Much of prognostic implications of ventricular arrhythmia storms remain unclear.
We evaluated the risk associated with electrical storm in patients with defibrillators in the Multicenter Automatic ...Defibrillator Implantation Trial II (MADIT-II) study.
Electrical storm was defined as > or =3 episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) in 24 hours.
Of the 719 patients who received internal cardiac defibrillator (ICD) implants and had follow-up in the MADIT-II, 27 patients (4%) had electrical storm, 142 (20%) had isolated episodes of VT/VF, and the remaining 550 patients had no ICD-recorded VT events. Baseline clinical characteristics among the groups were similar. Patients who experienced electrical storm had a significantly higher risk of death. After adjustments for relevant clinical covariates, the hazard ratio (HR) for death in the first 3 months after the storm event was 17.8 (95% confidence interval CI 8.0 to 39.5, P <.01) in comparison with those with no VT/VF. This risk continued even after 3 months for those with electrical storm (HR of 3.5, 95% CI 1.2 to 9.8, P = .02). Study patients with isolated VT/VF episodes also were at an increased risk of dying (HR = 2.5, 95% CI 1.5 to 4.0, P <.01) when compared with patients without VT/VF episodes. Statistically significant predictors of electrical storm were interim postenrollment coronary events (myocardial infarction or angina) HR 3.1 (95% CI 1.2 to 8.1, P = .02) and isolated VT or VF HR 9.2 (95% CI 4.0 to 20.9, P <.01).
Postinfarction patients with severe left ventricular dysfunction in whom electrical storm developed have significantly higher mortality than patients with only isolated VT/VF as well as those without any episodes of VT/VF. Patients who experienced postenrollment ventricular arrhythmias and/or interim coronary events during follow-up were at higher risk for VT/VF storms.
Patients with congenital structural heart disease (CSHD) and inherited arrhythmias (IAs) are at high risk of ventricular tachyarrhythmias and sudden cardiac death. The present study was designed to ...evaluate the short- and long-term outcomes of patients with CSHD and IA who received a wearable cardioverter-defibrillator (WCD) for the prevention of sudden cardiac death. The study population included 162 patients with CSHD (n = 43) and IA (n = 119) who were prospectively followed up in a nationwide registry from 2005 to 2010. The mortality rates were compared using Kaplan-Meier survival analysis. The mean age of the study patients was 38 ± 27 years. The patients with CSHD had a greater frequency of left ventricular dysfunction (ejection fraction <30%) than did the patients with IA (37% vs 5%, respectively; p = 0.002). The predominant indication for WCD was pending genetic testing in the IA group and transplant listing in the CSHD group. Compliance with the WCD was similar in the 2 groups (91%). WCD shocks successfully terminated 3 ventricular tachyarrhythmias in the patients with IA during a median follow-up of 29 days of therapy (corresponding to 23 appropriate WCD shocks per 100 patient-years). No arrhythmias occurred in the patients with CSHD during a median follow-up of 27 days. No patients died while actively wearing the WCD. At 1 year of follow-up, the survival rates were significantly lower among the patients with CSHD (87%) than among the patients with IA (97%, p = 0.02). In conclusion, our data suggest that the WCD can be safely used in high-risk adult patients with IA and CSHD. Patients with IA showed a greater rate of ventricular tachyarrhythmias during therapy but significantly lower long-term mortality rates.
Limited data regarding the effect of right ventricular pacing (RVP) on long-term survival following implantable cardioverter-defibrillator (ICD) implantation are available.
The purpose of this study ...was to evaluate the effect of RVP on the long-term survival benefit of primary ICD therapy.
Mortality data were obtained for all patients enrolled in the Multicenter Automatic Defibrillator Trial-II (MADIT-II) during an extended follow-up period of 8 years. The cumulative percent RVP during the trial was categorized as low (≤ 50% n = 369) and high (>50% n = 198). The benefit of ICD versus non-ICD therapy (n = 490) was evaluated in the two pacing categories during the early (0-3 years) and late (4-8 years) phases of the extended follow-up period.
During the early phase of the extended follow-up period, ICD therapy was associated with similar benefits in the low-RVP and high-RVP subgroups (hazard ratio HR = 0.35 and 0.38, respectively, P <.001 for both). In contrast, during the late phase, the long-term survival benefit of the ICD was maintained among patients with low RVP (HR = 0.60, P <.001) and attenuated among those with the high RVP (HR = 0.89, P = .45). An increased risk for late mortality associated with high versus low RVP was evident only among patients without left bundle branch LBBB at enrollment (HR = 1.63, P = .002).
Among ICD recipients, high RVP is associated with a significant increase in the risk of long-term mortality and with attenuated device efficacy. The deleterious effects of RVP are pronounced mainly in non-LBBB patients, suggesting a possible role for combined cardiac resynchronization-defibrillator therapy in this population.
There are limited data about the correlation between brain natriuretic peptide (BNP) levels and arrhythmic risk assessment in patients who receive device therapy for the treatment of heart failure ...(HF) or for the prevention of sudden cardiac death.
We aimed to investigate the association between BNP levels and the risk of ventricular tachyarrhythmias among mildly symptomatic HF patients who receive an intracardiac defibrillator (ICD) with or without cardiac resynchronization therapy (respectively, CRT-D or CRT).
The study population involved 1197 patients enrolled in MADIT-CRT. Plasma BNP was measured in a core laboratory at baseline and after 1-year follow-up. Ventricular tachycardia/fibrillation (VT/VF) events were identified from ICD/CRT-D interrogations.
Multivariate Cox hazards regression modeling showed that elevated baseline (> median = 72 ng/L) and 1-year BNP were associated with a significant increase in the risk of VT/VF (HR = 1.36, P = .026; and HR = 1.79, P < .001, respectively); and VT/VF or death (HR = 1.37, P = .008; and HR = 1.84, P < .0001, respectively) during follow-up. At 1 year post device implantation, BNP levels were significantly lower among study patients treated with CRT-D as compared with those who received ICD only (P = .014). CRT-D patients who had greater than median reductions in BNP levels (greater than one-third reduction of initial value) experienced a significantly lower risk of subsequent VT/VF (HR = 0.61, P = .021) and VT/VF or death (HR = 0.45, P < .0001) as compared to patients without such reductions.
In MADIT-CRT, elevated baseline and follow-up BNP levels were independent predictors of increased risk for subsequent ventricular tachyarrhythmias, whereas BNP reductions following CRT-D implantation identified patients with a lower incidence of VT/VF during follow-up.
Abstract The electrocardiogram (ECG) remains the most immediately accessible and widely used diagnostic tool for guiding emergency treatment strategies. The ECG recorded during acute myocardial ...ischemia is of diagnostic, therapeutic, and prognostic significance. In patients with myocardial ischemia as a result of decreased blood supply, the initial 12-lead ECG typically shows (1) predominant ST-segment elevation (STE) as part of STE acute coronary syndrome (STE-ACS), or (2) no predominant STE, that is, non–STE ACS (NSTE-ACS). Patients with predominant STE are classified as having either aborted myocardial infarction (MI) or ST-elevation MI (STEMI) based on the absence or presence of biomarkers of myocardial necrosis. The MI may be aborted either by spontaneous or therapeutic reperfusion of the ischemic myocardium before development of myocardial cell necrosis. NSTE-ACS patients are classified as having either unstable angina or NSTE-MI, based also on the absence or presence of biomarkers of mycardial necrosis. The information obtained from the 12-lead ECG at presentation should be complemented by repeated ECGs especially during symptoms indicative of ischemia and, if applicable, by comparing the findings with reference ECGs. Also, continuous ECG recording in a coronary care setting, including the comparison of ECGs with and without pain, adds to the information gained at patient presentation. In this article, mechanisms of ischemic ECG changes and the ECG patterns recorded in both STE-ACS and NSTE-ACS are described. ECG patterns of NSTE-ACS, which include ST depression, negative T wave, and even normal ECG, need to be better defined in future studies to correlate them with the severity and extent of ischemia and to explore to what extent they are explained by acute active ischemia or represent consequences of ischemia. One of the aims of this article is to propose a classification of the ECG patterns encountered in different clinical scenarios of ACS. How these patterns will aid in guiding the diagnostic and therapeutic process is discussed.
Data on inappropriate implantable cardioverter-defibrillator (ICD) therapy and effects of programming by heart rate are lacking.
We aimed to characterize inappropriate ICD therapy and assess the ...effects of novel programming by heart rate.
Incidence and causes of inappropriate therapy by heart rate range (below or above 200 bpm) were assessed. Predictors of inappropriate therapy and effects of programming by heart rate were evaluated with multivariate Cox regression models. Crossovers were excluded.
Inappropriate therapy occurred in 9.2% of the total patient population, with 19% of patients randomized to study arm A, 3.6% in arm B, and 4.7% in arm C. Inappropriate therapies <200 bpm were attributable to supraventricular tachycardia (SVT)/sinus tachycardia (78%) or atrial fibrillation/flutter (20%). Inappropriate therapy ≥200 bpm occurred because of SVT (47%), atrial fibrillation/flutter (41%), or electromagnetic interference (13%). Conventional ICD programming was associated with more inappropriate therapy <200 bpm than high-rate or delayed therapy, as were younger age, history of atrial arrhythmia, advanced New York Heart Association functional class, ICD versus cardiac resynchronization therapy with defibrillator, and absence of diabetes. High-rate and long-delay therapy significantly reduced the risk of inappropriate therapy in the <200 bpm range. Long delay was associated with further reduction of fast (≥200 bpm) inappropriate therapy (P = .032) and a reduction in subsequent inappropriate episodes (P = .006).
In MADIT-RIT, inappropriate ICD therapy is most frequent at rates below 200 bpm and can be predicted, and effectively prevented, with high-rate cutoff programming. Long-delay therapy effectively reduces fast inappropriate therapy ≥200 bpm and subsequent events.
http://clinicaltrials.gov/ct2/show/NCT00947310.
Objectives This study was designed to evaluate the clinical and prognostic aspects of long QT syndrome (LQTS)-related cardiac events that occur in the first year of life (infancy). Background The ...clinical implications for patients with long QT syndrome who experience cardiac events in infancy have not been studied previously. Methods The study population of 3,323 patients with QT interval corrected for heart rate (QTc) ≥450 ms enrolled in the International LQTS Registry involved 20 patients with sudden cardiac death (SCD), 16 patients with aborted cardiac arrest (ACA), 34 patients with syncope, and 3,253 patients who were asymptomatic during the first year of life. Results The risk factors for a cardiac event among 212 patients who had an electrocardiogram recorded in the first year of life included QTc ≥500 ms, heart rate ≤100 beats/min, and female sex. An ACA before age 1 year was associated with a hazard ratio of 23.4 (p < 0.01) for ACA or SCD during ages 1 to 10 years. During the 10-year follow-up after infancy, beta-blocker therapy was associated with a significant reduction in ACA/SCD only in those with a syncopal episode within 2 years before ACA/SCD but not for those who survived ACA in infancy. Conclusions Patients with LQTS who experience ACA during the first year of life are at very high risk for subsequent ACA or death during their next 10 years of life, and beta-blockers might not be effective in preventing fatal or near-fatal cardiac events in this small but high-risk subset.
Data on the impact of right ventricular (RV) lead location on clinical outcome and ventricular tachyarrhythmias in cardiac resynchronization therapy with defibrillator (CRT-D) patients are limited.
...To evaluate the impact of different RV lead locations on clinical outcome in CRT-D patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy trial.
We investigated 742 of 1089 CRT-D patients (68%) with adjudicated RV lead location enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy trial to evaluate the impact of RV lead location on cardiac events. The primary end point was heart failure or death; secondary end points included ventricular tachycardia (VT), ventricular fibrillation (VF), or death and VT or VF alone.
Eighty-six patients had the RV lead positioned at the RV septal or right ventricular outflow tract region, combined as nonapical RV group, and 656 patients had apical RV lead location. There was no difference in the primary end point in patients with nonapical RV lead location versus those with apical RV lead location (hazard ratio HR 0.98; 95% confidence interval CI 0.54-1.80; P = .983). Echocardiographic response to CRT-D was comparable across RV lead location groups (P > .05 for left ventricular end-diastolic volume, left ventricular end-systolic volume, and left atrial volume percent change). However, nonapical RV lead location was associated with significantly higher risk of VT/VF/death (HR 2.45; 95% CI 1.36-4.41; P = .003) and VT/VF alone (HR 2.52; 95% CI 1.36-4.65; P = .002), predominantly in the first year after device implantation. Results were consistent in patients with left bundle branch block.
In CRT-D patients, there is no benefit of nonapical RV lead location in clinical outcome or echocardiographic response. Moreover, nonapical RV lead location is associated with an increased risk of ventricular tachyarrhythmias, particularly in the first year after device implantation.
Abstract Background Clinical implications of complete left-sided reverse remodeling due to cardiac resynchronization therapy with a defibrillator (CRT-D), defined as reduction in both left ...ventricular end-systolic volume (LVESV) and left atrial volume (LAV), are unknown. Objectives This study aimed to evaluate the rate and predictive value of complete left-sided reverse remodeling on heart failure (HF) and death events in CRT-D patients with left bundle branch block (LBBB) enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy). Methods The study population comprised 533 CRT-D patients with LBBB, 212 (40%) with complete left-sided reverse remodeling (above-median change in both LAV and LVESV), 115 (22%) with discordant reverse remodeling (above-median change in only LAV or LVESV), and 206 (38%) with lesser reverse remodeling (below-median LAV and LVESV change). The primary endpoint was HF or death; secondary endpoints included HF alone and death alone during long-term follow-up. Results Patients with complete left-sided reverse remodeling had a significantly lower rate of HF or death than those with discordant reverse remodeling or lesser reverse remodeling (p < 0.001). Multivariate Cox proportional hazard models consistently showed a decreased risk for HF and death in patients with complete reverse remodeling compared with discordant reverse remodeling or lesser reverse remodeling (hazard ratio: 0.66 per each group; 95% CI: 0.50 to 0.85; p = 0.002). This finding was similar for HF alone and death alone. Conclusions In MADIT-CRT, >20% of CRT-D patients exhibited discordant reverse remodeling in the left ventricle and the left atrium. CRT-D patients with LBBB and complete left-sided reverse remodeling had a significantly lower risk of HF and death, HF alone, and death alone during long-term follow-up than patients with discordant or lesser reverse remodeling. (MADIT-CRT: Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy MADIT-CRT; NCT00180271 )
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