Intravenous amiodarone in the treatment of refractory life-threatening cardiac arrhythmias in the critically ill patient

Eleven critically ill patients with life-threatening cardiac arrhythmias refractory to currently approved antiarrhythmic drugs were treated with intravenous amiodarone. Two patients had acute myocarditis, five had acute myocardial infarction, two had left ventricular failure secondary to ischemic heart disease, one had Wolff-Parkinson-White syndrome, and one manifested postoperative atrial fibrillation. Eight of the patients had severe cardiac failure and five had hypotension requiring intravenous dopamine. Five patients were treated for recurrent ventricular fibrillation, two for recurrent ventricular tachycardia, and four for recurrent atrial arrhythmlas. Six patients had repeated cardioversions. The arrhythmias had lasted a mean of 88.3 hours resistant to a mean of 2.7 different intravenous antiarrhythmic drugs. The ventricular arrhythmias did not recur after commencing intravenous amiodarone, but some minor atrial arrhymias occurred for 24 hours. One patient died of intractable left ventricular failure, chronic obstructive lung disease, and respiratory arrest during treatment. The dose of amiodarone was 150 mg over 5 minutes, followed by 600 mg/24 hr for 3 to 4 days; one patient on total parenteral nutrition required intravenous amiodarone for 20 days. Hypotension, cardiac failure, and bradyarrhythmias were not induced by this treatment. Intravenous amiodarone can be used safely in critically ill patients with impaired left ventricular function to control life-threatening refractory cardiac arrhythmias.     

静脉应用胺碘酮治疗冠心病合并心房颤动伴快速心室反应和频发室性早搏

目的：评价经静脉应用胺碘酮治疗合并心房颤动伴快速心室反应和频发室性早搏的冠心病患者的临床疗效和安全性。方法：232例符合人选条件的冠心病患者，首剂静脉注射150mg胺碘酮负荷量，10min注入。随后以1．0mg／min静脉滴注维持6h，以后根据病情逐渐减量至0．5mg／min。对于心室率控制不满意者，间隔15～30min后，再次给予胺碘酮150mg的追加负荷量2～3次，24h总剂量在2000mg以内。用药期间，持续性心电图、血压及血氧饱和度监测，并判定疗效及副反应。心室率降至100次／min以下，或较用药前下降〉20％，或心律转复为窦性心律为有效；心室率仍〉100次／min或较用药前下降〈20％为无效。结果：232例患者总有效率为90．5％，副反应发生率为4．3％。结论：经静脉应用胺碘酮治疗合并心房颤动伴快速心室反应和频发室性早搏的冠心病患者是安全、有效的。     

Surgical management of life-threatening ventricular arrhythmias in patients with coronary artery disease.

Twenty-one patients with coronary artery disease and severe, symptomatic ventricular arrhythmias underwent cardiac surgery after failure of medical managememt. All had coronary artery disease and either localized areas of severe hypokinesis (three patients), or ventricular aneurysms (18 patients) documented angiographically prior to surgery. Operation within one month after acute infarction resulted in an 80% in-hospital mortality, whereas operation more than one month postinfarction showed a 20% mortality. Operative treatment that included myocardial resection had a significantly lower mortality (P less than 0.05) than that which did not. With an average of 36.5 months of follow-up, 13 of the 21 patients were long-term survivors, despite the persistence of ventricular arrhythmias. Surgical treatment which includes myocardial resection and occurs more than one month after infarction should be considered in patients with symptomatic ventricular arrhythmias and severe, well-localized left ventricular wall motion abnormalities.     

Use of intravenous amiodarone for emergency treatment of life-threatening ventricular arrhythmias

Efficacy, side effects and predictors of response for intravenous amiodarone were evaluated in 46 patients with recurrent drug-refractory sustained ventricular tachycardia or ventricular fibrillation, or both, who were treated with intravenous amiodarone. Of the 46 patients, 27 (58.5%) responded early to intravenous amiodarone and 6 (13%) showed a late response to amiodarone. The majority of patients who responded to intravenous amiodarone did so within the first 2 h of therapy, and all responded within 84 h. Patients with an ejection fraction greater than 25% were more likely to respond (p less than 0.05). Major side effects occurred in 13% of patients. The cumulative 2 year mortality rate due to arrhythmia recurrence or sudden death for responders discharged from the hospital was 23% and the cumulative overall 2 year mortality rate was 46%. In conclusion, intravenous amiodarone is rapidly effective in the majority of patients with recurrent ventricular tachycardia or ventricular fibrillation refractory to other drugs. The poor long-term outcome of patients who require this therapy, respond to it and are discharged on long-term oral amiodarone therapy warrants consideration of other long-term treatment of these patients. Use of intravenous amiodarone is an important new modality in the treatment of drug-refractory malignant ventricular arrhythmias.     

Staged revascularization in critically ill patients with coronary artery disease

BACKGROUND: Critically ill patients undergoing bypass surgery experience a higher mortality and morbidity. HYPOTHESIS: The study was undertaken to evaluate the efficacy and value of percutaneous transluminal coronary angioplasty (PTCA) as a bridge to coronary artery bypass graft surgery (CABG) in high-risk patients with refractory unstable angina or cardiogenic shock. METHODS: We present 11 seriously unstable patients with severe multivessel coronary artery disease undergoing culprit vessel PTCA. Angioplasty was performed not as a definitive procedure but rather as a bridge to surgical revascularization. All the patients had sustained at least one myocardial infarction prior to catheterization, all had refractory unstable angina, eight patients had only a single patent coronary artery, and five patients were in cardiogenic shock. RESULTS: Following PTCA, all patients enjoyed a stable in-hospital period. One patient died 12 weeks after successful PTCA while awaiting second CABG. Seven patients subsequently underwent CABG and are doing well. The remaining three patients were also advised to undergo CABG, but elected to continue medical management. CONCLUSIONS: Coronary angioplasty of the culprit vessel may play a role as a bridge to surgery in critically ill patients.     

Influence of amiodarone on QT dispersion in patients with life-threatening ventricular arrhythmias and clinical outcome

Increased QT dispersion, defined as the difference between the maximum and minimum QT interval on the standard 12-lead electrocardiogram, is assumed to reflect regional inhomogeneity of ventricular repolarization and has been shown to be associated with an increased risk of arrhythmic events. The purpose of the present study is to examine the influence of amiodarone on QT dispersion in patients with life-threatening ventricular arrhythmias and to evaluate the predictive value of QT dispersion after amiodarone therapy for further arrhythmic events. ECG's were obtained in 47 patients 1–2 days before and 6–8 weeks after amiodarone was started. All patients had coronary artery disease with a mean EF of 34±14%. The QT interval was measured in each lead of a digitized ECG displayed on a high resolution monitor (250 mm s⁻¹). Amiodarone therapy resulted in a significant increase in the maximal QT_c interval (476±44 to 505±44 ms, p<0.001). However, measurement of QT dispersion (70±34 vs 73±29 ms) and Qtc dispersion (78±37 vs 77±31 ms) revealed no significant difference before and after amiodarone. During a one year follow-up period 26 patients were free of arrhythmic events and 7 patients developed further arrhythmic events. The remaining 14 patients were excluded from the one year follow-up analysis because of drug discontinuation (n=8), death due to heart failure (n=1), medical intervention (n=3) and incomplete follow-up (n=2). No measure of QT dispersion was predictive of recurrent arrhythmic events during treatment with amiodarone.

Conclusion: Treatment with amiodarone results in significant QT prolongation without altering QT dispersion. Measurements of QT dispersion were not predictive of amiodarone efficacy in this patient population.     

胺碘酮对冠心病合并室性心律失常患者QT离散度影响的临床观察

目的观察胺碘酮对冠心病合并室性心律失常患者的QT离散度(QTd)及预后影响。方法选择的患者予以可达龙治疗8周,并比较治疗前后室性心律失常疗效及QTd的变化。结果治疗后室性心律失常均明显减少,有效率85.2%,QTd由(65.06±11.24)ms减至(33.9±16.2)ms(P<0.01=)。结论胺碘酮能有效减少冠心病伴室性心律失常而且使患者QTd明显减少,改善患者的预后。     

Coronary artery bypass grafting in the management of ventricular arrhythmias in patients with coronary artery disease

This review analyzes the role of coronary artery bypass grafting in ventricular arrhythmia associated with exertion, problematic sustained ventricular tachycardia, and sudden cardiac death associated with documented ventricular arrhythmia, or first manifestation of coronary artery disease. Specifically discussed is the role of acute ischemia in initiating and perpetuating ventricular arrhythmia. Coronary artery bypass grafting is indicated as a curative intervention for ventricular arrhythmia, but in only one rare instance: exercise-induced ischemia associated with problematic sustained ventricular arrhythmia, when the tachycardia is documented as being induced by acute ischemia. In other instances, indications for coronary artery bypass grafting follow the current guidelines based on clinical trials. Patients with the most severely damaged coronary artery anatomy associated with impaired left ventricular dysfunction have their life expectancy significantly prolonged after coronary artery bypass grafting. These results have been presented as evidence that coronary artery bypass grafting prevents ventricular arrhythmia and sudden cardiac death by modifying the two most powerful predicting factors of sudden cardiac death: coronary artery anatomy and left ventricular function.     

Functional and prognostic significance of exercise-induced ventricular arrhythmias in patients with suspected coronary artery disease

Our aims were to assess (1) the relation between exercise-induced ventricular arrhythmia (VA) and myocardial wall motion abnormalities during exercise echocardiography in patients with suspected coronary artery disease (CAD), and (2) the effect of this relation on outcome. We studied the clinical and prognostic significance of exercise-induced VA in 1,460 patients (mean age 64 +/- 10 years; 867 men) with intermediate pretest probability of CAD and no history of previous myocardial infarction or revascularization who underwent exercise echocardiography. Exercise-induced VA occurred in 146 patients (10%). Compared with patients without VA, those with VA had a greater prevalence of abnormal exercise echocardiographic findings (48% vs 29%, p = 0.001) and ischemia on exercise echocardiography (39% vs 22%, p = 0.001), greater increase in wall motion score index with exercise (0.14 +/- 0.28 vs 0.06 +/- 0.18, p <0.0001), and a greater percentage of abnormal segments with exercise (21 +/- 30% vs 9 +/- 19%, p <0.0001). During follow-up (median 2.7 years), cardiac death and nonfatal myocardial infarction occurred in 36 patients. In multivariate analysis of combined clinical and exercise stress test variables, independent predictors of cardiac events were exercise-induced VA (chi-square 4.7, p = 0.03) and exercise heart rate (chi-square 18, p = 0.0001). The percentage of abnormal myocardial segments with exercise echocardiography was the most powerful predictor of VA (chi-square 31, p = 0.0001) and cardiac events (chi-square 15, p = 0.0001). In patients with suspected CAD, exercise-induced VA is associated with a greater risk of cardiac death and nonfatal myocardial infarction. This risk is attributed to the relation between VA and the extent and severity of left ventricular functional abnormalities with exercise.     

Incidence of ventricular arrhythmias during transient myocardial ischemia in patients with stable coronary artery disease

To determine the incidence of ventricular arrhythmias related to episodes of transient myocardial ischemia during ambulatory electrocardiographic (ECG) monitoring, 97 patients with stable angina pectoris, angiographically proved coronary artery disease and an abnormal exercise test were studied. A total of 573 episodes with ST segment depression were documented: in 118 episodes (21%) the patients were symptomatic and in 455 (79%) they remained asymptomatic. Ventricular arrhythmias (greater than 5 premature ventricular beats/min, bigeminy, couplets or salvos of premature ventricular beats) occurred during 27 (5%) ischemic episodes in a subset of 10 patients (10%) (group A). The other 87 patients (90%) (group B) showed exclusively ischemic episodes without ventricular arrhythmias. Comparison of patients in group A and group B showed no differences in hemodynamic, angiographic, exercise testing and ambulatory ECG monitoring data. Ischemic episodes with and without ventricular arrhythmias showed a similar duration and amplitude of ST segment depression and a comparable heart rate at the onset of ischemia. Both types of ischemic episodes, with and without arrhythmias, occurred predominantly during the morning hours between 6:00 AM and noon, and both types remained asymptomatic to within similar percentages. The data demonstrate that ventricular arrhythmias are related to transient myocardial ischemia in only a few patients with stable angina pectoris; these arrhythmias are related neither to the degree of ischemia during ambulatory ECG monitoring nor to the occurrence of anginal symptoms.     

Exercise-induced ventricular arrhythmias in patients with coronary artery disease. Their relation to angiographic findings

Ventricular extrasystoles occurring before, during or after graded exercise testing were related to extent of coronary artery disease and to ventricular motion disorders in 81 symptomatic patients undergoing selective coronary and left ventricular angiography; the results were compared with data in 89 similar age-matched patients without arrhythmias. Compared with arrhythmia-free patients, 67 patients with exercise-induced arrhythmias had a significantly greater incidence of prior myocardial infarction, double or triple vessel disease and overall abnormal ventricular contractile patterns. Exercise induced extrasystoles occurred in only 11 percent of patients with insignificant coronary disease. Abolition of resting extrasystoles by exercise was not associated with less extensive coronary disease. Our study suggests that exercise-precipitated arrhythmias may represent a form of subclinical ischemia, signify more advanced degrees of coronary and left ventricular disease, and serve as an aid in detecting potentially high-risk patients.     

Prognostic value of early electrophysiologic studies for ventricular tachycardia recurrence in patients with coronary artery disease treated with amiodarone

Amiodarone was used in 86 patients with ventricular tachycardia (VT) (67 patients) or ventricular fibrillation (19 patients) secondary to coronary artery disease. The mean +/- standard deviation left ventricular ejection fraction was 30 +/- 12% (range 8 to 65%). Prior trials with 4 +/- 1.2 alternate antiarrhythmic agents had been unsuccessful. Amiodarone was loaded at dosages of 1,200 to 1,800 mg/day, with maintenance dosages of 400 to 600 mg/day. Drug efficacy was evaluated by programmed stimulation at 10 to 14 days in 68 patients. In 38 patients sustained VT or ventricular fibrillation was inducible (group I), whereas 30 patients (group II) had either no inducible VT (8) or had nonsustained VT induced (22). Holter monitoring was used to assess drug efficacy in 18 patients (group III). All patients were evaluated at 3- to 6-month intervals with Holter monitors for efficacy and a standard protocol for toxicity. During a long-term follow-up of 18 +/- 16 months, sudden death occurred in 5 patients and nonfatal arrhythmia recurrences were detected in 16. The actuarial probability of freedom from fatal and nonfatal arrhythmia recurrences at 24 months was 0.52 for group I, 0.97 for group II and 0.68 for group III. The mode of induction, rate change or hemodynamic tolerance of the induced ventricular tachycardia did not predict arrhythmia recurrence. Among the clinical variables analyzed, only an ejection fraction of less than or equal to 30% was identified as a significant predictor of arrhythmia recurrence. Nonsudden cardiac death occurred in 21 patients, including 19 from heart failure and 2 from myocardial infarction. Noncardiac death occurred in 7 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

胺碘酮和美西律治疗冠心病并室性心律失常56例疗效比较

目的比较胺碘酮和美西律治疗冠心病心肌缺血患者室性心律失常的疗效。方法56例冠心病心肌缺血合并室性心律失常患者,均接受冠心病正规治疗,其中30例同时口服胺碘酮片(胺碘酮组),26例口服美西律片(美西律组),疗程4周。疗程开始及结束时均行24h动态心电图及12导联心电图检查。结果两组患者用药后24h室性早搏、短阵室性心动过速的发作次数均明显减少,胺碘酮组用药后与用药前比较分别为(2801±356)个和(6935±1427)个,(1.28±0.92)次和(7.39±3.31)次;美西律组则分别为(3958±966)个和(6726±1395)个,(4.25±2.61)次和(8.10±3.32)次,P均<0.01。胺碘酮组的疗效高于美西律组(P<0.01)。两组均未见严重副作用。结论胺碘酮对冠心病伴室性心律失常的疗效优于美西律。     

Psychosocial status predicts mortality in patients with life-threatening ventricular arrhythmias

BACKGROUND: Quality-of-life (QoL) instruments evaluate various aspects of physical, mental, and emotional health, but how these psychosocial characteristics impact long-term outcome after cardiac arrest and ventricular tachycardia (VT) is unknown. OBJECTIVE: The purpose of this study was to evaluate the relationship of baseline QoL scores with long-term survival of patients enrolled in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial. METHODS: Formal QoL measures included SF-36 mental and physical components, Patient Concerns Checklist, and Ferrans and Powers Quality-of-Life Index-Cardiac Version. Multivariate Cox regression was used to assess the association of survival and these measures, adjusting for index arrhythmia type, gender, race, age, ejection fraction, history of congestive heart failure, antiarrhythmic therapy, and beta-blocker use. RESULTS: During mean follow-up of 546 +/- 356 days, 129 deaths occurred among 740 patients. Higher baseline SF-36 physical summary scores (P <.001), higher baseline QoL Index summary scores (P = .015), and lower baseline Patient Concerns Checklist summary scores (P = .047) were associated with longer survival, even after adjustment for clinical variables. When QoL measures were examined simultaneously, only the SF-36 physical summary score remained significant (P = .002). CONCLUSION: During recovery after sustained VT or cardiac arrest, formal baseline QoL assessment provides important prognostic information independent of traditional clinical data.