Hammill, Stephen C.

Background Patient sex and age may influence rates of death after receiving an implantable cardioverter‐defibrillator for primary prevention. Differences in outcomes other than mortality and whether these differences vary by heart failure symptoms, etiology, and left ventricular ejection fraction are not well characterized. Methods and Results We studied 2954 patients with left ventricular ejection fraction ≤0.35 undergoing first‐time implantable cardioverter‐defibrillator for primary prevention within the Cardiovascular Research Network; 769 patients (26%) were women, and 2827 (62%) were aged >65 years. In a median follow‐up of 2.4 years, outcome rates per 1000 patient‐years were 109 for death, 438 for hospitalization, and 111 for heart failure hospitalizations. Procedure‐related complications occurred in 8.36%. In multivariable models, women had significantly lower risks of death (hazard ratio 0.67, 95% CI 0.56 to 0.80) and heart failure hospitalization (hazard ratio 0.82, 95% CI 0.68 to 0.98) and higher risks for complications (hazard ratio 1.38, 95% CI 1.01 to 1.90) than men; patients aged >65 years had higher risks of death (hazard ratio 1.55, 95% CI 1.30 to 1.86) and heart failure hospitalization (hazard ratio 1.25, 95% CI 1.05 to 1.49) than younger patients. Age and sex differences were generally consistent in strata according to symptoms, etiology, and severity of left ventricular systolic dysfunction, except the higher risk of complications in women, which differed by New York Heart Association classification ( P =0.03 for sex–New York Heart Association interaction), and the risk of heart failure hospitalization in older patients, which differed by etiology of heart failure ( P =0.05 for age–etiology interaction). Conclusions The burden of adverse outcomes after receipt of an implantable cardioverter‐defibrillator for primary prevention is substantial and varies according to patient age and sex. These differences in outcome generally do not vary according to baseline heart failure characteristics.

Background— Racial and ethnic minorities are under-represented in clinical trials of primary prevention implantable cardioverter-defibrillators (ICDs). This analysis investigates the association between primary prevention ICDs and mortality among Medicare, racial/ethnic minority patients. Methods and Results— Data from Get With The Guidelines-Heart Failure Registry and National Cardiovascular Data Registry’s ICD Registry were used to perform an adjusted comparative effectiveness analysis of primary prevention ICDs in Medicare, racial/ethnic minority patients (nonwhite race or Hispanic ethnicity). Mortality data were obtained from the Medicare denominator file. The relationship of ICD with survival was compared between minority and white non-Hispanic patients. Our analysis included 852 minority patients, 426 ICD and 426 matched non-ICD patients, and 2070 white non-Hispanic patients (1035 ICD and 1035 matched non-ICD patients). Median follow-up was 3.1 years. Median age was 73 years, and median ejection fraction was 23%. Adjusted 3-year mortality rates for minority ICD and non-ICD patients were 44.9% (95% confidence interval [CI], 44.2%–45.7%) and 54.3% (95% CI, 53.4%–55.1%), respectively (adjusted hazard ratio, 0.79; 95% CI, 0.63–0.98; P =0.034). White non-Hispanic patients receiving an ICD had lower adjusted 3-year mortality rates of 47.8% (95% CI, 47.3%–48.3%) compared with 57.3% (95% CI, 56.8%–57.9%) for those with no ICD (adjusted hazard ratio, 0.75; 95% CI, 0.67%–0.83%; P <0.0001). There was no significant interaction between race/ethnicity and lower mortality risk with ICD ( P =0.70). Conclusions— Primary prevention ICDs are associated with lower mortality in nonwhite and Hispanic patients, similar to that seen in white, non-Hispanic patients. These data support a similar approach to ICD patient selection, regardless of race or ethnicity.

Background— Cardiac resynchronization therapy with defibrillator (CRT-D) reduces morbidity and mortality among selected patients with heart failure in clinical trials. The effectiveness of this therapy in clinical practice has not been well studied. Methods and Results— We compared a cohort of 4471 patients from the National Cardiovascular Data Registry’s Implantable Cardioverter-Defibrillator (ICD) Registry hospitalized primarily for heart failure and who received CRT-D between April 1, 2006, and December 31, 2009, to a historical control cohort of 4888 patients with heart failure without CRT-D from the Acute Decompensated Heart Failure National Registry (ADHERE) hospitalized between January 1, 2002, and March 31, 2006. Both registries were linked with Medicare claims to evaluate longitudinal outcomes. We included patients from the ICD Registry with left ventricular ejection fraction ≤35% and QRS duration ≥120 ms who were admitted for heart failure. We used Cox proportional hazards models to compare outcomes with and without CRT-D after adjustment for important covariates. After multivariable adjustment, CRT-D was associated with lower 3-year risks of death (hazard ratio, 0.52; 95% confidence interval, 0.48–0.56; P <0.001), all-cause readmission (hazard ratio, 0.69; 95% confidence interval, 0.65–0.73; P <0.001), and cardiovascular readmission (hazard ratio, 0.60; 95% confidence interval, 0.56–0.64; P <0.001). The association of CRT-D with mortality did not vary significantly among subgroups defined by age, sex, race, QRS duration, and optimal medical therapy. Conclusions— CRT-D was associated with lower risks of mortality, all-cause readmission, and cardiovascular readmission than medical therapy alone among patients with heart failure in community practice.

Background— Patients with heart failure and atrial fibrillation are at higher risk of thromboembolic events than patients with heart failure alone. Yet, the use of anticoagulation therapy varies in clinical practice, especially among older patients, for whom its effectiveness is poorly understood. Methods and Results— Using clinical registry data linked to Medicare claims from 2005 to 2011, we examined outcomes of older patients hospitalized with heart failure and atrial fibrillation who newly initiated anticoagulation therapy at discharge. We used Cox proportional hazards models and inverse probability-weighted treatment estimates to adjust for selection bias. Main outcomes were mortality and readmission at 1 and 3 years. Among 5105 patients in 195 hospitals, 1623 (31.8%) started anticoagulation therapy at discharge. Treated patients had lower unadjusted rates of all-cause mortality (26.4% versus 42.8%; P <0.001) and all-cause readmission (58.4% versus 63.7%; P <0.001) at 1 year. After inverse weighting for the probability of treatment and adjustment for other discharge medications, anticoagulation therapy was associated with significantly lower 1-year mortality (hazard ratio, 0.70; 99% confidence interval, 0.59–0.82), but there was no statistically significant difference in the risk of all-cause readmission (hazard ratio, 0.89; 99% confidence interval, 0.78–1.01) or other readmission outcomes. Results were similar at 3 years. Conclusions— Initiation of anticoagulation therapy at hospital discharge was associated with improved mortality at 1 and 3 years but was not associated with improved cardiovascular readmission among older patients with heart failure and atrial fibrillation.

Background— Guidelines recommend that implantable cardioverter-defibrillator (ICD) candidates have an estimated longevity of ≥1 year. Longevity can be affected by chronic kidney disease (CKD). Methods and Results— Using the National Cardiovascular Data Registry ICD registry linked with the Social Security Death Master File, we assessed the rate of death after primary prevention ICD placement between January 1, 2006, and December 31, 2007, according to CKD stage. Using Cox models, we identified factors associated with death among patients with CKD. Compared with patients without CKD (n=26 056), those with CKD (n=21 226) were older, less commonly men, more often white, and more frequently had comorbid illness. Compared with patients without CKD, patients with a glomerular filtration rate 30 to 60, glomerular filtration rate <30, and end-stage renal disease on dialysis had a higher risk of death after ICD placement (hazard ratio, 2.08; 95% confidence interval, 1.99–2.18; P <0.0001; hazard ratio, 4.20; 95% confidence interval, 3.92–4.50; P <0.0001; and hazard ratio, 4.80; 95% confidence interval, 4.46–5.17; P <0.0001, respectively). Corresponding 1-year death rates were 4.4%, 9.1%, 20.2%, and 22.4%. Among patients with CKD, factors associated with increased risk of death included CKD severity, age >65 years, heart failure symptoms, diabetes mellitus, lung disease, serum sodium <140 mEq/L, atrial fibrillation or flutter, and a lower ejection fraction. Conclusions— The risk of death after primary prevention ICD placement is proportional to CKD severity. Among patients with CKD, several factors are prognostically significant and could inform clinical decision making on primary prevention ICD candidacy.

ECG Lead I and Outflow Tract ArrhythmiaIntroductionOutflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown.Methods and ResultsThirty‐six consecutive patients (mean age 41 ± 14 years, 13 male) underwent catheter ablation for OTVA. OTVA origin was determined from intracardiac electrogram tracings and electroanatomic maps. Observers blinded to results measured QRS waveform amplitude and duration from standard 12‐lead ECG tracings. Measurements with highest diagnostic performance were modeled into an algorithm. Sites of successful ablation were anterior right ventricular outflow tract (RVOT; n = 6), posterior RVOT (n = 4), PV (n = 18), and right coronary cusp (RCC; n = 8). Highest performing surface ECG discriminators were from lead I to V1 vectors: RCC, lead I R wave ≥ 1.5 mV, and V1 R wave ≥2.0 mV (sensitivity 87%, specificity 93%); PV, V1 R wave > 0 mV, and lead I R/(R+S) ≤ 0.75 (sensitivity 78%, specificity 72%); anterior RVOT, V1 R wave = 0 mV, and lead I R/(R+S) <0.4 (sensitivity 67%, specificity 97%); posterior RVOT, V1 R wave > 0 mV, and lead I R/(R+S) > 0.75 (sensitivity 75%, specificity 84%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 72% in predicting site of OTVA origin.ConclusionsA relatively large R wave in lead I is seen with RCC origin but not PV origin. A sequential algorithm has limited but potentially significant value beyond assessment of lead I in approaching OTVA.

Background— The ICD Registry was established in 2006 in part to measure quality of care in patients undergoing implantation of implantable cardioverter-defibrillators (ICDs); however, whether outcomes have improved since initiation of the registry is unknown. Our objective was to examine changes over time in 3 quality metrics available from the registry. Methods and Results— We performed an observational study of 367 153 patients who received new ICD implants from April 2006 to March 2010. Three quality metrics were selected: Adverse events (in-hospital complications or mortality), optimal medical therapy (OMT), and cardiac resynchronization therapy (CRT). OMT was defined as prescription of β-blocker and either angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in eligible patients. CRT eligibility was determined by QRS ≥120 ms, left ventricular ejection fraction ≤35%, and New York Heart Association class III/IV. Observation periods were divided into four 12-month intervals. We analyzed changes over time and used hierarchical logistic regression to adjust for potential confounders. Adverse events decreased over time (3.7% to 2.8%, P <0.001). Among eligible patients, rates of OMT and CRT increased over time (OMT: 69.0% to 74.3%, P <0.001; CRT: 80.5% to 84.2%, P <0.001). After adjustment for potential confounders, patients were significantly less likely to experience adverse events in year 4 than in year 1 (odds ratio, 0.75; 95% confidence interval, 0.71–0.79) and significantly more likely to receive OMT (odds ratio, 1.29; 95% confidence interval, 1.26–1.32) and CRT (odds ratio, 1.42; 95% confidence interval, 1.35–1.49). Conclusions— Since initiation of the ICD Registry, adverse events have been decreasing, and rates of OMT and CRT among eligible patients have been increasing, although there is still significant room for improvement.