Citations

Abstract Aims This study aimed to evaluate the predictive value of a baseline speckle tracking strain rate imaging-derived discoordination index for response to cardiac resynchronization therapy (CRT). Methods and results Ninety-seven patients with QRS ≥120 ms and left ventricular (LV) ejection fraction ≤35% were prospectively followed after CRT in the Mayo CRT Registry. The LV discoordination index (stretch/shortening or thinning/thickening during ejection) was calculated from three types of deformation, radial, circumferential, and longitudinal, using two-dimensional speckle tracking strain rate imaging. The benefit of CRT was evaluated by reverse remodelling (i.e. reduction of LV end-systolic volume ≥15% at 6-month follow-up) and survival. The optimal cut-off value of the baseline discoordination index in discriminating responders from non-responders was determined by receiver operating characteristic curve analysis. Significant differences in baseline indices between responders and non-responders were noted for radial and circumferential discoordination indices. A mid-ventricular radial discoordination index (RDI-M) >38% best predicted responders, especially in patients with ischaemic cardiomyopathy (area under the curve 0.86 for all patients, sensitivity 80%, and specificity 91%). Death occurred in 28 patients over a median follow-up of 3.2 years. When adjusted for confounding variables, lack of significant discoordination (RDI-M <38%) before CRT was associated with a particularly high mortality (hazard ratio 7.05, 95% confidence interval 2.45–26.0). Conclusion LV discoordination assessed by speckle tracking RDI-M imaging was able to predict reverse remodelling at 6 months and survival of patients who received CRT.

Background— Postmarket medical device surveillance in the United States depends largely on voluntary reporting of adverse events. Consequently, early safety signals may be missed, exposing patients to potentially hazardous products. The aim of this study was to assess the feasibility of using an automated safety surveillance tool to detect early signals that a marketed implantable cardiac device was underperforming. Methods and Results— For this purpose, we performed simulated prospective monthly full-cohort and propensity-matched comparative survival analyses on our 3-center database of Sprint Fidelis and Quattro Secure implantable cardioverter-defibrillator leads, using a commercially available automated surveillance tool that was preset to trigger an alert if the log rank probability value was <0.05. During the study, 84 of 1035 Fidelis (8.1%) and 23 of 1675 Quattro (1.4%) leads failed. The simulated full-cohort analysis triggered a sustained alert for Fidelis leads beginning 13 months after the first implant and 2 years before Fidelis leads were removed from the market. Of the 1035 patients who had Fidelis leads, up to 969 (93.6%) were successfully matched to Quattro patients. In the propensity-matched analysis, the alert triggered 22 months after the first Fidelis implant and more than 1 year before the lead was recalled. Conclusions— An active automated safety surveillance system could have identified this implantable cardiovascular device problem substantially sooner than was achieved through existing postmarket surveillance methods. Such a tool, when applied to clinical registries and remote monitoring databases, may limit the exposure of large populations to underperforming and potentially hazardous cardiovascular devices.

Objective— Left atrial blood stasis is associated with increased risk for left atrial appendage thrombus (LAAT) and stroke in atrial fibrillation (AF). Von Willebrand factor (VWF) is associated with thromboembolism in AF. VWF thrombogenic activity is proportional to multimer size, which is regulated by VWF-cleaving protease (ADAMTS13). Methods and Results— To assess the association between left atrial blood stasis and VWF-ADAMTS13 system, plasma VWF antigen (VWF:Ag), VWF activity (VWF:Act), and ADAMTS13 activity were measured in 414 consecutive patients with nonvalvular AF (age 63±13 years; 25% women) and in 100 patients (age 64±14 years; 39% women) with normal sinus rhythm. Spontaneous echocardiographic contrast (SEC), left atrial appendage emptying velocity, and LAAT were assessed by transesophageal echocardiography. Presence and intensity of SEC varied directly with VWF:Ag and VWF:Act but not with ADAMTS13 activity. AF patients with LAAT had higher VWF:Ag (200±61 versus 155±52, P =0.0006) and VWF:Act (179±57 versus 141±51 P =0.0026) compared with those without LAAT. VWF:Ag and VWF:Act were independent predictors of LAAT after adjustment for CHADS 2 score ( P =0.0179 and P =0.0497, respectively). Conclusion— The association between VWF and SEC may explain the thrombotic propensity in AF. Elevated VWF:Ag may help identify AF patients at risk for LAAT.

Background— The efficacy of radiofrequency ablation for atrial fibrillation (AF) in patients with left ventricular (LV) systolic dysfunction and isolated diastolic dysfunction is uncertain. Methods and Results— A prospective cohort of patients with normal and abnormal LV function underwent ablation for antiarrhythmic drug (AAD)-refractory AF. Three groups were compared: 111 patients with systolic dysfunction, defined as LV ejection fraction (LVEF) ≤40%; 157 patients with isolated diastolic dysfunction but preserved LVEF ≥50%; and 100 patients with normal LV function. The primary end point was AAD-free AF elimination at 1 year after ablation. This end point was achieved in 62% of patients with systolic dysfunction, 75% of those with diastolic dysfunction, and 84% of controls ( P =0.007). AF control on or off AADs was achieved in 76% of patients with systolic dysfunction, 85% of those with diastolic dysfunction, and 89% of controls ( P =0.08). In the systolic dysfunction group, 49% experienced an increase in LVEF by ≥5% after ablation, of which 64% achieved normal LVEF. In the diastolic dysfunction group, 30% of patients demonstrated at least 1 grade improvement in diastolic dysfunction. Multivariable analysis demonstrated an increased relative risk of arrhythmia recurrence of 1.8 (95% CI, 1.1 to 3.1; P =0.02) in systolic dysfunction and 1.7 (1.0 to 2.7; P =0.04) in isolated diastolic dysfunction compared with normal function. Conclusions— Although an ablative approach for AF in patients with systolic or diastolic dysfunction is associated with an increased long-term recurrence risk, there is potential for substantial quality-of-life improvement and LV functional benefit.

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— Infection is a serious complication of cardiovascular implantable electronic device (CIED) placement and requires device removal for attempted cure. Methods and Results— We studied the rate, risk factors, and outcomes of CIED infection in 74 consecutive patients with bacteremia caused by Gram-positive cocci (GPC) other than Staphylococcus aureus between 2001 and 2007. CIED infection was defined as the presence of signs of infection at the generator site, lead vegetations seen on echocardiography, or microbiological growth from device cultures. Twenty-two (30%) of 74 patients with non– S aureus GPC bacteremia had CIED infections. Coagulase-negative staphylococci (CoNS) accounted for 73% of CIED infections. The rate of CIED infection in patients with CoNS bacteremia was almost 2-fold that of non-CoNS GPC bacteremia (36% versus 20%, P =0.13). The number of leads, the presence of abandoned leads, and prior generator replacement were associated with CIED infection. Among 33 patients without identifiable CIED infection at initial evaluation who did not undergo device removal, 5 (15%) had relapsing bacteremia within 12 weeks of completing antibiotic therapy. CoNS accounted for all relapses, and none had evidence of CIED infection at relapse. Conclusions— Patients with a CIED and bacteremia caused by GPC other than S aureus frequently had evidence of underlying CIED infection on clinical evaluation that included transesophageal echocardiography. This was particularly true among those with CoNS bacteremia. No evidence of underlying CIED infections was identified in the subgroup of patients who did not have manifestations of CIED infection on initial evaluation but subsequently had relapsing bacteremia caused by CoNS.

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.

Background— Outflow tract ventricular tachycardia originating above the semilunar valves has been reported in a small number of studies. Discrete potentials in the great arteries (above the semilunar valves) have been rarely described in patients undergoing electrophysiology evaluation and radiofrequency ablation for ventricular arrhythmias. The mechanisms of these discrete potentials in the great arteries and the utility of such potentials in guiding radiofrequency ablation are unknown. Methods and Results— Twelve patients with outflow tract ventricular arrhythmia originating above the semilunar valves with discrete arterial potentials were studied. The clinical characteristics, properties of the arterial potentials, electrophysiological evaluation and ablation, and short- and long-term outcomes were reviewed. Of the twelve patients, 8 (67%) were women. The patients’ average age was 41�14 years. The average ejection fraction was 0.52�0.16 (range: 0.16 to 0.75). Contact mapping in the great artery demonstrated discrete near-field electrograms that were separate from far-field ventricular electrograms in all patients (8 above the pulmonary valve and in 4 the aortic valve). One or more of the following electrophysiological characteristics, supportive of an arrhythmogenic substrate, were observed in 10 of 12 patients: (1) A fixed or reproducibly variable pattern of discrete potential–ventricular arrhythmia relationship was present at baseline or during pacing; (2) the discrete potential–ventricular electrogram relationship during sinus rhythm was the reverse of that during the ventricular arrhythmia; (3) during sustained ventricular tachycardia, spontaneous variation of the ventricular (V-V) cycle length was preceded by a similar variation of arterial spike potential–spike potential cycle length; and (4) ablation guided by the discrete arterial potential successfully eliminated the clinical arrhythmia. Ablation was successful in these patients. In the remaining 2 patients, the potentials were believed to be bystanders. Over 10�4 months (range: 5 to 32 months) of follow-up, there have been no recurrences of the premature ventricular complex or ventricular arrhythmia. Conclusions— Discrete potentials are present in the great arteries of a select group of patients with outflow tract ventricular tachycardia originating above the semilunar valves. When an arrhythmogenic relationship can be demonstrated, discrete potentials are useful in guiding ablation within the great vessels, despite significant anatomic complexity.

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.