Lack of prognostic implications of spontaneously occurring or stimulation induced atrial tachyarrhythmias in patients with dilated cardiomyopathy.

A prospective study was undertaken in 102 patients with idiopathic dilated cardiomyopathy to assess the significance of spontaneous and inducible atrial tachyarrhythmias (ATA). Twenty-six patients were in chronic atrial fibrillation (group I) and 76 patients were in sinus rhythm (group II); 14 patients in group II had a clinical history of ATA or episodes of ATA during Holter monitoring. An electrophysiological study was systematically performed. Programmed atrial stimulation was carried out in group II, and used up to two atrial premature stimuli from the right atrium at 2 cycle lengths (sinus cycle length--10%, 600 ms) and then one atrial extrastimulus under infusion of 1 to 4 micrograms. min-1 of isoproterenol. Programmed ventricular stimulation was performed in groups I and II. Sustained atrial tachyarrhythmia (ATA) was induced in 33 patients in group II (42%); isoproterenol infusion facilitated the induction of ATA in only one other patient, who had exercise-related ATA. Eleven patients in group II with spontaneous ATA had inducible sustained ATA. The sensitivity of programmed atrial stimulation to reproduce an ATA was 78.5% and its specificity 64.5%. Inducible ATA was related to a shorter atrial effective refractory period (209 +/- 25 ms vs 228 +/- 32, P less than 0.02). Inducible and spontaneous ATAs were related to older age but not to the existence of spontaneous or inducible ventricular tachycardia; they did not have prognostic significance: the left ventricular ejection fraction and the prognosis were similar in patients with spontaneous or inducible ATA and those without ATA.(ABSTRACT TRUNCATED AT 250 WORDS)     

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     

Shock occurrence and survival in 49 patients with idiopathic dilated cardiomyopathy and an implantable cardioverter-defibrillator

To determine shock occurrence and survival, 49 patients withidiopathic dilated cardiomyopathy presenting with cardiac arrest(82%), syncope (12%) or ventricular tachycardia without syncope(6%) were followed for 28 ±28 months after cardioverter-defibrillator(ICD) implant according to the intention to treat principle.Using the Kaplan-Meier method, the actuarial incidence for anyspontaneous shocks was 20%, 58%, and 77%, and the incidenceof appropriate shocks was 16%, 49%, and 72% at 1, 3, and 5 yearsof follow-up, respectively. Only two of 49 study patients (4%)with an active ICD died suddenly during follow-up. Another twopatients, however, with an inactive device died suddenly, resultingin a sudden death rate of 2% per year with an active ICD, and5% per year, according to the intention to treat principle.The incidence of cardiac death from any cause was 8%, 25%, and35%, and the incidence of total mortality was 14%, 39%, and49% during 1, 3, and 5 years of follow-up, respectively. Therewas no difference in the Kaplan-Meier survival curves for shockedvs non-shocked patients. Thus, in this selected patient populationwith idiopathic dilated cardiomyopathy the majority of patientsreceived ‘appropriate’ shocks during follow-up,and the sudden death rate with active ICD is low.     

Role of Implantable Cardioverter Defibrillators in Dilated Cardiomyopathy

ICDs in Dilated Cardiomyopathy. Idiopathic dilated cardiomyopathy (DCM) accounts for about 10,000 deaths per year in western countries. Of these deaths, 8% to 51% occur suddenly, with more than half of the events due to a ventricular arrhythmia. Improvement in diagnostic techniques and therapeutic strategies, together with changes in secular trends, have likely contributed to the reported trend toward improved survival in recent years. Identification of DCM patients at higher risk of sudden death is difficult. Poor left ventricular function is the strongest predictor of all‐cause death, whereas a history of sustained unstable ventricular arrhythmia or cardiac arrest identifies patients at high risk of sudden death. Recent data suggest that a history of syncope, regardless of inducibility at programmed electrical stimulation, may be a risk factor of sudden death. Despite the absence of controlled studies, use of implantable cardioverter defibrillator therapy for primary prevention can be considered in patients with unexplained syncope as well as subgroups of DCM patients awaiting transplantation. In patients who survive a cardiac arrest or an unstable ventricular tachycardia, use of implantable cardioverter defibrillator therapy is associated with improved survival during follow‐up and should be considered as a first‐line therapy.     

Natural history of Brugada syndrome: the prognostic value of programmed electrical stimulation of the heart

INTRODUCTION: The prognostic value of electrophysiologic studies in individuals with the syndrome of right bundle branch block and ST segment elevation in precordial leads V1 to V3 (Brugada syndrome) remains controversial. Our previous data from 252 individuals with the syndrome suggested that programmed ventricular stimulation had a good overall accuracy to predict events. However, studies from independent investigators questioned our results. We report here the largest population with Brugada syndrome ever studied by programmed electrical stimulation of the heart. METHODS AND RESULTS: Four hundred forty-three individuals with an ECG diagnostic of Brugada syndrome were studied by programmed electrical stimulation of the heart. The diagnosis was made because of the classic ECG showing a coved-type ST segment elevation in precordial leads V1 to V3. Of the 443 individuals, 180 had developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 263 were asymptomatic at the time the diagnosis was made. The ventricular stimulation protocol included a minimum of two basic pacing cycle lengths with two ventricular premature beats from the right ventricular apex. A sustained ventricular arrhythmia was induced in 217 cases (49%). Symptomatic patients were more frequently inducible [126/180 (70%)] than asymptomatic individuals [91/263 (34%); P = 0.0001]. Males were more frequently inducible than females (54% vs 32%, P < 0.0001). Inducible individuals had a longer HV interval than noninducible patients (50 +/- 12 msec vs 46 +/- 10 msec, P < 0.002). HV interval and number of premature beats needed to induce VF were not related to outcome. Inducibility was statistically a powerful predictor of arrhythmic events during follow-up. Sixty of 217 inducible patients (28%) had spontaneous ventricular fibrillation compared with 5 of 221 noninducible patients (2%; P = 0.0001). CONCLUSION: Inducibility of sustained ventricular arrhythmias during programmed ventricular stimulation of the heart is a good predictor of outcome in Brugada syndrome.     

Incidence of nonsustained and sustained ventricular tachyarrhythmias in patients with an implantable cardioverter defibrillator

INTRODUCTION: Nonsustained ventricular tachycardia (NSVT) is a frequent phenomenon in some patients with heart disease, but its association with sustained ventricular tachycardias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) is still not clear. The aim of this study was to determine whether NSVT incidence was associated with sustained VT/VF in patients with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: Retrospective data analysis was conducted in 923 ICD patients with a mean follow-up of 4 months. NSVT and sustained VT/VF were defined as device-detected tachycardias. The incidence rates of NSVT and sustained VT/VF as well as ICD therapies were determined as episodes per patient. The NSVT index was defined as the product of NSVT episodes/day times the mean number of beats per episode, i.e., total beats/day. The NSVT index peak was defined as the highest value on or prior to the day with sustained VT/VF episodes. Patients (n = 393) with NSVT experienced a higher incidence of sustained VT/VF (17.2 +/- 63.0 episodes/patient) and ICD therapies (15.2 +/- 61.4 episodes/patient) than patients (n = 530) without NSVT (sustained VT/VF: 0.5 +/- 6.6 and therapies: 0.5 +/- 5.6; P < 0.0001). Approximately 74% of NSVT index peaks occurred on the same day or <3 days prior to sustained VT/VF episodes. The index was higher for peaks < or =3 days prior to the day with sustained VT/VF (94.3 +/- 140.1 total beats/day) than for peaks >3 days prior to the day with sustained VT/VF (32.7 +/- 55.9 total beats/day; P < 0.0001). CONCLUSION: ICD patients with NSVT represent a population more likely to experience sustained VT/VF episodes with a temporal association between an NSVT surge and sustained VT/VF occurrence.     

Sudden cardiac death in isolated right ventricular hypertrabeculation/noncompaction cardiomyopathy

Hypertrabeculation/noncompaction of the myocardium is a rare disorder that involves most commonly the left ventricle of the heart and it has been recognized as a distinct cardiomyopathy by the World Health Organization. However, it is extremely rare for this condition to involve exclusively the right ventricle. We report the cases of three patients who presented with ventricular tachyarrhythmia and sudden cardiac death. They were found to have isolated right ventricular hypertrabeculation/noncompaction on echocardiography. This supports the hypothesis that this condition is highly arrhythmogenic and is associated with high mortality similarly to the left ventricular hypertrabeculation/noncompaction cardiomyopathy.     

Programmed ventricular stimulation in coronary artery disease and dilated cardiomyopathy: influence of the underlying heart disease on the results of electrophysiologic testing

In order to evaluate the clinical and prognostic significance of programmed ventricular stimulation (PVS), 100 patients were investigated. Twenty-four of 51 patients with coronary artery disease and 22 out of 49 with dilated cardiomyopathy had clinical ventricular tachycardia (VT). The study protocol included 24-h Holter ECG, cardiac catheterization and angiography, and PVS employing 1 and 2 premature extrastimuli and incremental pacing. In patients with coronary artery disease, VT was induced in 67% with prior VT and in 18% without such episodes (p less than 0.01). In dilated cardiomyopathy, however, patients with and without clinical VT did not differ with regard to VT inducibility (18% vs. 15%, NS). The inducibility of monomorphic sustained VT--most frequently induced in VT patients--was significantly higher in patients with coronary artery disease (p less than 0.05). Polymorphic nonsustained VT (in both coronary artery disease and dilated cardiomyopathy) was only initiated in patients without clinical VT. In patients with coronary artery disease, left ventricular ejection fraction could be correlated to clinical arrhythmia (p less than 0.001), while induced VT could only be correlated to depressed left ventricular function in patients with left ventricular aneurysm. Neither clinical nor induced VT could be correlated to left ventricular ejection fraction in patients with dilated cardiomyopathy. During a mean follow-up of 21 months, 7 patients died from sudden cardiac death. Six of them had clinical VT, but in only 1 patient with coronary artery disease was VT initiated. There was no apparent difference in the antiarrhythmic therapy of the patients with sudden death with respect to the surviving population. In conclusion, the response to PVS with the stimulation protocol applied is different in patients with coronary artery disease and dilated cardiomyopathy. The prognostic significance of the results obtained from PVS remains uncertain.     

Cardiac autonomic tone and its relation to nonsustained ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy

BACKGROUND: In contrast to postinfarct patients, little is known about cardiac autonomic tone and its relation to spontaneous ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy (IDC). Both heart rate variability (HRV) and baroreflex sensitivity (BRS) are indices of autonomic innervation of the heart. HYPOTHESIS: The aim of the present study was to determine the relation between cardiac autonomic tone assessed by HRV and BRS and spontaneous nonsustained ventricular tachycardia (NSVT) on Holter in a large patient population with IDC. METHODS: 24-h digital Holter recordings including HRV analysis and BRS testing were prospectively performed in 137 patients with IDC and preserved sinus rhythm. Mean age was 48 +/- 12 years, and mean left ventricular (LV) ejection fraction was 32 +/- 9%. The HRV analysis on Holter included the mean RR interval (RRm), the standard deviation of all normal RR intervals (SDNN), the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD), and the proportion of adjacent normal RR intervals differing more than 50 ms (pNN50). Testing for BRS was performed noninvasively using the phenylephrine method. RESULTS: Of 137 study patients, 42 (31%) had spontaneous NSVT on 24-h Holter. Compared with patients without NSVT, patients with NSVT on Holter had a higher New York Heart Association (NYHA) functional class (NYHA III: 40 vs. 18%, p < 0.01), a lower ejection fraction (29 +/- 9 vs. 34 +/- 9%, p = 0.01), and an increased LV end-diastolic diameter (69 +/- 8 mm vs. 66 +/- 7 mm, p = 0.03). The HRV variables rMSSD, pNN50, RRm, and BRS did not differ significantly between patients with and without spontaneous NSVT. Only SDNN on Holter was slightly lower in patients with versus without NSVT (106 +/- 45 vs. 121 +/- 46 ms, p = 0.08). CONCLUSIONS: Patients with IDC and spontaneous NSVT on Holter are characterized by a higher NYHA functional class, a lower LV ejection fraction, an increased LV end-diastolic diameter, and a tendency toward a lower SDNN value compared with patients without NSVT. The remaining measures of HRV including rMSSD and pNN50 reflecting primarily tonic vagal activity, as well as BRS reflecting predominantly reflex vagal activity, were similar in patients with and without NSVT. The prognostic significance of these findings in patients with IDC is currently under investigation in the Marburg Cardiomyopathy Study (MACAS) at our institution.     

Survival of antiarrhythmic or implantable cardioverter defibrillator treated patients with varying degrees of left ventricular dysfunction who survived malignant ventricular arrhythmias

INTRODUCTION: The relative effectiveness of the implantable cardioverter defibrillator (ICD) and antiarrhythmic drugs (AADs) varies with left ventricular ejection fraction (LVEF). However, once an ICD or AAD treatment strategy is chosen, the degree to which the LVEF influences survival is unknown. This article addresses that question. METHODS AND RESULTS: Using patient data from the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, the impact of LVEF on prognosis of patients who were treated with either an ICD or AAD was assessed. Survival within each quintile of LVEF was estimated by the method of Kaplan-Meier for patients treated with either the ICD or AADs. The Cox proportional hazards model was used to investigate the prognostic value of LVEF for estimating survival after adjustment for other baseline covariates among all patients in the subgroups treated by ICD or AAD. In the highest two quintiles of LVEF, survival was comparable in AAD-treated and ICD-treated patients. In the AAD-treated patients, higher LVEF was significantly and independently associated with survival free of all-cause mortality and arrhythmic death. In the ICD-treated patients, however, the statistical significance of the association was lost and only a trend toward greater survival was present. Death due to congestive heart failure remained independently and significantly associated with survival in both AAD-treated and ICD-treated patients. CONCLUSION: In patients treated with AADs but not patients treated with ICDs, survival is strongly associated with LVEF. The absence of a statistically significant association in the ICD patients is likely related to the effectiveness of the ICD in treating malignant ventricular arrhythmias, but a chance lack of association cannot be excluded.     

Electrophysiologic manifestations of ventricular tachyarrhythmias provoking appropriate defibrillator interventions in high-risk patients with hypertrophic cardiomyopathy

Introduction: Our objective was to determine features of ventricular tachyarrhythmias triggering appropriate implantable cardioverter-defibrillator (ICD) interventions in hypertrophic cardiomyopathy (HCM).
Methods and Results: The study cohort was 68 high-risk HCM patients who received ICDs for primary sudden cardiac death prevention from 1995 to 2003. All episodes of sustained ventricular tachyarrhythmias identified by stored intracardiac electrograms were analyzed. Nine patients had 51 episodes of sustained ventricular tachyarrhythmic events that required device therapy (mean follow-up, 3.4 ± 2.2 years; cumulative event rate, 3.2% per year): five had 47 episodes of monomorphic ventricular tachycardia (VT); four each had one episode of ventricular fibrillation (VF). Sinus tachycardia or atrial fibrillation was the initiating rhythm in five of nine patients and in 43 of 51 episodes of events. Of the 17 episodes of monomorphic VT detected in the VT zone, 16 (94%) were terminated by antitachycardia pacing. Thirty episodes of monomorphic VT were detected in the VF zone and were terminated by defibrillation.
Conclusion: Sustained monomorphic VT is common in a high-risk cohort with HCM. Sinus tachycardia is often the initiating rhythm, suggesting that high sympathetic drive may be proarrhythmic when a susceptible substrate is present. Antitachycardia pacing is highly effective in terminating VT in this patient population.     

The additive prognostic value of restrictive pattern and dipyridamole-induced contractile reserve in idiopathic dilated cardiomyopathy

BACKGROUND: Diastolic dysfunction and lack of contractile reserve are unfavorable prognostic predictors in patients with dilated cardiomyopathy (DCM). AIMS: This study aims to assess whether diastolic dysfunction and lack of dipyridamole-induced contractile reserve were additive predictors of poor outcome in patients with DCM. METHODS: A total of 116 patients with DCM and ejection fraction (EF<35%) were studied by dipyridamole echo (0.84 mg/kg over 10 min). At rest, a restrictive filling pattern was defined as: E/A ratio >2 and an E-wave deceleration time of <140 ms on transmitral flow velocity profile. RESULTS: Rest wall motion score index (WMSI) was 2.2+/-0.3 and decreased to 1.9+/-0.41 after dipyridamole (p<0.001). During follow-up (median 26.5 months), 22 cardiac deaths occurred. At multivariate analysis, dipyridamole-induced contractile reserve yielded significant incremental prognostic value (RR=0.275, p<0.006) over NYHA class (RR=1.971, p<0.03), angiotensin-converting enzyme inhibitor therapy (RR=0.173, p<0.001), and left ventricular end-diastolic diameter (RR=1.131, p<0.001). The worst prognostic combination was the presence of restrictive pattern at rest and the absence of contractile reserve (deltaWMSI<0.15). CONCLUSION: In patients with DCM, the ominous combination of restrictive transmitral flow pattern and lack of contractile reserve during dipyridamole stress predicts an unfavourable outcome.     

Long term results of cardioverter-defibrillator implantation in patients with right ventricular dysplasia and malignant ventricular tachyarrhythmias

OBJECTIVE—To study the outcome of patients with arrhythmogenic right ventricular dysplasia treated with an implantable cardioverter-defibrillator (ICD) for ventricular tachyarrhythmias complicated by haemodynamic collapse.
DESIGN—Observational study.
SETTING—University hospital.
PATIENTS—Nine consecutive patients (eight male, one female; mean (SD) age, 36 (18) years) with arrhythmogenic right ventricular dysplasia presenting with ventricular tachycardia and haemodynamic collapse (n = 6) or ventricular fibrillation (n = 3), treated with an ICD.
MAIN OUTCOME MEASURES—Survival; numbers of and reasons for appropriate and inappropriate ICD interventions.
RESULTS—After a mean (SD) follow up of 32 (24) months, all patients were alive. Six patients received a median of 19 (range 2-306) appropriate ICD interventions for events detected in the ventricular tachycardia window; four received a median of 2 (range 1-19) appropriate ICD interventions for events detected in the ventricular fibrillation window. Inappropriate interventions were seen for sinus tachycardia (18 episodes in three patients), atrial fibrillation (three episodes in one patient), and for non-sustained polymorphic ventricular tachycardia (one episode in one patient).
CONCLUSIONS—Patients with arrhythmogenic right ventricular dysplasia and malignant ventricular arrhythmias have a high recurrence rate requiring appropriate ICD interventions, but they also often have inappropriate interventions. Programming the device is difficult because this population develops supraventricular and ventricular tachyarrhythmias with similar rates.


Keywords: arrhythmogenic right ventricular dysplasia; implantable cardioverter defibrillator; arrhythmia     

Long-term follow-up in patients with arrhythmogenic right ventricular cardiomyopathy

Long‐Term Prognosis in Patients with ARVC. Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of sudden cardiac death due to tachyarrhythmias. The purpose of this study was to investigate the long‐term prognosis in patients with ARVC and the incidence of rapid ventricular arrhythmias during follow‐up. Methods: Thirty ARVC patients (19 male, 63.3%, mean age 48 ± 15 years) fulfilling modified Task Force criteria 2010 were included. Of them, 13 patients (43.3%) received implantable cardioverter‐defibrillator (ICD) implantation. Rapid ventricular arrhythmia was defined as electrical storm or the occurrence of ventricular tachycardia (VT) or ventricular fibrillation (VF) with a cycle length of 240 ms or less that necessitate shock delivery to 2 or more times within a 24‐hour period. Results: With a mean follow‐up of 68 ± 10 months, 6 patients (20%) with ICD implantation had recurrent rapid VT/VF. One (3.3%) of them died of multiple shocks and SCD, and 5 (16.7%) had multiple ICD therapies due to VT/VF and electrical storm. The interval between the diagnosis of ARVC and occurrence of rapid VT/VF was 13.4 ± 4.9 months. Most (5/6, 83.3%) events of recurrent rapid VT/VF occurred within 2 years. Ablated patients who did not receive an ICD implant were totally free of rapid VT/VF. Conclusions: For patients with ARVC, long‐term prognosis is favorable. During a long‐term follow‐up, patients meeting the criteria for ICD implantation have a higher rate of rapid and potentially life‐threatening arrhythmias. However, early and clustered recurrence of rapid VT/VF in patients with an ICD is common, whereas late occurrence of rapid VT/VF is very rare. (J Cardiovasc Electrophysiol, Vol. 23, pp. 750‐756, July 2012)     

Correlation between left ventricular contractility and relaxation in patients with idiopathic dilated cardiomyopathy

Background and hypothesis: It is not fully understood whether alterations in left ventricular (LV) relaxation in patients with idiopathic dilated cardiomyopathy (DCM) precede or follow alterations in LV systolic function. Accordingly, we investigated the relationship between LV systole and diastolic relaxation in patients with DCM using LV pressure-volume analysis. Methods: Hemodynamic data were collected for 38 consecutive patients with DCM in normal sinus rhythm and in the resting steady state (New York Heart Association functional class II to III). Continuous simultaneous pressure-volume relationships were obtained by conductance catheter. Left ventricular end-systolic elastance (Ees) was determined during transient occlusion of the inferior vena cava. Results: Left ventricular ejection fraction, peak negative dP/dt, and peak positive dP/dt were depressed (31 ± 11%, - 1242 ± 351 mmHg/s, and 1118 ±253 mmHg/s, respectively ). The LV end-diastolic volume index, the time constants of isovolumic LV pressure decay Tl and Td were increased (141 ±38 ml/m², 54+14 ms, and 69 ± 17 ms, respectively). Ees was markedly depressed (0.9 ± 0.5 mmHg/ml) and was not correlated with established systolic or diastolic indices except for peak positive dP/dt. Our results showed that abnormalities of relaxation were not correlated with contractile dysfunction in patients with DCM in the resting steady state however, most patients (79%) had both prolonged relaxation and extremely depressed contractility. Abnormal relaxation may have been transient or compensated in some patients (21%) with DCM who had preserved relaxation despite severely depressed contractility.     

Predictors of ventricular tachycardia recurrence in 100 patients receiving tiered therapy defibrillators

BACKGROUND AND HYPOTHESIS: Programmed electrical stimulation (PES) is a time-honored diagnostic tool in patients with ventricular tachyarrhythmias. The response to PES can be used to assess efficacy of pharmacologic or electrical therapy, as well as to obtain prognostic information. Reproducible induction of ventricular tachycardia with invasive electrophysiologic testing, or stimulation through defibrillator lead systems, can help optimize antiarrhythmic drug therapy and device programming during clinical follow-up. METHODS: We present our experience with 100 patients who had inducible sustained monomorphic ventricular tachycardia (SMVT) during invasive PES at baseline, and received a third-generation implantable cardioverter-defibrillator (ICD) alone, or in combination with antiarrhythmic drug therapy. Noninvasive programmed stimulation (NIPS) was performed prior to hospital discharge in 61 patients. RESULTS: The inducibility of SMVT was concordant between the invasive study and NIPS in a subgroup of 40 (82%) patients who had invasive PES on the same drug regimen. During a mean follow-up of 16 months, there were 12 nonarrhythmic deaths and recurrence of spontaneous SMVT in 36 (40%) of the surviving patients. Using a Cox proportional hazards model, the following variables were associated with early arrhythmia recurrence: persistent inducibility of SMVT during the NIPS session (relative risk 11, range 2.6-47); induction of SMVT with a cycle length > 280 ms during invasive baseline PES (2.5, 1.2-5) and presence of prior inferior myocardial infarction (2.1, 1-4.2). Timing to initial recurrence of spontaneous tachycardia was unaffected by other clinical variables or concomitant antiarrhythmic drug use. CONCLUSION: Programmed electrical stimulation techniques offer insight into the patterns of spontaneous ventricular tachycardia recurrence and have significant practical utility in the management of patients receiving third-generation ICDs.     

Indications and outcome of implantable cardioverter-defibrillators for primary and secondary prophylaxis in patients with noncompaction cardiomyopathy

Prophylactic ICDs for Noncompaction Cardiomyopathy . Background: Noncompaction cardiomyopathy (NCCM) is a rare, primary cardiomyopathy, with initial presentation of heart failure, emboli, or arrhythmias, including sudden cardiac death. Implantable cardioverter‐defibrillators (ICDs) are frequently used for primary and secondary prevention in different cardiomyopathy patients, but data about ICD in NCCM are scarce. The aim of this study was, therefore, to investigate ICD indications and outcomes in NCCM patients. Methods and Results: We collected prospective data from our NCCM cohort (n = 77 pts, mean age: 40 ± 14 years). ICD was implanted in 44 (57%) patients with NCCM according to the current ICD guidelines for nonischemic cardiomyopathies: in 12 for secondary prevention (7 × ventricular fibrillation, 5 × sustained ventricular tachycardia [VT]) and in 32 patients for primary prevention (heart failure/severe LV dysfunction). During a mean follow‐up of 33 ± 24 months, 8 patients presented with appropriate ICD shocks due to sustained VT after median 6.1 [1–16] months. This included 4 of 32 (13%) patients in the primary prevention group and 4 of 12 (33%) in the secondary prevention group (P = 0.04). 9 patients presented with inappropriate ICD therapy: 6 (19%) in the primary and 3 (25%) in the secondary prevention group, at a median follow‐up of 4 (2–23) months. Conclusions: In our cohort of NCCM patients, an ICD was frequently implanted for primary or secondary prevention of sudden cardiac death. At follow‐up, frequent appropriate ICD therapy was observed in both groups, supporting the application of current ICD guidelines for primary and secondary prevention of sudden cardiac death in NCCM. (J Cardiovasc Electrophysiol, Vol. 22, pp. 898‐904, August 2011)