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9,100 | Cost-effectiveness of automated external defibrillators in public places: con. | To discuss the clinical effectiveness, public health impact and cost-effectiveness of public access defibrillation.</AbstractText>High rates of survival from prehospital ventricular fibrillation have been documented in patients treated by first responders using automated external defibrillators. The recent Public Access Defibrillation trial demonstrated a doubling of cardiac arrest survival in community units where volunteers trained in cardiopulmonary resuscitation were additionally equipped with automated external defibrillators. The cost-effectiveness analysis of the Public Access Defibrillation trial has not yet been published, and previous analyses have lacked full data on cost, outcome, or both. Data from many sources indicate that automated external defibrillator placement at sites with an expected rate of one cardiac arrest per defibrillator per 5 years, as recommended by the American Heart Association, addresses only around 1-2% of prehospital arrests, and will have a minimal impact on population survival.</AbstractText>While highly targeted provision of automated external defibrillators in areas of greatest risk, such as casinos and airports, may be cost-effective, it will have little impact at a population level. Provision of more widespread public access defibrillation to sites with lower incidence of cardiac arrest is unlikely to be cost-effective, and may represent poorer value for money than alternative healthcare interventions in coronary artery disease.</AbstractText> |
9,101 | Gender differences in in-hospital mortality and mechanisms of death after the first acute myocardial infarction. | There are conflicting data about gender differences in short-term mortality after acute myocardial infarction (AMI) after adjusting for age and other prognostic factors. Therefore, we investigated the risk profile, clinical presentation, in-hospital mortality and mechanisms of death in women and men after the first AMI.</AbstractText>The data were obtained from a chart review of 3382 consecutive patients, 1184 (35%) women (69.7+/-10.9 years) and 2198 (65%) men (63.5+/-11.8 years) with a first AMI. The effect of gender and its interaction with age, risk factors and thrombolytic therapy on overall mortality and mechanisms of death were examined using logistic regression.</AbstractText>Unadjusted in-hospital mortality was higher in women (OR 1.77, 95% CI 1.47-2.15). Adjustment that included both age only and age and other baseline differences (hypertension, diabetes mellitus, hypercholesterolemia, smoking, AMI type, AMI site, mean peak CK value, thrombolytic therapy) decreased the magnitude of the relative risk of women to men but did not eliminate it (OR 1.26, 95% CI 1.03-1.54 and OR 1.31 95% CI 1.03-1.66, respectively). Multivariate analysis revealed that female gender was an independent predictor of in-hospital mortality after the first AMI. Women were dying more often because of mechanical complications - refractory pulmonary edema and cardiogenic shock (P=0.02) or electromechanical dissociation (P=0.03), and men were dying mostly by arrhythmic death, primary ventricular tachycardia/fibrillation (P=0.002). Female gender was independently associated with mechanical death (OR 1.56, 95% CI 1.35-2.58; P=0.01) and anterior AMI was independently associated with arrhythmic death (OR 0.54, 95% CI 0.34-0.86; P=0.01).</AbstractText>Our results demonstrate significant differences in mechanisms of in-hospital death after the first AMI in women and men, suggesting the possibility that higher in-hospital mortality in women exists primarily because of the postponing AMI death due to the gender-related differences in susceptibility to cardiac arrhythmias following acute coronary events.</AbstractText> |
9,102 | Prediction of intrapulmonary right to left shunt with left atrial size in patients with liver cirrhosis. | We screened a large number of liver transplant candidates with contrast echocardiography to detect intrapulmonary right to left shunt (IPS). We found that IPS is frequently present in patients with left atrial enlargement. This finding raises a question concerning the correlation between IPS and left atrial size in patients with liver cirrhosis.</AbstractText>The aim of this prospective study was to evaluate the possible correlation between left atrial size and IPS in patients with liver cirrhosis.</AbstractText>Adult patients (>18 years old) with documented liver cirrhosis underwent trans-thoracic contrast echocardiography with agitated saline. Left atrial dimension was measured by M-mode echocardiography. Stroke volume was calculated using left ventricular M-mode echocardiography. Patients with atrial fibrillation, intracardiac shunt, congenital heart defects, valvular heart disease and diastolic dysfunction were excluded.</AbstractText>A total of 92 patients met all study criteria. Of these, 39 (42.3%) had IPS. Cardiac output was significantly greater in patients with IPS compared with those without IPS (5.68 +/- 0.83 L/min vs 4.75 +/- 0.76 L/min, P < 0.01). In a multi-variable model, after adjustment for body surface area and body mass index, left atrial enlargement was the strong predictor of IPS (area under the curve = 0.66) but when controlling for cardiac output, left atrial size was not an independent predictor of IPS.</AbstractText>In the context of liver cirrhosis, patients with IPS have greater cardiac output compared with those without shunt. Left atrial enlargement, which reflects one aspect of increased cardiac output, is an indirect marker of IPS and greater left atrial dimension is associated with the presence of intrapulmonary right-to-left shunt.</AbstractText> |
9,103 | Innovative approaches to anti-arrhythmic drug therapy. | Normal cardiac function requires an appropriate and regular beating rate (cardiac rhythm). When the heart rhythm is too fast or too slow, cardiac function can be impaired, with derangements that vary from mild symptoms to life-threatening complications. Irregularities, particularly those involving excessively fast or slow rates, constitute cardiac 'arrhythmias'. In the past, drug treatment of cardiac arrhythmias has proven difficult, both because of inadequate effectiveness and a risk of serious complications. However, a variety of recent advances have opened up exciting possibilities for the development of novel and superior approaches to arrhythmia therapy. This article will review recent progress and future prospects for treating two particularly important cardiac arrhythmias: atrial fibrillation and ventricular fibrillation. |
9,104 | Ventricular fibrillation due to severe mitral valve prolapse. | Mitral valve prolapse usually has a good prognosis. However, an association between mitral valve prolapse and atrial and ventricular arrhythmias has been described. This case presents a patient who was admitted after cardiac resuscitation due to ventricular fibrillation. A severe mitral valve prolapse was the only pathology found. |
9,105 | A comparison of electrically induced cardiac arrest with cardiac arrest produced by coronary occlusion. | The present study was undertaken to compare an animal model of electrically induced VF with ischemically induced VF. In a preponderance of models of cardiac arrest and resuscitation in intact animals, ventricular fibrillation (VF) is induced by an alternating current delivered directly to the epicardium or endocardium. Yet, the applicability of such animal models has been challenged for it is not an electrical current alone but rather a current generated in the ischemic myocardium that triggers VF. Accordingly, a potentially more clinically relevant model was investigated in which spontaneous VF followed acute myocardial ischemia.</AbstractText>Twenty anesthetized pigs were randomized to either electrical fibrillation or myocardial ischemia following transient occlusion of the left anterior descending (LAD) coronary artery.</AbstractText>VF was untreated for 7 min in both models after which mechanical ventilation and precordial compression were begun. Defibrillation was attempted after 5 min of CPR in both groups. VF appeared within 5.7+/-2.0 min of LAD occlusion.</AbstractText>A significant increase in the number of post-resuscitation premature ventricular beats and recurrent VF followed ROSC and a significantly greater number of shocks was required for restoration of spontaneous circulation (ROSC) after LAD occlusion. Nevertheless, early post-resuscitation myocardial dysfunction, neurological recovery and 72 h survival were indistinguishable between the two models.</AbstractText> |
9,106 | Relation of arterial stiffness to left ventricular diastolic function and cardiovascular risk prediction in patients > or =65 years of age. | There is a paucity of data regarding the relation between the various noninvasive indexes of arterial stiffness and left ventricular diastolic function. In 188 subjects aged > or =65 years (mean 75 +/- 5; 71% men), the concordance and strength of the association between measures of arterial stiffness and left ventricular diastolic function were evaluated. Indexes of arterial stiffness (brachial and aortic pulse pressure [PP], carotid-femoral pulse-wave velocity [PWV], and augmentation pressure [AP]) were measured using applanation tonometry. Diastolic function was classified in terms of instantaneous diastolic function grade and quantitated as left atrial volume, a measure of chronic diastolic burden. Risk for new cardiovascular events was estimated using a validated clinical echocardiographic risk algorithm. Aortic and brachial PP, PWV, and AP were correlated positively with left atrial volume and diastolic function grade. After adjusting for age, gender, and clinical and echocardiographic covariates, 1-SD increases in aortic PP, brachial PP, PWV, and AP were associated with 6%, 6%, 4%, and 4% increases in indexed left atrial volume, respectively. Similarly, 1-SD increases in aortic PP, brachial PP, and AP were associated with 84%, 81%, and 83% increased risk for diastolic dysfunction, respectively (all p <0.04). PWV and aortic and brachial PP were superior to AP in discriminating subjects with the highest risk of having new cardiovascular events (5-year risk >50%; area under receiver-operating characteristic curve 0.67, 0.67, 0.70, and 0.56, respectively; p <0.05). In conclusion, increased arterial stiffness was associated with more severe left ventricular diastolic dysfunction, although the strength of the association varied according to the specific measure used. Aortic PP, brachial PP, and PWV appeared superior to AP in risk discrimination in this elderly cohort. |
9,107 | P-wave dispersion is increased in pregnancy due to shortening of minimum duration of P: does this have clinical significance? | Most pregnant women complain of palpitation, and various kinds of arrhythmias can be observed during pregnancy. We investigated P-wave and QT dispersion during pregnancy. Healthy pregnant women (n=162) and healthy age-matched, non-pregnant women (n=150) were included. We performed electrocardiography and transthoracic echocardiography and determined serum oestradiol levels in both groups, and performed Holter monitoring in the pregnant group only. Resting heart rate, P-wave dispersion, left ventricular diastolic diameter, left atrial diameter and serum oestradiol levels in the pregnant group were significantly higher than in the control group. Minimum P-wave duration was shorter in the control group than in the pregnant group; however, there was no statistically significant difference in maximum P wavelength and corrected QT dispersion between the groups. No atrial fibrillation was detected in the pregnant group during Holter monitoring. Shortening of the minimum P-wave duration leads to increased P-wave dispersion during pregnancy. In contrast to other pathologies with increased P-wave dispersion, paroxysmal atrial fibrillation is absent in pregnant women; this may be a result of the stable maximum P wavelength that is present during pregnancy. |
9,108 | Modeling cardiac ischemia. | Myocardial ischemia is one of the main causes of sudden cardiac death, with 80% of victims suffering from coronary heart disease. In acute myocardial ischemia, the obstruction of coronary flow leads to the interruption of oxygen flow, glucose, and washout in the affected tissue. Cellular metabolism is impaired and severe electrophysiological changes in ionic currents and concentrations ensue, which favor the development of lethal cardiac arrhythmias such as ventricular fibrillation. Due to the burden imposed by ischemia in our societies, a large body of research has attempted to unravel the mechanisms of initiation, sustenance, and termination of cardiac arrhythmias in acute ischemia, but the rapidity and complexity of ischemia-induced changes as well as the limitations in current experimental techniques have hampered evaluation of ischemia-induced alterations in cardiac electrical activity and understanding of the underlying mechanisms. Over the last decade, computer simulations have demonstrated the ability to provide insight, with high spatiotemporal resolution, into ischemic abnormalities in cardiac electrophysiological behavior from the ionic channel to the whole organ. This article aims to review and summarize the results of these studies and to emphasize the role of computer simulations in improving the understanding of ischemia-related arrhythmias and how to efficiently terminate them. |
9,109 | [Ventricular fibrillation during induction of anesthesia in a patient with polycythemia vera]. | A 53-year-old male patient complained of the pain with bilateral hip area and right hip joint and underwent emergency arthroscopy and drainage. Twenty-eight years before, he had suffered from gout and from his abnormal increase of blood cells was diagnosed as polycythemia vera. The laboratory examination at admission showed a marked increase of hemoglobin (17.7 g x dl(-1)) and hematocrit (69.5%). Immediately before induction of anesthesia, 1000 ml of phlebotomy was performed with large fluid infusion. After induction of anesthesia and oro-tracheal intubation, electrocardiogram (ECG) suddenly showed ventricular fibrillation (Vf). Defibrillation was applied and the ECG recovered to sinus rhythm, but 30 min later, ECG showed Vf, again. The increased blood viscosity with polycythemia might have induced coronary ischemia and fatal arrhythmia in the patient. Vigourous hemodilution before surgery should have been performed as prophylactic management of the cardiac episodes in this patient. |
9,110 | Prevalence of abnormal urinary albumin excretion rate in hypertensive patients with impaired fasting glucose and its association with cardiovascular disease. | The prevalence and significance of microalbuminuria in hypertensive patients with impaired fasting glucose (IFG) has received very little attention. A total of 10,320 hypertensive patients who attended primary care centers were enrolled in this study, and the final analysis was done in 7625 patients: 1459 without IFG (plasma glucose <100 mg/dl), 3010 with IFG (plasma glucose > or =100 mg/dl and <126 mg/dl), and 3156 with type 2 diabetes (plasma glucose >126 mg/dl). Microalbuminuria was determined using the Micro Albustix reactive strip from Bayer (high urinary albumin excretion [UAE]: Albumin/creatinine ratio > or =3.4 mg/mmol). The proportion of patients with high UAE was 39.4, 48.3, and 65.6%, respectively, in the three groups (P < 0.01 for the trend). The differences in UAE between the group with IFG and the group with normal fasting glucose persisted after adjustment for age, gender, systolic BP, fasting plasma glucose, and cardiovascular comorbidity (odds ratio 1.74; 95% confidence interval 1.08 to 2.80). Hypertensive patients with IFG and high UAE showed a higher prevalence of ischemic heart disease, cardiac insufficiency, left ventricular hypertrophy, atrial fibrillation, and renal insufficiency than the group with normal UAE. Global prevalence of cardiovascular conditions was 30.4% in the group with high UAE compared with 21.4% in the group with normal UAE (odds ratio 1.60; 95% confidence interval 1.31 to 1.95). It is concluded that almost half of hypertensive patients with IFG have high UAE and a higher prevalence of associated cardiovascular involvement and renal insufficiency. |
9,111 | Familial idiopathic atrial fibrillation with fetal bradyarrhythmia. | A woman presented at 28 wk gestation with fetal bradycardia 50 bpm, which persisted until 42 wk when an asymptomatic male baby was delivered. Electrocardiograph at 3 wk of age documented an incessant atrial fibrillation with slow ventricular response. He continued to be asymptomatic, but on follow-up at 16 y of age, 24-h Holter monitor showed a heart rate of 23 bpm and pauses of up to 6 s when a VVIR programme endocardial pacing system was employed. ECG carried out on his asymptomatic father showed intermittent atrial fibrillation, again with a slow ventricular response.</AbstractText>Atrial fibrillation is extremely rare in children with normal cardiac structure. Most instances of fetal bradycardia are caused by congenital complete heart block. Other rare causes such as atrial fibrillation with fetal bradycardia need to be considered. This case might be a familial disorder and looks to have a good prognosis.</AbstractText> |
9,112 | Fractionation of memory in medial temporal lobe amnesia. | We report a comprehensive investigation of the anterograde memory functions of two patients with memory impairments (RH and JC). RH had neuroradiological evidence of apparently selective right-sided hippocampal damage and an intact cognitive profile apart from selective memory impairments. JC, had neuroradiological evidence of bilateral hippocampal damage following anoxia due to cardiac arrest. He had anomic and "executive" difficulties in addition to a global amnesia, suggesting atrophy extending beyond hippocampal regions. Their performance is compared with that of a previously reported hippocampal amnesic patient who showed preserved recollection and familiarity for faces in the context of severe verbal and topographical memory impairment [VC; Cipolotti, L., Bird, C., Good, T., Macmanus, D., Rudge, P., & Shallice, T. (2006). Recollection and familiarity in dense hippocampal amnesia: A case study. Neuropsychologia, 44, 489-506.] The patients were administered experimental tests using verbal (words) and two types of non-verbal materials (faces and buildings). Receiver operating characteristic analyses were used to estimate the contribution of recollection and familiarity to recognition performance on the experimental tests. RH had preserved verbal recognition memory. Interestingly, her face recognition memory was also spared, whilst topographical recognition memory was impaired. JC was impaired for all types of verbal and non-verbal materials. In both patients, deficits in recollection were invariably associated with deficits in familiarity. JC's data demonstrate the need for a comprehensive cognitive investigation in patients with apparently selective hippocampal damage following anoxia. The data from RH suggest that the right hippocampus is necessary for recollection and familiarity for topographical materials, whilst the left hippocampus is sufficient to underpin these processes for at least some types of verbal materials. Face recognition memory may be adequately subserved by areas outside of the hippocampus. |
9,113 | [Utility of vasopressin in cardiopulmonary resuscitation]. | Many vasopressants have been studied in cardiopulmonary resuscitation (CPR) to increase cerebral and coronary perfusion. Although there is a debate on the utility of epinephrine, this is the one that has been used historically, above all after verifying that other agents such as norepinephrine, metoxamine or phenylephrine, have not been shown to be more effective. Currently, due to the good experimental results, the use of vasopressin (ADH) in CPR is being evaluated. However there is little (only three studies) and debated evidence based on randomized clinical trials (norepinephrine or ADH) in humans. Once these are reviewed, it can be concluded: The results of the three randomized studies in humans obtain different results regarding the utility of ADH in cardiorespiratory arrest (CRA) secondary to ventricular fibrillation, electro-mechanical dissociation or asystole. More prospective studies are needed to know the role of ADH in prolonged CRA and in asystole, that may be the subgroups that can benefit the most from this drug. The neurological repercussion of a drug in the context of CRA should be evaluated before its inclusion in the CPR guides. |
9,114 | Prognostic value of the Doppler index of myocardial performance in postoperative of coronary artery bypass surgery. | Myocardial Performance Index (MPI) obtained by Doppler echocardiography for the non-geometrical evaluation of systolic and diastolic function has been described as a method for prognostic evaluation in patients with acute myocardial infarction (AMI). Using the same condition, the objective of this study was to evaluate the predictive value of MPI for cardiovascular complications in patients at low risk during the postoperative period of CABG.</AbstractText>Eighty patients submitted to CABG with adequate left ventricular function in the preoperative period were studied, with MPI measured during the first hours postoperatively. Patients were followed until hospital discharge. Statistical analysis included Chi-Square test, Student t test, Mann-Whitney test, and estimation of relative risks with 95% confidence intervals, sensitivity and specificity plus a ROC curve.</AbstractText>The data were evaluated by two independent observers blinded to the clinical data with non-significant intra and interobserver variability. MPI=0.43 was found as the cutoff point, considering patients with a higher probability of postoperative events those who had MPI above 0.43. The relevant events for analysis were AMI (RR 0.87 ci 0.21-3.65), atrial fibrillation (RR 0.65 ci 0.24 - 1.76), other arrhythmias (RR 1.51 ci 0.36-6.33), LV dysfunction (RR 1.74 ci 0.32-9.88), with no association between patients with MPI>0.43 and the occurrence of these events.</AbstractText>No association was found between MPI and cardiovascular complications and longer hospital stay in this group of patients, and this index was considered not adequate as an isolated predictive method.</AbstractText> |
9,115 | Bi-atrial subxiphoid epicardial pacemaker in superior vena cava syndrome. | A patient with a bi-atrial-ventricular permanent pacemaker due to paroxystic atrial fibrillation associated to sinus bradycardia, in chronic use of oral anticoagulant, presented clinical signs of superior vena cava syndrome. Digital subtraction venography showed total obstruction of the right brachiocephalic venous trunk and severe stenosis of the connection of the left trunk to the superior vena cava. The therapeutic approach consisted of complete removal of transvenous system followed by re-implant of the bi-atrial-ventricular system using an epicardial subxiphoid access with fluoroscopic assistance. |
9,116 | Clinical and electrophysiological characteristics of binodal disease. | Although coexistence of atrioventricular conduction disturbances with sick sinus syndrome (SSS), so-called binodal disease (BND), is a frequently encountered disorder, its clinical significance and electrophysiological characteristics remain unknown.</AbstractText>One hundred and seven patients with SSS were divided into BND (n=30) and N-BND groups (n=77). Sinus cycle length, sinus node recovery time (SRT), sino-atrial conduction time (SACT), the number of isolated sinus node electrograms, atrio-His (AH) interval, His-ventricular (HV) interval, intra-atrial conduction time (PA intervals) and QRS width were measured. In addition, the prevalence of bundle-branch block was obtained. The parameters of sino-atrial and intra-atrial conduction were significantly longer in the BND group: SRT (5,070+/-2,628 vs 3,122+/-1,856 ms, p<0.05), SACT (115+/-30 vs 87+/-21 ms, p<0.05), PA intervals (56+/-13 vs 41+/-8 ms, p<0.05). The BND group was more likely to have atrial fibrillation than the N-BND group (83.3% vs 53.2%, p<0.01). HV interval, QRS width and the prevalence of associated bundle-branch block did not differ between the 2 groups.</AbstractText>BND patients not only had sino-atrial and atrioventricular node dysfunction, but also widespread atrial conduction disturbances. Thus, in the clinical setting BND should be categorized as severe SSS.</AbstractText> |
9,117 | Atrial electrophysiological abnormality in patients with Brugada syndrome assessed by P-wave signal-averaged ECG and programmed atrial stimulation. | There is evidence that some patients with Brugada syndrome (BS) exhibit atrial tachyarrhythmias including paroxysmal atrial fibrillation. We investigated whether BS associated not only with vulnerability to ventricular fibrillation, but also with vulnerability to atrial fibrillation.</AbstractText>In 15 patients with BS and Brugada-type electrocardiogram (ECG) (14 men, 1 woman; age 52.8+/-12.9 years) and 15 age-matched control patients (12 men, 3 women; age 50.9+/-18.9 years), the P-wave signal-averaged ECG was recorded, and the filtered P-wave duration was derived from the vector magnitude obtained by X, Y, Z leads. In 11 of the 15 patients with BS and Brugada-type ECG, invasive electrophysiologic testing was conducted. Filtered P-wave duration was significantly increased in patients with BS and Brugada-type ECG in comparison with control subjects (143.2+/-12.9 vs 129.6+/-10.1 ms, p<0.001). Ventricular late potential (root mean square voltage <20 muV in the last 40 ms and <40 muV at a low amplitude signal duration >38 ms) was present in 10 of the 12 BS patients in whom a QRS wave signal-averaged electrogram was also recorded. In all 11 patients with Brugada-type ECG who underwent electrophysiologic testing, sustained atrial fibrillation (>5 min) was induced by 1 or 2 atrial extrastimuli. In 10 of these 11 patients, ventricular fibrillation was also induced by 2 or 3 right ventricular extrastimuli.</AbstractText>The electrical abnormality in BS is not limited to the ventricular level; similar changes occur in the atria. Such abnormal conduction properties could be a substrate for re-entrant atrial tachyarrhythmias.</AbstractText> |
9,118 | Left ventricular remodeling of hypertrophic cardiomyopathy: longitudinal observation in rural community. | The purpose of the present study was to assess the clinical long-term course of hypertrophic cardiomyopathy (HCM) in a rural Japanese cohort.</AbstractText>A total of 137 consecutive HCM patients (mean age at diagnosis: 52+/-13 years) were enrolled. During a follow-up period of 11.4+/-5.7 years, 28 patients died of HCM-related causes. Eleven patients died suddenly, 10 died of progressive heart failure, 6 died of stroke associated with atrial fibrillation and 1 died of a postoperative complication of alcohol septal ablation. For the overall study group, 5-, 10- and 15-year cumulative survival rates were 91%, 88% and 79%, respectively. Although sudden death was the predominant cause of HCM-related death during the follow-up period of <10 years, heart failure death increased after follow-up period of >10 years. Fifteen (13%) of 114 patients who had follow-up echocardiography became ;end-stage' HCM and 8 patients died of severe and refractory heart failure. They already showed minimally dilated left ventricular (LV) dimension and lower LV fractional shortening at initial evaluation.</AbstractText>Although HCM patients in a Japanese rural community showed relatively benign clinical course (the same as cohorts in the developed world), heart failure death because of LV remodeling became equally important to sudden death when they were followed for more than 10 years.</AbstractText> |
9,119 | Antioxidants decrease reperfusion induced arrhythmias in myocardial infarction with ST-elevation. | In myocardial infarctions with ST-segment elevation, ischemia followed by reperfusion (IR) leads to arrhythmia, myocardial stunning and endothelial dysfunction injury by reactive oxygen species (ROS). To determine the impact of ROS, we examined the effect of antioxidant vitamins on biochemical changes and arrhythmias induced by reperfusion before and after therapeutic thrombolysis (Actilyse). As compared with those receiving placebo, in individuals who received antioxidants, there was a significant decrease in premature ventricular beats (100% vs 38%), atrial fibrillation (44% vs 6%), ventricular tachycardia (31% vs 0%), first-degree atrial-ventricular block (44% vs 6%), plasma malondialdehyde at the first hour after initiation of thrombolysis (1.07 +/- 0.10 vs 0.53 +/- 0.10 nmols plasma malondialdehyde/mg protein) and circulating neutrophils after 24 hr after reperfusion. The antioxidant capacity of plasma was increased from 1.89 +/- 0.15 to 3.00 +/- 0.31 units/mg protein and paraoxonase-1 rose from 0.77 +/- 0.08 to 1.27 +/- 0.11 nmol/min/mg protein. These findings suggest that antioxidants might be useful as adjuvants in controlling reperfusion induced arrhythmias following therapeutic alteplase thrombolysis. |
9,120 | Electrocardiographic findings in 888 patients > or =90 years of age. | The oldest old are the fastest growing component of many national populations. No large-scale analysis of electrocardiographic findings in this group exists to date. This study cataloged the frequencies of specific electrocardiographic (ECG) findings in the target population and compared the frequencies of these findings by gender and race. The electrocardiograms of 888 subjects aged > or =90 years presenting for any reason were retrospectively analyzed using standard criteria for 128 separate ECG findings. Left ventricular enlargement (28%), first-degree atrioventricular block (16%), and atrial fibrillation (15%) were the most common abnormalities found in the population as a whole. In contrast to previous studies, which demonstrated a predominance of left-axis deviation, 91% of the electrocardiograms analyzed in our study demonstrated a mean frontal QRS axis ranging from -30 degrees to +90 degrees . Sinus rhythm was observed in 79% of the population. More Caucasians than African-Americans had atrial fibrillation (19% vs 12%, p = 0.004). Women had more normal ECG results than men (6% vs 2%, p = 0.02), and more women demonstrated complete right bundle branch block (13% vs 7%, p = 0.002). In conclusion, few patients aged > or =90 years who have their electrocardiograms recorded at hospitals have completely normal ECG results. The frequencies of some ECG findings in the target population vary by gender and race. |
9,121 | Does the type of out-of-hospital airway interfere with other cardiopulmonary resuscitation tasks? | Out-of-hospital rescuers often perform tracheal intubation (TI) prior to other cardiopulmonary resuscitation (CPR) interventions. TI is a complex and error-prone procedure that may interfere with other key resuscitation tasks. We compared the effects of TI versus esophageal tracheal combitube (ETC) insertion on the accomplishment of other interventions during simulated cardiopulmonary resuscitation.</AbstractText>In this prospective trial using a human simulator, two-paramedic teams simulated resuscitation of a ventricular fibrillation cardiopulmonary arrest using standard Advanced Cardiac Life Support guidelines. In each of two trials, teams used either TI or ETC as the primary airway device. Following delivery of three rescue shocks, we measured time intervals to successful airway placement, intravenous (IV) line insertion, drug administration, delivery of fourth rescue shock and completion of all four tasks. We also measured the total time without chest compressions. We compared task completion times using non-parametric statistics (Wilcoxon signed-ranks test) with a Bonferroni-adjusted p-value of 0.008.</AbstractText>Twenty teams each completed two scenarios. Participants required a median of 172.5 s (IQR: 146.5-225.5) to accomplish all four tasks. Elapsed time to airway placement was significantly less for ETC than TI (median difference 26.5 s (IQR 13-44.5), p=0.002). Time without chest compressions was less for ETC than TI (median difference 8.5 s (IQR 2.5-23.5), p=0.005). There were no differences between ETC and TI in times to IV placement (median difference 23.5 s (IQR -20 to 61), p=0.11), drug delivery (39.5 s (IQR -18 to 63), p=0.07), delivery of fourth rescue shock (39.5 s (IQR -21.5 to 87.5), p=0.07) or completion of all four tasks (33 s (IQR -11 to 74.5), p=0.08).</AbstractText>Compared with TI, ETC reduced time to airway placement and time without chest compressions, but did not affect elapsed times to accomplish other interventions. Additional time differences may be realized if translated to clinical out-of-hospital conditions.</AbstractText> |
9,122 | [Therapeutic success of a prospective cardioversion protocol for persistent atrial fibrillation]. | The best therapeutic approach for persistent atrial fibrillation has yet to be defined. Our aim was to investigate the effects of cardioversion in unselected patients with persistent atrial fibrillation who were treated according to a strict protocol involving pretreatment, cardioversion, and follow-up.</AbstractText>Consecutive patients with persistent atrial fibrillation of at least 1 months' duration were included prospectively in a cardioversion protocol that involved standard antiarrhythmic pretreatment, with amiodarone being offered first, and follow-up.</AbstractText>The study included 295 patients, 87.5% of whom were taking the antiarrhythmic drug amiodarone. Sinus rhythm was restored in 92.5%, with pharmacologic cardioversion occurring in 9.5%. The recurrence rate was 33.5% in the first month and 54.9% by month 12. Antiarrhythmic treatment had to be modified in 10.8% of patients. Independent risk factors for recurrence during the first year after cardioversion were an atrial fibrillation duration greater than one year, previous cardioversion, and left ventricular dilatation. A simple risk scoring system was able to differentiate between subgroups of patients with a low, intermediate or high risk of recurrence in the first year after cardioversion.</AbstractText>Sinus rhythm was maintained for 1 year after effective cardioversion in 45.1% of patients who received homogeneous antiarrhythmic pretreatment. There were few side effects. Recurrence can be predicted using clinical variables such as left ventricular dilatation, arrhythmia duration, and previous cardioversion.</AbstractText> |
9,123 | Pharmacotherapy considerations in advanced cardiac life support. | Cardiac arrest and sudden cardiac death remain major causes of mortality. Early intervention has been facilitated by emergency medical response systems and the development of training programs in basic life support and advanced cardiac life support (ACLS). Despite the implementation of these programs, the likelihood of a meaningful outcome in many life-threatening situations remains poor. Pharmacotherapy plays a role in the management of patients with cardiac arrest, with new guidelines for ACLS available in 2005 providing recommendations for the role of specific drug therapies. Epinephrine continues as a recommended means to facilitate defibrillation in patients with pulseless ventricular tachycardia or ventricular fibrillation; vasopressin is an alternative. Amiodarone is the primary antiarrhythmic drug that has been shown to be effective for facilitation of defibrillation in patients with pulseless ventricular tachycardia or fibrillation and is also used for the management of atrial fibrillation and hemodynamically stable ventricular tachycardia. Epinephrine and atropine are the primary agents used for the management of asystole and pulseless electrical activity. Treatment of electrolyte abnormalities, severe hypotension, pulmonary embolism, acute ischemic stroke, and toxicologic emergencies are important components of ACLS management. Selection of the appropriate drug, dose, and timing and route of administration are among the many challenges faced in this setting. Pharmacists who are properly educated and trained regarding the use of pharmacotherapy for patients requiring ACLS can help maximize the likelihood of positive patient outcomes. |
9,124 | HLa-class II (DRB & DQB1) in Thai sudden unexplained death syndrome (Thai SUDS) families (Lai-Tai families). | Thai Sudden Unexplained Death Syndrome (Thai SUDS), or Lai-Tai, is a major health problem among rural residents of northeastern Thailand. The cause has been identified as a genetic disease. SUDS, a disorder found in Southeast Asia, is characterized by an abnormal electrocardiogram with ST-segment elevation in leads V1-V3, identical to that seen in Brugada Syndrome (Brugada Sign, BS) and sudden death due to ventricular fibrillation and cardiac arrest (represents an arrhythmogenic marker that identifies high-risk for SUDS). SUDS victims have a sleeping disorder (narcolepsy). The HLA-DR locus is tightly associated with narcoleptic Japanese patients and HLA-DR2, DQ haplotypes were also found in Oriental narcoleptic patients. These circumstances prompted us to study the association between the disease and HLA Class II by HLA DNA typing using a PCR-SSO method, with five Thai SUDS families (18 BS-positive subjects as the cases, and 27 BS-negatives as the controls). We found that the HLA-DRB1 *12021 allele was significantly increased in BS-positive subjects (p = 0.02; OR = 4.5), the same as the HLA-DRB1*12021-DQB1 *0301/09 haplotype (p = 0.01; OR = 7.95). Our data suggests that the HLA-DRB1* 12021 allele associated with BS and the HLA-DRB1*12021-DQB1 *0301/09 is a haplotype susceptible to arrhythmogenic markers that can identify a high risk for SUDS. |
9,125 | Terlipressin as an adjunct vasopressor in refractory hypotension after tricyclic antidepressant intoxication. | To report the management of cardiovascular failure refractory to standard catecholamine therapy with terlipressin in a patient with tricyclic antidepressant (TCA) intoxication.</AbstractText>A 41-year-old woman, with suicidal ingestion of 11.25 g amitriptyline and 1500 mg diclofenac, was admitted to the emergency department. After 30 min in ventricular fibrillation, with ongoing CPR, she regained a potentially perfusing rhythm, but with hypotension refractory to standard catecholamine therapy with adrenaline, 2 microg/kg/min (norepinephrine); adrenaline, 1 microg/kg/min (epinephrine) until 55 min after admission. An injection of 1 mg terlipressin restored mean arterial blood pressure >65 mmHg within 10 min. Ten hours after admission to the intensive care unit, catecholamine support could be withdrawn because of a stable haemodynamic state. Within 7 days, all organ function recovered, and the patient regained full neurological function.</AbstractText>Successful management of cardiovascular failure with terlipressin after TCA intoxication refractory to catecholamines suggests a potential role for terlipressin as an adjunct vasopressor in severely hypotensive patients.</AbstractText> |
9,126 | A case of symptomatic coronary artery fistula. | A 57-year-old man presented with dyspnea and presyncope on exertion. He had previously been diagnosed with hypertension, hypercholesterolemia and atrial fibrillation. A soft (grade II/VI), dynamic continuous murmur was noted in the mid precordium.</AbstractText>Electrocardiography, stress echocardiography and coronary angiography.</AbstractText>Right coronary artery to coronary sinus fistula with coronary steal, exertional ischemia and ventricular arrhythmia.</AbstractText>Coil embolization of coronary left ventricular fistula.</AbstractText> |
9,127 | Emergency gastric ulcer complications in elderly. Factors affecting the morbidity and mortality in relation to therapeutic approaches. | In elderly the incidence of the emergency gastric ulcer complications, perforation and bleeding are increasing, with a difficult management of these patients for their concomitant diseases. The aim of this work is to analyze the therapeutical approach of emergency gastric ulcer complications in elderly patients, in order to establish the factors affecting the morbidity and mortality.</AbstractText>Patients older than 70 years, presenting gastric ulcer, observed in a tertiary University Hospital from 1995 to 2003, have been considered for the present study. Two groups of diseases have been examined: ulcer perforation and bleeding ulcer. Age, sex, risk factors, comorbidity, methods of diagnosis, ulcer characteristics, treatment, morbidity, mortality, hospitalization time and follow-up have been considered in each group.</AbstractText>Thirteen elderly patients with perforated gastric ulcer have been observed: 9 (69.2%) females and 4 (30.8%) males with a mean age of 80.5 years (range 70-90). Four patients were hospitalized in suburban hospital with an average time between the diagnosis and the surgery of 36 h, while the remnants were hospitalized directly in our Department with a medium waiting time of about 2 h. The surgical procedures were: simple closure with omentum patch in 11 cases (84.6%), and antrectomy in 2 cases (15.4%), in which the antrum was multiply perforated. Two patients presented an ulcer larger than 2 cm treated with simple suture and omental patch without morbidity and mortality. Three patients (23%) died postoperatively, due to septic shock, ventricular fibrillation and intraoperative massive haemorrhage, 2 of these patients came from other hospitals. Twenty-eight elderly patients with bleeding gastric ulcer have been observed during the same period: 13 (46.4%) females and 15 (53.6%) males with a mean age of 79.6 years (range 71-91). Except 2 patients submitted to endoscopic treatment both with adrenaline injection, all the remnant patients were managed with medical therapy (H2-receptor antagonist or proton pump inhibitors and in 7 patients [24.1%] antihaemorrhage drugs), and clinical observation, with a endoscopic control 3-4 days after from the first endoscopy. One of the 2 patients endoscopically treated developed a ulcer perforation after 11 days, and the other one rebled, without possibility of any kind of treatment due to his instable condition of health. Three patients (10.7%) died during their hospital stay not for causes strictly due to the gastric haemorrhage.</AbstractText>Our results suggest that the early diagnoses and early treatment are 2 basic factor on the prognosis of elderly patients with perforated gastric ulcer. The choice between simple closure, with or without vagotomy, or gastrectomy depends from preoperative and operative health conditions of the patient. In patients with ulcer larger than 2 cm, Graham's technique can be performed safely if the preoperative and intraoperative conditions are favourable. Elderly patients with gastric ulcer bleeding show an high risk of morbidity and mortality, related to the risk factors like non steroid anti-inflammatory drugs (NSAIDs) intake or smoke. Repeated endoscopy and antiulcer drugs can manage the high stage patients of Forrest's classification with a low rate of morbidity and mortality. According to literature surgical treatment should be reserved after the second failure of endoscopic treatment.</AbstractText> |
9,128 | Efficacy of radiofrequency catheter ablation in treatment of elderly patients with supraventricular tachyarrhythmias and ventricular tachycardia. | Radiofrequency catheter ablation was performed in 100 men and 81 women, mean age 78 +/- 5 years, referred for ablation of atrial flutter, supraventricular tachycardia, and ventricular tachycardia, and for ablation of the atrioventricular junction with permanent pacemaker implantation in patients with atrial fibrillation and a rapid ventricular rate not controlled by drug therapy. A hematoma in 1 of 182 ablation procedures (<1%) was the only complication. Radiofrequency catheter ablation was successful in treating 63 of 70 patients (90%) with atrial flutter, in treating 60 of 66 patients (91%) with supraventricular tachycardia, in treating 2 of 2 patients (100%) with ventricular tachycardia, and in ablating the atrioventricular junction in 43 of 44 patients (98%) with atrial fibrillation and a rapid ventricular rate not controlled by drug therapy. |
9,129 | Cardiac effects of postconditioning depend critically on the duration of index ischemia. | Postconditioning (POC) is known as the phenomenon whereby brief intermittent ischemia applied at the onset of reperfusion following index ischemia limits myocardial infarct size. Whereas there is evidence that the algorithm of the POC stimulus is an important determinant of the protective efficacy, the importance of the duration of index ischemia on the outcome of the effects of POC has received little attention. Pentobarbital sodium-anesthetized Wistar rats were therefore subjected to index ischemia produced by coronary artery occlusions (CAO) of varying duration (15-120 min) followed by reperfusion, without or with postconditioning produced by three cycles of 30-s reperfusion and reocclusion (3POC30). 3POC30 limited infarct size produced by 45-min CAO (CAO45) from 45 +/- 3% to 31 +/- 5%, and CAO60 from 60 +/- 3% to 47 +/- 6% (both P < or = 0.05). In contrast, 3POC30 increased infarct size produced by CAO15 from 3 +/- 1% to 19 +/- 6% and CAO30 from 36 +/- 6 to 48 +/- 4% (both P < or = 0.05). This deleterious effect of 3POC30 was not stimulus sensitive because postconditioning with 3POC5 and 3POC15 after CAO30 also increased infarct size. The cardioprotection by 3POC30 after CAO60 was accompanied by an increased stimulation of Akt phosphorylation at 7 min of reperfusion and a 36% lower superoxide production, measured by dihydroethidium fluorescence, after 2 h of reperfusion. Consistent with these results, cardioprotection by 3POC30 was abolished by phosphatidylinositol-3-OH-kinase inhibition, as well as nitric oxide (NO) synthase inhibition. The deleterious effect of 3POC30 after CAO15 was accompanied by an increased superoxide production with no change in Akt phosphorylation and was not affected by NO synthase inhibition. In conclusion, the effect of cardiac POC depends critically on the duration of the index ischemia and can be either beneficial or detrimental. These paradoxical effects of POC may be related to the divergent effects on Akt phosphorylation and superoxide production. |
9,130 | Downregulation of connexin40 and increased prevalence of atrial arrhythmias in transgenic mice with cardiac-restricted overexpression of tumor necrosis factor. | Atrial arrhythmias, primarily atrial fibrillation, have been independently associated with structural remodeling and with inflammation. We hypothesized that sustained inflammatory signaling by tumor necrosis factor (TNF) would lead to alterations both in underlying atrial myocardial structure and in atrial electrical conduction. We performed ECG recording, intracardiac electrophysiology studies, epicardial mapping, and connexin immunohistochemical analyses on transgenic mice with targeted overexpression of TNF in the cardiac compartment (MHCsTNF) and on wild-type (WT) control mice (age 8-16 wk). Atrial and ventricular conduction abnormalities were always evident on ECG in MHCsTNF mice, including a shortened atrioventricular interval with a wide QRS duration secondary to junctional rhythm. Supraventricular arrhythmias were observed in five of eight MHCsTNF mice, whereas none of the mice demonstrated ventricular arrhythmias. No arrhythmias were observed in WT mice. Left ventricular conduction velocity during apical pacing was similar between the two mouse groups. Connexin40 was significantly downregulated in MHCsTNF mice. In contrast, connexin43 density was not significantly altered in MHCsTNF mice, but rather dispersed away from the intercalated disks. In conclusion, sustained inflammatory signaling contributed to atrial structural remodeling and downregulation of connexin40 that was associated with an increased prevalence of atrial arrhythmias. |
9,131 | Amiodarone-induced thyroid dysfunction in clinical practice. | Amiodarone is a potent class III anti-arrhythmic drug used in clinical practice for the prophylaxis and treatment of many cardiac rhythm disturbances, ranging from paroxismal atrial fibrillation to life threatening ventricular tachyarrhythmias. Amiodarone often causes changes in thyroid function tests mainly related to the inhibition of 5'-deiodinase activity resulting in a decrease in the generation of T3 from T4 with a consequent increase in rT3 production and a decrease in its clearance. In a group of amiodarone-treated patients there is overt thyroid dysfunction, either amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH). AIT is primarily related to excess iodine-induced thyroid hormone synthesis in an abnormal thyroid gland (type I AIT) or to amiodarone-related destructive thyroiditis (type II AIT). The pathogenesis of AIH is related to a failure to escape from the acute Wolff-Chaikoff effect due to defects in thyroid hormonogenesis, or, in patients with positive thyroid autoantibody test, to concomitant Hashimoto's thyroiditis. Both AIT and AIH may develop either in apparently normal thyroid glands or in glands with preexisting, clinically silent abnormalities. AIT is more common in iodine-deficient regions of the world, whereas AIH is usually seen in iodine-sufficient areas. In contrast to AIH, AIT is a difficult condition to diagnose and treat, and discontinuation of amiodarone is usually recommended. In this review we analyse, according to data from current literature, the alterations in thyroid laboratory tests seen in euthyroid patients under treatment with amiodarone and the epidemiology and treatment options available of amiodarone-induced thyroid dysfunctions (AIT and AIH). |
9,132 | [Do we use digitalis properly in the management of elderly patients suffering from the signs of chronic heart failure?]. | The indications of digoxin therapy has been significantly narrowed and also the effective target therapeutic blood level has been decreased (0.9 micromol/L) compared to the previously desired one.</AbstractText>In this retrospective trial the data of 60 consecutive patients over 65 years (25 male, 35 female, mean age 77.3 +/- 5.0 y), hospitalized between 01. 01. 2002 and 31. 12. 2003 with a diagnosis of chronic heart failure and elevated (> 1.2 microg/I) serum level of digoxin, were analyzed.</AbstractText>Beside the analysis of the age, sex, serum level of digoxin and potassium, creatinine clearance value, symptoms and ECG-signs of digitalis intoxication, presence of atrial fibrillation, concomitant diseases and left ventricular ejection fraction value, the reasonability of digitalis treatment and therapy applied at the time of discharge (considering actual treatment guidelines) were also reviewed.</AbstractText>At the admission mean serum level of digoxin was 2.1 +/- 0.9 microg/l. 20 patient's value (33.3%) was found above 2.2 microg/l. Symptoms characteristic for digitalis intoxication were observed in 28 patients. On the ECG performed at admission signs of digitalis effect/overdose were observed in 54 cases ("bigemin" ventricular extrasystoles, bradycardia, characteristic down-sloping ST-depressions). The mean left ventricular ejection fraction of the patients (51.5 +/- 12.7%) did not suggest to a significant left ventricular systolic dysfunction. For the elevated serum level of digoxin the impaired renal function (mean creatinine clearance 42.9 +/- 21.3 mL/min) was responsible in most cases. In patients with the highest serum level of digoxin (n = 20, 3.2 +/- 0.7 microg/L) the creatinine clearance was even lower, 30.4 +/- 13.7 mL/min. During hospital treatment the administration of digitalis was found to be unnecessary and thus terminated in 44 patients. At the discharge only 16 patients were receiving digitalis, 14 of them digoxin and 2 patients digitoxin.</AbstractText>The authors emphasize, that in case of elderly patients the indication and control of digitalis therapy requires greater precaution and tight doctor-patient cooperation.</AbstractText> |
9,133 | Milrinone administered before ischemia or just after reperfusion, attenuates myocardial stunning in anesthetized swine. | We assessed the dose or timing effect of milrinone administered against myocardial stunning in 37 anesthetized open-chest swine.</AbstractText>All swine were subjected to 12-min ischemia followed by reperfusion to produce myocardial stunning. Group A (n = 12) received saline in place of milrinone both before and after ischemia. Group B (n = 9) and C (n = 9) received intravenous milrinone at a rate of 5 microg/kg/min for 10 min followed by 0.5 microg/kg/min for 10 min and 10 microg/kg/min for 10 min followed by 1 microg/kg/min for 10 min, respectively, until 30 min before coronary occlusion. Group D (n = 7) received the same dose of milrinone as group B starting 1 min after reperfusion. Myocardial contractility was assessed by percentage segment shortening (%SS).</AbstractText>Five swine in group A and two swine in groups B and C each had ventricular fibrillation or tachycardia after reperfusion, and were thus excluded from further analysis. The percentage changes of %SS from the baseline 90 min after reperfusion in groups B, C, and D were 78 +/- 9%, 82 +/- 13%, and 79 +/- 7%, respectively, which were significantly higher than those in group A (43 +/- 13%).</AbstractText>We conclude that milrinone administered before ischemia or just after reperfusion attenuates myocardial stunning.</AbstractText> |
9,134 | Epidemiology, trends, and outcome of out-of-hospital cardiac arrest of non-cardiac origin. | The majority of victims who experience out-of-hospital cardiac arrest (OHCA) have ventricular fibrillation (VF) as the presenting rhythm and are thought to have a cardiac etiology for their arrest. Over the past decade, the incidence of VF OHCA has declined. The aims of this study were to describe the epidemiology of OHCA of non-cardiac origin in Olmsted County MN and to determine the trends that have occurred over time.</AbstractText>All residents with a traumatic OHCA from 1995 to 2005 were included for analysis. OHCA data were collected prospectively according to the Utstein method. Cardiac arrests were classified as cardiac or non-cardiac in origin and the etiology determined based on autopsy reports, electronic medical records, and/or emergency medical services reports.</AbstractText>During the study period, 414 OHCAs were identified, 90 (21.7%) of which were classified as non-cardiac. Mean age was 61.5+/-19.7 years. Response time was 7.73+/-2.9 min, and 40 (44.4%) were bystander-witnessed. Sixty-eight (75.6%) arrests occurred at home, 13 (14.4%) in a public place, and 9 (10%) in other locations. Bystander CPR was performed in 17 (18.9%) cases. The presenting rhythm was VF in 2 (2.2%) cases, PEA in 54 (60%), and asystole in 34 (37.8%). Eight (8.9%) patients survived to hospital discharge. Respiratory failure (35.6%), unknown (15.6%), and pulmonary embolism (13.3%) were the most common etiologies. The mean percentage of arrests due to a non-cardiac cause in three sequential time-periods (1995-1999, 2000-2002, 2003-2005) was 9.4%, 20.1% and 37.7%, respectively.</AbstractText>Over the study period, 21.7% of OHCAs were non-cardiac in origin. PEA was the most common presenting rhythm and respiratory failure the most common etiology. 8.9% of patients survived. The decreasing number of VF arrests may be a contributing factor to the increasing proportion of OHCAs of non-cardiac etiology observed in the out-of-hospital setting.</AbstractText> |
9,135 | Amiodarone and polymorphic ventricular tachycardia: to slow down or to accelerate the underlying rhythm? | Polymorphic ventricular tachycardia (VT) comprises a variety of different subforms. Two patients were admitted to our hospital and developed polymorphic VT under treatment with amiodarone. However, each of them turned out to have a very different form of the arrhythmia and therefore required a different therapeutic approach. The clinical decision-making required a distinction between the two forms, and the following therapeutic approach included terminating the administration of amiodarone in the first case and continuing administration in the other case. As the most common forms of polymorphic VT are described, it becomes clear that each different form should be identified because of the important therapeutic implications. In particular, the role of amiodarone can be quite different in the management of these different forms of polymorphic VT. |
9,136 | Changes in escape rhythms several years after radiofrequency ablation of the atrioventricular junction combined with pacemaker implantation. | Escape rhythm is thought to play a considerable role in protection against adverse outcome due to pacemaker malfunction. We studied the escape rhythms in 32 patients with supraventricular tachyarrhythmia refractory to medical therapy who underwent radiofrequency ablation of the atrioventricular junction combined with implantation of a pacemaker.</AbstractText>We performed the escape rhythm analysis immediately and 2.6 +/- 1.9 years after the radiofrequency ablation by decreasing the pacing rate. In the initial study, escape rhythms (41 +/- 8 beats/min) were documented in 20 patients (63%). Non-cardiac death occurred in 3 patients with escape rhythm, and cardiac death occurred in I patient without escape rhythm. In the follow-up study, escape rhythms were detected in 22 of 28 patients (79%). Escape rhythm had developed in 6 (55%) of 11 patients who were without escape rhythm initially, while escape rhythm disappeared in 1 of 17 (5.9%) patients who had escape rhythm initially. The changes in escape rhythm were not related to QRS width of the intrinsic beat. There was no correlation between the number of radiofrequency applications or the ratio between atrial and ventricular electrocardiogram voltages of radiofrequency applications and the development of escape rhythms.</AbstractText>The present long-term follow-up study demonstrated that the emergence of an escape rhythm increased several years after ablation, but was unrelated to procedural factors. There are, however, certain patients in whom the disappearance of escape rhythms occur. The evaluation of escape rhythms is thus necessary to determine the risk associated with pacemaker failure.</AbstractText> |
9,137 | Left atrial function in patients with a high C-reactive protein level and paroxysmal atrial fibrillation. | We evaluated left atrial dimensions and function in high C-reactive protein (CRP) patients with paroxysmal atrial fibrillation.</AbstractText>In patients with increased plasma levels of CRP left atrial dysfunction may enhance the occurrence of arrhythmias.</AbstractText>Two-dimensional and pulsed Doppler echocardiography, were performed in 20 consecutive patients with high CRP levels and paroxysmal atrial fibrillation (group CRf) and in 20 patients with high CRP levels without this arrhythmia (group CR). Twenty normal subjects (group N) were also investigated. Groups were matched for age and gender.</AbstractText>CRP was increased in the CRf (median = 1.03 mg/dl), CR (median = 0.84 mg/dl) and N groups (median = 0.23 mg/dl), (p < 0.001) for all comparisons. The CRf, CR and N groups had similar systolic and diastolic blood pressure, left ventricular mass index, left ventricular ejection fraction, isovolumic relaxation time and peak early and late transmitral Doppler flow velocities. Maximal left atrial volume was greater only in the CRf group (54.4 +/- 6.3 ml) compared with the N group (50.3 +/- 4.9 ml, p < 0.05). Left atrial volume preceding atrial contraction was similar in all groups, p=NS. Left atrial minimal volume decreased from 23.0 +/- 1.8 ml in the CRf group, to 19.8 +/- 1.8 ml in the CR group, p < 0.001 and to 18.1 +/- 2.1 ml in the N group, (p < 0.02). The passive emptying fraction of the CRf and CR groups was comparable to that of normal subjects. The CRf group had a decreased left atrial active emptying fraction (0.25 +/- 0.08) compared with the CR (0.36 +/- 0.09) and N groups (0.39 +/- 0.08), p < 0.001 for both comparisons. The reservoir fraction was decreased only in the CRf group compared to normal subjects (1.37 +/- 0.25 vs. 1.82 +/- 0.43, p < 0.001).</AbstractText>These results suggest that the occurrence of paroxysmal atrial fibrillation in patients with a high CRP level is associated with enlargement of the left atrium, depression of its contractile function and is independent of left ventricular hypertrophy and function. The mechanisms linking these variables remain undefined.</AbstractText> |
9,138 | Outcome after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: a multicenter study. | Brugada syndrome is an arrhythmogenic disease characterized by an increased risk of sudden cardiac death (SCD) by ventricular fibrillation. At present, an implantable cardioverter-defibrillator (ICD) is the recommended therapy in high-risk patients. This multicenter study reports the outcome of a large series of patients implanted with an ICD for Brugada syndrome.</AbstractText>All patients (n=220, 46+/-12 years, 183 male) with a type 1 Brugada ECG pattern implanted with an ICD in 14 centers between 1993 and 2005 were investigated. ICD indication was based on resuscitated SCD (18 patients, 8%), syncope (88 patients, 40%), or positive electrophysiological study in asymptomatic patients (99 patients, 45%). The remaining 15 patients received an ICD because of a family history of SCD or nonsustained ventricular arrhythmia. During a mean follow-up of 38+/-27 months, no patient died and 18 patients (8%) had appropriate device therapy (10+/-15 shocks/patient, 26+/-33 months after implantation). The complication rate was 28%, including inappropriate shocks, which occurred in 45 patients (20%, 4+/-3 shocks/patient, 21+/-20 months after implantation). The reasons for inappropriate therapy were lead failure (19 patients), T-wave oversensing (10 patients), sinus tachycardia (10 patients), and supraventricular tachycardia (9 patients). Among implantation parameters, high defibrillation threshold, high pacing threshold, and low R-wave amplitude occurred, respectively, in 12%, 27%, and 15% of cases.</AbstractText>In this large Brugada syndrome population, a low incidence of arrhythmic events was found, with an annual event rate of 2.6% during a follow-up of >3 years, in addition to a significant risk of device-related complications (8.9%/year). Inappropriate shocks were 2.5 times more frequent than appropriate ones.</AbstractText> |
9,139 | Intracellular calcium and vulnerability to fibrillation and defibrillation in Langendorff-perfused rabbit ventricles. | The role of intracellular calcium (Ca(i)) in defibrillation and vulnerability is unclear.</AbstractText>We simultaneously mapped epicardial membrane potential and Ca(i) during shock on T-wave episodes (n=104) and attempted defibrillation episodes (n=173) in 17 Langendorff-perfused rabbit ventricles. Unsuccessful and type B successful defibrillation shocks were followed by heterogeneous distribution of Ca(i), including regions of low Ca(i) surrounded by elevated Ca(i) ("Ca(i) sinkholes") 31+/-12 ms after shock. The first postshock activation then originated from the Ca(i) sinkhole 53+/-14 ms after the shock. No sinkholes were present in type A successful defibrillation. A Ca(i) sinkhole also was present 39+/-32 ms after a shock on T that induced ventricular fibrillation, followed 22+/-15 ms later by propagated wave fronts that arose from the same site. This wave propagated to form a spiral wave and initiated ventricular fibrillation. Thapsigargin and ryanodine significantly decreased the upper limit of vulnerability and defibrillation threshold. We studied an additional 7 rabbits after left ventricular endocardial cryoablation, resulting in a thin layer of surviving epicardium. Ca(i) sinkholes occurred 31+/-12 ms after the shock, followed in 19+/-7 ms by first postshock activation in 63 episodes of unsuccessful defibrillation. At the Ca(i) sinkhole, the rise of Ca(i) preceded the rise of epicardial membrane potential in 5 episodes.</AbstractText>There is a heterogeneous postshock distribution of Ca(i). The first postshock activation always occurs from a Ca(i) sinkhole. The Ca(i) prefluorescence at the first postshock early site suggests that reverse excitation-contraction coupling might be responsible for the initiation of postshock activations that lead to ventricular fibrillation.</AbstractText> |
9,140 | High plasma aldosterone levels on admission are associated with death in patients presenting with acute ST-elevation myocardial infarction. | Aldosterone, the final mediator of the renin-angiotensin-aldosterone pathway, is at its highest plasma levels at presentation for ST-elevation myocardial infarction (STEMI). Whether aldosterone level at presentation for STEMI is associated with adverse outcome remains unknown.</AbstractText>Plasma aldosterone levels were measured at presentation in consecutive patients referred for primary percutaneous coronary intervention for STEMI. We assessed the association between aldosterone levels and in-hospital events and mortality during a 6-month follow-up. Of 356 STEMI patients, 23 and 36 died during the hospital stay and 6-month follow-up period, respectively. Nine other patients survived in-hospital cardiac arrest. High aldosterone levels were associated with an almost stepwise increase in rates of in-hospital death (P=0.01), cardiovascular death (P=0.03), heart failure (P=0.005), ventricular fibrillation (P=0.02), and resuscitated cardiac arrest (P=0.01). After adjustment for age, Killip class, and reperfusion status, compared with patients in the first aldosterone quartile group, those in the highest quartile were at higher risk of death (hazard ratio 3.28, 95% CI 1.09 to 9.89, P=0.035) and death or resuscitated cardiac arrest (hazard ratio 3.74, 95% CI 1.40 to 9.98, P=0.008) during the follow-up.</AbstractText>Plasma aldosterone levels on admission among patients referred for primary percutaneous coronary intervention for STEMI are associated with early and late adverse clinical outcomes, including mortality. The association between high aldosterone levels and late mortality is independent of age, heart failure, and reperfusion status. Such results underline the pivotal role of aldosterone and justify a randomized trial to assess the early administration of aldosterone antagonists in the setting of STEMI.</AbstractText> |
9,141 | Dietary n-3 fatty acids promote arrhythmias during acute regional myocardial ischemia in isolated pig hearts. | Dietary supplementation with fish oil-derived n-3 fatty acids reduces mortality in patients with myocardial infarction, but may have adverse effects in angina patients. The underlying electrophysiologic mechanisms are poorly understood. We studied the arrhythmias and the electrophysiologic changes during regional ischemia in hearts from pigs fed a diet rich in fish oil.</AbstractText>Pigs received diets rich in fish oil, in sunflower oil, or a control diet for 8 weeks. Hearts were isolated and perfused. Ischemia was created by occluding the left anterior descending artery. Diastolic stimulation threshold, refractory period, conduction velocity, activation recovery intervals and the maximum downstroke velocity of 176 electrograms were measured in the ischemic zone. Spontaneous arrhythmias during 75 min of regional ischemia were counted.</AbstractText>More episodes of spontaneous ischemia-induced sustained ventricular tachycardia and ventricular fibrillation occurred in the fish oil and sunflower oil group than in the control group. More inexcitable myocardium was present in the ischemic zone in the group fed fish oil or sunflower oil than in the control group after 20 min of ischemia. After 40 min of ischemia, more block occurred in the control group than in the other groups. The downstroke velocity of the electrograms in the ischemic border zone was lower in the fish oil group and sunflower oil group than in the control after 20 min.</AbstractText>A diet rich in fish oil results in proarrhythmia compared to a control diet during regional ischemia in pigs. Myocardial excitability is reduced in the fish oil and sunflower oil group during the early phase of arrhythmogenesis. In the late phase of arrhythmogenesis, excitability is more reduced in the control group than in the fish oil and sunflower oil group.</AbstractText> |
9,142 | Use of the implantable loop recorder in children and adolescents. | Recurrent but infrequent syncopes represent a diagnostic challenge, since they frequently remain unexplained despite extensive investigations. This applies specifically for patients who carry an increased risk of potentially lifethreatening arrhythmias, either due to congenital cardiac disease or primary electrical disorders. Implantable loop recorders permit long-term electrocardiographic monitoring. Experience with these devices is still limited in children.</AbstractText>Between January 1999 and August 2005, 12 patients underwent implantation of a loop recorder in our tertiary referral centre. The mean age was 10.9 years, with a range from 2 to 17 years. Of the patients, 6 had structural disease, 3 had primary electrical abnormalities, and 3 had no cardiovascular disease.</AbstractText>Resyncope occured in 9 of the 12 patients. Arrhythmic origin of the syncope was diagnosed in 4 of these patients. The events recorded were ventricular fibrillation in 2, intermittent asystole in 1, and pacemaker-syndrome in the other patient. Malignant arrhythmia was ruled out in the remaining 5 patients. There were no complications related to implantation of the loop recorder, and the mean duration until explantation was 8.3 months.</AbstractText>Based on our experience, we suggest that implantation of a loop recorder represents an additional tool for a selected group of children. Due to its invasive nature, it should be restricted to patients at high risk, or those in which there is substantial clinical suspicion of the likelihood of serious arrhythmias when conventional testing has been inconclusive. In this cohort, implantation of the loop recorder either helps to establish the correct diagnosis, or to exclude an arrhythmic event, thus avoiding unnecessary escalation of therapy and providing reassurance for the family.</AbstractText> |
9,143 | Permanent direct his bundle pacing does not induce ventricular dyssynchrony unlike conventional right ventricular apical pacing. An intrapatient acute comparison study. | Benefits of A-V synchrony during right ventricular apical pacing are neutralized by induction of ventricular dyssynchrony. Only a few data are reported about direct His bundle pacing influence on ventricular synchronism.</AbstractText>Was to assess the capability of direct His bundle pacing to prevent pacing-induced ventricular dyssynchrony comparing DDD- (or VVI- in case of Atrial Fibrillation) right ventricular apical pacing with DDD- (or VVI-) direct His bundle pacing in the same patients cohort.</AbstractText>23 of 24 patients (mean age 75.1 +/- 6.4 years) with narrow QRS (HV < 65 ms) underwent permanent direct His bundle pacing for "brady-tachy syndrome" (11) or supra-Hisian II/III-degree AV Block (permanent atrial fibrillation 7, AV Node ablation 1). A 4.1 F screw-in lead was fixed in His position, guided by endocardial pacemapping and unipolar recordings. Additional permanent (13 patients) or temporary right ventricular apical pacing leads were also positioned. Inter- and left intra-ventricular dyssynchrony, mitral regurgitation and left systolic ventricular function Tei index were assessed during either direct His bundle pacing or right ventricular apical pacing.</AbstractText>Permanent direct His bundle pacing was obtained in 23 of 24 patients. Indexes of ventricular dyssynchrony were drastically reduced, mitral regurgitation decreased and left systolic ventricular function Tei index improved during direct His bundle pacing (or His bundle and septum pacing) in comparison to apical pacing (p < 0.05). No statistically significant differences were observed between direct His bundle pacing and combined His bundle and septum pacing.</AbstractText>Direct His bundle pacing (also fused with adjacent septum capture) prevents pacing-induced ventricular dyssynchrony.</AbstractText> |
9,144 | Intrathoracic pressure regulation for intracranial pressure management in normovolemic and hypovolemic pigs. | To evaluate the potential to use subatmospheric intrathoracic pressure to regulate intracranial pressure (ICP) in normovolemic and hypovolemic animals, we tested the hypothesis that mechanical devices designed to reduce intrathoracic pressure will decrease ICP in a dose-related manner. An inspiratory impedance threshold device was used in spontaneously breathing animals and an intrathoracic pressure regulator was attached to a positive pressure ventilator and used in apneic animals: both devices lower intrathoracic pressure.</AbstractText>Prospective, randomized animal study.</AbstractText>Animal laboratory facilities.</AbstractText>A total of 36 female farm pigs in four different protocols (n = 12, 6, 12, and 6, respectively).</AbstractText><AbstractText Label="INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS" NlmCategory="RESULTS">In all protocols, endotracheal, right atrial, central aortic, and ICP were measured continuously. In protocol 1, spontaneously breathing animals were randomized to breath for 15 mins through an impedance threshold device with a cracking pressure of -10 or -15 mm Hg. In protocol 2, after untreated ventricular fibrillation for 4 mins and successful defibrillation to a normal rhythm, spontaneously breathing pigs were used to evaluate the effect of two different impedance threshold device cracking pressures (-10 and -15 mm Hg) on increased ICP. In protocol 3, the acute effects of an intrathoracic pressure regulator on ICP were evaluated in combination with a positive pressure mechanical ventilator in apneic hypovolemic hypotensive pigs after 35% or 50% blood loss. In protocol 4, after 40% blood loss, an intrathoracic pressure regulator was applied for 120 mins and ICP was recorded to determine whether the intrathoracic pressure regulator effects were sustained over time. Inspiratory impedance successfully decreased ICP in spontaneously breathing pigs in a dose-dependent manner and decreased elevated ICP immediately after cardiac arrest and successful resuscitation. The same effect was seen in apneic animals with the use of the intrathoracic pressure regulator. The effect was more pronounced in hypovolemia, and it was sustained for >/=2 hrs.</AbstractText>Reduction of intrathoracic pressure to subatmospheric levels resulted in an instantaneous and sustained reduction in ICP in spontaneously breathing and apneic animals. The effect was most pronounced in the hypovolemic animals.</AbstractText> |
9,145 | delta-Opioid-induced pharmacologic myocardial hibernation during cardiopulmonary resuscitation. | Cardiac arrest and cardiopulmonary resuscitation is an event of global myocardial ischemia and reperfusion, which is associated with severe postresuscitation myocardial dysfunction and fatal outcome. Evidence has demonstrated that mammalian hibernation is triggered by cyclic variation of a delta-opiate-like compound in endogenous serum, during which the myocardial metabolism is dramatically reduced and the myocardium tolerates the stress of ischemia and reperfusion without overt ischemic and reperfusion injury. Previous investigations also proved that the delta-opioid agonist elicited the cardioprotection in a model of regional ischemic intact heart or myocyte. Accordingly, we were prompted to search for an alternative intervention of pharmacologically induced myocardial hibernation that would result in rapid reductions of myocardial metabolism and therefore minimize the myocardial ischemic and reperfusion injury during cardiac arrest and cardiopulmonary resuscitation.</AbstractText>Prospective, controlled laboratory study.</AbstractText>University-affiliated research laboratory.</AbstractText>In the series of studies performed in the established rat and pig model of cardiac arrest and cardiopulmonary resuscitation, the delta-opioid receptor agonist, pentazocine, was administered during ventricular fibrillation.</AbstractText>: The myocardial metabolism reflected by the concentration of lactate, or myocardial tissue PCO2 and PO2, is dramatically reduced during cardiac arrest and cardiopulmonary resuscitation. These are associated with less severe postresuscitation myocardial dysfunction and longer duration of postresuscitation survival.</AbstractText>delta-Opioid-induced pharmacologic myocardial hibernation is an option to minimize the myocardial ischemia and reperfusion injury during cardiac arrest and cardiopulmonary resuscitation.</AbstractText> |
9,146 | Simultaneous blockade of alpha1- and beta-actions of epinephrine during cardiopulmonary resuscitation. | Experimental and clinical studies have implicated that alpha1- and beta-adrenergic effects of epinephrine significantly increased the severity of postresuscitation myocardial dysfunction by increasing myocardial oxygen consumption during ventricular fibrillation. This prompted experimental studies to investigate the effect of simultaneous blockade of alpha1- and beta-actions of epinephrine during cardiopulmonary resuscitation.</AbstractText>Literature review.</AbstractText>Improved postresuscitation myocardial dysfunction was observed in epinephrine-treated animals after its alpha1- and beta-actions were blocked, which were associated with less postresuscitation arrhythmia, lower blood lactate level, better neurologic recovery, and longer duration of survival.</AbstractText>After simultaneous alpha1- and beta-adrenergic blockade, epinephrine administered during cardiopulmonary resuscitation yielded improved postresuscitation myocardial functions and significantly better postresuscitation outcomes.</AbstractText> |
9,147 | Microcirculation during cardiac arrest and resuscitation. | Direct observations of the microcirculation using orthogonal polarization spectral imaging have attracted attention and revealed that, especially in cardiogenic and distributive shock, there is discordance between the macrocirculation and the microcirculation. We evaluated serial changes and the effects of epinephrine on microcirculatory blood flow in the most severe form of circulatory failure, namely, cardiac arrest.</AbstractText>: Controlled laboratory animal study.</AbstractText>A total of 15 pigs were subjected to 5 mins of ventricular fibrillation and 5 mins of precordial compression before electrical defibrillation was attempted. In a subset, six animals received 1 mg of epinephrine after 1 min of precordial compression.</AbstractText>Microcirculatory blood flow was visualized in the sublingual mucosa at baseline and 0.5, 1, and 5 mins of ventricular fibrillation, at 1 and 5 mins of precordial compression, and at 1 and 5 mins after return of spontaneous circulation. In addition, coronary perfusion pressure was recorded. Microcirculatory blood flow decreased dramatically in the 0.5 min after the onset of ventricular fibrillation. Precordial compression partially restored microcirculatory blood flow in each animal but to a significantly greater extent in animals that achieved return of spontaneous circulation. These changes were paralleled by similar changes in coronary perfusion pressure. Both variables were highly correlated. Administration of epinephrine resulted in a massive reduction of microcirculatory blood flow that lasted for >/=5 mins.</AbstractText>In this model, microcirculatory blood flow was highly correlated with macrocirculatory hemodynamics, including coronary perfusion pressure in distinction with septic shock. Administration of epinephrine dramatically decreased microcirculatory blood flow.</AbstractText> |
9,148 | Preterminal gasping and effects on the cardiac function. | Gasping, also known as agonal respirations, is the terminal pattern that occurs after anoxia or ischemia and is a universal phenomenon in mammals. In this article we review the physiology of gasping, the prevalence and significance of gasping in cardiac arrest, and the effects of gasping on cardiac function.</AbstractText>Review relevant human and animal literature on gasping and cardiac function during gasping.</AbstractText>Gasping originates in the medullary area of the central nervous system. Gasping is prevalent during cardiac arrest: it occurs in all animals during ventricular fibrillation, in a majority of infants (31 of 32) with sudden infant death syndrome, and in 30-40% of witnessed episodes of cardiac arrest in adults. Animal studies demonstrated that gasping is associated with a decrease in intrathoracic pressure during the inspiratory phase, which promotes venous return and an increase in intrathoracic pressure during the expiratory phase, which favors coronary perfusion. Gasping increases cardiac output and cardiac contractility in immature animals exposed to anoxia.</AbstractText>Gasping is auto-resuscitative in immature mammals and improves the outcome of cardiopulmonary resuscitation in mature mammals. Gasping is associated with important cardiorespiratory changes: improved pulmonary gas exchange, increased venous return to the heart, increased cardiac output, cardiac contractility, aortic pressure, and coronary perfusion pressure.</AbstractText> |
9,149 | Analysis of the ventricular fibrillation waveform in refibrillation. | Frustrating outcomes are driving investigation of alternative resuscitation protocols. Previous analysis of the ventricular fibrillation (VF) waveform has focused on guiding whether to shock immediately or to delay for delivery of cardiopulmonary resuscitation in the case of presenting VF. The same issues emerge in the case of refibrillation.</AbstractText>All cases of witnessed VF cardiac arrest in the Rochester, MN, area in a 9-yr period were analyzed. Rochester rescuers employed an early defibrillation protocol during the study period. A summary measure of the VF waveform before the shock delivered in 35 incidents of refibrillation was compared with the time elapsed from the initial shock, the intervening electrocardiographic rhythm, ambulance response time, and call-to-shock time for prediction of early return of spontaneous circulation and of neurologically intact survival. VF waveform analysis separated patients with good outcomes when treated with early defibrillation of refibrillation from those without good outcomes more clearly than other predictors.</AbstractText>Analysis of VF waveform offers promise for real-time guidance of resuscitation efforts on the basis of individual patient characteristics, in refibrillation and in the initial shock. It has advantages over guidance based on individual or aggregate system response times.</AbstractText> |
9,150 | Definition of successful defibrillation. | The definition of defibrillation shock "success" endorsed by the International Liaison Committee on Resuscitation since the publication of Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiac Care has been removal of ventricular fibrillation at 5 secs after shock delivery. Although this success criterion provides a direct assessment of the primary task of a shock, it may not be the only clinically useful measure of shock outcome. We evaluated a different defibrillation success criterion to determine whether it could provide additional insight into the relative performance of different defibrillation shocks.</AbstractText>A randomized study comparing monophasic and biphasic waveform shocks is reported with return of organized rhythm as the primary outcome measure of defibrillation success.</AbstractText>A total of 120 patients with out-of-hospital ventricular fibrillation as the first recorded rhythm were treated with defibrillation with automated external defibrillators.</AbstractText>Return of organized rhythm (two QRS complexes, <5 secs apart, <60 secs after defibrillation) was achieved in 31 monophasic shock (45%) and 35 biphasic shock (69%) patients (relative risk, 1.53, 95% confidence interval, 1.11-2.10). Logistic regression analysis revealed that shock waveform was the strongest independent predictor of return of organized rhythm (odds ratio, 4.0; 95% confidence interval, 1.67-10.0). Defibrillation success with the conventional International Liaison Committee on Resuscitation criterion was very high (91% and 98%, respectively) and not significantly different between groups.</AbstractText>Return of organized rhythm proved to be a more sensitive measure of relative defibrillation shock performance than the conventional shock success criterion. Inclusion of return of organized rhythm as an end point in future clinical research could help discern more subtle defibrillation shock effects and contribute to further optimization of defibrillation technology.</AbstractText> |
9,151 | Outcomes from out-of-hospital cardiac arrest in Detroit. | To determine the out-of-hospital cardiac arrest survival rate, and prevalence of modifiable factors associated with survival, in Detroit, Michigan, over a 6-month period of time in 2002.</AbstractText>A retrospective review of all out-of-hospital cardiac arrests responded to by the Detroit Fire Department, Division of Emergency Medical Services. All elements of the EMS runsheet were transcribed to a database for analysis. Patient hospital records were reviewed to determine survival to hospital admission. All survivors to hospital admission were surveyed later in the Michigan Department of Vital Records death registry search.</AbstractText>During this study timeframe, there were 538 confirmed out-of-hospital cardiac arrests within the City of Detroit, of which 67 were excluded for being dead on scene [51 (12.5%)] or having no available hospital records [16 (3.0%)]. Of the remaining 471 patients, 443 (94.1%) died before hospital admission. Only 44 (9.9%) of the 471 patients had a first recorded rhythm of ventricular fibrillation (VF), and 339 (76.5%) were asystolic. Of the 28 patients who survived to hospital admission, only 2 (7.1%) were noted to have a first rhythm of VF, and 15 (53.6%) were asystolic. Only one patient survived to hospital discharge.</AbstractText>In this urban setting, out-of-hospital cardiac arrest is an almost uniformly fatal event.</AbstractText> |
9,152 | Assessment of CPR-D skills of nurses in Göteborg, Sweden and Espoo, Finland: teaching leadership makes a difference. | Construction of an effective in-hospital resuscitation programme is challenging. To document and analyse resuscitation skills assessment must provide reliable data. Benchmarking with a hospital having documented excellent results of in-hospital resuscitation is beneficial. The purpose of this study was to assess the resuscitation skills to facilitate construction of an educational programme.</AbstractText>Nurses working in a university hospital Jorvi, Espoo (n=110), Finland and Sahlgrenska University Hospital, Göteborg (n=40), Sweden were compared. The nurses were trained in the same way in both hospitals except for the defining and teaching of leadership applied in Sahlgrenska. Jorvi nurses are not trained to be, nor do they act as, leaders in a resuscitation situation. Their cardiopulmonary resuscitation (CPR) skills using an automated external defibrillator (AED) were assessed using Objective Structured Clinical Examination (OSCE) which was build up as a case of cardiac arrest with ventricular fibrillation (VF) as the initial rhythm. The subjects were tested in pairs, each pair alone. Group-working skills were registered.</AbstractText>All Sahlgrenska nurses, but only 49% of Jorvi nurses, were able to defibrillate. Seventy percent of the nurses working in the Sahlgrenska hospital (mean score 35/49) and 27% of the nurses in Jorvi (mean score 26/49) would have passed the OSCE test. Statistically significant differences were found in activating the alarm (P<0.001), activating the AED without delay (P<0.01), setting the lower defibrillation electrode correctly (P<0.001) and using the correct resuscitation technique (P<0.05). The group-working skills of Sahlgrenska nurses were also significantly better than those of Jorvi nurses.</AbstractText>Assessment of CPR-D skills gave valuable information for further education in both hospitals. Defining and teaching leadership seems to improve resuscitation performance.</AbstractText> |
9,153 | Candesartan in the prevention of relapsing atrial fibrillation. | Several studies have indicated that treatment with angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor blockers (ARBs) may reduce the incidence of atrial fibrillation (AF) in hypertensive patients and patients with left ventricular dysfunction. However, there is limited data on the effect of ACE-inhibitors and ARBs in patients undergoing electrical cardioversion for persistent AF. We hypothesized that treatment with the ARB candesartan, without adjunct antiarrhythmic therapy, would reduce the recurrence rate of AF after successful cardioversion.</AbstractText>In a double blind, placebo-controlled study, 171 patients with persistent AF were randomized to receive candesartan 8 mg once daily (n=86) or placebo (n=85) for 3-6 weeks before and candesartan 16 mg once daily or placebo for 6 months after electrical cardioversion. Primary endpoint was recurrence of AF.</AbstractText>A total of 68 patients in the candesartan group and 69 patients in the placebo group were successfully cardioverted. Forty-eight patients (71%) in the candesartan group and 45 (65%) in the placebo group had a recurrence of AF during 6 months follow-up. Median time to recurrence was 8 and 9 days in the candesartan and placebo groups, respectively. The differences between the groups were not statistically significant.</AbstractText>Treatment with the ARB candesartan for 3-6 weeks before and 6 months after electrical cardioversion had no effect on the recurrence rate of AF.</AbstractText> |
9,154 | Study of the restitution of action potential duration using the artificial neural network. | It is widely accepted that the APD (action potential duration) restitution plays a key role in the initializing and maintaining of the reentry arrhythmias. The Luo-Rudy II models paced with different protocols showed that the current APD had a complex relation with the previous APDs and diastole intervals (DIs). This relation could not be accurately described by a single exponential function. We used an artificial neural network to formularize this relation. The results suggested that back-propagation (BP) network could predict the current APD from the information of the first three previous beats. This would help provide a target for potential anti-arrhythmic therapies. |
9,155 | Prevalence of arrhythmias and their risk factors mid- and long-term after the arterial switch operation. | Early results of the arterial switch operation (ASO) for transposition of the great arteries (TGA) are good, but there are few mid- and long-term data on postoperative arrhythmias, especially in Japan. In this study, clinical data on 624 1-year survivors who had an ASO between 1976 and 1995 were collected from six institutes in Japan up to October 2002. Sixty (9.6%) 1-year survivors had significant arrhythmias. Bradycardia occurred in 22 patients, including complete atrioventricular block (CAVB) in 12, sick sinus syndrome (SSS) in 6, and second-degree atrioventricular block in 4. Syncope developed in 2 with CAVB and 2 with SSS. Ten patients with bradycardia underwent permanent pacemaker implantation. Supraveutricular tachycardia (SVT) was seen in 25 patients, including paroxysmal supraventricular tachycardia in 16, atrial flutter in 7, and atrial fibrillation in 2. Six patients with SVT received antiarrhythmic medication. SVT was transient in 20 and persistent in 5. Ventricular arrhythmias occurred in 13 patients, including nonsustained ventricular tachycardia in 5, paroxysmal ventricular contractions with couplets in 5, ventricular flutter in 2, and sustained ventricular tachycardia in 1. Four patients with ventricular arrhythmias received antiarrhythmic medication. Of the study patients, 8 died 1 year or more after ASO. Death was directly related to arrhythmia in 1 patient and was due to nonsustained ventricular tachycardia with severe congestive heart failure. The presence of a ventricular septal defect (VSD) was a risk factor for postoperative arrhythmia. Patients with TGA and VSD had more arrhythmias than those with TGA and an intact ventricular septum (13.7 vs 8.7%, p < 0.05), and this was especially true for CAVB (3.9% vs 1.0%, p < 0.05). In 36 patients clearly documented time onset of postoperative arrhythmia arrhythmia developed in 18 (50%) after less than 1 year and in 15 (42%) after more than 5 years. In summary serious arrhythmias after ASO were uncommon, but postoperative arrhythmias, such as unpaced CAVB, SSS, and VT, were related to morbidity and mortality. VSD was a risk factor for postoperative arrhythmia, especially CAVB. Approximately half of the arrhythmias developed late. Lifelong monitoring with respect to arrhythmia is needed for patients after ASO. |
9,156 | The effect of an adenosine and lidocaine intravenous infusion on myocardial high-energy phosphates and pH during regional ischemia in the rat model in vivo. | We have previously shown that an intravenous infusion of adenosine and lidocaine (AL) solution protects against death and severe arrhythmias and reduces infarct size in the in vivo rat model of regional ischemia. The aim of this study was to examine the relative changes of myocardial high-energy phosphates (ATP and PCr) and pH in the left ventricle during ischemia-reperfusion using 31P NMR in AL-treated rats (n = 7) and controls (n = 6). The AL solution (A: 305 microg.(kg body mass)-1.min-1; L: 608 microg.(kg body mass)-1.min-1) was administered intravenously 5 min before and during 30 min coronary artery ligation. Two controls died from ventricular fibrillation; no deaths were recorded in AL-treated rats. In controls that survived, ATP fell to 73% +/- 29% of baseline by 30 min ischemia and decreased further to 68% +/- 28% during reperfusion followed by a sharp recovery at the end of the reperfusion period. AL-treated rats maintained relatively constant ATP throughout ischemia and reperfusion ranging from 95% +/- 6% to 121% +/- 10% of baseline. Owing to increased variability in controls, these results were not found to be significant. In contrast, control [PCr] was significantly reduced in controls compared with AL-treated rats during ischemia at 10 min (68% +/- 7% vs. 99% +/- 6%), at 15 min (68% +/- 10% vs. 93% +/- 2%), and at 20 min (67% +/- 15% vs. 103% +/- 5%) and during reperfusion at 10 min (56% +/- 22% vs. 99% +/- 7%), at 15 min (60% +/- 10% vs. 98% +/- 7%), and at 35 min (63% +/- 14% vs. 120% +/- 11%) (p < 0.05). Interestingly, changes in intramyocardial pH between each group were not significantly different during ischemia and fell by about 1 pH unit to 6.6. During reperfusion, pH in AL-treated rats recovered to baseline in 5 min but not in controls, which recovered to only around pH 7.1. There was no significant difference in the heart rate, mean arterial pressure, and rate-pressure product between the controls and AL treatment during ischemia and reperfusion. We conclude that AL cardioprotection appears to be associated with the preservation of myocardial high-energy phosphates, downregulation of the heart at the expense of a high acid-load during ischemia, and with a rapid recovery of myocardial pH during reperfusion. |
9,157 | AICD treatment in 2004--state of the art. | Primary and secondary prevention of sudden cardiac death is not sufficiently assured by medication. The (automatic) implantable cardioverter/defibrillator ((A)ICD) is able to terminate life-threatening arrhythmias (ventricular fibrillation/flutter, ventricular tachycardia) reliably. The identification and care of risk patients is of crucial importance. Initially, only survived resuscitation for ventricular fibrillation or ventricular tachycardia was regarded as a confirmed indication. Several studies (CABG patch, MADIT, MADIT II, MUSTT, DINAMIT, CAT AMIOVIRT, DEFINITE, COMPANION, SCD-HeFT) have examined the prophylactic indication for ICD therapy in risk groups. Patients with chronic state after myocardial infarction with markedly impaired left ventricular function and/or spontaneous, non-sustained ventricular tachycardia have been documented to benefit. Patients with moderately severe or severe heart failure also profit from ICD implantation, where appropriate in combination with cardiac resynchronization therapy in conduction disorders. There is divergent data on dilated cardiomyopathy. ICD is not indicated in patients with acute infarctions or undergoing elective bypass surgery. |
9,158 | Outcome prediction for guidance of initial resuscitation protocol: Shock first or CPR first. | Ventricular fibrillation (VF) is treated optimally with a defibrillation shock shortly after patient collapse, but may benefit from initial cardiopulmonary resuscitation (CPR) if the shock is delayed. An objective measure of potential responsiveness to defibrillation could help decide optimal initial therapy.</AbstractText>a new electrocardiogram (ECG) analysis algorithm was compared with response interval (call-to-shock) for prediction of patient outcome in a population of 87 VF patients in the Rochester, Minnesota area. In a retrospective analysis, both call-to-shock interval (p = 0.009) and ECG analysis (p < 0.001) predicted neurologically intact survival, with ECG analysis the stronger predictor (p = 0.034). When applied to advising initial patient treatment, ECG analysis compared favorably with the call-to-shock interval. Using a 7 min call-to-shock time criterion, 69% of patients would receive shocks first treatment using ECG analysis versus 67% using the call-to-shock interval (p = NS), 94% of survivors would retain successful shocks first treatment versus 85% (p = NS), and 48% of non-survivors receive alternate CPR-first treatment versus 45% (p = NS). Similarly, no significant differences were observed between ECG analysis and call-to-shock interval using an 8 min criterion.</AbstractText>Both call-to-shock interval and a real-time ECG analysis are predictive of patient outcome. The ECG analysis is more predictive of neurologically intact survival. Moreover, the ECG analysis is dependent only upon the patient's condition at the time of treatment, with no need for knowledge of the response interval, which may be difficult to estimate at the time of treatment.</AbstractText> |
9,159 | Postresuscitation myocardial dysfunction: correlated factors and prognostic implications. | To evaluate the clinical factors correlated with postresuscitation myocardial dysfunction and the prognostic implication such dysfunction may have.</AbstractText>Prospective observational study in a university medical center</AbstractText>58 adult patients successfully resuscitated from nontraumatic out-of-hospital cardiac arrest over 2 years.</AbstractText>Echocardiographic evaluation of the left ventricular systolic and diastolic functions was performed 6 h postresuscitation and was analyzed in correlation to the clinical features and resuscitation factors. Univariate analysis revealed left ventricular ejection fraction (LVEF) to be significantly lower in patients with hypertension, past history of myocardial infarction, resuscitation duration longer than 20 min, defibrillation, and use of more than 5 mg epinephrine. Isovolumic relaxation time (IVRT) was significantly longer in patients with noncardiac cause and initial rhythm of nonventricular fibrillation/tachycardia. Multiple regression analysis showed epinephrine dose and past history of myocardial infarction to be independent factors for LVEF, while the cause of cardiac arrest was independently associated with IVRT. For prognosis, 27 patients survived to hospital discharge. Both LVEF under 40% and IVRT 100 ms or longer were associated with poor survival outcomes. In Cox regression analysis IVRT 100 ms or longer served as an independent factor predicting poor survival prognosis.</AbstractText>Postresuscitation left ventricular dysfunction is correlated with a number of clinical factors, among which past history of myocardial infarction, epinephrine dose, and the cause of cardiac arrest play independent roles. Meanwhile, IVRT 100 ms or longer 6 h postresuscitation predicts poor survival outcomes and serves as a marker of poor prognosis.</AbstractText> |
9,160 | Appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy: long term follow-up. | The implantable cardioverter defibrillator (ICD) has proved effective in preventing sudden death and decreasing mortality in randomised secondary prevention trials. Some nonrandomized studies have reported different incidences and predictors of appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy (DCM). The antiarrhythmic and other medical therapies were different between the published studies and it was reported that not using beta-blockers was a predictor of appropriate ICD therapy. In the present study, we report on our long-term experience with ICD therapy in patients with DCM, the majority of whom were treated with beta-blockers and amiodarone. The study population consisted of 25 patients with DCM who underwent initial transvenous ICD implantation between December 1995 and May 2005. Indications for ICD implantation were monomorphic sustained ventricular tachycardia (VT) in 16 patients (64%), cardiac arrest in 8 patients (32%), and syncope plus inducible VT in one patient. Twenty-four patients underwent an electrophysiologic study (EPS). In 18 patients, the ICDs were programmed to only shocks and in 7 patients an additional antitachycardia pacing program was performed. One patient was lost to follow-up and 24 patients were followed-up primarily in our ICD pacemaker outpatient clinic. Appropriate ICD therapy was defined as antitachycardia pacing therapy or shock for tachyarrhythmia determined by evaluation of the clinical information and by device diagnostics to be either ventricular fibrillation or ventricular tachycardia. The mean follow-up was 39.29 +/- 30.59 months after ICD implantation. At follow-up, 17 patients were using a beta-blocker and 16 patients amiodarone. Appropriate ICD therapy was observed in 14 patients (58%). The detected arrhythmias were VT in 12 patients, ventricular fibrillation (VF) in one, and VT and VF in one patient. The time to first ICD therapy was 15.93 +/- 18.45 (range, 1-74) months. Using the Kaplan-Meier method, the percent survival free of appropriate ICD therapy was 82%, 72%, 66%, and 55% at 1, 2, 3, and 4 years follow-up, respectively. The clinical, echocardiographic, and electrophysiologic characteristics did not differ between those who did and did not receive appropriate ICD therapy. However, the mean QRS duration was significantly longer in patients who received appropriate ICD therapies. Cox regression analysis did not reveal any factors that predicted appropriate ICD therapy. Five patients (21%) died during follow-up. Four deaths were classified as cardiac and one as noncardiac. The cumulative survival from total death was 94%, 82%, 82%, and 69%, and the cumulative survival from cardiac death was 94%, 82%, 82%, and 76% during 1, 2, 3, and 4 years of follow-up, respectively. In summary, in this selected patient population with DCM, the majority of patients were unresponsive to beta-blocker and antiarrhythmic therapy. Most of these patients received appropriate ICD therapy during follow-up. Cox regression analysis did not identify any factors that predicted appropriate ICD therapy. Additional trials with larger patient populations are needed to detect the predictors of appropriate ICD therapy in patients with DCM. |
9,161 | Performance of a new single-chamber ICD algorithm: discrimination of supraventricular and ventricular tachycardia based on vector timing and correlation. | Interval- and morphology-based algorithms have been used in modern implantable cardioverter defibrillators (ICDs) to discriminate supraventricular tachycardia (SVT) from other rhythms. A newly developed ICD discrimination algorithm, Rhythm ID (Guidant Corporation, St Paul, MN, USA), uses both interval-based metrics and an electrogram vector timing and correlation (VTC) algorithm in a dual-chamber ICD. In a single-chamber ICD, Rhythm ID contains only the VTC component. This study conducted a retrospective analysis of the performance of Rhythm ID for the detection of induced and spontaneous rhythms in a single-chamber ICD.</AbstractText>This study gathered the data from a prospective, multicentre clinical trial. Ninety-six patients were implanted with a dual-chamber ICD. For this study, each episode was analysed to determine the performance of the single-chamber ICD Rhythm ID algorithm. The mean age of the patients implanted with the device was 67+/-11 years. Seventy-eight patients were male. The primary cardiovascular disease was coronary artery disease and the primary tachyarrhythmia was monomorphic ventricular tachycardia (VT). The mean follow-up time was 11.4 months. A total of 369 induced and spontaneous ventricular arrhythmias was analysed. The algorithm detected 100% of ventricular arrhythmias. Four hundred and forty-two SVT episodes were analysed, including 145 induced and 297 spontaneous. The SVTs were atrial fibrillation (n=199), atrial flutter (n=135), and 1:1 SVT (n=108). The single-chamber ICD Rhythm ID algorithm successfully discriminated 403 SVT episodes and achieved a specificity of 91%.</AbstractText>The single-chamber version of Rhythm ID demonstrated high specificity without compromising sensitivity.</AbstractText> |
9,162 | QT variability strongly predicts sudden cardiac death in asymptomatic subjects with mild or moderate left ventricular systolic dysfunction: a prospective study. | The most widely accepted marker for stratifying the risk of sudden cardiac death (SCD) in post myocardial infarction patients is a depressed left ventricular function. Left ventricular ejection fractions (EF) of 35% or less increase the risk of sudden death but values between 35 and 40% raise concern. The underlying pathophysiological mechanism is sustained ventricular tachycardia or fibrillation, both associated with increased cardiac repolarization variability. We assessed whether the indices of QT variability from a short-term electrocardiographic (ECG) recording predict sudden death.</AbstractText>A total of 396 subjects with chronic heart failure (CHF) due to post-ischaemic cardiomyopathy, with an EF between 35 and 40% and in NYHA class I, underwent a 5 min ECG recording to calculate the following variables: QT variance (QT(v)), QT normalized for the square of the mean QT (QTVN), and QT variability index (QTVI). Corrected QT (QT(c)) was calculated from a 12-lead ECG recording. All participants were followed for 5 years. A multivariable survival model indicated that a QTVI greater than or equal to the 80th percentile indicated a high risk of SCD [hazards ratio (HR) 4.6, 95% confidence interval (CI) 1.5-13.4, P = 0.006] and, though to a lesser extent, a high risk of total mortality (HR 2.4, 95% CI 1.2-4.9, P = 0.017). The model including QTVI as a continuous variable confirmed a similar high risk for SCD (HR 2.9, 95% CI 1.3-6.5, P = 0.01) and for total mortality (HR 2.6, 95% CI 1.3-5.2, P = 0.008).</AbstractText>Although asymptomatic patients with CHF who have a slightly depressed EF are at low risk of sudden death, the category is extraordinarily numerous. The QTVI could be helpful in stratifying the risk of sudden death in this otherwise undertreated population.</AbstractText> |
9,163 | Arterial minus end-tidal CO2 as a prognostic factor of hospital survival in patients resuscitated from cardiac arrest. | The purpose of this study was to determine the clinical value of arterial minus end-tidal CO(2) [P(a-et)CO(2)] and alveolar dead space ventilation ratio (V(dA)/V(t)) as indicators of hospital mortality in patients that have been resuscitated from cardiac arrest at emergency department.</AbstractText>Forty-four patients with a return of spontaneous circulation (ROSC) after cardiac arrest were studied in the emergency department of a university teaching hospital from March 2004 to February 2006. Mean arterial pressure (MAP), serum lactate, arterial blood gas studies, end-tidal CO(2) (EtCO(2)), P(a-et)CO(2), and V(dA)/V(t) were evaluated at 1 h after ROSC. We compared these variables between hospital survivors and non-survivors.</AbstractText>The rates of ventricular fibrillation and pulseless ventricular tachycardia in hospital survivors were higher than those of non-survivors (53.0 and 9.7%, respectively, p=0.002). Hospital survivors had significantly higher MAP, lower serum lactate, lower P(a-et)CO(2), and lower V(dA)/V(t) value than non-survivors. Receiver operator characteristic (ROC) curves of serum lactate, P(a-et)CO(2), and V(dA)/V(t) showed significant sensitivity and specificity for hospital mortality. Specifically, lactate > or = 10.0 mmol/L, P(a-et)CO(2) > or = 12.5 mmHg, and V(dA)/V(t) > or = 0.348 were all associated with high hospital mortality (p=0.000, 0.001 and 0.000, respectively).</AbstractText>This study showed that high serum lactate, high P(a-et)CO(2) and high V(dA)/V(t) during early ROSC in cardiac arrest patients suggest high hospital mortality. If future studies validate this model, the P(a-et)CO(2) and V(dA)/V(t) may provide useful guidelines for the early post-resuscitation care of cardiac arrest patients in emergency departments.</AbstractText> |
9,164 | Structural and functional assessment of arrhythmogenic right ventricular dysplasia/cardiomyopathy by multi-slice computed tomography: comparison with cardiovascular magnetic resonance. | Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an uncommon inheritable cardiomyopathy involving predominant right ventricle with progressive fibrofatty tissue replacement. An integrated assessment of electrical, functional and anatomic abnormalities, in addition to personal and family history would be used to diagnose this disease entity. We present the case of a 69-year-old man with a history of sustained ventricular tachycardia. Fatty infiltration and regional wall motion abnormalities over biventricular myocardium were clearly demonstrated by cardiac 64-slice computed tomography (CT), as consistent with magnetic resonance imaging. Thus, multi-slice CT may have a significant role in the assessment and follow-up of patients with ARVD/C by providing excellent structural, functional assessment and tissue characterization. |
9,165 | Myopotentials leading to ventricular fibrillation detection after advisory defibrillator generator replacement. | We present an unusual source of oversensing following an internal cardioverter-defibrillator generator change. The early appearance of reproducible myopotentials in the defibrillator sensing channel is usually due to a technical complication at the time of device implantation. Clues such as abrupt impedance change or reproduction with mechanical stimulation can help to localize a problem. Frequently the complication requires reoperation to examine the system. What do you do when everything seems to be working fine? |
9,166 | Evaluation of atrial thrombus formation and atrial appendage function in patients with pacemaker by transesophageal echocardiography. | Physiologic pacing is claimed to be superior to ventricular pacing in as much as it entails lower risk of atrial fibrillation, stroke, and atrial remodeling. There are few data on the relation between atrioventricular (AV) synchrony and atrial clot formation. Utilizing transesophageal echocardiography (TEE), this study sought to evaluate the effect of AV synchrony loss on left atrial physiology, atrial stasis, and clot formation.</AbstractText>We conducted a cross-sectional study on patients with both AV and ventricular pacing with left ventricular ejection fraction (LVEF) >30%. TEE enabled us to explore atrial and pacing leads thrombi and measure left atrial appendage (LAA) flow velocity.</AbstractText>A total 72 patients (mean age, 65 +/- 11.7) were enrolled in the study. The pacing mode was VVI in 53% and AV sequential in 47% of patients. LVEF (mean +/- SD; %) was 53.3 +/- 6.2% in ventricular pacing mode and 52.2 +/- 6.6 in physiologic pacing mode. Thrombus formation on pacing lead (<10 mm in 97% of patients) was observed in 32% of all the patients (23% in patients with AV sequential pacing mode and 39% with VVI mode). Left atrial appendage flow velocity (LAA-FV) was significantly higher among the patients with AV sequential pacing mode (49.44 +/- 18 cm/s vs 40.94 +/- 19.4 cm/s, P value = 0.02). LAA-FV >40 cm/s was detected in 60% of the patients, 60% of whom were in physiologic mode. Left atrial size was significantly larger among the patients with VVI pacing mode (42.3 +/- 2.3 mm vs 37.79 +/- 4.5 mm, P = 0.001). Multivariate analysis showed no relation between LAA-FV and age, hypertension, diabetes mellitus, left atrial size, and left ventricular function. Only one patient had right atrial clot. There was no thrombus in the ventricles and atrial appendage.</AbstractText>Long-term loss of AV synchrony induced by VVI pacing is associated with the impairment of LAA contraction. Thrombus formation in the LAA is not increased by VVI pacing in patients with relatively good left ventricular (LV) function and sinus rhythm.</AbstractText> |
9,167 | Comparison of a standard versus accelerated dosing regimen for D,L-sotalol for the treatment of atrial and ventricular dysrhythmias. | The current recommended starting dose of sotalol is 80 mg orally twice per day, followed by a judicious increase in dosage every 3 days under continuous telemetry monitoring. We hypothesized that sotalol administered at a higher starting dose (120 or 160 mg twice daily) would allow a more rapid attainment of therapeutic response with an acceptable safety and comparable efficacy profile.</AbstractText>Two hundred nine inpatients with various atrial and ventricular dysrhythmias were begun on either a standard starting dose (80 mg b.i.d.) or an accelerated dose (120 or 160 mg b.i.d.) of sotalol. In-hospital occurrences of drug-related adverse effects (proarrhythmic and others), drug efficacy, and length of hospitalization were retrospectively compared between the two groups.</AbstractText>Ten patients (9.3%) in the 80 mg b.i.d. starting dose group experienced a cardiac adverse effect of sotalol as compared to 15 patients (14.9%) in the accelerated dose group (P = 0.286). The mean amount of corrected QT (QTc) prolongation over baseline was not significantly different between the two groups at hospital discharge (22.5 ms vs 21.6 ms, P = 0.898). There was a trend toward more noncardiac side effects of sotalol in the accelerated dose group: 2 (1.9%) versus 7(6.9%), P = 0.092. The average length of hospital stay was similar in the two groups (6.8 days vs 7.4 days, P = 0.558).</AbstractText>Initiating sotalol at 120-160 mg orally twice per day marginally increases the risk of cardiac and non-cardiac side effects compared to the standard starting regimen of 80 mg b.i.d. Such an accelerated dosing regimen neither shortened hospitalization nor had any effect on treatment efficacy in this retrospective analysis.</AbstractText> |
9,168 | Steeper restitution slopes across right ventricular endocardium in patients with cardiomyopathy at high risk of ventricular arrhythmias. | Steep action potential duration (APD) restitution slopes (>1) and spatial APD restitution heterogeneity provide the substrate for ventricular fibrillation in computational models and experimental studies. Their relationship to ventricular arrhythmia vulnerability in human cardiomyopathy has not been defined. Patients with cardiomyopathy [left ventricular (LV) ejection fraction <40%] and no history of ventricular arrhythmias underwent risk stratification with programmed electrical stimulation or T wave alternans (TWA). Low-risk patients (n = 10) had no inducible ventricular tachycardia (VT) or negative TWA, while high-risk patients (n = 8) had inducible VT or positive TWA. Activation recovery interval (ARI) restitution slopes were measured simultaneously from 10 right ventricular (RV) endocardial sites during an S1-S2 pacing protocol. ARI restitution slope heterogeneity was defined as the coefficient of variation of slopes. Mean ARI restitution slope was significantly steeper in the high-risk group compared with the low-risk group [1.16 (SD 0.31) vs. 0.59 (SD 0.19), P = 0.0002]. The proportion of endocardial recording sites with a slope >1 was significantly larger in the high-risk patients [47% (SD 35) vs. 13% (SD 21), P = 0.022]. Spatial heterogeneity of ARI restitution slopes was similar between the two groups [29% (SD 16) vs. 39% (SD 34), P = 0.48]. There was an inverse linear relationship between the ARI restitution slope and the minimum diastolic interval (P < 0.001). In cardiomyopathic patients at high risk of ventricular arrhythmias, ARI restitution slopes along the RV endocardium are steeper, but restitution slope heterogeneity is similar compared with those at low risk. Steeper ARI restitution slopes may increase the propensity for ventricular arrhythmias in patients with impaired left ventricular function. |
9,169 | Panoramic optical mapping reveals continuous epicardial reentry during ventricular fibrillation in the isolated swine heart. | During ventricular fibrillation (VF), activation waves are fragmented and the heart cannot contract synchronously. It has been proposed that VF waves emanate from stable sources ("mother rotors"). Previously, we used new optical mapping technology to image VF wavefronts from nearly the entire epicardial surface of six isolated swine hearts. We found that VF was not driven by epicardial rotors, but could not exclude the presence of stable rotors hidden within the ventricular walls. Here, we use graph theoretic analysis to show that, in all 17 VF episodes we analyzed, it was always possible to trace sequences of wavefronts through series of fragmentation and collision events from the beginning to the end of the episode. The set of wavefronts that were so related (the dominant component) consisted of 92%+/-1% of epicardial wavefronts. Because each such wavefront sequence constitutes a continuous activation front, this finding shows that complete reentrant pathways were always present on the epicardial surface and therefore, that wavefront infusion from nonepicardial sources was not strictly necessary for VF maintenance. These data suggest that VF in this model is not driven by localized sources; thus, new anti-VF treatments designed to target such sources may be less effective than global interventions. |
9,170 | Syncopal monomorphic ventricular tachycardia with pleomorphism, sensitive to antitachycardia pacing in a patient with Brugada syndrome. | Polymorphic ventricular tachycardia and ventricular fibrillation are the most common arrhythmias in Brugada syndrome, causing syncope or sudden death. Sustained monomorphic ventricular tachycardias are rare in this context. We report the case of a 41-year-old man with repetitive syncopal episodes and an ajmaline-induced characteristic Brugada ECG pattern, in whom episodes of monomorphic ventricular tachycardia with pleomorphism and response to ventricular pacing were documented. |
9,171 | Single beat determination of regional myocardial strain measurements in patients with atrial fibrillation. | Atrial fibrillation (AF) and congestive heart failure share several features and often coexist in the same patients; therefore, serial assessment of regional myocardial function is important for patients with AF. However, the clinical assessment of regional myocardial function in AF is unreliable and difficult because of beat-to-beat variation. Recent reports have shown that the ratio of the preceding to the prepreceding R-R interval (RR1/RR2) can be used to assess global left ventricular systolic function. Accordingly, we tested the hypothesis that regional wall motion can be estimated from a single beat based on RR1/RR2 in patients with AF. Peak systolic strain at basal, mid, and apical segments of the septal wall was measured by Doppler tissue imaging from an apical 4-chamber view for 30 seconds in 50 patients with AF (mean ejection fraction 52.1 +/- 15.3%; mean heart rate 76.4 +/- 16.0/min). There was a positive linear relationship between peak strain and RR1/RR2 and RR1, and a negative relationship with RR2, with the correlation of peak strain to RR1/RR2 was better than that in RR1 or RR2. Furthermore, peak strain at RR1/RR2 = 1 was calculated from the linear regression and compared with the average measured value of all recorded cardiac cycles in each patient. In all cases, average peak strain showed a significant positive correlation with RR1/RR2 at each segment (r = 0.99). In conclusion, regional myocardial strain at RR1/RR2 = 1 on the linear regression represents the average value of all recorded cardiac cycles in patients with AF. |
9,172 | Mild therapeutic hypothermia after cardiac arrest - a nationwide survey on the implementation of the ILCOR guidelines in German intensive care units. | To investigate the implementation of mild therapeutic hypothermia (MTH) after cardiac arrest into clinical practice.</AbstractText>A structured evaluation questionnaire was sent to all German hospitals registered to have ICUs; 58% completed the survey. A total of 93 ICUs (24%) reported to use MTH. Of those, 93% started MTH in patients after out-of-hospital resuscitation with observed ventricular fibrillation and 72% when other initial rhythms were observed. Only a minority of ICUs initiate MTH in patients after cardiac arrest with cardiogenic shock (28%), whereas 48% regarded cardiogenic shock as a contra-indication for MTH. On average, target temperature was 33.1+/-0.6 degrees C and duration of cooling 22.9+/-4.9 h. Many centres used economically priced cold packs (82%) and cold infusions (80%) for cooling. The majority of the ICUs considered infection, hypotension and bleeding as relevant complications of hypothermia which was of therapeutic relevance in less than 25% of the cases.</AbstractText>MTH is underused in German ICUs. Centres which use MTH widely follow the recommendations of ILCOR with respect to the indication and timing of cooling. In hospitals that use MTH the technique is considered to be safe and inexpensive. More efforts are needed to promote this therapeutic option and hypothermia since MTH has now been included into European advanced cardiovascular life support protocols.</AbstractText> |
9,173 | Rapidly induced hypothermia with extracorporeal lung and heart assist (ECLHA) improves the neurological outcome after prolonged cardiac arrest in dogs. | We reported previously that therapeutic hypothermia with extracorporeal lung and heart assist (ECLHA) improved neurological outcome after 15 min cardiac arrest (CA) in dogs, although 45 min was needed to achieve hypothermia. We now investigate whether rapidly induced hypothermia with ECLHA (RHE) would result in a better outcome than slowly induced hypothermia with ECLHA (SHE) in dogs.</AbstractText>Fifteen mongrel female dogs were divided into two groups: an RHE (n = 7) and an SHE (n = 8) group. Normothermic ventricular fibrillation was induced for 15 min and the animals were resuscitated by ECLHA. Rapid hypothermia was induced with a heat exchanger added to the ECLHA circuit in the RHE group, and by immersing the drainage tube of the ECLHA circuit in an ice water bath in the SHE group. Hypothermia (33 degrees C) was maintained for 20 h. The dogs were weaned from ECLHA at 24 h after resuscitation and treated for 96 h; neurological deficit scores (NDS) were measured throughout this period.</AbstractText>It took 1.6+/-0.8 min to reach 33 degrees C in the RHE group and 49.5+/-12.1 min to reach 33 degrees C in the SHE group. There was no difference in survival rate between the two groups. The NDS at 96 h in the RHE group was better than that in the SHE group (26% (range: 10-28%) versus 32% (26-37%); p < 0.05) although there was no significant difference in NDS between the two groups until 72 h.</AbstractText>Rapid hypothermic induction might be an important factor to improve neurological outcomes in prolonged CA models.</AbstractText> |
9,174 | An unusual cause of atrial fibrillation: exposure to insecticides. | Although there are many well-known cardiac results of insecticide poisoning, atrial fibrillation (AF) has not been reported as the result of insecticide intoxication.</AbstractText>Twenty-six-year-old male, complaining of nausea and vomiting, presented to the emergency department with a history of methomyl dust exposure. All physical examination findings were normal except irregular heart rate on cardiac auscultation. The electrocardiogram of the patient showed AF with normal ventricular response. Patient's acetylcholinesterase (ACE) level was 3,319 IU/L in presentation and pralidoxim use was seen unnecessary for the treatment. The patient's rhythm spontaneously returned to sinus rhythm 24 hr after the presentation and no cardiopulmonary pathology was found during the follow-up. The patient was discharged without symptoms.</AbstractText>AF is a rare complication of insecticide intoxication. In this case, treatment of symptoms was adequate until a normal sinus rhythm returned.</AbstractText>(c) 2006 Wiley-Liss, Inc.</CopyrightInformation> |
9,175 | Underuse of standard care and outcome of patients with acute myocardial infarction and chronic renal insufficiency. | To investigate characteristics, management and outcome of patients with acute myocardial infarction (AMI) and chronic renal insufficiency (CRI).</AbstractText>Patients with AMI and CRI are considered to be at high risk of complications and death. Physicians may be reluctant to prescribe life-saving medications to patients with concomitant CRI.</AbstractText>We compared clinical characteristics, management and outcome of 1,683 consecutive AMI patients in three categories of renal function: (1) normal renal function (<1.5 mg/dl) (n = 1,559), (2) mild to moderate CRI (1.5-3.5 mg/dl) (n = 77), and (3) severe CRI (>3.5 mg/dl) (n = 47).</AbstractText>CRI patients were older and were more likely to have other co-morbidities such as hypertension, diabetes mellitus, prior AMI, stroke, angina and heart failure. Compared with patients with normal renal function, standard therapy for AMI including thrombolysis, aspirin, angiotensin-converting-enzyme inhibitors, beta-blockers and lipid lowering agents was underutilized in CRI patients and these patients were more likely to have in-hospital complications such as heart failure, atrial or ventricular fibrillation, cardiogenic shock, sepsis, worsening of renal function and death within 30 days [odds ratio (OR) = 3.3; 95% confidence interval (CI) = 2.0-4.8]. After adjustment for age and co-morbidities, the association between mild to moderate CRI and 30-days mortality declined, whereas severe CRI remained an independent determinant of mortality (OR = 4.8; 95% CI = 2.0-11.4). Adjustment for aspirin, angiotensin-converting-enzyme inhibitors and beta-blocker therapy weakened the association between CRI and death within 30 days after AMI.</AbstractText>CRI patients are more likely to experience serious complications and death early after AMI. Underutilization of standard care, particularly beta-blocker therapy, contributes to increased mortality risk in these patients.</AbstractText>2007 S. Karger AG, Basel</CopyrightInformation> |
9,176 | Up-regulation of the inward rectifier K+ current (I K1) in the mouse heart accelerates and stabilizes rotors. | Previous studies have suggested an important role for the inward rectifier K+ current (I K1) in stabilizing rotors responsible for ventricular tachycardia (VT) and fibrillation (VF). To test this hypothesis, we used a line of transgenic mice (TG) overexpressing Kir 2.1-green fluorescent protein (GFP) fusion protein in a cardiac-specific manner. Optical mapping of the epicardial surface in ventricles showed that the Langendorff-perfused TG hearts were able to sustain stable VT/VF for 350 +/- 1181 s at a very high dominant frequency (DF) of 44.6 +/- 4.3 Hz. In contrast, tachyarrhythmias in wild-type hearts (WT) were short-lived (3 +/- 9 s), and the DF was 26.3 +/- 5.2 Hz. The stable, high frequency, reentrant activity in TG hearts slowed down, and eventually terminated in the presence of 10 mum Ba2+, suggesting an important role for I K1. Moreover, by increasing I K1 density in a two-dimensional computer model having realistic mouse ionic and action potential properties, a highly stable, fast rotor (approximately 45 Hz) could be induced. Simulations suggested that the TG hearts allowed such a fast and stable rotor because of both greater outward conductance at the core and shortened action potential duration in the core vicinity, as well as increased excitability, in part due to faster recovery of Na+ current. The latter resulted in a larger rate of increase in the local conduction velocity as a function of the distance from the core in TG compared to WT hearts, in both simulations and experiments. Finally, simulations showed that rotor frequencies were more sensitive to changes (doubling) in I K1, compared to other K+ currents. In combination, these results provide the first direct evidence that I K1 up-regulation in the mouse heart is a substrate for stable and very fast rotors. |
9,177 | Increased survival despite a reduction in out-of-hospital ventricular fibrillation in north-east Italy. | We have reported the epidemiology and survival rate of out-of-hospital cardiac arrest (OOH-CA) in a north-east region of Italy previously, the Friuli-Venezia-Giulia Arrest Cooperative Study (FACS). We present the results of a second observational, prospective, multicentre study on OOH-CA victims in a local area in the same geographical Italian region.</AbstractText>The area investigated, Pordenone province, is representative of the entire region studied in 1994. In the 1994 FACS study, the heterogeneous ambulance personnel, ranging from volunteers to registered nurses and physicians, were not all trained in basic life support and early defibrillation. In 2003 all rescuers had advanced cardiac life support (ACLS) skills. Moreover, in 2003 dispatch-guided CPR was used. The time from dispatch to defibrillation of victims of OOH-CA from cardiac aetiology was comparable between 1994 and 2003. However, the rate of ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) as presenting rhythm decreased significantly between 1994 and 2003 from 30.2% to 20.1% (p < 0.05). Despite this, survival to hospital discharge for VF/VT almost tripled (15.4% versus 41.0%; p < 0.05). Hospital discharge for asystole or pulseless electrical activity remained dismal (3.1% and 1.7%).</AbstractText>Despite a reduction in the rate of VF/VT as presenting rhythm, survival was almost tripled. Manning all ambulances with professional emergency medical personnel and ACLS training together with dispatch-guided CPR may have contributed to the improvements observed in survival rates.</AbstractText> |
9,178 | Growth hormone decreases phase II ventricular tachyarrhythmias during acute myocardial infarction in rats. | GH (growth hormone) administration during acute MI (myocardial infarction) ameliorates subsequent LV (left ventricular) dysfunction. In the present study, we examined the effects of such treatment on arrhythmogenesis. A total of 53 Wistar rats (218+/-17 g) were randomized into two groups receiving two intraperitoneal injections of either GH (2 international units/kg of body weight; n=26) or normal saline (n=27), given at 24 h and 30 min respectively, prior to MI, which was generated by left coronary artery ligation. A single-lead ECG was recorded for 24 h post-MI, using an implanted telemetry system. Episodes of VT (ventricular tachyarrhythmia) and VF (ventricular fibrillation) during the first hour (phase I) and the hours following (phase II) MI were analysed. Monophasic action potential was recorded from the lateral LV epicardium at baseline and 24 h post-MI, and APD90 (action duration at 90% of repolarization) was measured. Infarct size was calculated 24 h post-MI. Infarct size and phase I VT+VF did not differ significantly between groups, but phase II hourly duration of VT+VF episodes was 82.8+/-116.6 s/h in the control group and 18.3+/-41.2 s/h in the GH group (P=0.0027), resulting in a lower arrhythmic (P=0.016) and total (P=0.0018) mortality in GH-treated animals. Compared with baseline, APD90 was prolonged significantly 24 h post-MI in the control group, displaying an increased beat-to-beat variation, but remained unchanged in the GH group. We conclude that GH decreases phase II VTs during MI in the rat. This finding may have implications in cardiac repair strategies. |
9,179 | [Treatment of hydroxychloroquine poisoning with extracorporeal circulation]. | We report a case of massive overdose of hydroxychloroquine treated with circulatory assistance by peripheral extracorporeal circulation (ECC). We expose the case of a 39-year-old woman who ingested 12 g of hydroxychloroquine with bromazepam, paroxetine, and zolpidem, in a suicide attempt. Patient has developed central nervous system depression, hemodynamic failure, life-threatening ventricular arrhythmias, and serious hypokalemia. Initially the patient has received conventional treatment with gastric lavage and activated charcoal for gastrointestinal decontamination, blood volume expansion and vasopressive drugs, intubation and mechanical ventilation, high dose of diazepam, and potassium replacement. A ventricular fibrillation was treated with external cardiac massage. In spite of this treatment, cardiogenic shock was uncontrolled, and imposed circulatory assistance. After extracorporeal circulation, we observed a spectacular improvement of hemodynamic parameters and electrocardiographic normalization at day one. Extracorporeal circulation could be used as a rescue treatment of cardiotrope and hydroxychloroquine overdoses. |
9,180 | Imaging of left main coronary artery dissection with multislice computed tomography. | We occurred in a left main (LM) dissection during primary coronary intervention in a 45-year-old man with anterior acute myocardial infarction. Successful, multiple direct stenting was performed from the ostial to the mid left anterior descending coronary artery (LAD). Nonetheless, an LM dissection involving the proximal circumflex artery (Cx) was still evident at the end of the intervention. Multislice Computed Tomography (MSCT) coronary angiography images showed that LM dissection was definitely long and close to the ostium; moreover, the proximal stent had both excluded the false lumen in the LAD and stabilized the dissection towards the Cx. Two months later, at MSCT coronary angiography the LM dissection was still evident and the patient had remained totally asymptomatic. MSCT coronary angiography can be recommended as a complementary diagnostic tool for the assessment of LM anatomy because of the possibility of three-dimensional reconstructions and consequent clear evaluation of its take-off, course and bifurcation. |
9,181 | A case of a borderline-broad complex tachycardia. | Prompt and correct treatment of broad complex tachycardias in the emergency department can often be life-saving to the patient and satisfying for the emergency physician. They, however, are often a diagnostic challenge. Here, we present a case of posterior fascicular ventricular tachycardia, an idiopathic form of ventricular tachycardia that occurs in patients without coronary artery disease and verapamil sensitive. The differential diagnoses of posterior fascicular ventricular tachycardia and supraventricular tachycardia with aberrancy will also be discussed. |
9,182 | Improved electrodes for electrical defibrillation of rats. | Experimental induction of ventricular fibrillation in animals yields valuable information about this deadly arrhythmia. Human adult or pediatric defibrillators and their paddles can be used easily in larger animals such as dogs and pigs, but these animals are more difficult to house and handle, and available biochemical assays may be limited. In contrast, rats are easy and relatively inexpensive to house and handle, and numerous biochemical tests are available. However, in most cases, even pediatric electrodes are impractical for use in rats. Proper placement of defibrillation electrodes on the thorax requires that the electrical axis of the heart be situated between the defibrillator paddles. The most common approach to defibrillation in rats uses 2 electrodes: one is built into a board that underlies and touches the rat's back, and another is positioned manually on the anterior thorax. The aim of this study was to produce electrodes that are 1) easy to handle, 2) specifically designed for rats, 3) efficiently deliver defibrillation shocks along the electric axis of the heart, and 4) can be used for both in vivo defibrillation and on isolated heart preparations. |
9,183 | [A case of Brugada syndrome with convulsive seizure during antidepressant administration: relation of antidepressant agents and arrhythmia leading to sudden death]. | Brugada syndrome is an arrhythmogenetic disease characterized by electrocardiographic ST segment elevation in right precordial leads, which is called "coved type", and an increased risk of sudden death as the result of ventricular fibrillation. We presented a case of Brugada syndrome with a convulsive seizure, during administration of a tricyclic antidepressant for the treatment of a depressive state. A 43-year-old man with bipolar II disorder and obsessive-compulsive disorder was admitted to our hospital for the treatment of a depressive state. There was no medical history of heart failure. Nortriptyline was effective for his depressive as well as for obsessive symptoms. During the treatment, however, he presented a convulsive syncope. Electrocardiography (ECG) showed "coved type" ST segment elevation, and the patient consulted a cardiologist. Electrophysiological study revealed Brugada syndrome, and an implantable cardioverter defibrillator was placed. An overdose of antidepressants has been reported to produce a Brugada-type ECG because of its Na channel antagonism. However, in the present case, the abnormal ECG findings occurred following a usual dosage of nortriptyline. Thus, it is suggested that Brugada syndrome is related to a susceptibility to antidepressants in the present case. Every psychiatrist managing antidepressant therapy should be aware of Brugada syndrome and this ECG pattern, which may be a marker of sudden death. |
9,184 | [From implantable cardioverter-defibrillator to cardiac resynchronization therapy with the use of epicardial left ventricular lead. The evolution of the treatment of post inflammatory heart failure--a case report]. | The authors present a case of a 77-year-old man with heart failure in the course of dilated cardiomyopathy (DCM) and atrial fibrillation (AF), after implantation of an automatic cardioverter-defibrillator (ICD) due to recurrent symptomatic ventricular tachycardia (VT). Addition of cardiac resynchronization therapy (CRT) was decided due to the heart-failure dependent intensification of the arrhythmia and poststimulation enlargement of QRS. CRT was led to withdraw patient's arrhythmia and to improvement of the general condition of the patient for approximately one year. After the arrhythmia reoccurred due to dislocation of the electrode in the coronary sinus with loss of left ventricle stimulation. Multiple attempts at restoration of resynchronization function via a transvenous approach failed. The patient was qualified for implantation of an epicardial left ventricle electrode. The surgery was combined with a planned exchange of ICD-CRT. Basing on a 6-month observation period an improvement heart performance and general state of health have been observed. No arrhythmic event has been noted in device memory. Performed procedures are picturing the evolution of in pacing techniques and automatic defibrillation in Poland over recent years. |
9,185 | Atrial fibrillation onset circumstances and their relation to patients' quality of life. | As assessed by patients, paroxysmal atrial fibrillation (AF) is very bothersome and significantly decreases quality of life (QoL).</AbstractText>To learn the circumstances that patients attribute to the onset of episodes of paroxysmal AF and attempt to characterise the psychological importance of these situations and their influence on patients' QoL.</AbstractText>The study involved 76 patients (54 males, aged 17-74 years, mean 53.2), referred for ablation of paroxysmal AF. Disease duration ranged from 1 to 30 years, mean 8.3 years. Physical examination included searching for comorbidities and maximum ventricular rate during AF. Patients underwent psychological evaluation prior to ablation. The QoL was assessed with the SF-36v2 questionnaire. Questionnaire detailing the symptoms was also used.</AbstractText>Fifty-five (72%) patients were able to indicate situations accompanying onset of paroxysmal AF. From depicted situations cluster analysis distinguished three clusters: I--heavy meals, alcohol and coffee intake, exercise or stress; II--single sudden movement and rest following stressful events; III--sleep. Significant difference in QoL assessment was observed between these 3 groups. Patients in whom paroxysmal AF occurred after a single sudden movement and at rest find their QoL definitely the worst. The best QoL was in subjects with AF starting at night. Maximum ventricular rate during AF did not correlate with QoL in the whole study group; however, gender-matched analysis revealed significant correlation in females (r=-0.58; p=0.03). There was no significant correlation between other analysed variables and QoL.</AbstractText>Objective indicators between patient health, such as disease duration or comorbidities, do not affect patients' subjective assessment of QoL. Maximum ventricular rate during AF correlated with QoL only in females. Circumstances of AF event onsets, their relationship with disorganisation of activities and psychological value significantly influence QoL of the patients.</AbstractText> |
9,186 | Right ventricular apex versus right ventricular outflow tract pacing: prospective, randomised, long-term clinical and echocardiographic evaluation. | In patients treated with permanent pacing, the electrode is typically placed in the right ventricular apex (RVA). Published data indicate that such electrode placement leads to an unfavourable ventricular depolarization pattern, while right ventricular outflow tract (RVOT) pacing seems to be more physiological.</AbstractText>To compare long-term effects of RVOT versus RVA pacing on clinical status, left ventricular (LV) function, and the degree of atrioventricular valve regurgitation.</AbstractText>Patients with indications for permanent pacing, admitted to hospital between 1996 and 1997, were randomised to receive RVA or RVOT pacing. In 2004 during a final control visit in 27 patients clinical status, echocardiographic parameters and QRS complex duration as well as NT-proBNP level were measured. Analysed parameters were compared between groups and in the case of data available during the perioperative period also their evolution in time was assessed.</AbstractText>Out of 27 patients 14 were randomised to the RVA group and 13 to the RVOT group. No significant differences between groups were observed before the procedure with respect to age, gender, comorbidities or echocardiographic parameters. Mean duration of pacing did not differ significantly between the groups (89+/-9 months in RVA group vs 93+/-6 months in RVOT group, NS). In the RVA group significant LV ejection fraction decrease was observed (from 56+/-11% to 47+/-8%, p <0.05); in the RVOT group LV ejection fraction did not change (54+/-7% and 53+/-9%; NS). Progression of tricuspid valve regurgitation was also observed in the RVA group but not in the RVOT group. During the final visit NT-proBNP level was significantly higher in the RVA group: 1034+/-852 pg/ml vs 429+/-430 pg/ml (p <0.05).</AbstractText>In patients with normal LV function permanent RVA pacing leads to LV systolic and diastolic function deterioration. RVOT pacing can reduce the unfavourable effect and can slow down cardiac remodelling caused by permanent RV pacing. Clinical and echocardiographic benefits observed in the RVOT group after 7 years of pacing are reflected by lower NT-proBNP levels in this group of patients.</AbstractText> |
9,187 | Detection of ventricular fibrillation in the presence of cardiopulmonary resuscitation artefacts. | Providing cardiopulmonary resuscitation (CPR) to a patient in cardiac arrest introduces artefacts into the electrocardiogram (ECG), corrupting the diagnosis of the underlying heart rhythm. CPR must therefore be discontinued for reliable shock advice analysis by an automated external defibrillator (AED). Detection of ventricular fibrillation (VF) during CPR would enable CPR to continue during AED rhythm analysis, thereby increasing the likelihood of resuscitation success. This study presents a new adaptive filtering method to clean the ECG. The approach consists of a filter that adapts its characteristics to the spectral content of the signal exclusively using the surface ECG that commercial AEDs capture through standard patches. A set of 200 VF and 25 CPR artefact samples collected from real out-of-hospital interventions were used to test the method. The performance of a shock advice algorithm was evaluated before and after artefact removal. CPR artefacts were added to the ECG signals and four degrees of corruption were tested. Mean sensitivities of 97.83%, 98.27%, 98.32% and 98.02% were achieved, producing sensitivity increases of 28.44%, 49.75%, 59.10% and 64.25%, respectively, sufficient for ECG analysis during CPR. Although satisfactory and encouraging sensitivity values have been obtained, further clinical and experimental investigation is required in order to integrate this type of artefact suppressing algorithm in current AEDs. |
9,188 | On-pump beating-heart mitral valve plasty without aortic cross-clamping. | Patients with ischemic cardiomyopathy often have mitral regurgitation, which should be corrected for better long-term survival. Mitral valve surgery is usually performed during cardiopulmonary bypass under the arrested heart condition. The ascending aorta is cross-clamped and the heart is arrested using a cardioplegic solution. However, because ischemic cardiomyopathy patients often have a severely atherosclerotic ascending aorta and low cardiac function, aortic cross-clamping and cardiac arrest increase the risk of postoperative thromboemboli and low cardiac output syndrome. Under the on-pump beating-heart condition, we performed mitral valve plasty concomitant with coronary artery bypass grafting, tricuspid annuloplasty, left ventricular aneurysmectomy, and the maze procedure without aortic cross-clamping for a patient with ischemic dilated cardiomyopathy and bradycardial atrial fibrillation. The patient had no postoperative complications and re covered rapidly. Thus, to prevent serious postoperative complications, on-pump beating-heart mitral valve surgery without aortic cross-clamping may be a suitable surgical option for patients with ischemic cardiomyopathy. |
9,189 | Cardiac resynchronization therapy in chronic heart failure. | Cardiac resynchronisation therapy (CRT) has emerged as a treatment option for patients with severe, drug-refractory heart failure and signs of intraventricular dyssynchrony. In clinical trials CRT reduced the overall mortality, improved symptoms, exercise tolerance, and left ventricular function, as compared with optimised medical therapy alone. One of the challenging fields in patient selection for CRT is to identify the 20-30% of heart failure patients with bundle branch block that will not respond to this novel therapy. Other fields of uncertainty, such as CRT in patients with atrial fibrillation or chronic right ventricular stimulation as well as the role of a back-up defibrillator will be discussed. |
9,190 | From hypertension to heart failure -- are there better primary prevention strategies? | Although in the developed world the incidence of and mortality from coronary heart disease (CHD) and stroke have been declining over the last 15 years, heart failure is increasing in incidence, prevalence and overall mortality, despite advances in the diagnosis and management of the condition. Hypertension, alone or in combination with CHD, precedes the development of heart failure in the majority of both men and women. Whilst there have been improvements in the overall management of hypertension, as reflected in rates of diagnosis, awareness, treatment and control of blood pressure (BP), there are still many patients with hypertension who remain undiagnosed or untreated and of those who do receive treatment many fail to achieve current targets for BP control. Placebo-controlled trials in hypertension, largely based on diuretic and beta-blocker-based regimens, have unequivocally demonstrated that the treatment of hypertension can significantly reduce the incidence of heart failure. Newer treatment strategies offer theoretical and proven practical advantages over established antihypertensive therapy. In particular, AT1-receptor blockers appear to provide benefits beyond BP control and are effective in the treatment of both hypertension and heart failure. Thus, the primary prevention of heart failure in hypertensive patients should be based upon strategies that provide tight and sustained BP control necessitating the use of multiple drugs. However, there is now compelling evidence to suggest that this therapy should include an antihypertensive agent that inhibits the reninangiotensin- aldosterone system (RAAS). |
9,191 | Ryanodine receptors and ventricular arrhythmias: emerging trends in mutations, mechanisms and therapies. | It has been six years since the first reported link between mutations in the cardiac ryanodine receptor Ca(2+) release channel (RyR2) and catecholaminergic polymorphic ventricular tachycardia (CPVT), a malignant stress-induced arrhythmia. In this time, rapid advances have been made in identifying new mutations, and in understanding how these mutations disrupt normal channel function to cause VT that frequently degenerates into ventricular fibrillation (VF) and sudden death. Functional characterisation of these RyR2 Ca(2+) channelopathies suggests that mutations alter the ability of RyR2 to sense its intracellular environment, and that channel modulation via covalent modification, Ca(2+)- and Mg(2+)-dependent regulation and structural feedback mechanisms are catastrophically disturbed. This review reconciles the current status of RyR2 mutation-linked etiopathology, the significance of mutational clustering within the RyR2 polypeptide and the mechanisms underlying channel dysfunction. We will also review new data that explores the link between abnormal Ca(2+) release and the resultant cardiac electrical instability in VT and VF, and how these recent developments impact on novel anti-arrhythmic therapies. Finally, we evaluate the concept that mechanistic differences between CPVT and other arrhythmogenic disorders may preclude a common therapeutic strategy to normalise RyR2 function in cardiac disease. |
9,192 | [Observation on the safety: clinical trail on intracoronary autologous bone marrow mononuclear cells transplantation for acute myocardial infarction]. | To investigate the safety of autologous bone marrow mononuclear cell (BM-MNCs) transplantation by intracoronary infusion in patients with acute myocardial infarction (AMI).</AbstractText>One hundred and eighty-four patients with AMI treated with percutaneous coronary intervention (PCI) were randomized in a 1:1 way to either intracoronary transplantation of autologous BM-MNCs (n = 92) right after PCI or to sodium chloride concluding heparin (controlled, n = 92) via a micro infusion catheter. In the process of the intracoronary infusion of BM-MNCs, the complications should be recorded, which were aberration reflect (including of pale, syncope, nausea, hypotension and shock), deterioration of angina or heart failure, arrhythmias (including of bradycardia, sinus arrest or atrial ventricular block or ventricular fibrillation), embolism etc. Body temperature, blood pressure and heart rates should be monitored during the first week after transplantation. Holter, coronary angiography and ultrasonic cardiography were performed at the designed time points. Main heart accidents, restenosis and tumor were recorded during 2-years follow up.</AbstractText>During the period of bone marrow puncture and intracoronary infusion of BM-MNCs, few patients occurred pale, dizziness, bradycardia and hypotension, which were transient and due to vagus reflect. No stem cell-related arrhythmias, deterioration of angina were noted. In BM-MNCs group one patient developed in-stent reocclusion in one week after transplantation, five developed in-stent restenosis during further follow-up 30 months, which were similar with control group. There were no deaths, major adverse cardiac events, tumor and other late adverse events during follow-up period in both groups.</AbstractText>Intracoronary transplantation of autologous BM-MNCs in the acute phase after AMI is feasible and seems safe in the 30 months of follow-up.</AbstractText> |
9,193 | Newly detected atrial fibrillation following dual chamber pacemaker implantation. | Pacemaker (PPM)-detected atrial high-rate episodes (AHREs) of even 5-minute duration may identify patients at increased risk for stroke and death. In this study, we sought to determine the incidence of newly detected atrial fibrillation (AF defined as an AHRE > or = 5 minutes) in patients following dual-chamber PPM implantation and to define the clinical predictors of developing AF.</AbstractText>We evaluated 262 patients (142 male; age 74 +/- 12 years) without documented AF who underwent PPM implantation for sinus node dysfunction (n = 122) or atrioventricular block (n = 140). Information regarding patient demographics, cardiovascular diseases, and medication history was obtained. The cumulative percentages of ventricular pacing as well as the frequency, duration, and time to first episode of an AHRE were also determined. During follow-up of 596 +/- 344 days, an AHRE > or = 5 minutes was detected in 77 (29%) patients. Of these, 47 (61%) patients had an AHRE > or = 1 hour, 22 (29%) patients had an AHRE > or = 1 day, and 12 (16%) patients had an AHRE > or = 1 week. An AHRE > or = 5 minutes was seen in 24% and 34% of patients at 1 year and 2 years, respectively. Among patients with sinus node dysfunction, > or = 50% cumulative ventricular pacing was the only significant predictor of an AHRE > or = 5 minutes (HR 2.2; CI 1.0-4.7; P = 0.04).</AbstractText>Within 1 year of PPM implantation, AF is detected in 24% of patients without history of AF. In patients with sinus node dysfunction, > or = 50% cumulative right ventricular pacing is associated with a 2-fold increase in risk of developing AF.</AbstractText> |
9,194 | Reversal of left ventricular dysfunction following ablation of atrial fibrillation. | Evaluation of ventricular rate control in atrial fibrillation (AF) can be difficult, and the presence of an AF-induced ventricular cardiomyopathy due to intermittent poor rate control or other causes may be underestimated. The outcome with AF ablation in patients with a decreased left ventricular ejection fraction (LVEF) may provide insight into this important clinical issue.</AbstractText>To determine the effect of pulmonary vein isolation on LVEF in patients with AF and decreased LVEF (< or = 50%).</AbstractText>Ablation consisted of proximal isolation of arrhythmogenic pulmonary veins (PVs) and elimination of non-PV triggers. LVEF was determined within 24 hours after ablation and again at up to 6 months follow-up. Transtelephonic monitoring was performed routinely for 2-3 weeks prior to ablation, at 6 weeks, and 6 months post and with symptoms following ablation. AF control was defined as freedom from AF or marked (>90%) reduction in AF burden on or off previously ineffective antiarrhythmic medication.</AbstractText>AF ablation was performed in 366 patients and 67 (18%) patients had decreased LV function with a mean LVEF of 42 +/- 9%. An average of 3.4 +/- 0.9 PVs were isolated. AF control in the depressed LVEF group compared favorably with the normal EF group (86% vs. 87% P = NS), although more redo procedures were required (1.6 +/- 0.8 vs 1.3 +/- 0.6 procedures; P < or = 0.05). Only 15 of 67 patients (22%) with decreased LVEF had shown tachycardia (>100 bpm) on repeated preablation ECG recordings during AF. In the decreased LVEF group, the LVEF increased from 42 +/- 9% to 56 +/- 8% (P < 0.001) after ablation.</AbstractText>Patients with AF and decreased LVEF undergoing AF ablation have similar success to patients with normal LVEF and have improvement in LVEF after ablation. These results suggest the presence of a reversible AF-induced ventricular cardiomyopathy in many patients with AF and depressed LV function. The presence of under-recognized and reversible cardiomyopathy even when tachycardia is not persistent is important to recognize.</AbstractText> |
9,195 | The Managed Ventricular pacing versus VVI 40 Pacing (MVP) Trial: clinical background, rationale, design, and implementation. | Implantable cardioverter defibrillators (ICDs) reduce mortality among appropriately selected patients who have had or are at risk for life-threatening ventricular arrhythmia. Right ventricular apical (RVA) pacing has been implicated in worsening heart failure and death. The optimal pacemaker mode for bradycardia support while minimizing unnecessary and potentially harmful RVA pacing has not been determined.</AbstractText>The Managed Ventricular pacing vs. VVI 40 Pacing Trial (MVP) is a prospective, multicenter, randomized, single-blind, parallel, controlled clinical trial designed to establish whether atrial-based dual-chamber managed ventricular pacing mode (MVP) is equivalent or superior to back-up only ventricular pacing (VVI 40) among patients with standard indications for ICD therapy and no indication for bradycardia pacing. The MVP Trial is designed with 80% power to detect a 10% reduction in the primary endpoint of new or worsening heart failure or all-cause mortality in the MVP-treated group. Approximately 1,000 patients at 80 centers in the United States, Canada, Western Europe, and Israel will be randomized to MVP or VVI 40 pacing after successful implantation of a dual-chamber ICD. Heart failure therapies will be optimized in accordance with evidence-based guidelines. Prespecified secondary endpoints will include ventricular arrhythmias, atrial fibrillation, new indication for bradycardia pacing, health-related quality of life, and cost effectiveness. Enrollment began in October 2004 and concluded in April 2006. The study will be terminated upon recommendation of the Data Monitoring Committee or when the last patient enrolled and surviving has reached a minimum 2 years of follow-up.</AbstractText>The MVP Trial will meet the clinical need for carefully designed prospective studies to define the benefits of atrial-based dual-chamber minimal ventricular pacing versus single-chamber ventricular pacing in conventional ICD patients.</AbstractText> |
9,196 | [Thrombo-embolic events in patients with mechanical prosthetic valves--echocardiography in diagnostic and therapeutic decision making]. | Mechanical prosthetic valves (PV) are prone to thrombosis which may result in death or cripple hood due to PV blockade and embolisation (EM). In most pts with clinical symptoms of PV thrombosis (TPV) and in pts with a history of EM transthoracic echocardiography (TTE) and Doppler echocardiography are sufficient in diagnosing but not in stating the exact mechanism of PV stenosis. Transesophageal echocardiography (TEE) is a method of choice in the therapeutic decision making in this group of pts. PV replacement is indicated in pts with a thrombus floating in the left atrium (LA), large, peduncle-like thrombus in LA, TPV in mitral or aortic position with blockade of the disc and symptoms of heart failure < III NYHA, TPV with a high risk of spontaneous or post-thrombolytic EM (large thrombus on the PV annulus >5 mm or >0.8 cm2, highly mobile thrombus, history of EM). Thrombolysis is recommended in tricuspid TPV, TPV in mitral or aortic position with blockade of the disc and symptoms of heart failure III/IV NYHA. Intravenous heparin infusion can be effective as a short-term bridging to PV replacement or an alternative for thrombolysis in case of TPV with no signs of disc blockade. The results of thrombolysis and heparin infusion should be controlled by TEE. In pts with proper function of PV on clinical examination and negative history of EM, TTE/TEE should be considered if the risk factors of EM are present: incorrect INR control, atrial fibrillation, left ventricular dysfunction, III/IV NYHA, diabetes, certain types of PV cage PV, pivoting-disc PV other than Medtronic-Hall valve. |
9,197 | Documentation of dynamic electrocardiographic changes shortly after the onset of tako-tsubo cardiomyopathy. | A 76-year-old female with atrial fibrillation and prior cerebral infarction had chest discomfort during rehabilitation for left hemiparesis, and visited the nearby hospital. Her ECG, which was obtained 10 min after the onset, showed marked ST-segment elevation in leads I, II, III, aV(F) and V(2-6), and she was referred to our hospital for cardiac examination. On admission, her ECG, which was obtained 50 min after the onset, showed poor R wave progression and mild ST-segment elevation in leads V(5-6). During only 10 min after the admission, the ST-segment level increased dynamically, and it decreased spontaneously again. Left ventriculography showed akinesia of the mid-to-distal portion and hyperkinesia of the basal portion of the left ventricular chamber, and coronary angiography showed no significant coronary artery disease despite of significant ST-segment elevation. We diagnosed her as having tako-tsubo cardiomyopathy. She was discharged well 10 days later. |
9,198 | [Characteristics of action of various drugs blocking atrioventricular conduction (beta-blockers, verapamil, diltiazem) in constant fibrillation tachyarrhythmia. Is monotherapy optimal?]. | To characterize actions of beta-blockers and Ca antagonists (verapamil and diltiazem) on the rate, structure and parameters of ventricular rhythm variability in constant cardiac fibrillation (CCF) and to evaluate validity of monotherapy with these drugs.</AbstractText>Thirty patients with CCF (mean age 64.5 +/- 9.5 years) received beta-blockers (n = 10, atenolol in a dose 50.0 +/- 23.2 mg/day or metoprolol in a dose 45.0 +/- 20.9 mg/day), verapamil (n = 10, 192.0 +/- 83.9 mg/day) and diltiazem (n = 10, 286.6 +/- 107.2 mg/day). The patients were studied with Holter ECG monitoring (Schiller MT-100, Switzerland) and high resolution ECG (electrocardioanalyser Cardis, Geolink-electronics, RF) with construction of periodograms of ff waves and interval histograms RR (IHrr), estimation of the rhythm variability (SDRR, rMSSD, PNN50).</AbstractText>Beta-blockers (atenolol, metoprolol), verapamil and diltiazem had no significant effect on the period of ff waves. The degree of a mean heart rate lowering decreased in the following order: beta-blockers-verapamil-diltiazem (30.1 +/- 12.5, 25.0 +/- 18.8 and 22.0 +/- 23.6 beat/min, differences are insignificant), this corresponded to the degree of Rrmin increase (0.12 +/- 0.04, 0.08 +/- 0.07 and 0.07-0.08). In CCF the inhibiting effect of beta-blockers and verapamil is substrate-dependent: the shorter baseline Rrmin (and higher heart rate), the more potent is the effect due to action of beta-blockers and verapamil (r = -0.58 and r = -0.57, p < 0.05) and reduction of a mean heart rate (r = -0.74 and r = -0.84, p < 0.05). Dependence of diltiazem effect on initial Rrmin is inverse. In contrast to Ca antagonists (verapamil, diltiazem), beta-blockers increased latent conduction manifesting in a significant rise of Rrmax, range of RR intervals (the difference between Rrmax and Rrmin) and in increased latent conduction (Rrmax/Rrmin) by 0.4 versus 0 and 0.1 in the groups on verapamil and diltiazem). In addition to insufficient shift RRmod, there appeared non-optimal rhythm structure--combination of a large number of short and long RR in small number of middle ones. Verapamil and diltiazem improved the rhythm pattern due to proportional increase of RRmin shift RRmod (r = 0.72 and r = 0.71, p < 0.05) and absence of a distinct effect on latent conduction. The between groups differences by SDRR, RMSSD and PNN50 dynamics were insignificant. Diltiazem in doses 360-480 mg/ day moderately increased latent conduction, but was low effective in the presence of early peak RR (0.28-0.46 s).</AbstractText>Monotherapy with AB-blocking drugs was possible only in patients with moderate tachycardia, no waves of fibrillation of large and middle periods (0.15 s and higher) and should be conducted under Rrmin control. In the other cases, the above drugs are either low effective or promote non-optimal rhythm structure. Therefore, combined therapy with AB-blocking drugs and cardiac glycosides is indicated for CCF patients.</AbstractText> |
9,199 | Estimated risk of a first stroke and conditioning factors in Spanish hypertensive women. The RIMH study. | Stroke is the leading cause of mortality in women in Spain. RIMHA is a cross-sectional multicenter study in hypertensive women aged 55 or more in primary care to estimate the 10-year risk for a first stroke. Clinical history, cardiovascular risk factors and diseases, electrocardiogram, blood samples and blood pressure (BP) were recorded. Stroke and coronary risk were estimated using the appropriate Framingham scales; 12875 patients were included (mean age 68.0+/-8.5 years, 29.1% with diabetes, 19.7% with cardiovascular disease). Electrocardiographic left ventricular hypertrophy (LVH) was present in 19.2% BP was controlled in 42.9% of non-diabetic (BP<140/90 mmHg) and 9.7% of diabetic patients (BP<130/80 mmHg). The 10-year risk (+/- SD) for a first stroke was estimated as 15.8+/-16.3%, and the coronary risk as 12.0+/-6.3. In the multivariate analysis, the most contributing factors for stroke risk estimation were age, systolic BP, LVH and atrial fibrillation. In conclusion, the 10-year estimated stroke risk for Spanish hypertensive women aged 55 years or more was higher than the estimated coronary risk, in accordance with the high rates of morbidity and mortality due to stroke among women in Spain. The most powerful risk factors were older age, poor BP control, LVH and atrial fibrillation. |
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