Survivors Of Sudden Cardiac Death Research Articles

Defibrillation Testing During Defibrillator Implantation.

Implantable cardioverter defibrillators (ICDs) terminate ventricular tachycardia (VT) and ventricular fibrillation (VF) with high efficacy. ICDs improve mortality in patients after survived sudden cardiac death (SCD) and in patients at high risk of dying suddenly. All trials which show a benefit of ICD therapy, have performed some kind of defibrillation testing in order to prove correct system function, sensing of VF and effective defibrillation. Current devices show a shock efficacy of 80-90 % for singular shocks and devices provide up to seven rescue shocks. The probability that a device does not terminate an episode of VT or VF should therefore be very low. However, it is difficult to abandon defibrillation testing because prospective data is lacking that demonstrate non-inferiority, if ICDs are implanted without some kind of test. Two prospective trials are on the way and will be finish by 2013/14: the SIMPLE and NORDIC trial, which will answer the question if defibrillation testing can be abandoned without any effect on the benefit of ICD therapy or if testing may even be harmful.

Definition of Early Repolarization

Early repolarization pattern (ERP) is a common ECG variant, characterized by J point elevation manifested either as terminal QRS slurring (the transition from the QRS segment to the ST segment) or notching (a positive deflection inscribed on terminal QRS complex) associated with concave upward ST-segment elevation and prominent T waves in at least two contiguous leads.1,2 The J point deflection occurring at the QRS-ST junction (also known as Osborn wave or J wave) was first described in 1938, and is seen in both extracardiac and cardiac disorders like hypothermia, hypercalcemia, brain injury, hypervagotonia, or spinal cord injury leading to loss of sympathetic tone, vasospastic angina. Besides recently described early repolarization syndrome,3–5 ERP has generally been considered a normal ECG variant with good long-term prognosis. However, this long-held concept has been challenged, and recently published population-based studies and reports of associations with ventricular fibrillation and sudden death continue to fuel more momentum.6–9 In the seminal article by Haissaguerre et al, cases of ERP associated with cardiac arrest had at least 0.1-mV J point elevation manifested as QRS slurring or notching in the 2 contiguous inferior or lateral leads.6 ERP has also emerged as a marker of increased long-term mortality (cardiac and arrhythmic) in the general population.10,11 Thus, ERP is probably not as benign as traditionally believed. Article see p 2208 The potential consequences of such an association are huge, especially as related to ECG screening and risk stratification in the general population. It is therefore extremely …

Brugada Syndrome

Brugada Syndrome

Epileptic patients who survived sudden cardiac death have increased risk of recurrent arrhythmias and death

Cardiac arrhythmogenesis and cryptogenic epilepsy can be due to ion channel dysfunction and may coexist in the same patient. Sudden unexplained death in epilepsy (SUDEP) is a known entity with unknown cause, with the possibility of ventricular tachyarrhythmias being one of the causes. However, no prior study has investigated epileptic survivors of sudden cardiac death (SCD), recurrent life-threatening ventricular tachyarrhythmia (LTVA) and other outcomes in this patient population. The Antiarrhythmics Versus Implantable Cardioverter Defibrillators (AVID) Trial (n = 1016) was a multicenter trial comparing a cardioverter-defibrillator device (ICD) (n = 507) and anti-arrhythmic drugs (AADs) (n = 499) for secondary prevention of LTVAs. Mean follow-up duration was 916 ± 471 days per patient. Patients with a history of epilepsy (n = 6) in the ICD arm were included in this analysis. End points were recurrence of LTVA, cardiac death and all-cause mortality. History of epilepsy (n = 6) was a significant predictor of recurrent LTVA [hazard ratio 3.53, 95% confidence interval (CI) 1.30-9.56], cardiac death (hazard ratio 4.14, 95% CI 1.30-13.14) and all-cause mortality (hazard ratio 3.82, 95% CI 1.40-10.48) in the ICD arm (n = 498). This relationship remained unchanged on multivariate analysis after controlling for baseline clinical differences. This is the first study to investigate the effect of epilepsy on secondary prevention of LTVA. Epileptic survivors of SCD are at significantly greater risk of recurrent arrhythmias and death as compared to other survivors of recurrent LTVA. Role of coexisting channelopathies in both epilepsy and arrhythmogenesis may explain SUDEP and requires further investigation.

Clinical and Electrophysiological Profile of Brugada Syndrome in the Tunisian Population

Most clinical studies of the clinical profile of Brugada syndrome (BS) have been conducted in either Asia, Europe, or America and their applicability to North African populations is largely unknown. The aim of the study was to analyze the clinical profile of BS in Tunisian patients. The clinical and follow-up data of 24 patients (22 men, mean age: 40.8 ± 13.7 years) were collected since 2002. Baseline characteristics, morbidity, and mortality data were obtained from medical records. One patient (4.16%) survived sudden cardiac death (SCD), four patients (16.3%) had syncope, and 19 patients (79.1%) were asymptomatic. Eleven patients (45.8%) had a family history of SCD. Twenty patients showed a spontaneous coved-type ST-segment elevation on electrocardiogram and after medical challenge on the four remnants. An electrophysiological study was performed in 15 of 24 patients (62.5%), during which ventricular fibrillation was induced in six patients (40%); three of the six patients were previously asymptomatic. An implantable cardioverter defibrillator (ICD) was implanted in 14 patients (58.3%). After a mean follow-up of 26 ± 21 months, one patient died from a noncardiac cause and one patient (with a history of aborted SCD) received an appropriate shock from his ICD. None of the asymptomatic and noninducible patients experienced a cardiac event. BS is present in the North African population and is probably under-recognized. Tunisian patients with BS share with their western and Asiatic counterparts similar clinical profile.

Renal disease and cardiac mortality in survivors of sudden cardiac death

Objective - Renal disease is associated with increased all-cause mortality and cardiovascular mortality. However, the role of ICD implantation on cardiac mortality in patients with renal disease has not been well studied. Implantable cardioverter-defibrillator (ICD) implantation is protective against cardiac death in a secondary prevention population with renal disease.Methods - The Antiarrhythmics Versus Implantable Cardioverter Defibrillators (AVID) Trial (n??=??1016) was a multicentre trial comparing ICD (n = 507) and anti-arrhythmic drugs (AAD) (n = 509) for secondary prevention of life-threatening ventricular tachyarrhythmias.We performed a post-hoc analysis of the AVID trial using the National Heart, Lung, and Blood Institute limited access dataset. Individuals in the original AVID study with history of renal disease (n = 82) were included in this analysis. Outcomes of our analysis were cardiac death and all-cause mortality.Results- 41 patients had renal disease in both the ICD and AAD arms. A total of 116 patients died in the ICD arm, while 162 died in the AAD arm. Renal disease was an independent predictor (HR, 95% CI) of cardiac death (1.967, 1.09-3.57, P = 0.02) and all-cause mortality (2.04, 1.23-3.39, P = 0.01) in the AAD arm. Renal disease was also a predictor of all-cause mortality in the ICD arm (1.75, 1.01-3.01, P = 0.04). However, renal disease did not influence cardiac death in the ICD arm.Conclusions- Our study investigates the effect of ICD implantation in an entirely secondary prevention population with renal disease. ICD implantation appears to be equally protective against cardiac death in renal disease when compared to AAD.

Ventrikuläre Tachykardien mit Ursprung im spezifischen Reizleitungssystem

Ventricular tachycardias (VT) associated with the His-Purkinje system may occur in patients with and without organic heart disease. The former may encounter bundle branch reentrant VT, a macroreentrant VT utilizing the specific conduction system. It frequently occurs in patients with preexisting conduction disturbance such as complete left bundle branch block and may be eliminated by catheter ablation of the right bundle branch. After successful ablation, patient's prognosis depends on the presence or absence of structural heart disease.In patients without structural heart disease, VT with right bundle branch block pattern and superior axis, referred to as idiopathic left ventricular tachycardia, is observed. It is a reentrant VT utilizing the posterior left fascicle and the Purkinje network. The two treatment options include antiarrhythmic drug therapy with verapamil or curative catheter ablation.Another form of ventricular arrhythmia originating in the Purkinje network is idiopathic ventricular fibrillation (IVF). Focal triggers from the right and left ventricular Purkinje network induce premature ventricular contractions inducing IVF. This is amenable to catheter ablation leading to a significant reduction in ICD (implantable cardioverter defibrillator) interventions in sudden cardiac death survivors.

Comparison of risk profiles between survivors and victims of sudden cardiac death from an acute coronary event

Aim. This study was designed to compare the risk profiles of sudden cardiac death (SCD) victims and survivors of an acute coronary event.Method. A case-control study included consecutive victims of SCD (n=425) verified to be due to an acute coronary event at medicolegal autopsy and consecutive patients surviving an acute myocardial infarction (AMI) (n=644).Results. Family history of SCD (odds ratio (OR) 1.5, 95% confidence interval (CI) 1.0–2.2, P=0.03), male gender (OR 1.8, 95% CI 1.3–2.4, P<0.001), current smoking (OR 2.0, 95% CI 1.5–2.6, P<0.001), cardiac hypertrophy (OR 3.0, 95% CI 2.3–3.9, P<0.001) and three-vessel coronary artery disease (CAD) (OR 5.4, 95% CI 3.6–8.2, P<0.001) were more common among the victims of SCD as compared to survivors of AMI. There was a cumulative increase of risk of being a SCD victim versus AMI survivor when more than one risk factor was present, with the OR rising to 44.3 (95% CI 8.0–246.7) in a current male smoker with a family history of SCD and cardiac hypertrophy.Conclusions. There are specific features that differentiate the victims of SCD from survivors of an acute coronary event. Clustering of several variables, such as family history of SCD, smoking, cardiac hypertrophy and three-vessel CAD are alarm signals of a very high risk of SCD.

Patients' perceptions of research in emergency settings: A study of survivors of sudden cardiac death

Conditions such as stroke, sudden cardiac death, and major traumatic injury are major causes of morbidity and mortality, and there is a need for clinical research to improve treatment for these conditions. However, because informed consent is often impossible, research in these situations poses ethical concerns. Despite growing literature on the ethics of emergency research, little is known about the views of relevant patient populations regarding research in emergency settings conducted under an exception from informed consent (EFIC). In this qualitative study, survivors of sudden cardiac death (SCD) – recruited from an outpatient cardiology clinic in late 2005 – were asked their views on scenarios representing different types of EFIC research. Patients were generally accepting of such research, more than previous studies would have predicted. Their concerns focused primarily on study risks and benefits and less on waiving consent or randomization. EFIC research is of international importance and ethical controversy. This study represents the first attempt to assess views of SCD survivors on this type of research and one of the first to assess patients' views in-depth. Findings indicate broad acceptance of EFIC research among this population and re-focus discussion on what risks are reasonable for non-autonomous subjects. The study also demonstrates potential for valuable input from patients regarding complicated and ethically challenging issues using a method that allows them to develop opinions on unfamiliar issues.

Workup of the Cardiac Arrest Survivor: For the Symposium on Sudden Cardiac Death For Progress in Cardiovascular Diseases

Sudden cardiac death is a significant cause of mortality. Survivors of sudden cardiac death pose a significant diagnostic and management challenge for the clinician. Investigation strategies are directed at elucidating a cause or mechanism of sudden cardiac death and ultimately preventing recurrence. Detailed herein is a comprehensive approach to the assessment of a sudden cardiac death survivor.

Ambulatory ECG‐Based T‐Wave Alternans Predicts Sudden Cardiac Death in High‐Risk Post‐MI Patients with Left Ventricular Dysfunction in the EPHESUS Study

Exercise microvolt T-wave alternans (TWA) identifies sudden cardiac death (SCD) risk. TWA can be measured from ambulatory ECGs (AECGs) using modified moving average (MMA) method. Whether MMA TWA from AECGs predicts SCD in post-MI patients with left ventricular dysfunction (LVD) is unknown. EPHESUS enrolled hospitalized post-MI patients with heart failure and/or diabetes with LVD. Before randomization to drug treatment, AECGs were obtained in 493 patients. Of them, 46 died of cardiovascular causes, including 18 of SCD. Patients alive at end of follow-up (N = 92) were matched with 46 nonsurvivors based on age, gender, and diabetes. MMA TWA was analyzed using MARSPC system (GE Healthcare, Milwaukee, WI, USA). The three highest TWA values from artifact-free periods were averaged for AECG channels corresponding to leads V(1) and V(3). SCD prediction was tested with a prespecified 47 microV cutpoint and at a cutpoint maximizing the separation between SCD patients versus survivors or non-SCD. TWA in either lead was higher for patients with SCD (P < or = 0.05) versus survivors or non-SCD. TWA > or = 47 microV was associated with RR = 5.2 (95%CI = 1.8-13.6, P = 0.002) in V(1) and RR = 5.5 (95% CI = 2.2-13.8, P < 0.001) in V(3) for SCD. The optimal cutpoint for TWA in V(1) was > or = 43 microV (RR = 5.9 [95%CI = 2.2-15.8, P < 0.001]). The optimal cutpoint in V(3) was > or = 47 microV. TWA greater than the optimal cutpoint in either lead was associated with RR = 7.1 (95%CI = 2.7-18.3, P < 0.001) for SCD, with 11 out of 18 patients dying of SCD. AECG-based TWA measured with MMA is a powerful predictor of SCD in high-risk post-MI patients with LV dysfunction.

The Role of Antiarrhythmic Drug Therapy for the Prevention of Sudden Cardiac Death

Sudden cardiac death (SCD) accounts for more than 300,000 deaths annually in the United States alone. The utility of antiarrhythmic drugs in survivors of SCD (secondary prevention) is limited because of their incomplete efficacy and long-term toxicity. Efforts to target primary prevention of SCD have focused on left ventricular dysfunction in conjunction with congestive heart failure. Antiarrhythmic drugs are not able to decrease mortality in this patient population either; in fact, certain drugs may actually increase overall mortality. In both primary and secondary prevention patients, only implantable cardioverter-defibrillator implantation is associated with improved survival. Antiarrhythmic drugs like azimilide, dofetilide, sotalol, and amiodarone can be used as adjunct treatment for management of atrial arrhythmias and to decrease implantable cardioverter-defibrillator shocks. There is an unmet need for more effective and less toxic antiarrhythmic medications.

Abstract 3667: Comparison of Risk Profiles between Survivors and Victims of Sudden Cardiac Death of an Acute Coronary Event

Introduction. There is little information on the specific risk factors leading to sudden cardiac death (SCD) during an acute coronary event, because the risk variables may overlap with those of non-fatal coronary event. This study was designed to compare the risk profiles of SCD victims and survivors of an acute coronary event. Methods and Results. A case-control study included consecutive victims of SCD (n=425, mean age 64±11 years) verified to be due to an acute coronary event at medicolegal autopsy and consecutive patients surviving an acute myocardial infarction (AMI, n=644, mean age 62±10 years). Common cardiovascular risk factors, cardiac hypertrophy, and severity of coronary artery disease (CAD) were assessed in both groups. Family history of SCD (odds ratio 1.5, 95% CI 1.0 to 2.2, p=0.03), male gender (odds ratio 1.8, 95% CI 1.3 to 2.4, p&lt;0.001), current smoking (odds ratio 2.0, 95% CI 1.5 to 2.6, p&lt;0.001), cardiac hypertrophy (odds ratio 3.0, 95% CI 2.3 to 3.9, p&lt;0.001) and 3-vessel CAD (odds ratio 5.4, 95% CI 3.6 to 8.2, p&lt;0.001) were more common among the victims of SCD as compared to survivors of AMI. On the contrary, history of hypercholesterolemia (p&lt;0.001) was less common among the SCD victims. There was a cumulative increase of risk of being a SCD victim vs. AMI survivor when more than one risk factor was present, the odds ratio being 44.3 (95% CI 8.0 to 246.7) in a current male smoker with a family history of SCD and cardiac hypertrophy. When 3-vessel CAD was added to the combined risk score, all subjects (7% of the SCD victims) were in the group of SCD giving a 100% sensitivity and specificity, respectively, in differentiating between the SCD victims and AMI survivors. Conclusions. There are specific features that differentiate the victims of SCD from survivors of an acute coronary event. Clustering of several variables, such as family history of SCD, smoking, cardiac hypertrophy, and 3-vessel CAD indicate a very high risk of SCD.

An unusual combination of possible causes of sudden death imaged by 64-slice computed tomography

Hypertrophic cardiomyopathy and anomalous origin of the coronary arteries are important causes of sudden cardiac death in the young, for which several diagnostic imaging modalities are currently available. We report the case of a young sudden cardiac death survivor in whom the unusual coexistence of hypertrophic cardiomyopathy and anomalous origin of the left circumflex artery was demonstrated using 64-slice computed tomography.

Living With an Implantable Cardioverter Defibrillator

Life-threatening cardiac dysrhythmias that cause sudden cardiac death claim more than a thousand lives a day. Many sudden cardiac death survivors and those at high risk receive an implantable cardioverter defibrillator (ICD). Despite the large number of people living with an ICD, little is known about their ICD knowledge and the impact of this knowledge on their uncertainty and quality of life (QOL). The purpose of this study was to determine if ICD knowledge and uncertainty predict QOL in individuals living with an ICD. A purposive sample of 90 ICD recipients was recruited from a large rural Northeastern cardiac clinic. A descriptive correlational design was used. Multiple regression analysis was used to assess relationships among ICD knowledge, uncertainty, and QOL. Confounding variables of age, education, left ventricular ejection fraction, and number of years postimplantation were controlled in the analyses. Statistically significant relationships were found between uncertainty and QOL, but ICD knowledge was not significantly related to uncertainty or QOL. Younger recipients reported a lower QOL. Education, ejection fraction, number of ICD shocks since implantation, and number of months since implantation were unrelated to ICD knowledge, uncertainty, or QOL in these ICD recipients. It is important to evaluate ICD recipients' understanding of the information they receive and to determine what ICD knowledge, uncertainty, and QOL means from the patient's perspective to assist them in the transitional process of learning to live with an ICD.

Clinical Use of Magnetic Resonance Imaging for the Diagnosis of Acute Myocardial Infarction in the Survivors of Cardiac Arrest

The ventricular arrhythmias with underlying coronary artery disease are a leading cause of sudden cardiac death (SCD). While the SCD survivors with proven AMI are considered to be at low risk of SCD recurrence, those without the evidence of AMI represent a high risk group that benefits from implantable cardioverter defibrillator. Therefore, the evaluation of SCD survivors for the presence of acute myocardial infarction (AMI) as a triggering factor of cardiac arrest is essential. In SCD survivors, the use of the standard diagnostic criteria of AMI may be difficult, as both serum cardiac biomarkers and electrocardiogram can be influenced by previous cardiac arrest. A novel technique that may be used for the diagnosis of AMI is magnetic resonance imaging (MRI). We report its use in four patients after cardiopulmonary resuscitation where the diagnosis of AMI could not be definitely established or excluded by means of other diagnostic procedures.

CPR in medical schools: learning by teaching BLS to sudden cardiac death survivors – a promising strategy for medical students?

BackgroundCardiopulmonary resuscitation (CPR) training is gaining more importance for medical students. There were many attempts to improve the basic life support (BLS) skills in medical students, some being rather successful, some less. We developed a new problem based learning curriculum, where students had to teach CPR to cardiac arrest survivors in order to improve the knowledge about life support skills of trainers and trainees.MethodsMedical students who enrolled in our curriculum had to pass a 2 semester problem based learning session about the principles of cardiac arrest, CPR, BLS and defibrillation (CPR-D). Then the students taught cardiac arrest survivors who were randomly chosen out of a cardiac arrest database of our emergency department. Both, the student and the Sudden Cardiac Death (SCD) survivor were asked about their skills and knowledge via questionnaires immediately after the course. The questionnaires were then used to evaluate if this new teaching strategy is useful for learning CPR via a problem-based-learning course. The survey was grouped into three categories, namely "Use of AED", "CPR-D" and "Training". In addition, there was space for free answers where the participants could state their opinion in their own words, which provided some useful hints for upcoming programs.ResultsThis new learning-by-teaching strategy was highly accepted by all participants, the students and the SCD survivors. Most SCD survivors would use their skills in case one of their relatives goes into cardiac arrest (96%). Furthermore, 86% of the trainees were able to deal with failures and/or disturbances by themselves. On the trainer's side, 96% of the students felt to be well prepared for the course and were considered to be competent by 96% of their trainees.ConclusionWe could prove that learning by teaching CPR is possible and is highly accepted by the students. By offering a compelling appreciation of what CPR can achieve in using survivors from SCD as trainees made them go deeper into the subject of resuscitation, what also might result in a longer lasting benefit than regular lecture courses in CPR.

Surgery for Ventricular Tachycardia in Patients Undergoing Left Ventricular Reconstruction by the Dor Procedure

Surgical ventricular restoration (the Dor procedure) is an option in patients with coronary artery disease and postinfarction left ventricular aneurysm. The procedure can be extended to treat ventricular tachycardia (VT). The aim of this study was to evaluate the Dor procedure including VT surgery in our institution. From July 1997 to December 2003, 53 consecutive patients with left ventricular aneurysm and VT underwent surgical ventricular restoration including nonguided endocardiectomy and cryoablation. Twenty-four patients had at least one preoperative episode of spontaneous VT, of which 8 were survivors of sudden cardiac death. Twenty-nine patients had inducible-only VT. In 45 patients, who underwent preoperative programmed stimulation, sustained uniform VT could be initiated. Arrhythmia control was evaluated by programmed stimulation or analysis of events registered by implanted defibrillators and by review of patient's records. Early mortality was 2 of 53 (3.8%). Mean follow-up was 3.7 years. At 1, 3, and 5 years overall actuarial survival was 94%, 80%, and 59%, respectively. Surgical success rate in patients with preoperative spontaneous VT was 91%. Inducible VT was found in 5 of 35 patients who underwent postoperative programmed stimulation. There was no arrhythmia-related late death and there was no loss to follow-up. The Dor procedure including VT surgery is an effective treatment for postinfarction left ventricular aneurysm and VT and eliminates the need for an implantable defibrillator in most patients. Early and long-term results are good in terms of survival and arrhythmia control.

Mechanism of sudden cardiac death in pigs with viable chronically dysfunctional myocardium and ischemic cardiomyopathy

Pigs with viable chronically dysfunctional myocardium and ischemic cardiomyopathy are at high risk of sudden cardiac death (SCD). We sought to identify the arrhythmic mechanism of SCD, the relation to changes in left ventricular (LV) function, and inducibility of malignant arrhythmias before SCD. Juvenile pigs (n = 72) were instrumented with chronic stenoses on proximal left anterior descending and circumflex arteries. Survival was only 29% 3 mo after instrumentation, and all deaths were sudden and without prodromal symptoms of heart failure. Triphenyltetrazolium chloride staining demonstrated necrosis in only nine animals averaging 2.3 +/- 0.9% of the LV, with no difference between SCD animals and survivors. Implantable loop recorders (n = 13) documented both ventricular fibrillation (n = 6) and bradyasystole (n = 2) as the arrhythmic mechanism of death. Although regional and global function were depressed [anteroseptal wall thickening 1.8 +/- 0.2 vs. 4.2 +/- 0.2 mm in Sham animals (P < 0.001); fractional shortening 21 +/- 2 vs. 31 +/- 1% in Sham animals (P < 0.01)], there were no differences between SCD animals and survivors. LV mass increased in animals with ischemic cardiomyopathy and was greater in animals with SCD (4.0 +/- 0.2 vs. 3.1 +/- 0.1 g/kg in survivors; P < 0.001). Serial programmed ventricular stimulation failed to induce any sustained arrhythmias. We conclude that pigs with viable dysfunctional myocardium and globally reduced LV function have a high rate of SCD with a spectrum of arrhythmias similar to patients with ischemic cardiomyopathy. The risk is independent of necrosis but appears to increase with LV hypertrophy. Like patients with ischemic cardiomyopathy, programmed stimulation is insensitive to predict SCD when viable dysfunctional myocardium is the pathological substrate.

Long‐Term Incidence of Malignant Ventricular Arrhythmia and Shock Therapy in Patients with Primary Defibrillator Implantation Does Not Differ from Event Rates in Patients Treated for Survived Cardiac Arrest

Recent trials have demonstrated benefit of prophylactic defibrillator (ICD) implantation compared to conventional treatment in high-risk patients. However, many patients have rare or no sustained arrhythmias following implantation. Our study addresses the question, whether patients with prophylactic defibrillator implantation have a lower risk for life-threatening ventricular tachycardia (VT) or ventricular fibrillation (VF) compared to sudden cardiac death (SCD) survivors. Over 7 years we enrolled 245 patients. Occurrence of spontaneous sustained VT/VF resulting in adequate ICD treatment was the endpoint. Incidence, type, and treatment of sustained arrhythmia in 43 previously asymptomatic ICD recipients (group B) were compared to data of 202 survivors of imminent SCD (group A). All patients had severely impaired left ventricular ejection fraction (<45%). Group B patients had long runs (>6 cycles, <30 s) of VT during Holter monitoring and inducible sustained arrhythmia. Incidence of rapid VT and VF (cycle length <240 ms/heart rate >250 bpm) after 4 years (35% in both groups, P = ns) and adequate defibrillator therapies (57% vs 55%, P = ns) were similar in both groups after univariate and multivariate analysis. Cumulative mortality tended to be lower in group B compared to group A, but the difference was not statistically significant. During long-term follow-up, incidence of sustained rapid ventricular arrhythmia in prophylactically treated patients is as high as that of SCD survivors. Benefit from defibrillator implantation for primary prevention (group B) appears to be comparable to that for survived cardiac arrest (group A).