Citations

Background— Sprint Fidelis (Fidelis) implantable cardioverter-defibrillator leads are prone to fractures that have caused adverse events, primarily inappropriate shocks, and a few reported deaths. More than 100 000 patients have Fidelis leads. No independent multicenter long-term performance information exists for this lead, and single-center studies suggest that certain patients are at increased risk for Fidelis failure. Our aim was to assess the longevity of Fidelis leads and to evaluate clinical variables and adverse events associated with Fidelis failure. The results were compared with like data for Quattro Secure (Quattro) implantable cardioverter-defibrillator leads implanted at our centers. Methods and Results— This 3-center study included adults ≥18 years of age who received Fidelis or Quattro leads for the prevention of sudden cardiac death. From November 2001 to January 2009,1023 Fidelis and 1668 Quattro leads were implanted and followed up. The failure rate for Fidelis leads was 2.81%/y compared with 0.43%/y for Quattro leads ( P <0.0001). No deaths or injuries occurred as a result of lead failure, but 42% of fractures caused inappropriate shocks. The survival of Fidelis leads at 4 years was 87.0% (95% confidence interval, 83.6 to 90.1) compared with 98.7% (95% confidence interval, 97.9 to 99.4) for Quattro leads ( P <0.0001). Multivariate predictors of Fidelis failure were younger age (hazard ratio, 0.98; 95% confidence interval, 0.96 to 0.99), female gender (hazard ratio, 0.61; 95% confidence interval, 0.40 to 1.00), and cardiac disease ( P =0.041). Conclusions— Compared with Quattro leads, the survival of Fidelis leads continues to decline, and Fidelis failure is notably higher in younger patients, women, individuals with hypertrophic cardiomyopathy, and patients with arrhythmogenic right ventricular dysplasia or channelopathies. These findings have significant implications for the management of patients who have Fidelis leads, and they demonstrate the importance of weighing clinical variables in assessments of implantable cardioverter-defibrillator lead performance.

Background— Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results— Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy ( P =0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR ( P <0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions— These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Background— Right ventricular pacing increases the risk of heart failure in adults with structural heart disease. The impact of prolonged right ventricular pacing in adults without structural heart disease is not fully characterized and may depend on interactions of pacing with abnormal substrate predisposing to ventricular dysfunction. Methods and Results— We assessed the effect of right ventricular pacing in patients who underwent pacemaker implantation for isolated congenital atrioventricular block between 1964 and 2005. To assess for immunologic contribution to cardiac dysfunction, outcomes were compared between patients with (Ab + ) and without (Ab − ) antinuclear antibody during adulthood and an age- and sex-matched Olmsted County, Minnesota, population. Of 103 patients (mean±SD age, 32±19 years), 18 were Ab + . Long-term survival free of new heart failure after pacemaker implantation in isolated congenital atrioventricular block patients was worse than in the matched population ( P <0.001). This difference was attributable to the development of heart failure in 12 Ab + patients (67%; P <0.001), without differences between Ab − patients (2%) and the matched population (2%; P =0.7). Compared with baseline, at last follow-up, left ventricular ejection fraction did not decline in Ab − (53±9% to 57±12%) but decreased in Ab + (52±10% to 38±12%; P =0.03) patients. Survival was similar in Ab − patients and the Minnesota population (98%; P =0.7) but worse in Ab + patients (79%; P <0.01). Conclusions— The natural history of patients with isolated congenital atrioventricular block who require pacing depends upon their antibody status. Antinuclear antibody status was a predictor for the development of heart failure and death. Long-term right ventricular pacing alone does not appear to be associated with development of heart failure, deterioration in ventricular function, or reduced survival in Ab − isolated congenital atrioventricular block patients.

Objective— Patients with venous thromboembolism (VTE) often require temporary warfarin interruption for an invasive procedure. The incidence of thromboembolism and bleeding related to periprocedural anticoagulation management of such patients is unknown. Methods and Results— In a protocol-driven, inception cohort design study, all VTE patients (n=775) referred for periprocedural anticoagulation management (1997–2007) were followed-up to estimate the 3-month cumulative incidence of thromboembolism and bleeding. Patients were stratified by thrombus acuity (acute, <30 days; subacute, 31–90 days; or chronic ≥91 days). Decisions to provide “bridging” low-molecular-weight heparin were based on estimated thromboembolism and bleeding risk. Low-molecular-weight heparin was more often administered in acute (87%) and subacute (81%) VTE compared to chronic VTE (59%; P <0.001). The 3-month cumulative incidence of thromboembolism (1.8%), major hemorrhage (1.8%), and mortality (1.7%) were low and did not differ by management strategy. Active cancer was the only independent predictor of thrombotic recurrence (HR, 4.86; 95% CI, 1.6–14.5; P =0.005), major hemorrhage (HR, 6.8; 95% CI, 2.1–21.7; P =0.001), and death (HR, 32.7; 95% CI, 4.3–251.2; P =0.0008). Conclusion— Thromboembolism, bleeding, and death among VTE patients in whom anticoagulation is temporarily interrupted for an invasive procedure is low. Cancer patients require particular care given their propensity for both clotting and bleeding.

Background— The risk of syncope occurring while driving has obvious implications for personal and public safety. We aimed to define the clinical characteristics, causes, and prognosis of syncope while driving. Methods and Results— In this case-control study of consecutive patients evaluated for syncope from 1996 through 1998 at an academic medical center, we documented causes, clinical characteristics, and recurrence of syncope while driving. Of 3877 patients identified, 381 (9.8%) had syncope while driving (driving group). Compared with the 3496 patients (90.2%) who did not have syncope while driving, the driving group was younger ( P =0.01) and had higher percentages of male patients ( P <0.001) and patients with a history of any cardiovascular disease ( P =0.01) and stroke ( P =0.02). Syncope while driving was commonly caused by neurally mediated syncope (37.3%) and cardiac arrhythmias (11.8%). Long-term survival in the driving group was comparable to that of an age- and sex-matched cohort from the Minnesota population ( P =0.15). Among the driving group, syncope recurred in 72 patients, 35 of whom (48.6%) had recurrence >6 months after the initial evaluation. Recurrences during driving happened in 10 patients in the driving group, 7 of which (70%) were >12 months after the initial evaluation. Conclusions— In our study, neurally mediated syncope was the most common type of syncope while driving. The causes of syncope, the late recurrences of syncope (during ≥6 months of follow-up), and the overall low incidence of recurrent syncope while driving provide useful information to supplement current recommendations on driving for these patients.

Background— Appropriateness criteria for stress imaging have been published to promote the effective use of stress nuclear scintigraphy and stress echocardiography. We sought to evaluate the application of the stress echocardiography appropriateness criteria to patients undergoing stress echocardiography in an academic medical center. Methods and Results— The stress echocardiography criteria were applied to 298 consecutive patients who underwent stress echocardiography. Patients were rated as appropriate, uncertain, inappropriate, or not classifiable. Results were compared with those of a previous analysis in the same patients using the single-photon computed tomography myocardial perfusion imaging (SPECT MPI) criteria. The level of agreement between 2 cardiac nurse abstractors for categorizing appropriateness by the stress echocardiography criteria was good (κ=0.72). Overall, 54% of patients were classified as appropriate, 8% as uncertain, and 19% as inappropriate; 19% were not classifiable. By the SPECT MPI criteria, 64% of patients were classified as appropriate, 9% as uncertain, and 18% as inappropriate; 9% were not classifiable ( P <0.001 compared with stress echocardiography criteria). By the stress echocardiography criteria, 6 clinical situations or indications accounted for more than 90% of the inappropriate tests; most of these involved asymptomatic patients. Conclusions— Applying stress echocardiography appropriateness criteria to a patient population is feasible, although 1 in 5 of our patients was not classifiable. Overall, the stress echocardiography criteria classified patients differently compared with the SPECT MPI criteria. Future refinements of the appropriateness criteria for stress imaging should address gaps in the criteria and disparities between the stress echocardiography and SPECT MPI criteria.

Background— The clinical efficacy of alcohol septal ablation for drug-refractory hypertrophic cardiomyopathy remains unclear. This study examines the outcome of alcohol septal ablation performed at a tertiary hypertrophic cardiomyopathy referral center. Methods and Results— Among 601 patients with severely symptomatic obstructive hypertrophic cardiomyopathy referred for alcohol septal ablation or myectomy from 1998 to 2006, 138 patients (median age, 64 years; 39% men) chose to undergo ablation. Procedural complications included death in 1.4%, sustained ventricular arrhythmias in 3%, tamponade in 3%, and pacemaker implantation in 20%. This rate was higher than a combined complication rate of 5% in age- and gender-matched patients who had undergone septal myectomy at Mayo Clinic ( P <0.0001). Four-year survival free of all mortality was 88.0% (95% confidence interval, 79.4 to 97.5%), which was similar to that of the age- and gender-matched patients who had undergone myectomy ( P =0.18). Six patients had documented ventricular arrhythmias after ablation, 4 of whom had successful intervention. Four-year survival free of death and severe New York Heart Association class III/IV symptoms after septal ablation was 76.4%, and 71 patients (51%) became asymptomatic. Myectomy patients ≤65 years of age had significantly better survival free of death and severe symptoms ( P =0.01). Conclusions— Alcohol septal ablation is an efficacious procedure if performed in an experienced institution and may resolve symptoms in a subset of patients with obstructive hypertrophic cardiomyopathy. However, the procedural complication rate exceeds that of myectomy. Patients ≤65 years of age have better symptom resolution with myectomy. No impairment in short-term survival was noted in this nonrandomized study, but the long-term outcome remains unknown.

Background— Obesity is a risk factor for atrial fibrillation and other cardiovascular conditions. Our objective was to determine whether catheter-based ablation effectively treated atrial fibrillation in obese patients. Methods and Results— Five hundred twenty-three consecutive patients with symptomatic, medication-refractory atrial fibrillation underwent catheter ablation. Patients were grouped by body mass index (lean, <25 kg/m 2 ; overweight, 25 to 29.9 kg/m 2 ; obese, ≥30 kg/m 2 ). Outcome and quality of life were measured with a general health survey (Medical Outcomes Study 36-item Short-Form General Health Survey [SF-36]); patients were assessed before ablation and at 3 and 12 months after the procedure. Two hundred twenty-eight study patients (44%) were overweight, and 201 (38%) were obese. Twelve months after curative ablation, 72% of patients were free of atrial fibrillation without the use of antiarrhythmic agents; 84% were arrhythmia free when those receiving medication were included. Atrial fibrillation was eliminated in 75%, 72%, and 70% of the lean, overweight, and obese patients, respectively, at 12 months ( P =0.41, trend test). SF-36 scores were lower for patients with higher body mass index ( P <0.05) at baseline. SF-36 scores improved in every functional domain for all body mass index groups after ablation. The mean SF-36 total physical score increased from 59±20 at baseline to 77±19 in 12 months ( P <0.001). The total mental health score improved from 66±18 to 79±16 in 12 months ( P <0.001). Conclusions— Catheter ablation of atrial fibrillation was effective in obese patients. Coexistence of atrial fibrillation and obesity indicated lower SF-36 scores, but the improvement in quality of life was consistent across all body mass index categories.