0.0002), and more frequently developed congestive heart failure (25% vs 10%, p = 0.005) and stroke (16% vs 5%, p = 0.005). By multivariable analysis, preoperative AF was an independent predictor of late adverse cardiac and cerebrovascular events, but not late death.</AbstractText>Performance of concomitant arrhythmia surgery in patients undergoing aortic valve surgery may reduce late morbidity; however, its potential impact on late mortality in this high-risk subset of patients remains unclear.</AbstractText> |
9,292 | Prognostic significance of left atrial size in patients with hypertrophic cardiomyopathy (from the Italian Registry for Hypertrophic Cardiomyopathy). | This study assessed left atrial (LA) dimension as a potential predictor of outcome in hypertrophic cardiomyopathy (HC). From the Italian Registry for Hypertrophic Cardiomyopathy, 1,491 patients (mean age 47 +/- 17 years; 61% men; 19% obstructive), followed for 9.4 +/- 7.4 years after the initial echocardiographic evaluation, constituted the study group. The mean LA transverse dimension was 43 +/- 9 mm and was larger in patients with severe symptoms (48 +/- 9 mm for New York Heart Association classes III and IV vs 42 +/- 9 mm for classes I and II, p <0.001), atrial fibrillation (47 +/- 9 vs 42 +/- 8 mm in sinus rhythm, p <0.001), and left ventricular outflow obstruction (46 +/- 9 mm for >or=30 mm Hg at rest vs 42 +/- 9 mm for <30 mm Hg at rest, p <0.001). On univariate analysis, each 5-mm increase in LA size was associated with a hazard ratio (HR) of 1.2 for all-cause mortality (p <0.0001). On multivariate analysis, a LA dimension >48 mm (the 75th percentile) had a HR of 1.9 for all-cause mortality (p = 0.008), 2.0 for cardiovascular death (p = 0.014), and 3.1 for death related to heart failure (p = 0.008) but was unassociated with sudden death (p = 0.81). Similar results were obtained after the exclusion of patients with atrial fibrillation (HR 1.7, p = 0.008) or outflow obstruction (HR 1.8, p = 0.003). The predictive power of LA dimension >48 mm was also validated in an independent HC cohort from the United States, with similar HRs (1.8 for all-cause mortality, p = 0.019). In conclusion, in a large cohort of patients with HC from a nationwide registry, a marked increase in LA dimension were predictive of long-term outcome, independent of co-existent atrial fibrillation or outflow obstruction. LA dimension is a novel and independent marker of prognosis in HC, particularly relevant to the identification of patients at risk for death related to heart failure. |
9,293 | Distribution and prognostic significance of QT intervals in the lowest half centile in 12,012 apparently healthy persons. | The presence of an abnormally short QT interval has been noted among survivors of idiopathic ventricular fibrillation and among close relatives of victims of unexplained sudden death. Most reported cases have had rate-corrected QT (QTc) intervals of <300 ms. The prevalence of such values in the community has not been documented. We reviewed the electrocardiograms (ECGs) of 12,012 subjects who underwent routine medical examinations for occupational reasons. The QT interval was measured by 2 physicians in all cases, and QTc interval was calculated. All ECGs with QTc values in the lowest 5% were reviewed by 2 cardiologists expert in QT analysis, and the QT measurement was corrected if necessary. Information about subsequent survival was obtained from the case file or from public records. In the lowest 1/2 centile, the distribution of QTc values continued to follow a normal pattern without evidence of a distinct subpopulation of low values. The shortest QTc encountered was 335 ms. Information about subsequent survival was available for 36 of the 60 subjects with the lowest 1/2 centile of QTc values. None of these subjects died during the 7.9 +/- 4.5 years subsequent to the ECG that demonstrated the short QT interval. In conclusion, a QTc interval of <or=330 ms is extremely rare in healthy subjects, and the presence of a QT interval in the lowest 1/2 centile of the normal range does not imply a significant risk of sudden death. |
9,294 | A comparative analysis of short- and long-term outcomes after ventricular fibrillation out-of-hospital cardiac arrest in patients with ischemic and nonischemic heart disease. | Although ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) occurs primarily in the setting of severe ischemic heart disease (IHD), a significant proportion of events occurs in patients who do not have severe IHD. The relative effect of IHD on survival after VF OHCA is unknown. All residents of Rochester, Minnesota, who presented with a VF OHCA from November 1990 to December 2004, treated by emergency medical services, were included in the study. During the study, emergency medical services treated 208 patients (64.1 +/- 13.6 years of age) for VF OHCA, with an average call-to-shock time of 6.3 +/- 1.8 minutes. Of these patients, 156 had IHD and 39 had non-IHD. In 13, the underlying heart disease was unknown. Eighty-seven patients (41.8%) survived to hospital discharge with neurologic recovery (66 with IDH [42%] vs 21 with non-IHD [54%], p = 0.211)]. Five-year survival was 79 +/- 6% for patients with IHD versus 100% for those with non-IHD (p = 0.047). After adjustment for other patient characteristics, IHD was not predictive of 5-year survival (hazard ratio [HR] 2.2, 95% confidence interval [CI] 0.7 to 9.8, p = 0.177). Variables associated with poor outcomes included age >65 years (HR 4.9, 95% CI 2.0 to 13.4, p = 0.0003), ejection fraction <0.35% (HR 3.0, 95% CI 1.3 to 7.3, p = 0.012), and hypertension (HR 4.9, 95% CI 1.4 to 16.3, p = 0.001). In patients with IHD, use of an implantable cardioverter-defibrillator (HR 0.32, 95% CI 0.16 to 0.88, p = 0.024) and statin therapy (HR 0.68, 95% CI 0.17 to 0.73, p = 0.001) were associated with decreased mortality. In conclusion, compared with patients with non-IHD, those with IHD had similar short- and long-term survival rates. Long-term survival in patients with IHD was primarily influenced by other co-morbid conditions. Nonetheless, in patients with IHD, use of an implantable cardioverter-defibrillator and statin therapy were associated with higher long-term survival rates. |
9,295 | ST-segment abnormalities and premature complexes are predictors of new-onset atrial fibrillation: the Niigata preventive medicine study. | Left ventricular hypertrophy is a known risk factor for atrial fibrillation (AF). However, it is not well understood whether other electrocardiogram abnormalities are associated with development of AF.</AbstractText>This was a community-based cohort study based upon a database of annual health examinations. We included 63,386 subjects aged > or = 50 years, without baseline AF (including atrial flutter), structural heart disease, or heart failure, who completed the annual examination during a 10-year follow-up period (1991-2002). The electrocardiographic risk factors for AF were studied in the subjects.</AbstractText>Atrial fibrillation developed in 873 subjects. Age, male sex, body mass index, hypertension, systolic and diastolic blood pressure, and diabetes were significant risk factors for the development of AF. In multivariable logistic regression analysis adjusted for these risk factors, electrocardiographic left ventricular hypertrophy (odds ratio [OR], 1.43), ST-segment abnormality without left ventricular hypertrophy (OR, 1.89), and the presence of premature complexes during a 10-second recording (OR, 2.89) were significantly associated with AF, whereas either right (OR, 0.84) or left bundle branch block (OR, 0.96) was unrelated. The risk for AF increased progressively with the severity of both ST-segment change and premature complexes.</AbstractText>ST-segment abnormality and comparably high-frequency premature complexes were each associated with increased risk for the development of AF. These electrocardiographic findings may be useful to stratify high-risk subjects for new-onset AF.</AbstractText> |
9,296 | A history of heart failure predicts arrhythmia treatment efficacy: data from the Antiarrythmics versus Implantable Defibrillators (AVID) study. | In survivors of life-threatening ventricular tachycardia (VT), a history of CHF (HxCHF) before the VT episode may provide different prognostic information than their measured left ventricular ejection fraction (LVEF).</AbstractText>We evaluated outcomes from patients in the AVID study. Patients were included in the study if they presented with ventricular fibrillation, VT with syncope or VT with hemodynamic compromise, and LVEF < or = 40%. Treatment options included implantable cardioverter defibrillator (ICD) or antiarrhythmic drugs (AAD), usually amiodarone.</AbstractText>As expected, a HxCHF is associated with an increased and high risk of arrhythmic and nonarrhythmic death. However, an interaction was observed between arrhythmia treatment (ICD or AAD) and HxCHF status: the survival advantage with an ICD, as compared with AAD therapy, is largely restricted to HxCHF patients.</AbstractText>The ICD is no better than AAD therapy in preventing arrhythmic death in patients with no HxCHF. In this data set, a HxCHF is somewhat more accurate in predicting prognosis and the response to therapy than a reduced LVEF.</AbstractText> |
9,297 | Quantification of the risk and predictors of hyperkalemia in patients with left ventricular dysfunction: a retrospective analysis of the Studies of Left Ventricular Dysfunction (SOLVD) trials. | Limited data are available to predict the occurrence of hyperkalemia. Risk assessment is complicated by the lack of consistency of definition between trials.</AbstractText>We conducted a retrospective analysis of the SOLVD to evaluate the incidence of hyperkalemia and the value of several baseline characteristics as predictors of hyperkalemia in patients with left ventricular dysfunction.</AbstractText>The incidence of hyperkalemia was 6.0% and 1.1% using a definition of > or = 5.5 and > or = 6.0 mmol/L, respectively. Independent predictors of hyperkalemia (> or = 5.5 mmol/L) were randomization to enalapril, baseline serum creatinine, serum potassium, New York Heart Association functional class III or IV, a history of diabetes, and atrial fibrillation (all P < .05). The use of loop diuretics was also associated with an increased risk of hyperkalemia but only in patients included in the SOLVD prevention trial. Similar results were obtained when renal function was evaluated using the estimated creatinine clearance.</AbstractText>The definition of hyperkalemia is important when evaluating its incidence in clinical trials. Renal dysfunction, baseline serum potassium, diabetes, atrial fibrillation, New York Heart Association functional class, and treatment with an angiotensin-converting enzyme inhibitor are factors associated with the development of hyperkalemia in patients with left ventricular dysfunction. More specifically, our results suggests that before initiating drugs that can cause hyperkalemia in patients with heart failure, a strong consideration should be given to calculate creatinine clearance and that patients with a creatinine clearance < 60 mL/min should undergo a close monitoring of their serum potassium to prevent the development of hyperkalemia.</AbstractText> |
9,298 | [In-hospital resuscitation. Concept of first-responder resuscitation using semi-automated external defibrillators (AED)]. | The prognosis after in-hospital resuscitation has not significantly improved in the last 40 years. This account presents the results over a three-year period of a hospital-wide emergency plan which implements the use of an automated external defibrillator (AED) by the first responder to the emergency call.</AbstractText>15 "defibrillator points" were installed, which could be reached within 30 s from all wards, out-patient departments and other areas, thus making them accessible for immediate defibrillator application. The hospital personnel is trained periodically in the alarm sequence, cardiopulmonary resuscitation and use of the defibrillator. Data on 57 patients who had sustained a cardiac arrest were prospectively recorded and analysed.</AbstractText>In 46 patients (81%) the "on-the-spot" personnel (first-responder) was able to apply AED before arrival of the hospital's resuscitation team. Mean period between arrest alarm and activation of the AED was 2.2 (0.7-4.7) min. Ventricular fibrillation or ventricular tachyarrhythmia was recorded in 40 patients, making immediate shock delivery by AED possible. Restoration of the circulation was achieved in 23 (80%) of the patients and 20 (50%) were discharged home, 17 (43%) without neurological deficit. The high proportion of first-responder AED applications and evaluation of the personnel training indicate a wide acceptance of the emergency plan among the personnel.</AbstractText>An immediate resuscitation plan consisting of an integrated programme of early defibrillation is feasible and seems to achieve an improved prognosis for patients who have sustained an in-hospital cardiac arrest.</AbstractText> |
9,299 | Outcome of cardiopulmonary resuscitation in intensive care units in a university hospital. | The purpose of this study is to evaluate the demographic characteristics of patients who suffered cardiac arrest in our intensive care units (ICUs) as well as to identify those factors influencing outcome after resuscitation following cardiac arrest.</AbstractText>We reviewed the records of all patients who underwent cardiopulmonary resuscitation (CPR) in our ICUs at the Georg-August University Hospital, Goettingen, Germany, from January 1, 1999 to December 31, 2003.</AbstractText>One hundred and sixty-nine patients underwent CPR. Severity of illness assessed by SAPS II score on admission was 51.8+/-18.5 (predicted mortality 46.6%). The initially monitored rhythm at the time of arrest was asystole in 51 (30.2%) patients. Ventricular tachycardia/fibrillation (VT/VF) was recorded in 65 (38.5%) and pulseless electrical activity in 49 (29.0%) patients. Twenty (23.8%), 28 (33.3%) and 33 (39.3%) patients with initially recorded asystole, VT/VF and pulseless electrical activity (PEA) rhythms, respectively, survived to ICU discharge. Eighty of the 169 patients survived to hospital discharge giving a survival rate of 47.3%. The highest ICU mortality was seen in patients admitted for neurosurgery (80%) followed by major vascular surgery (77.8%), non-surgical patients (67.4%) and patients with severe sepsis (66.7%). The occurrence of cardiac arrest within the first 24h was associated with a significantly lower ICU mortality compared to a later incident. At hospital discharge 66 patients (82.5% of the survivors) achieved good cerebral recovery, 12 patients (15.0%) were severely disabled (CPC 3) while 2 (2.5%) remained unconscious.</AbstractText>Several factors affect the outcome from CPR. However, quicker triage to ICU, closer monitoring along with prompt intervention might minimise the consequences of cardiac arrest and its complications.</AbstractText> |
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