Thomas A. Dewland

Dual-chamber implantable cardioverter-defibrillator selection is associated with increased complication rates and mortality among patients enrolled in the NCDR implantable cardioverter-defibrillator registry.

OBJECTIVES The aim of this study was to compare single- versus dual-chamber implantable cardioverter-defibrillator (ICD) implantation and complication rates in a large, real-world population. BACKGROUND The majority of patients enrolled in ICD efficacy trials received single-chamber devices. Although dual-chamber ICDs offer theoretical advantages over single-chamber defibrillators, the clinical superiority of dual-chamber models has not been conclusively proven, and they may increase complications. METHODS The National Cardiovascular Data Registry ICD Registry was used to examine the association between baseline characteristics and device selection in 104,049 patients receiving single- and dual-chamber ICDs between January 1, 2006, and December 31, 2007. A longitudinal cohort design was then used to determine in-hospital complication rates. RESULTS Dual-chamber devices were implanted in 64,489 patients (62%). Adverse events were more frequent with dual-chamber than with single-chamber device implantation (3.17% vs. 2.11%, p < 0.001), as was the rate of in-hospital mortality (0.40% vs. 0.23%, p < 0.001). After adjusting for demographics, medical comorbidities, diagnostic test data, and ICD indication, the odds of any complication (odds ratio: 1.40; 95% confidence interval: 1.28 to 1.52; p < 0.001) and in-hospital mortality (odds ratio: 1.45; 95% confidence interval: 1.20 to 1.74; p < 0.001) were increased with dual-chamber versus single-chamber ICD implantation. CONCLUSIONS In this large, multicenter cohort of patients, dual-chamber ICD use was common. Dual-chamber device implantation was associated with increases in periprocedural complications and in-hospital mortality compared with single-chamber defibrillator selection.

Incident Atrial Fibrillation Among Asians, Hispanics, Blacks, and Whites

Background— Because the association between atrial fibrillation (AF) and race has only been rigorously compared in population-based studies that dichotomized participants as white or black, it is unclear whether white race confers elevated AF risk or black race affords AF protection. Methods and Results— The Healthcare Cost and Utilization Project was used to identify patients receiving hospital-based care in California between January 1, 2005 and December 31, 2009. The association between race and incident AF was examined using Cox proportional hazards models. Interaction analyses were performed to elucidate the mechanism underlying the race-AF association. Among 13 967 949 patients, 375 318 incident AF episodes were observed over a median 3.2 (interquartile range 1.8–4.3) years. In multivariable Cox models adjusting for patient demographics and established AF risk factors, blacks (hazard ratio, 0.84; 95% confidence interval, 0.82–0.85; P<0.001), Hispanics (hazard ratio, 0.78; 95% confidence interval, 0.77–0.79; P<0.001), and Asians (hazard ratio, 0.78; 95% confidence interval, 0.77–0.79; P<0.001) each exhibited a lower AF risk compared with whites. AF risk among whites was disproportionately higher in the absence of acquired cardiovascular risk factors and diminished or reversed in the presence of comorbid diseases. Although Hispanics and Asians also had a lower adjusted risk of incident atrial flutter compared with whites, the risk of flutter was significantly higher among blacks. Conclusions— In a large hospital-based cohort, whites have an increased risk of AF whether compared with blacks, Asians, or Hispanics. The heightened AF risk among whites is most pronounced in the absence of cardiovascular comorbidities.

Atrial Ectopy as a Predictor of Incident Atrial Fibrillation: A Cohort Study

BACKGROUND Atrial fibrillation (AF) prediction models have unclear clinical utility given the absence of AF prevention therapies and the immutability of many risk factors. Premature atrial contractions (PACs) play a critical role in AF pathogenesis and may be modifiable. OBJECTIVE To investigate whether PAC count improves model performance for AF risk. DESIGN Prospective cohort study. SETTING 4 U.S. communities. PATIENTS A random subset of 1260 adults without prevalent AF enrolled in the Cardiovascular Health Study between 1989 and 1990. MEASUREMENTS The PAC count was quantified by 24-hour electrocardiography. Participants were followed for the diagnosis of incident AF or death. The Framingham AF risk algorithm was used as the comparator prediction model. RESULTS In adjusted analyses, doubling the hourly PAC count was associated with a significant increase in AF risk (hazard ratio, 1.17 [95% CI, 1.13 to 1.22]; P < 0.001) and overall mortality (hazard ratio, 1.06 [CI, 1.03 to 1.09]; P < 0.001). Compared with the Framingham model, PAC count alone resulted in similar AF risk discrimination at 5 and 10 years of follow-up and superior risk discrimination at 15 years. The addition of PAC count to the Framingham model resulted in significant 10-year AF risk discrimination improvement (c-statistic, 0.65 vs. 0.72; P < 0.001), net reclassification improvement (23.2% [CI, 12.8% to 33.6%]; P < 0.001), and integrated discrimination improvement (5.6% [CI, 4.2% to 7.0%]; P < 0.001). The specificity for predicting AF at 15 years exceeded 90% for PAC counts more than 32 beats/h. LIMITATION This study does not establish a causal link between PACs and AF. CONCLUSION The addition of PAC count to a validated AF risk algorithm provides superior AF risk discrimination and significantly improves risk reclassification. Further study is needed to determine whether PAC modification can prospectively reduce AF risk. PRIMARY FUNDING SOURCE American Heart Association, Joseph Drown Foundation, and National Institutes of Health.

Association of Single- vs Dual-Chamber ICDs With Mortality, Readmissions, and Complications Among Patients Receiving an ICD for Primary Prevention

IMPORTANCE Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain. OBJECTIVE To compare outcomes of single- and dual-chamber ICDs for primary prevention of sudden cardiac death. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of admissions in the National Cardiovascular Data Registrys (NCDR) ICD registry from 2006-2009 that could be linked to Centers for Medicare & Medicaid Services fee-for-service Medicare claims data. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing. MAIN OUTCOMES AND MEASURES Adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician, and hospital factors. RESULTS Among 32,034 patients, 12,246 (38%) received a single-chamber device and 19,788 (62%) received a dual-chamber device. In a propensity-matched cohort, rates of complications were lower for single-chamber devices (3.51% vs 4.72%; P < .001; risk difference, -1.20 [95% CI, -1.72 to -0.69]), but device type was not significantly associated with 1-year mortality (unadjusted rate, 9.85% vs 9.77%; hazard ratio [HR], 0.99 [95% CI, 0.91 to 1.07]; P = .79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs 44.83%; HR, 1.00 [95% CI, 0.97-1.04]; P = .82), or hospitalization for heart failure (unadjusted rate, 14.73% vs 15.38%; HR, 1.05 [95% CI, 0.99-1.12]; P = .19). CONCLUSIONS AND RELEVANCE Among patients receiving an ICD for primary prevention without indications for pacing, the use of a dual-chamber device compared with a single-chamber device was associated with a higher risk of device-related complications and similar 1-year mortality and hospitalization outcomes. Reasons for preferentially using dual-chamber ICDs in this setting remains unclear.

Ventricular Ectopy as a Predictor of Heart Failure and Death

BACKGROUND Studies of patients presenting for catheter ablation suggest that premature ventricular contractions (PVCs) are a modifiable risk factor for congestive heart failure (CHF). The relationship among PVC frequency, incident CHF, and mortality in the general population remains unknown. OBJECTIVES The goal of this study was to determine whether PVC frequency ascertained using a 24-h Holter monitor is a predictor of a decrease in the left ventricular ejection fraction (LVEF), incident CHF, and death in a population-based cohort. METHODS We studied 1,139 Cardiovascular Health Study (CHS) participants who were randomly assigned to 24-h ambulatory electrocardiography (Holter) monitoring and who had a normal LVEF and no history of CHF. PVC frequency was quantified using Holter studies, and LVEF was measured from baseline and 5-year echocardiograms. Participants were followed for incident CHF and death. RESULTS Those in the upper quartile versus the lowest quartile of PVC frequency had a multivariable-adjusted, 3-fold greater odds of a 5-year decrease in LVEF (odds ratio [OR]: 3.10; 95% confidence interval [CI]: 1.42 to 6.77; p = 0.005), a 48% increased risk of incident CHF (HR: 1.48; 95% CI: 1.08 to 2.04; p = 0.02), and a 31% increased risk of death (HR: 1.31; 95% CI: 1.06 to 1.63; p = 0.01) during a median follow-up of >13 years. Similar statistically significant results were observed for PVCs analyzed as a continuous variable. The specificity for the 15-year risk of CHF exceeded 90% when PVCs included at least 0.7% of ventricular beats. The population-level risk for incident CHF attributed to PVCs was 8.1% (95% CI: 1.2% to 14.9%). CONCLUSIONS In a population-based sample, a higher frequency of PVCs was associated with a decrease in LVEF, an increase in incident CHF, and increased mortality. Because of the capacity to prevent PVCs through medical or ablation therapy, PVCs may represent a modifiable risk factor for CHF and death.

The QT interval and risk of incident atrial fibrillation

BACKGROUND Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine. OBJECTIVE To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF. METHODS We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas. RESULTS Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts. CONCLUSIONS A prolonged QT interval is associated with an increased risk of incident AF.

Cardiac Perforation From Implantable Cardioverter-Defibrillator Lead Placement Insights From the National Cardiovascular Data Registry

Background—Cardiac perforation is a feared complication of implantable cardioverter-defibrillator (ICD) lead implantation because of the potential for significant morbidity and mortality. Predictors of perforation and the severity of associated adverse events have not been well studied. We sought to identify predictors of cardiac perforation from ICD lead implantation and subsequent outcomes. Methods and Results—We studied 440 251 first-time ICD recipients in the ICD Registry implanted between January 2006 and September 2011. Using hierarchical multivariable logistic regression adjusting for patient, implanting physician, and hospital characteristics, we examined the predictors of perforation and the association of perforation with other major complications, length of stay, and in-hospital mortality. Cardiac perforation occurred in 625 patients (0.14%). After multivariable adjustment, older age, female sex, left bundle branch block, worsened heart failure class, higher left ventricular ejection fraction, and non–single-chamber ICD implant were associated with a greater odds of perforation. Conversely, atrial fibrillation, diabetes mellitus, previous cardiac bypass surgery, and higher implanter procedural volume were associated with a lower odds of perforation (all P<0.05). After adjustment, ICD recipients with perforation had greater odds of other associated major complications (odds ratio, 27.5; 95% confidence interval, 19.9–38.0; P<0.0001), postprocedural hospital stays >3 days (odds ratio, 16.3; 95% confidence interval, 13.7–19.4; P<0.0001), and in-hospital death (odds ratio, 17.7; 95% confidence interval, 12.2–25.6; P<0.0001). Conclusions—In a large population of ICD recipients, specific patient and implanter characteristics predicted cardiac perforation risk. Cardiac perforation was associated with a substantially increased risk of other major complications, prolonged hospital stays, and death.

Sequential Percutaneous LAA Ligation and Pulmonary Vein Isolation in Patients with Persistent AF: Initial Results of a Feasibility Study

Left atrial appendage (LAA) ligation results in LAA electrical isolation and a decrease in atrial fibrillation (AF) burden. This study assessed the feasibility of combined percutaneous LAA ligation and pulmonary vein isolation (PVI) in patients with persistent AF.

Safety of radiofrequency catheter ablation without coronary angiography in aortic cusp ventricular arrhythmias

BACKGROUND Ventricular arrhythmias (VAs) originating from the aortic root are common. Coronary angiography is typically recommended before catheter ablation to document proximity of the ablation catheter to the coronary ostia. OBJECTIVE To investigate how often catheter ablation in the aortic root could be guided by phased-array intracardiac echocardiography (ICE) and electroanatomic mapping without requiring aortography or coronary angiography. METHODS We reviewed consecutive patients referred for aortic root VAs to operators experienced in the use of ICE at a single center. An ICE catheter and a 3.5-mm irrigated ablation catheter were used in all cases, and the need for angiography before ablation was documented. Acute success and acute and 30-day complications were noted. RESULTS Thirty-five patients (age 58 ± 13 years; 74% men) were referred for the ablation of VAs; 32 of 35 (91%) underwent ablation using ICE and 3-dimensional mapping without the need for coronary angiography. Successful acute ablation was achieved in 29 of 35 (83%) patients. In all cases, the catheter tip was directly visualized with ICE >1 cm from the coronary ostia. The site of origin of the earliest VA was the left cusp (17 of 35 [49%]), right cusp (9 of 35 [26%]), right-left cusp junction (8 of 35 [23%]), or right-noncoronary cusp junction (1 of 35 [3%]). There were no cases of coronary injury, embolic stroke, aortic root perforation, worsening of aortic regurgitation, or death acutely or at 30 days. CONCLUSION Radiofrequency ablation of VAs originating from the aortic root may be safely performed using ICE and electroanatomic mapping in the majority of cases without the need for coronary angiography.

Randomized trial of conventional transseptal needle versus radiofrequency energy needle puncture for left atrial access (the TRAVERSE-LA study).

Background Transseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative effectiveness of an RF versus conventional needle for transseptal LA access. Methods and Results In this prospective, single‐blinded, controlled trial, 72 patients were randomized in a 1:1 fashion to an RF versus conventional (BRK‐1) transseptal needle. In an intention‐to‐treat analysis, the primary outcome was time required for transseptal LA access. Secondary outcomes included failure of the assigned needle, visible plastic dilator shavings from needle introduction, and any procedural complication. The median transseptal puncture time was 68% shorter using the RF needle compared with the conventional needle (2.3 minutes [interquartile range {IQR}, 1.7 to 3.8 minutes] versus 7.3 minutes [IQR, 2.7 to 14.1 minutes], P=0.005). Failure to achieve transseptal LA access with the assigned needle was less common using the RF versus conventional needle (0/36 [0%] versus 10/36 [27.8%], P<0.001). Plastic shavings were grossly visible after needle advancement through the dilator and sheath in 0 (0%) RF needle cases and 12 (33.3%) conventional needle cases (P<0.001). There were no differences in procedural complications (1/36 [2.8%] versus 1/36 [2.8%]). Conclusions Use of an RF needle resulted in shorter time to transseptal LA access, less failure in achieving transseptal LA access, and fewer visible plastic shavings. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01209260.