Preston M Schneider

Clinical InvestigationElectrophysiologyAdherence to dabigatran therapy and longitudinal patient outcomes: Insights from the Veterans Health Administration

BACKGROUND Dabigatran is a novel oral anti-coagulant (NOAC) that reduces risk of stroke in patients with non-valvular atrial fibrillation (NVAF). It does not require routine monitoring with laboratory testing which may have an adverse impact on adherence. We aimed to describe adherence to dabigatran in the first year after initiation and assess the association between non-adherence to dabigatran and clinical outcomes in a large integrated healthcare system. METHODS We studied a national cohort of 5,376 patients with NVAF, initiated on dabigatran between October-2010 and September-2012 at all Veterans Affairs hospitals. Adherence to dabigatran was calculated as proportion of days covered (PDC) and association between PDC and outcomes was assessed using standard regression techniques. RESULTS Mean age of the study cohort was 71.3 ± 9.7 years; 98.3% were men and mean CHADS2 score was 2.4 ± 1.2 (mean CHA2DS2VASc score 3.2 ± 1.4). Median PDC was 94% (IQR 76%-100%; mean PDC 84% ± 22%) over a median follow-up of 244 days (IQR 140-351). A total of 1,494 (27.8%) patients had a PDC <80% and were classified as non-adherent. After multivariable adjustment, lower adherence was associated with increased risk for combined all-cause mortality and stroke (HR 1.13, 95% CI 1.07-1.19 per 10% decrease in PDC). Adherence to dabigatran was not associated with non-fatal bleeding or myocardial infarction. CONCLUSIONS In the year after initiation, adherence to dabigatran for a majority of patients is very good. However, 28% of patients in our cohort had poor adherence. Furthermore, lower adherence to dabigatran was associated with increased adverse outcomes. Concerted efforts are needed to optimize adherence to NOACs.

Utility of Cardiac Magnetic Resonance Imaging to Differentiate Cardiac Sarcoidosis from Arrhythmogenic Right Ventricular Cardiomyopathy

Some patients diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) are eventually found to have cardiac sarcoidosis (CS). Accurate differentiation between these 2 conditions has implications for immunosuppressive therapy and familial screening. We sought to determine whether cardiac magnetic resonance imaging (MRI) could be used to identify the characteristic findings to accurately differentiate between CS and ARVC. Consecutive patients with a diagnostic MRI scan indicating CS and/or ARVC constituted the cohort. All patients diagnosed with CS had histologic confirmation of sarcoidosis, and all patients with ARVC met the diagnostic task force criteria. The cardiac MRI data were retrospectively analyzed to identify possible differentiating characteristics. Of the patients, 40 had CS and 21 had ARVC. Those with CS were older and had more left ventricular scar. The presence of mediastinal lymphadenopathy or left ventricular septal involvement was seen exclusively in the patients with CS (p <0.001). A family history of sudden cardiac death was seen only in the ARVC group (p = 0.012). The right ventricular ejection fraction and ventricular volumes were also significantly different between the 2 groups. In conclusion, patients with CS have significantly different cardiac MRI characteristics than patients with ARVC. The cardiac volume, in addition to the degree and location of cardiac involvement, can be used to distinguish between these 2 disease entities. The presence of mediastinal lymphadenopathy and left ventricular septal scar favors a diagnosis of CS and not ARVC. Consideration of CS should be given if these MRI findings are observed during the evaluation for possible ARVC.

Prevalence of Guideline-Directed Medical Therapy Among Patients Receiving Cardiac Resynchronization Therapy Defibrillator Implantation in the National Cardiovascular Data Registry During the Years 2006 to 2008

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality among selected patients with left ventricular systolic dysfunction and severe heart failure symptoms despite guideline-directed medical therapy (GDMT). Contemporaneous guidelines provided clear recommendations regarding selection of patients for CRT, including that all patients should first receive GDMT with β blockers and renin-angiotensin axis antagonists. Prevalence of GDMT among real-world patients receiving CRT defibrillators (CRT-D) has not been well studied. We identified 45,392 patients in the National Cardiovascular Data Registry Implantable Cardioverter-Defibrillator Registry who underwent first CRT-D implantation for primary prevention of sudden death from January 2006 to June 2008. We calculated the proportion of patients with contemporaneous class I guideline indications for CRT-D, the proportion receiving GDMT for heart failure, and the proportion receiving GDMT who had class I guideline indications for CRT-D. Among patients without contraindications, 87% were prescribed β blockers, 78% an angiotensin-converting enzyme inhibitor or an angiotensin II receptor inhibitor, and 70% both a β blocker and an angiotensin-converting enzyme or angiotensin II receptor inhibitor at discharge. Finally, 50% of patients met class I guideline indications and were prescribed GDMT at discharge; 9% neither met class I indications nor were prescribed GDMT at discharge. The major limitation of this study is the lack of dosage information in the Implantable Cardioverter-Defibrillator Registry and lack of prescribing information at times other than discharge. In conclusion, many patients receiving CRT-D are not receiving GDMT at discharge. Ensuring that all patients receiving CRT-D are also receiving GDMT appears to be a quality improvement target.

Defibrillation time intervals and outcomes of cardiac arrest in hospital: retrospective cohort study from Get With The Guidelines-Resuscitation registry.

Objective To describe temporal trends in the time interval between first and second attempts at defibrillation and the association between this time interval and outcomes in patients with persistent ventricular tachycardia or ventricular fibrillation (VT/VF) arrest in hospital. Design Retrospective cohort study Setting 172 hospitals in the United States participating in the Get With The Guidelines-Resuscitation registry, 2004-12. Participants Adults who received a second defibrillation attempt for persistent VT/VF arrest within three minutes of a first attempt. Interventions Second defibrillation attempts categorized as early (time interval of up to and including one minute between first and second defibrillation attempts) or deferred (time interval of more than one minute between first and second defibrillation attempts). Main outcome measure Survival to hospital discharge. Results Among 2733 patients with persistent VT/VF after the first defibrillation attempt, 1121 (41%) received a deferred second attempt. Deferred second defibrillation for persistent VT/VF increased from 26% in 2004 to 57% in 2012 (P<0.001 for trend). Compared with early second defibrillation, unadjusted patient outcomes were significantly worse with deferred second defibrillation (57.4% v 62.5% for return of spontaneous circulation, 38.4% v 43.6% for survival to 24 hours, and 24.7% v 30.8% for survival to hospital discharge; P<0.01 for all comparisons). After risk adjustment, deferred second defibrillation was not associated with survival to hospital discharge (propensity weighting adjusted risk ratio 0.89, 95% confidence interval 0.78 to 1.01; P=0.08; hierarchical regression adjusted 0.92, 0.83 to 1.02; P=0.1). Conclusions Since 2004, the use of deferred second defibrillation for persistent VT/VF in hospital has doubled. Deferred second defibrillation was not associated with improved survival.

Body mass index and outcomes of in-hospital ventricular tachycardia and ventricular fibrillation arrest

BACKGROUND Due to higher transthoracic impedance, obese patients may be less likely to be successfully defibrillated from ventricular tachycardia or ventricular fibrillation (VT/VF) arrest. However, the association between patient body mass index (BMI), defibrillation success, and survival outcomes of VT/VF arrest are poorly understood. METHODS We evaluated 7110 patients with in-hospital VT/VF arrest at 286 hospitals within the Get With The Guidelines(®)-Resuscitation (GWTG-R) Multicenter Observational Registry between 2006 and 2012. Patients were categorized as underweight (BMI<18.5kg/m(2)), normal weight (BMI 18.5-24.9kg/m(2)), over-weight (BMI 25.0-29.9kg/m(2)), obese (BMI 30.0-34.9kg/m(2)), and extremely obese (BMI≥35.0kg/m(2)). Using generalized linear mixed regression, we determined the risk-adjusted relationship between BMI and patient outcomes while accounting for clustering by hospitals. The primary outcome was successful first shock defibrillation (a post-shock rhythm other than VT/VF) with secondary outcomes of return of spontaneous circulation, survival to 24h, and survival to discharge. RESULTS Among adult patients suffering VT/VF arrest, 304 (4.3%) were underweight, 2061 (29.0%) were normal weight, 2139 (30.1%) were overweight, and 2606 (36.6%) were obese or extremely obese. In a risk-adjusted analysis, we observed no interaction between BMI and energy level for the successful termination of VT/VF with first shock. Furthermore, the risk-adjusted likelihood of successful first shock termination of VT/VF did not differ significantly across BMI categories. Finally, when compared to overweight patients, obese patients had similar risk-adjusted likelihood of survival to hospital discharge (odds ratio 0.786, 95% confidence interval 0.593-1.043). CONCLUSIONS There was no significant difference in the likelihood of successful defibrillation with the first shock attempt among different BMI categories.