Impact of shocks on mortality in patients with ischemic or dilated cardiomyopathy and defibrillators implanted for primary prevention.

BACKGROUND: Emerging interest is seen in the paradox of defibrillator shocks for ventricular tachyarrhythmia and increased mortality risk. Particularly in patients with dilated cardiomyopathy (DCM), the prognostic importance of shocks is unclear. The purpose of this study was to compare the outcome after shocks in patients with ischemic cardiomyopathy (ICM) or DCM and defibrillators (ICD) implanted for primary prevention. METHODS AND RESULTS: Data of 561 patients were analyzed (mean age 68.6±10.6 years, mean left ventricular ejection fraction 28.6±7.3%). During a median follow-up of 49.3 months, occurrence of device therapies and all-cause mortality were recorded. 74 out of 561 patients (13.2%) experienced ≥1 appropriate and 51 out of 561 patients (9.1%) ≥1 inappropriate shock. All-cause mortality was 24.2% (136 out of 561 subjects). Appropriate shock was associated with a trend to higher mortality in the overall patient population (HR 1.48, 95% CI 0.96-2.28, log rank p = 0.072). The effect was significant in ICM patients (HR 1.61, 95% CI 1.00-2.59, log rank p = 0.049) but not in DCM patients (HR 1.03, 95% CI 0.36-2.96, log rank p = 0.96). Appropriate shocks occurring before the median follow-up revealed a much stronger impact on mortality (HR for the overall patient population 2.12, 95% CI 1.24-3.63, p = 0.005). The effect was driven by ICM patients (HR 2.48, 95% CI 1.41-4.37, p = 0.001), as appropriate shocks again did not influence survival of DCM patients (HR 0.63, 95% CI 0.083-4.75, p = 0.65). Appropriate shocks occurring after the median follow-up and inappropriate shocks occurring at any time revealed no impact on survival in any of the groups (p = ns). CONCLUSION: Appropriate shocks are associated with reduced survival in patients with ICM but not in patients with DCM and ICDs implanted for primary prevention. Furthermore, the negative effect of appropriate shocks on survival in ICM patients is only evident within the first 4 years after device implantation

Response to intravenous ajmaline: a retrospective analysis of 677 ajmaline challenges.

International audienceAIMS: The diagnostic type I ECG in Brugada syndrome (BS) is often concealed and fluctuates between the diagnostic and non-diagnostic pattern. Challenge with intravenous ajmaline is used to unmask the diagnostic Brugada ECG. The aim of this study was to evaluate the safety of the test and to identify predictors for the response to an intravenous ajmaline challenge. METHODS AND RESULTS: In four tertiary referral centres, 677 consecutive patients underwent an intravenous ajmaline challenge for diagnosis or exclusion of BS in accordance with the recommendations of the Brugada consensus conferences. Two hundred and sixty-two ajmaline challenges (39%) were positive. Male gender, familial BS, sudden cardiac arrest (SCA), first-degree AV-block, basal saddleback type ECG, and basal right bundle branch block were identified as predictors for a positive ajmaline challenge. A predictor for negative ajmaline test was the absence of ST-segment elevation at baseline. Six of 12 patients who had experienced SCA, and five of 25 patients with a familial sudden death exhibited a positive response to ajmaline. Only one patient (0.15%) developed sustained ventricular tachyarrhythmias (ventricular fibrillation) during ajmaline challenge, which was terminated by a single external defibrillator shock. CONCLUSION: Ajmaline challenge is a safe procedure to unmask the electrocardiographic pattern of BS. Electrocardiographic and clinical parameters were identified to predict patients' response to ajmaline. The results of this study guide the clinician in which setting an ajmaline challenge is an appropriate diagnostic step

The development of the extravascular defibrillator with substernal lead placement: A new Frontier for device-based treatment of sudden cardiac arrest

Introduction: The extravascular implantable cardioverter-defibrillato (EV ICD) system with substernal lead placement is a novel nontransvenous alternative to current commercially available ICD systems. The EV ICD provides defibrillation and pacing therapies without the potential long-term complications of endovascular lead placement but requires a new procedure for implantation with a safety profile under evaluation. Methods: This paper summarizes the development of the EV ICD, including the preclinical and clinical evaluations that have contributed to the system and procedural refinements to date. Results: Extensive preclinical research evaluations and four human clinical studies with >140 combined acute and chronic implants have enabled the development and refinement of the EV ICD system, currently in worldwide pivotal study. Conclusion: The EV ICD may represent a clinically valuable solution in protecting patients from sudden cardiac death while avoiding the long-term consequences of transvenous hardware. The EV ICD offers advantages over transvenous and subcutaneous systems by avoiding placement in the heart and vasculature; relative to subcutaneous systems, EV ICD requires less energy for defibrillation, enabling a smaller device, and provides pacing features such as antitachycardia and asystole pacing in a single system

A-B. Kaplan Meier survival estimation after occurrence of appropriate shocks before median follow-up.

<p>Kaplan Meier Curves displaying that the significant effect of appropriate shocks on survival in the overall patient population is primarily driven by the ICM subgroup.</p

A-C. Kaplan Meier survival estimation after appropriate shocks (complete follow-up).

<p>A significant association between appropriate shocks and survival is only determined in patients with ICM.</p

Baseline characteristics of the study population.

<p>Data are presented as the mean value ± SD for continuous variables and number (percentage) for categorical variables. ACE  =  angiotensin converting enzyme; ARB  =  angiotensin receptor blockers; COPD = chronic obstructive pulmonary disease, CRT-D  =  cardiac resynchronisation therapy – defibrillator; ICD  =  implantable cardioverter-defibrillator; LBBB  =  left bundle branch block; LVEF  =  left ventricular ejection fraction; NYHA  =  New York Heart Association.</p

Significant differences in baseline characteristics between ICD patients with ICM and DCM.

<p>Data are presented as the mean value ± SD for continuous variables and number (percentage) for categorical variables. DCM  =  dilated cardiomyopathy; ICD  =  implantable cardioverter-defibrillator; ICM  =  ischemic cardiomyopathy; LVEF  =  left ventricular ejection fraction; NYHA  =  New York Heart Association.</p

Comparison of VTA episodes and appropriate shocks in patients with DCM and ICM.

<p>app. shock  =  appropriate shock; DCM  =  dilated cardiomyopathy; ES  =  electrical storm; ICM  =  ischemic cardiomyopathy; VF  =  ventricular fibrillation; VT  =  ventricular tachycardia; VTA  =  ventricular tachyarrhythmia.</p