Mian Bilal Alam

Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators

AIMS Cardiac resynchronization therapy (CRT) implantable cardioverter defibrillators (ICDs) deliver high burden ventricular pacing to heart failure patients, which has a significant effect on battery longevity. The aim of this study was to investigate whether battery longevity is comparable for CRT-ICDs from different manufacturers in a contemporary cohort of patients. METHODS AND RESULTS All the CRT-ICDs implanted at our institution from 1 January 2008 to 31 December 2010 were included in this analysis. Baseline demographic and clinical data were collected on all patients using the electronic medical record. Detailed device information was collected on all patients from scanned device printouts obtained during routine follow-up. The primary endpoint was device replacement for battery reaching the elective replacement indicator (ERI). A total of 646 patients (age 69 ± 13 years), implanted with CRT-ICDs (Boston Scientific 173, Medtronic 416, and St Jude Medical 57) were included in this analysis. During 2.7 ± 1.5 years follow-up, 113 (17%) devices had reached ERI (Boston scientific 4%, Medtronic 25%, and St Jude Medical 7%, P < 0.001). The 4-year survival rate of device battery was significantly worse for Medtronic devices compared with devices from other manufacturers (94% for Boston scientific, 67% for Medtronic, and 92% for St Jude Medical, P < 0.001). The difference in battery longevity by manufacturer was independent of pacing burden, lead parameters, and burden of ICD therapy. CONCLUSION There are significant discrepancies in CRT-ICD battery longevity by manufacturer. These data have important implications on clinical practice and patient outcomes.

Echocardiography-guided left ventricular lead placement for cardiac resynchronization therapy in ischemic vs nonischemic cardiomyopathy patients

BACKGROUND Echocardiography-guided (EG) left ventricular (LV) lead placement at the site of latest mechanical activation improves outcome in heart failure (HF) patients receiving a cardiac resynchronization therapy (CRT)-defibrillator (CRT-D). OBJECTIVE The purpose of this study was to examine the effect of a strategy of EG LV lead placement in each of ischemic (ICM) vs nonischemic (NICM) cardiomyopathy patients. METHODS Patients enrolled in the Speckle Tracking Assisted Resynchronization Therapy for Electrode Region (STARTER) prospective, randomized trial who were treated with a CRT-D device (108 EG strategy and 75 routine strategy) were followed to the end-points of death, appropriate CRT-D therapy, or HF hospitalization. RESULTS Of the patients enrolled in STARTER, 115 had ICM and 68 had NICM. Over mean follow-up of 3.7 ± 2.1 years, 62 patients died, 40 received appropriate CRT-D therapy, and 67 had HF hospitalizations. Compared to NICM patients, patients with ICM had worse survival (P = .0003), worse survival free from implantable cardioverter-defibrillator therapy (P = .004), and survival free from HF hospitalization (P = .0001). A strategy of EG LV lead placement improved the outcome of CRT-D therapy-free survival primarily in ICM patients and the outcome of HF hospitalization-free survival in both ICM and NICM patients. Achieving LV resynchronization was most critical in ICM patients in whom arrhythmic and HF outcomes improve with resynchronization to levels comparable to those of NICM patients. CONCLUSION A strategy of EG LV lead placement improves HF-free survival equally in ICM and NICM patients and CRT-D therapy-free survival more favorably in ICM patients to levels comparable to those of NICM patients.

Outcomes of Sprint Fidelis and Riata lead extraction: Data from 2 high-volume centers

BACKGROUND The Sprint Fidelis (SF) and the Riata (RT) implantable cardioverter-defibrillator leads have been recalled for premature failure. OBJECTIVE Data on SF and RT extractions are limited; therefore, we performed a pooled analysis to compare the safety and efficacy of lead extraction for the SF and RT lead families. METHODS We retrospectively reviewed consecutive patients undergoing transvenous extraction of SF and RT leads at Emory University and the University of Pittsburgh Medical Center from January 2007 to October 2013. Patients were placed into 2 groups based on the presence of an SF or RT lead. The primary endpoint was a major procedural complication, defined as death, need for urgent cardiac surgery, and hemopericardium or hemothorax that required an intervention. RESULTS A total of 462 patients underwent extraction of recalled leads (SF, n = 360; RT, n = 102). The mean number of leads extracted in the RT group was higher than in the SF group (1.8 ± 0.9 vs 1.3 ± 0.7, P < .001), and there was a longer implantation time in the RT group (5.5 ± 2.5 vs 4.3 ± 2.0 years, P < .001). Complete procedural success was higher in the SF group (99.4% vs 96.1%, P =.024). Clinical success was similar (SF 99.4% vs RT 97.1%, P = .075). There were 6 major procedural complications in the entire cohort (1.3%). The rate of major complications was not different between the SF and RT groups (SF 1.1% vs RT 2.0%, P = .618). Total mortality was 0.65%, with no difference between the groups CONCLUSION Our data from 2 high-volume centers suggest that extraction of SF and RT leads is associated with excellent clinical success and a similar rate of major procedural complications.

Comparative effectiveness of antiarrhythmic drugs for rhythm control of atrial fibrillation

INTRODUCTION Although there are many different antiarrhythmic drugs (AADs) approved for rhythm management of atrial fibrillation (AF), little comparative effectiveness data exist to guide drug selection. METHODS We followed 5952 consecutive AF patients who were prescribed amiodarone (N=2266), dronedarone (N=488), dofetilide (N=539), sotalol (N=1718), or class 1C agents (N=941) to the primary end point of AF recurrence. RESULTS Median follow-up time was 18.2 months (range 0.1-101.6 months). Patients who were prescribed amiodarone had the highest, while patients on class 1C agents had the lowest baseline CHA2DS2-VASc score, Charlson comorbidity index, and burden of comorbid illnesses including coronary artery disease, congestive heart failure, diabetes mellitus, hyperlipidemia, chronic obstructive lung disease, chronic kidney disease, or cancer (p<0.05 for all comparisons). After adjusting for baseline characteristics, using dronedarone as benchmark, amiodarone [hazard ratio (HR) 0.58, p<0.001], class 1C agents (HR 0.70, p<0.001), and sotalol (HR 0.79, p=0.008), but not dofetilide (HR 0.87, p=0.178) were associated with less AF recurrence. In addition, compared to dronedarone, amiodarone and class 1C agents were associated with lower rates of admissions for AF (HR 0.55, p<0.001 for amiodarone; HR 0.71, p=0.021 for class 1C agents) and all-cause mortality was lowest in patients treated with class 1C agents (HR 0.42, p=0.018). The risk of stroke was similar among all groups. CONCLUSION Compared with dronedarone, amiodarone, class 1C agents, and sotalol are more effective for rhythm control, while dofetilide had similar efficacy. These findings have important implications for clinical practice.

Risk of Stroke and Death in Atrial Fibrillation by Type of Anticoagulation: A Propensity‐Matched Analysis

We examined the effect of novel oral anticoagulants (NOACs) compared to warfarin on the risk of death or stroke in atrial fibrillation (AF) patients in every day clinical practice.

Patient Outcomes According to Adherence to Treatment Guidelines for Rhythm Control of Atrial Fibrillation

Background Although guidelines for antiarrhythmic drug therapy in atrial fibrillation (AF) were published in 2006, it remains uncertain whether adherence to these guidelines affects patient outcomes. Methods and Results We retrospectively evaluated the records of 5976 consecutive AF patients who were prescribed at least 1 antiarrhythmic drug between 2006 and 2013. Patients with 1 or more prescribed antiarrhythmic drugs that did not comply with guideline recommendations comprised the non–guideline‐directed group (=2920); the remainder constituted the guideline‐directed group (=3056). Time to events was assessed using the survival analysis method and adjusted for covariates using Cox regression. Rates of adherence to the guidelines increased significantly with a higher degree of prescriber specialization in arrhythmias (49%, 55%, and 60% for primary care physicians, general cardiologists, and cardiac electrophysiologists, respectively, P=0.001) for the first prescribed antiarrhythmic drug. Compared to the non–guideline‐directed group, the guideline‐directed group had higher rates of heart failure, but lower baseline CHADS2‐VASc scores (P<0.001) and lower rates of coronary artery disease, valvular disease, hypertension, hyperlipidemia, pulmonary disease, and renal insufficiency (P<0.05 for all). During 45±26 months follow‐up, the guideline‐directed group had a lower risk of AF recurrence (hazard ratio=0.86, 95% CI=0.80 to 0.93), fewer hospital admissions for AF (hazard ratio=0.87, 95% CI=0.79 to 0.97), and fewer procedures for recurrent AF, including electrical cardioversion, pacemaker implantation, and atrioventricular nodal ablation (P<0.01 for all). The mortality and stroke risks were similar between the groups. Conclusions Adherence to published guidelines in the antiarrhythmic management of AF is associated with improved patient outcomes.

Mortality risk of long-term amiodarone therapy for atrial fibrillation patients without structural heart disease.

BACKGROUND Amiodarone is often prescribed in the management of atrial fibrillation (AF) but is known to cause significant end-organ toxicities. In this study, we examined the impact of amiodarone on all-cause mortality in AF patients with structurally normal hearts. METHODS We performed a retrospective cohort analysis of all AF patients with structurally normal hearts who were prescribed antiarrhythmic drugs (AAD) for rhythm control of AF at our institution from 2006 to 2013 (n = 2,077). Baseline differences between the amiodarone (AMIO: n = 403) and other AADs (NON-AMIO: n = 1,674) groups were corrected for using propensity score matching. RESULTS Amiodarone use as first-line therapy decreased significantly with a higher degree of prescriber specialization in arrhythmia management (31%, 22%, and 9% for primary care physicians, general cardiologists and cardiac electrophysiologists, respectively, p < 0.001). After propensity score matching, baseline comorbidities were balanced between the AMIO and NON-AMIO groups. Over a median follow-up of 28.2 months (range 6.0-100.9 months), amiodarone was associated with increased all-cause (HR 2.41, p = 0.012) and non-cardiac (HR 3.55, p = 0.008) mortality, but not cardiac mortality. AF recurrence and cardiac hospitalizations were similar between the two study groups. CONCLUSIONS Amiodarone treatment of AF is associated with increased mortality in patients without structural heart disease and therefore should be avoided or only used as a second-line therapy, when other AF therapies fail. Adherence to guideline recommendations in the management of AF patients impacts clinical outcome.

Antithrombotic Therapy in Nonvalvular Atrial Fibrillation: Consensus and Challenges

ABSTRACT Atrial fibrillation (AF) is associated with high risk of systemic thromboembolism leading to significant morbidity and mortality. Warfarin, previously the mainstay for stroke prevention in AF, requires close monitoring because of multiple food and drug interactions. In recent years, food and drug administration has approved several direct oral anticoagulants (DOACs) for use in patients with nonvalvular AF. These agents have not been studied in patients with valvular AF who are at an even higher risk of systemic thromboembolism. DOACs do not require frequent blood testing or changes in dosage except when renal function deteriorates, however, the lack of established antidotes for many of these agents remains a challenge. Also, currently there is no head‐to‐head comparison between these agents to guide clinical choice. This article discusses the advantages and disadvantages of currently approved oral antithrombotics in nonvalvular AF, with a special emphasis on the DOACs and their individual characteristics.

ADHERENCE TO PUBLISHED GUIDELINES IN PRESCRIBING ANTI-ARRHYTHMIC MEDICATIONS AND ITS IMPACT ON CLINICAL OUTCOMES OF ATRIAL FIBRILLATION

Although guidelines for antiarrhythmic drug (AAD) therapy in atrial fibrillation (AF) were published in 2006, it remains uncertain whether adherence to these guidelines affects patient outcome. We evaluated the records of 5,976 AF patients who were prescribed at least one AAD between 2006 and 2013

Interference by Human Anti-mouse Antibodies in Immunoassays: Falsely Elevated Cardiac Troponins Leading to Negative Coronary Angiograms

Cardiac Troponins are an extremely important indicator of myocardial injury and American College of Cardiology (ACC) and American Heart Association (AHA) guidelines include Cardiac Troponins as one of the major diagnostic criteria for myocardial damage. However in some instances the presence of heterophilic antibodies like Human Anti-Mouse Antibodies (HAMA) may interfere with the sandwich assays used for the detection and quantification of cardiac troponins giving false results which can have a major impact on the management of an individual suspected to have myocardial injury. Case Report Alam et al.; ARRB, 6(5): 323-327, 2015; Article no.ARRB.2015.091 324 We present a case of a 56 year old Caucasian male who had negative coronary angiogram 2 years ago presenting with acute chest pain and significantly elevated levels of Cardiac Troponin I (cTnI). He underwent cardiac catheterization which again turned out to be completely normal. His cTnI levels continued to be consistently elevated for months after cardiac catheterization. The reason for elevated cTnI levels was due to high levels of HAMA antibodies that caused heterophilic antibody interference in the assay of cTnI, resulting in falsely elevated levels of cTnI.