Risk stratification and long-term therapy with amiodarone in patients with idiopathic dilated cardiomyopathy]

Patients with cardiomyopathy are known to suffer from a high prevalence of tachyarrhythmic complications and sudden cardiac death. In a prospective study, 30 patients (25 men, 5 women, mean age: 52 +/- 12 years) with dilated cardiomyopathy underwent 48-h-Holter monitoring and programmed electrical stimulation and, independent from the results of the diagnostic work-up, were then randomized either to amiodarone or to a conventional or no antiarrhythmic therapy. At baseline, frequent ventricular arrhythmias (> 30 ventricular premature beats/h) were observed in 15/30 patients (50%), 13 patients (43%) had repetitive ventricular arrhythmias, additionally. Four patients suffered spontaneous sustained tachyarrhythmias. During programmed electrical stimulation, sustained monomorphic ventricular tachycardia was induced in 3/3 patients with and in 1/25 patients (4%) without a history of sustained tachycardia. Sustained monomorphic ventricular tachycardia was induced with one to two extrastimuli; three extrastimuli only increased the incidence of inducible ventricular fibrillation (8 patients, 28%). During a mean follow-up of 28 +/- 6 months 10/30 patients (33%) died for cardiac reasons (sudden cardiac death: 4/10 patients). Cardiac death was most likely in patients with a left-ventricular ejection fraction < 35% (5/18 patients, 28% versus 1/12 patients with ejection fraction > 35%, 8%) and further increased in the presence of reduced exercise tolerance and frequent and repetitive ventricular arrhythmias (4/7 patients, 57%). In the amiodarone group 4/15 patients died (27%, sudden cardiac death: one patient), while in patients not treated by amiodarone 8/15 patients died (54%; sudden cardiac death: three patients). Amiodarone therapy was well tolerated in all but one patient.     

Nonsustained ventricular tachycardia in dilated cardiomyopathy

In patients with structural heart disease, ventricular arrhythmias are associated with an increased risk of overall mortality and sudden cardiac death (SCD). Nonsustained ventricular tachycardia (NSVT) is common in patients with dilated cardiomyopathy of both ischemic and nonischemic origin. Recent studies suggest that NSVT may be a marker, but not a significant predictor, of mortality and SCD in that suppression of NSVT in these patients using antiarrhythmic drugs is of questionable benefit. Additionally, indications for implantable cardioverter defibrillator implantation do not include NSVT. This article focuses on the prognostic significance and treatment of patients with NSVT and ischemic or nonischemic dilated cardiomyopathy.     

The Clinical Significance of Nonsustained Ventricular Tachycardia

Nonsustained Ventricular Tachycardia. Nonsustained ventricular tachycardia (NSVT) is an arrhythmia not often associated with symptoms; however, its occurrence in patients with structural heart disease is a prognostic indicator of an increased risk of mortality and sudden death. The management of asymptomatic patients with NSVT should first attempt to identify which patients are at highest risk for cardiac arrest, and second, devise a treatment that can reduce the incidence and/or mortality of cardiac arrest in this group. In patients with chronic coronary artery disease (CAD) and NSVT, programmed electrical stimulation identifies both a low and high risk group with respect to occurrence of ventricular arrhythmias. The negative predictive value of programmed electrical stimulation in patients with CAD and NSVT has been well established; however, uncertainty remains as to the optimal therapy for CAD patients with inducible ventricular arrhythmias. A number of reports suggest that patients whose inducible ventricular arrhythmias are rendered noninducible with antiarrhythmic drugs have a much lower risk of sudden death. It is yet to be resolved whether arrhythmias rendered noninducible identify a subgroup at low risk for cardiac arrest, independent of treatment. There is some evidence to suggest that the frequency of NSVT in patients with nonischemic dilated cardiomyopathy identifies a group at higher risk of sudden death. Programmed electrical stimulation adds little in helping to identify which of these patients are most likely to have cardiac arrest. The presence of NSVT in asymptomatic patients with hypertrophic cardiomyopathy may identify a group at higher risk for cardiac arrest. Further clinical studies are needed to define the best management strategy for NSVT in different types of structural heart disease.     

Ambulatory ECG in cardiomyopathies

DILATED CARDIOMYOPATHY - Conduction and rhythm disturbances are frequent findings in dilated cardiomyopathy. 65 patients with dilated cardiomyopathy underwent 24-hour electrocardiographic monitoring: 95.4% showed ventricular arrhythmias, 80% complex ventricular arrhythmias and 44% runs of non-sustained ventricular tachycardia. Over 1000 ventricular extrasystoles in 24 hours were present in 44% of cases. Ventricular tachycardia and multiform and paired ventricular extrasystoles correlated significantly with the severity of cardiac dysfunction and with a worse prognosis. Patients undergoing antiarrhythmic therapy (amiodarone) showed a significant reduction in the number of ventricular extrasystoles and in the incidence of complex ventricular arrhythmias. HYPERTROPHIC CARDIOMYOPATHY - The high incidence of arrhythmias, particularly ventricular arrhythmias (approx. 70% of cases) in hypertrophic cardiomyopathy is well recognized: episodes of ventricular tachycardia are present in 20% of cases and are related to an elevated risk of sudden death. Antiarrhythmic treatment with amiodarone significantly reduces the number of ventricular extrasystoles and the episodes of ventricular tachycardia, may prevent sudden death and improve survival. RESTRICTIVE CARDIOMYOPATHY - Very little information is present in literature concerning this extremely rare form, in which every type of rhythm and conduction disturbance has been observed. CONCLUSIONS - Electrocardiographic monitoring is nowadays a very important tool in the management of cardiomyopathy patients, to identify possible patients at risk and to monitor the antiarrhythmic treatment.     

Ventricular arrhythmia in congestive heart failure.

The importance of ventricular arrhythmia is based on its association with sudden death. In certain groups of patients, ventricular arrhythmia--primarily runs of nonsustained ventricular tachycardia (NSVT)--is associated with an increased risk for sudden death. Although this relationship has been most often reported in patients with recent myocardial infarction, it has also been recognized in patients with dilated cardiomyopathy, regardless of etiology. Therefore, ventricular arrhythmia is common in patients with CHF due to cardiomyopathy. A number of studies have reported that 70-95% of patients with cardiomyopathy and congestive heart failure (CHF) have frequent ventricular premature beats, and 40-80% will manifest runs of NSVT. Many factors are responsible for ventricular arrhythmia in such patients, including structural abnormalities, electrolyte imbalance, hemodynamic impairment, activation of neurohormonal mechanisms, and pharmacologic therapy. Many studies have reported a high yearly mortality in patients with cardiomyopathy and CHF; greater than 40% of deaths are sudden, most often the result of sustained ventricular tachyarrhythmia. Most studies have noted an association between presence (and frequency) of NSVT and risk of sudden cardiac death in these patients. Unfortunately, other techniques--such as the signal-averaged electrocardiogram and electrophysiologic testing--are not helpful in identifying the individual at risk. Although several drug interventions will reduce mortality from progressive CHF, these drugs have not been shown to reduce sudden death and, indeed, have a variable effect on ventricular arrhythmia. Although NSVT is a marker for increased risk for sudden death, it is uncertain if antiarrhythmic drugs will prevent this outcome. Antiarrhythmic drugs have not been shown to be effective for preventing sudden death, although there are as yet no well-controlled randomized trials. Several studies suggest that amiodarone and beta blockers are beneficial, but this requires confirmation. For patients who have been resuscitated following an episode of sudden death due to a sustained ventricular tachyarrhythmia, antiarrhythmic therapy guided by invasive and noninvasive techniques appears to reduce risk of recurrent arrhythmia. However, the response rate to antiarrhythmic agents is low and side effects are common in patients with CHF. Especially important is the increased risk of precipitating CHF and aggravating the arrhythmia being treated. For many such patients who have had serious ventricular tachyarrhythmia, the automatic implantable cardioverter defibrillator may prove a better option. Other drugs used for management of CHF reduce overall mortality, but not risk of sudden death.     

Sustained ventricular tachycardia in patients with idiopathic dilated cardiomyopathy: electrophysiologic testing and lack of response to antiarrhythmic drug therapy

Eleven consecutive patients with idiopathic dilated cardiomyopathy and spontaneous, sustained ventricular tachycardia (VT) of uniform morphology underwent programmed ventricular stimulation and serial antiarrhythmic drug testing. The mean ejection fraction was 30 +/- 6.4%. Sustained VT was induced by programmed electrical stimulation in all 11 patients. A mean of 3.7 +/- 2.4 antiarrhythmic drugs were evaluated by programmed stimulation, including at least one experimental agent in eight patients. In nine of 11 patients VT remained inducible on all drug therapy. During a mean follow-up period of 21 +/- 14 months there were four sudden deaths and two patients with recurrences of VT. In all six patients with sudden death or recurrence of VT, the arrhythmia remained inducible on drug therapy. Three patients who died suddenly had a hemodynamically stable, induced tachycardia on antiarrhythmic therapy. Of eight patients treated with amiodarone, only two were successfully treated. We conclude that in patients with sustained VT and idiopathic dilated cardiomyopathy, VT can be induced by programmed electrical stimulation. VT will usually remain inducible on antiarrhythmic therapy, and sudden death can occur despite slowing and improved tolerance of the induced arrhythmia. Amiodarone may have limited efficacy, and more aggressive therapy, such as surgery or implantation of an automatic internal defibrillator, should be considered in this patient population.     

Ventricular arrhythmias in dilated cardiomyopathy: efficacy of amiodarone

Sixty-five patients with dilated cardiomyopathy were studied by means of 24-hour ECG monitoring. Ventricular arrhythmias were present in 62 (95.4%), of whom 52 (80%) showed a complex form (multiform ventricular extrasystoles, pairs, and ventricular tachycardia). Forty-one patients, presenting with complex ventricular arrhythmias, received antiarrhythmic treatment with amiodarone (600 mg/day in the first week, 400 mg/day in the second week, and 200 to 400 mg/day chronically), and were then controlled with periodic 24-hour ambulatory monitoring. A significant reduction in the number of ventricular extrasystoles was seen in over 70% of patients during a 3-year period. There was also a significant decrease in the incidence of complex ventricular arrhythmias (particularly of ventricular tachycardia). Adverse effects were noted in 23 patients, but only four had to stop treatment. During the follow-up period, 19 patients died: 14 of heart failure, four of sudden death, and one of a noncardiac cause; all patients who died suddenly were not treated with amiodarone (p = 0.022). Complex ventricular arrhythmias are frequent in dilated cardiomyopathy and it is suggested that amiodarone is effective in short- and long-term control of these arrhythmias.     

Equivalent arrhythmic risk in patients recently diagnosed with dilated cardiomyopathy compared with patients diagnosed for 9 months or more.

BACKGROUND: The Centers for Medicare and Medicaid Services (CMS) recently expanded coverage for implantable cardioverter-defibrillators (ICDs) in patients with left ventricular ejection fraction < or =35% and nonischemic dilated cardiomyopathy for > or =9 months. To investigate the ramifications of these criteria, the ICD registry from Tufts-New England Medical Center was analyzed for arrhythmic events and death in patients with newly diagnosed (<9 months) vs late-diagnosed (> or =9 months) nonischemic dilated cardiomyopathy. OBJECTIVES: The purpose of this study was to analyze the arrhythmic risk in patients with recent vs late diagnosis of nonischemic dilated cardiomyopathy. METHODS: One hundred thirty-one patients with nonischemic dilated cardiomyopathy were divided into two cohorts (<9 or > or =9 months of symptoms) and analyzed for any occurrence of treated ventricular arrhythmia, potentially lethal arrhythmias defined as ventricular flutter rates > or =230 bpm, and ventricular fibrillation. Patients with documented sustained ventricular tachycardias (included in prior CMS coverage) were excluded. RESULTS: In the study group, the mean age was 58.1 +/- 15 years and ejection fraction 20.6% +/- 8%. In a follow-up period of 25.3 +/- 24 months, the 52 patients with a recent diagnosis (1.4 +/- 2 months) had no difference in the occurrence of ventricular arrhythmias (P = .49) and malignant ventricular arrhythmias (P = .16) compared with the 79 patients diagnosed > or =9 months (mean 58.1 +/- 39 months). CONCLUSION: Patients with nonischemic dilated cardiomyopathy experienced equivalent occurrences of treated and potentially lethal arrhythmias irrespective of diagnosis duration. These findings suggest that the 9-month time qualifier used in the CMS guidelines for ICD reimbursement may not reliably discriminate patients at high risk for sudden cardiac death in this selected population.     

Prognostic value of non-sustained ventricular tachycardia and the potential role of amiodarone treatment in hypertrophic cardiomyopathy: assessment in an unselected non-referral based patient population

Background—Amiodarone has been reported to reduce the likelihood of sudden death in patients with hypertrophic cardiomyopathy (HCM). However, data regarding the clinical course in HCM have traditionally come from selected referral populations biased toward assessment of high risk patients.
Aims—To evaluate antiarrhythmic treatment for sudden death in an HCM population not subject to tertiary referral bias, closely resembling the true disease state present in the community.
Methods—Cardiovascular mortality was assessed in relation to the occurrence of non-sustained ventricular tachycardia (NSVT) on 24 or 48 hour ambulatory Holter recording, a finding previously regarded as a marker for sudden death, particularly when the arrhythmia was frequent, repetitive or prolonged. 167 consecutive patients were analysed by multiple Holter ECG recordings (mean (SD) 157 (129) hours) and followed for a mean of 10 (5) years. Only patients with multiple repetitive NSVT were treated with amiodarone, and in relatively low doses (220 (44) mg/day).
Results—Nine HCM related deaths occurred: 8 were the consequence of congestive heart failure, but only 1 was sudden and unexpected. Three groups of patients were segregated based on their NSVT profile: group 1 (n = 39), multiple ( 2 runs) and repetitive bursts (on 2 Holters) of NSVT, or prolonged runs of ventricular tachycardia, included 4 deaths due to heart failure; group 2 (n = 38), isolated infrequent bursts of NSVT, included 1 sudden death; group 3 (n = 90), without NSVT, included 4 heart failure deaths. Kaplan-Meier survival analysis showed no significant differences in survival between the three groups throughout follow up.
Conclusions—In an unselected patient population with HCM, isolated, non-repetitive bursts of NSVT were not associated with adverse prognosis and so this arrhythmia does not appear to justify chronic antiarrhythmic treatment. Amiodarone, administered in relatively low doses, did not carry an independent and additive risk for cardiac mortality. Amiodarone may have contributed to the absence of sudden cardiac death in patients believed to be at higher risk because of multiple repetitive NSVT.

Keywords: hypertrophic cardiomyopathy; ventricular tachycardia; amiodarone     

恶性室性心律失常埋藏式心脏复律除颤器与药物治疗的对比研究

观察埋藏式心脏复律除颤器 (ICD)与药物对恶性室性心律失常的治疗效果 ,探讨其对心源性猝死的预防。94例患者 ,均有室性心动过速 (简称室速 )和 /或心室颤动等恶性室性心律失常发作史 ,其中冠心病 68例、原发性扩张型心肌病 2 6例。根据电生理心室程序刺激结果将患者分为药物治疗组 (A组 )、ICD组 (B组 )和慢频率室速药物治疗组 (C组 )。分别给予胺碘酮和 /或阿替洛尔药物治疗和ICD治疗。观察随访 1 ,2 ,5年的总生存率 ,不同左室射血分数 (EF)值亚组的生存率和心律失常性死亡的发生率。结果显示 ,随访 5年的总生存率C组明显低于A、B两组(P <0 .0 5 ) ,B组的低EF(≤ 0 .40 )值亚组的 5年生存率明显高于A、C两组的低EF值亚组 (P <0 .0 5 )。B组随访期间无心律失常死亡者 ,其心律失常性死亡事件的发生率明显低于A、C两组 (P <0 .0 5 )。结论 :ICD对于合并有恶性室性心律失常的心脏病人预防猝死的总体效果优于 β 阻断剂和胺碘酮等药物治疗。这尤其见于长期随访 (≥ 5年 )和伴有心功能不全 (EF值≤ 0 .40 )的病人。对于有过恶性室性心律失常发作史的患者 ,若心电生理检查不能诱发室速 ,在没有条件安装ICD时 ,胺碘酮与 β 阻断剂联合应用仍可在一定程度上减少心源性猝死的发生。     

Hemodynamics during chronic amiodarone administration in Japanese patients with idiopathic dilated cardiomyopathy and ventricular arrhythmia: a retrospective study

OBJECTIVES: Nonischemic heart disease, especially idiopathic dilated cardiomyopathy, is relatively common among Japanese patients receiving amiodarone for concomitant ventricular arrhythmia, but the hemodynamic effects of amiodarone in these Japanese patients are unclear. The hemodynamic changes during chronic amiodarone administration were retrospectively studied in patients with idiopathic dilated cardiomyopathy and ventricular arrhythmia. METHODS: Fifty-two patients [42 males, 10 females, 53 +/- 2 years (mean age +/- SE)] with ventricular tachyarrhythmia and idiopathic dilated cardiomyopathy with left ventricular ejection fraction of 27 +/- 1% (mean +/- SE) were treated with 200-400 mg daily of oral amiodarone as the loading dose for the initial 14 days and 100-200 mg daily maintenance dose for a further 6 months. No patients were taking beta-blockers or positive inotropic drugs. Echocardiographic examination was performed before (baseline), at week 2 and at month 6 of amiodarone therapy. Twenty four-hour Holter monitoring during the same time period was also performed in 34 patients. Seventeen patients underwent right heart catheterization before and at week 2. RESULTS: Echocardiographic measurements showed no significant change in left ventricular end-diastolic dimension, although there was a slight increase in fractional shortening from 16 +/- 1% to 19 +/- 1% (p < 0.05) and 18 +/- 1% (mean +/- SE) (p < 0.01) at week 2 and month 6 of amiodarone therapy, respectively. Amiodarone markedly reduced the mean heart rate and the frequency of premature ventricular complexes on ambulatory monitoring. The cardiac index did not change and the pulmonary capillary wedge pressure tended to decrease slightly at week 2 in the 17 patients who underwent catheterization. CONCLUSIONS: This retrospective study showed no worsening of the hemodynamic state during chronic amiodarone administration in Japanese patients with idiopathic dilated cardiomyopathy and ventricular arrhythmia.     

Role of nonsustained ventricular tachycardia and programmed ventricular stimulation for risk stratification in patients with idiopathic dilated cardiomyopathy

Background: The prognostic role of asymptomatic nonsustained ventricular tachycardia (NSVT) and programmed ventricular stimulation (PVS) in patients with idiopathic dilated cardiomyopathy (IDC) remains controversial. Methods: The prognostic significance of ventricular arrhythmias, ejection fraction, NYHA class, atrial fibrillation and age for overall and sudden death mortality was prospectively studied in 157 patients with IDC (group 1) free of documented sustained ventricular arrhythmia and syncope. In 99 patients with asymptomatic NSVT (group 2), PVS with 2 – 3 extrastimuli was performed. Non-inducible patients were discharged without specific antiarrhythmic therapy, whereas those with inducible monomorphic ventricular tachycardia were implanted with an ICD. Results: In group 1, 48% of patients had NSVT. Overall and sudden death mortality were significantly higher in patients with NSVT (34.2 vs. 9.8%, p = 0.0001 and 15.8 vs. 3.7%, p = 0.0037; follow-up 22 ± 14 months). Multivariate analysis revealed that NSVT independently predicts both overall and sudden death mortality (p = 0.0021 and .0221, respectively; adjusted for EF, NYHA class and age). In group 2, inducibility of sustained ventricular tachyarrhythmia was 7%, but sustained monomorphic VT occurred in 3% only. Two of 7 inducible patients experienced arrhythmic events during a follow-up of 25 ± 21 months (positive predictive value 29%). Overall and sudden death mortality were 29% and 0% in the inducible group vs. 17 and 4% in the non-inducible group. Both overall and sudden death mortality were signi.cantly lower in non-inducible patients from group 2 as compared to patients from group 1 with NSVT (p = 0.0043 and 0.0048), most likely due to a more common use of betablockers and a higher EF in the former group (p < 0.001, respectively). Conclusions: In patients with IDC, NSVT independently predicts both overall and sudden death mortality. Due to a low inducibility rate and a poor positive predictive value, PVS seems inappropriate for further arrhythmia risk assessment. However, in spite of documented NSVT, the incidence of SCD in patients on optimized medical treatment including betablockers seems to be very low, questioning the need for specific arrhythmia risk stratification. Received: 21 August 2002, Returned for revision: 24 September 2002, Revision received: 8 October 2002, Accepted: 7 November 2002, Published online: 12 May 2003 Correspondence to: R. Becker, MD     

Ambulatory ventricular arrhythmias in patients with heart failure do not specifically predict an increased risk of sudden death. PROMISE (Prospective Randomized Milrinone Survival Evaluation) Investigators

BACKGROUND: Ventricular arrhythmias are a frequent finding in congestive heart failure (CHF) patients and a cause of concern for physicians caring for them. Previous studies have reached conflicting conclusions regarding the importance of ventricular arrhythmias as predictors of sudden death in patients with CHF. This study examined the independent predictive value of ventricular arrhythmias for sudden death and all-cause mortality in PROMISE (Prospective Randomized Milrinone Survival Evaluation). METHODS AND RESULTS: Ventricular arrhythmias were analyzed and quantified by use of prespecified criteria on baseline ambulatory ECGs from 1080 patients with New York Heart Association (NYHA) class III/IV symptoms and a left ventricular ejection fraction 相似文献   

Resting and ambulatory ECG predictors of mode of death in dilated cardiomyopathy.

With the purpose of verifying whether the electrocardiogram (ECG) pattern alone can predict the mode of death in dilated cardiomyopathy, data from 12-lead ECGs and 48-hour arrhythmia monitoring were evaluated in 67 patients with dilated cardiomyopathy. During a mean follow-up period of 3 +/- 2 years, death from congestive heart failure occurred in 18 patients (27%), whereas 10 (15%) died suddenly (NS). Multivariate analysis showed that left bundle branch block (p < 0.001) and left atrial enlargement (p < 0.001) were independently related to death from congestive heart failure. Ventricular arrhythmias of Lown grade 4A or 4B (p < 0.001) and repolarization time, as assessed by QTc-QRS interval (p < 0.05), were independent predictors of sudden death. It is concluded that ECG features alone may be helpful for risk factor characterization of dilated cardiomyopathy patients, provided that multiple ECG criteria are utilized at time of diagnosis.     

Amiodarone and sustained ventricular arrhythmias: statistical evidence of drug effectiveness

Previous studies have shown that amiodarone prevents sustained ventricular arrhythmias in 77% to 93% of patients. To date, a study using statistical analysis to verify the drug's effectiveness has not been reported. Amiodarone was given to 17 patients with drug refractory sustained ventricular arrhythmias. All patients had serious underlying heart disease including coronary artery disease (15 patients) or cardiomyopathy (two patients). Ten patients had angiographic evidence of a left ventricular aneurysm. All patients had left ventricular dysfunction. The mean left ventricular ejection fraction was 33%. In the 5.5 +/- 8.3 months prior to amiodarone, these 17 patients had documented sustained ventricular arrhythmias requiring countershock (41 episodes), overdrive pacing (four episodes), or intravenous drugs (three episodes). Amiodarone was given as a loading dose (1 gm/day for 10 days) and a maintenance dose (200 to 600 mg/day). During a follow-up period of 8.9 +/- 5.7 months, only eight episodes occurred requiring countershock (5) or overdrive pacing (2); one patient died suddenly. A statistical test constructed for this problem showed a significant (p greater than 0.001) reduced risk of experiencing a sustained ventricular arrhythmia after amiodarone. This statistical model confirms previous studies showing that amiodarone prevents sustained ventricular arrhythmias and prevents sudden cardiac death.     

Late potentials in idiopathic dilated cardiomyopathy

Twenty-five patients with idiopathic dilated cardiomiopathy were investigated in order to evaluate the role of late ventricular potentials as possible markers of ventricular tachycardia or sudden cardiac death. Holter monitoring showed ventricular tachycardia in 9 patients (group A) all of whom had late ventricular potentials, (mean +/- SD length 37.22 +/- 15.83 ms and mean +/- SD voltage 5.62 +/- 2.78 microV). Mean +/- SD ejection fraction in this group was 20 +/- 9.39%. In 16 patients (group B), without ventricular tachycardia, means +/- SD ejection fraction 27.5 +/- 8.17%; late ventricular potentials were recorded in 2 patients. During the follow-up period (means +/- SD 11.53 +/- 7.19 months), 3 patients underwent heart transplantation, 2 patients underwent pace-maker implantation and 2 patients from the ventricular tachycardia group died one from sudden cardiac death and the other from progressive heart failure. No significant differences were found in the ejection fraction either between the ventricular tachycardia and the non-ventricular tachycardia group, or between the late ventricular potentials and the non-late ventricular potential groups. Negative data were also obtained when we tried to find a correlation between the ejection fraction and late ventricular potential length and/or voltage. Good results were observed with regard to sensitivity (100%), specificity (87%) and predictive accuracy (81%) but follow-up data did not specify a definite prognostic value for late ventricular potentials. The Authors conclude that late ventricular potentials are markers of patients with idiopathic dilated cardiomyopathy who are prone to ventricular tachycardia. However, the role of late ventricular potentials in sudden cardiac death is still uncertain.     

Spectrum and prognostic significance of arrhythmias on ambulatory Holter electrocardiogram in hypertrophic cardiomyopathy

OBJECTIVES: The goal of this study was to assemble a profile and assess the significance of arrhythmias in a nontertiary-based hypertrophic cardiomyopathy (HCM) cohort. BACKGROUND: Hypertrophic cardiomyopathy is associated with arrhythmia-related consequences, particularly sudden death. Ventricular tachyarrhythmias on Holter electrocardiograms (ECG) have been reported as markers for sudden death in highly selected HCM populations. METHODS: We assessed the profile of ventricular and supraventricular ectopy and bradyarrhythmia on ambulatory 24-h Holter ECG and also related these findings to clinical outcome in 178 HCM patients. RESULTS: Of the 178 study patients, 157 (88%) had premature ventricular complexes (PVCs), including 21 (12%) with >/=500 PVCs, 74 (42%) had couplets, 67 (37%) had supraventricular tachycardia (SVT), and 56 (31%) had nonsustained ventricular tachycardia (NSVT). Mean number of PVCs was 330 +/- 763 (range 1 to 5,435) and increased with age (p < 0.01); NSVT was associated with greater left ventricular hypertrophy (p = 0.01) and severe symptoms (New York Heart Association functional classes III and IV) (p = 0.04); SVT occurred more commonly in patients with outflow obstruction (p = 0.02). Over a follow-up of 5.5 +/- 3.4 years, 11 (6%) patients died suddenly (annual mortality rate, 1.1%) including 5 patients with NSVT. For sudden death, NSVT on Holter ECG had negative and positive predictive values of 95% and 9%, and sensitivity and specificity of 45% and 69%, respectively. CONCLUSIONS: In this nontertiary-based HCM cohort, ventricular and supraventricular tachyarrhythmias were particularly frequent and demonstrated a broad spectrum on ambulatory (Holter) ECG. Paradoxically, despite such a highly arrhythmogenic substrate, sudden death events proved to be relatively uncommon. Ventricular tachyarrhythmias had a low positive and relatively high negative predictive value for sudden death in this HCM population.     

Management of arrhythmias in heart failure

The literature for coronary artery disease as well as ischemic and dilated cardiomyopathy suggests that ventricular arrhythmias and left ventricular dysfunction are independent risk factors for sudden death, but that the presence of organic heart disease provides the substrate for potentially lethal arrhythmias. Patients with a cardiomyopathy and ventricular tachycardia are at a high risk for sudden death as a group. The general risk, then, is high for the group with CHF and arrhythmias. The prognostic indices for hypertrophic cardiomyopathy are imprecise, but the risk for sudden death for the group is high in the young and remains high even among the adult survivors. Many conditions associated with CHF and its treatment may lead to arrhythmias and are potentially reversible. Most studies suggest that EPS and exercise provocation have limited power in predicting the risk to the individual patient. Therapeutically, reversible causes of arrhythmias should be sought and corrected. In general, antiarrhythmic drug therapy has been disappointing with adequate control being achieved in only about 30 per cent of patients and uncertainties about the effectiveness of such therapy in altering long-term prognosis. This is due to various causes including the inability to find an effective drug, problems with patient compliance, the failure of physicians to properly monitor drug levels, and changes in the anatomical and physiologic substrate due to disease and therapy. Surgical ablation or resection of arrhythmogenic foci is effective in selected patients. The AICD will become first-line therapy in patients at high risk for sudden death due to ventricular arrhythmias, with antiarrhythmic drugs and other approaches being used to minimize the frequency of the arrhythmias.     

Unsuitability of corrected QT dispersion as a marker for ventricular arrhythmias and cardiac sudden death after acute myocardial infarction.

The present study investigated whether corrected QT (QTc) dispersion could play a role as a marker of ventricular arrhythmias and sudden cardiac death after acute myocardial infarction (MI). The study included 76 males and 24 females with a mean age of 60+/-11 years. Standard 12-lead ECGs were recorded during the recovery phase (15+/-9 days) after the onset of MI. The QTc was calculated according to Bazett's formula and QTc dispersion was calculated as the difference between the maximum and minimum QTc intervals. Patients were divided into 2 groups: 21 patients (group A) had a QTc dispersion of > or =80ms, and the other 79 patients (group B) had a QTc dispersion of <80ms in the recovery stage (15+/-9 days). Clinical, angiographical, and Holter monitoring data, and prognosis (mean follow-up period 29+/-18 months) were compared between these 2 groups. The frequencies of early coronary reperfusion and recanalization of infarct-related vessels during the recovery phase were significantly higher in group B than group A. The left ventricular ejection fraction was also higher in group B than group A (51+/-12 vs 43+/-12%, p=0.0029). There were no significant differences in the number of premature ventricular contractions, the percentage of patients with repetitive ventricular arrhythmias, or in the frequency of sudden cardiac death during the follow-up period between the 2 groups. In summary, QTc dispersion in the recovery stage is not a useful marker for ventricular arrhythmias or sudden cardiac death after acute MI, although increased QTc dispersion may correlate with an ineffective early coronary reperfusion and with the degree of depressed left ventricular function.     

Prognostic role of non-sustained ventricular tachycardia in a large cohort of patients with idiopathic dilated cardiomyopathy.

BACKGROUND: The identification of patients with idiopathic dilated cardiomyopathy (IDC) at higher risk of sudden death (SD) is still an unsolved issue, and the role of non-sustained ventricular tachycardia (NSVT) uncertain. METHODS: The effect of NSVT on total mortality, SD and life-threatening arrhythmias was evaluated in 554 patients with IDC on optimal medical treatment and at long-term follow-up (81 +/- 58 months). RESULTS: At diagnosis, 240 patients (43%) had NSVT at Holter monitoring and 314 (57%) did not. During follow-up, 189 patients (5/100 patients-year) died or underwent heart transplantation; SD occurred in 53 patients (1.4/100 patients-year); SD + non-fatal ventricular arrhythmias occurred in 75 patients (2/100 patients-year). Patients with and without NSVT at diagnosis had the same 5-year transplant-free survival rate (76 vs 76%, p = NS) and a similar incidence of SD (10 vs 7%, p = NS). The length and rate of NSVT did not show any significant relationship with the outcome. Only heart failure symptoms (NYHA class III-IV) (hazard ratio [HR] 1.9, p = 0.015) and severe left ventricular impairment (left ventricular ejection fraction < or = 0.30 and left ventricular end-diastolic diameter > or = 70 mm) (HR 2.7, p < 0.0001) were independently associated with higher SD risk. At multivariate analysis the presence of frequent NSVT episodes (> or = 3 runs/day) was associated with an increased risk of total mortality (HR 1.68, p = 0.041) and of major ventricular arrhythmias (HR 2.11, p = 0.037), but only in the subgroup of patients with severe left ventricular impairment. CONCLUSIONS: Patients with advanced heart failure symptoms, severe left ventricular dysfunction and dilation had a higher risk of SD independently of NSVT. The finding of more frequent NSVT was associated with an increased risk of all-cause mortality and of major ventricular arrhythmias in patients with severe left ventricular impairment.