Predictors for early mortality and arrhythmic events in patients with a CRT-D: A two center cohort study.

BACKGROUND Guidelines of heart failure therapy include cardiac resynchronization as standard of care in patients with severely depressed left ventricular function and wide QRS complex. It has been shown that patients benefit regarding mortality and morbidity. However, early mortality precludes long-term benefits from the device. The aim of the study was to identify predictors for early occurrence of both death and first-ever implantable cardioverter-defibrillator (ICD) therapy using a large combined database of patients with cardiac resynchronization therapy with defibrillator (CRT-D). METHODS From two registries (tertiary care centres) 904 patients were identified, no single patient was excluded. Early death was defined as death occurring within the 3 years after implantation whereas early ICD therapy as such occurring within the first year. 33 baseline parameters were compared using uni- and multivariate analysis with the Cox model and binary logistic regression. RESULTS The population was predominantly male (77%), with mean age of 63 ± 11 years and primary prevention indication in 80%. Mean follow-up was 55 ± 38 months. 256 (28%) patients had ICD therapies whereof the first-ever event occurred early in 52%. 270 (30%) patients died after 41 ± 31 months, mostly from advancing heart failure (41%), 141 (52%) patients of them early. Independent predictors for early ICD therapy were secondary prevention and renal failure. Independent predictors for early mortality were a history of percutaneous coronary intervention and of peripheral vascular disease. CONCLUSIONS Predictors for early mortality after CRT-D implantation were a history of percutaneous coronary intervention and peripheral vascular disease, present in only a minority of patients, thus limiting their use in clinical practice

Reassessment of cardiovascular parameters and comorbidities in implantable cardioverter-defibrillator patients at the time of first replacement.

BACKGROUND Guidelines provide extensive recommendations regarding implantable cardioverter-defibrillator (ICD) implantation. However, ICD replacement at the time of battery depletion is rarely studied. HYPOTHESIS Our objectives were to identify patients at high-risk of death after ICD replacement, with a reassessment of changes in risk factors and comorbidities at the time of replacement, and to determine predictors for subsequent mortality. METHODS Patients undergoing ICD replacement for regular battery depletion were selected from a prospective single-center ICD registry. Both at implant and replacement, 3 demographic parameters, 9 cardiovascular parameters, 5 comorbidities, and 4 laboratory parameters were collected. Cox proportional hazard analyses were used. RESULTS We included 308 patients who were predominantly male (86%) with a median age at ICD replacement of 66 years. Replacement was performed 65 months (interquartile range, 52-91) after implantation. Median follow-up after replacement was 41 months, during which 82 patients (27%) died. Multivariable analysis revealed 4 independent predictors of mortality after ICD replacement: age/year (hazard ratio [HR]: 1.05, 95% confidence interval [CI]: 1.03-1.08, P = 0.01), worsening heart failure by 1 class (HR: 1.53, 95% CI: 1.15-2.03, P = 0.003), presence of left bundle branch block (HR: 1.98, 95% CI: 1.22-3.23, P = 0.006), and ICD therapy prior to replacement (HR: 2.22, 95% CI: 1.37-3.58, P = 0.001). Incorporated into a dichotomous score, they strongly correlated with mortality at 5 years after replacement (5% with 0 parameters, 15% with 1 parameter, and 30%-55% with >2 parameters). CONCLUSIONS Focused reassessment of selected patient characteristics at the time of ICD replacement correlates with subsequent mortality and can impact decision making at this point in time

Association of ECG parameters with late gadolinium enhancement and outcome in patients with clinical suspicion of acute or subacute myocarditis referred for CMR imaging.

BACKGROUND Risk stratification of myocarditis is challenging due to variable clinical presentations. Cardiovascular magnetic resonance (CMR) is the primary non-invasive imaging modality to investigate myocarditis while electrocardiograms (ECG) are routinely included in the clinical work-up. The association of ECG parameters with CMR tissue characterisation and their prognostic value were investigated in patients with clinically suspected myocarditis. METHODS AND RESULTS Consecutive patients with suspected myocarditis who underwent CMR and ECG were analysed. Major adverse cardiovascular event (MACE) included all-cause death, hospitalisation for heart failure, heart transplantation, documented sustained ventricular arrhythmia, or recurrent myocarditis. A total of 587 patients were followed for a median of 3.9 years. A wide QRS-T angle, low voltage and fragmented QRS were significantly associated with late gadolinium enhancement. Further, a wide QRS-T angle, low voltage and prolonged QTc duration were associated with MACE in the univariable analysis. In a multivariable model, late gadolinium enhancement (HR: 1.90, 95%CI: 1.17-3.10; p = 0.010) and the ECG parameters of a low QRS voltage (HR: 1.86, 95%CI: 1.01-3.42; p = 0.046) and QRS-T-angle (HR: 1.01, 95%CI: 1.00-1.01; p = 0.029) remained independently associated with outcome. The cumulative incidence of MACE was incrementally higher when findings of both CMR and ECG were abnormal (p<0.001). CONCLUSION In patients with clinically suspected myocarditis, abnormal ECG parameters are associated with abnormal tissue characteristics detected by CMR. Further, ECG and CMR findings have independent prognostic implications for morbidity and mortality. Integrating both exams into clinical decision-making may play a role in risk stratification in this heterogeneous patient population

Predicting defibrillator benefit in patients with cardiac resynchronization therapy: a competing risk study.

BACKGROUND Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected heart failure patients but decision-making regarding selection of CRT-defibrillator or CRT-pacemaker is an ongoing debate. OBJECTIVE Aim was to construct predictive models and scoring systems for "ICD-therapy" and "death without ICD-therapy (prior death)". METHODS We pooled two prospective cohorts of CRT-D patients with primary prevention indication and used Fine and Gray models to develop independent prognostic models for time to first ICD-therapy (event of interest) or death without prior ICD-therapy (competing event). We defined CRT-D benefit as a high probability of ICD-therapy combined with moderate/low probability of prior death. RESULTS 720 patients were included. Median follow-up was 7.2 years, 247 patients died (34%). Cumulative incidence of ICD-therapy/prior death at 5 years was 24%/17%. In multivariable models, higher NYHA classes, diuretic use, and ischemic cardiomyopathy were predictors of ICD-therapy (HR1.89 [1.30-2.75]; 1.91 [1.12-3.24] ; 1.40[1.02-1.92]), but not of prior death. Males with comorbidities (cancer; renal failure; peripheral artery disease, BMI>30) or systolic blood pressure ≤100 were at higher risk of prior death. Higher age was associated with lower risk of ICD-therapy, but higher risk of prior death. A quarter of patients had low predicted benefit from CRT-D implantation using a scoring system for the dual prediction of "appropriate ICD-therapy" and "death without appropriate ICD-therapy. CONCLUSION Different factors predict ICD-therapy or prior death in CRT-D patients using competing risk models. Scoring allows identifying patients with predicted low benefit of CRT-D (low chance of ICD-therapy, high chance of prior death)

High incidence of diaphragmatic myopotential oversensing by a specific implantable cardioverter defibrillator.

INTRODUCTION Diaphragmatic myopotential oversensing (dMPO) by implantable cardioverter defibrillators (ICDs) is thought to be a rare condition that can be misdiagnosed as lead failure and lead to unnecessary lead replacement. We observed several cases of dMPO in patients with Sorin/LivaNova ICDs (MicroPort Sci.). We sought to systematically assess the incidence of dMPO in patients with Sorin/LivaNova ICDs. METHODS AND RESULTS A predefined number of 100 consecutive patients with Sorin/LivaNova ICDs were prospectively included in the device clinic of our center. Stored arrhythmia episodes were checked for spontaneous dMPO. In addition, we performed provocation maneuvers by Valsalva. At least one episode of spontaneous or provoked dMPO was seen in 12 (12%) of the 100 patients included in the study (86% males, median age: 66 years). Nine of 89 patients (10%) with true bipolar and 3 of 11 patients (27%) with integrated bipolar sensing configuration were affected. Spontaneous dMPO was observed in 7 of 58 patients (12%) with sensitivity programmed to 0.4 mV and in 2 of 42 patients (5%) with sensitivity programmed to 0.6 mV (not significant). In three patients, dMPO could be provoked with no spontaneous episodes recorded. In two nonpacemaker-dependent patients with a CRT-D, ventricular pacing was temporarily inhibited. No antitachycardia therapy was triggered by dMPO in any patient. CONCLUSIONS DMPO is frequent in patients with Sorin/LivaNova ICDs, especially with sensitivity programmed to 0.4 mV. It also frequently occurs with true bipolar sensing configuration. DMPO should not be misinterpreted as lead failure to avoid unnecessary lead replacement

Leadless cardiac resynchronization therapy - an in-vivo proof-of-concept study of wireless pacemaker synchronization.

BACKGROUND Contemporary leadless pacemakers (PMs) only feature single-chamber ventricular pacing. However, the majority of patients requires dual-chamber pacing or cardiac resynchronization therapy (CRT). Several leadless PMs implanted in the same heart would make that possible if they are able to synchronize their activity in an efficient, safe and reliable way. Thus, a dedicated ultra-low-power wireless communication method for pacemaker synchronization is required. OBJECTIVE The purpose of this study was to develop a leadless CRT system and to evaluate its function in vivo. METHODS Device synchronization was implemented using conductive intracardiac communication (CIC). Communication frequencies were optimized for intracardiac device-device communication. Energy consumption, safety, and reliability of the leadless PM system were tested in animal experiments. RESULTS We successfully performed CRT pacing with three independent devices synchronizing their action using CIC. No arrhythmias were induced by the novel communication technique. 98% of all communication impulses were transmitted successfully. The optimal communication frequency was around 1 MHz with a corresponding transmitted power of only 0.3 μW at a heart rate of 60 beats per minute. CONCLUSION Leadless pacemakers are able to synchronize their action using CIC and may overcome the key limitation of contemporary leadless pacemakers