BACKGROUND:Despite cardiac resynchronization therapy (CRT), some patients with heart failure progress and undergo left ventricular assist device (LVAD) implantation. Management of CRT after LVAD implantation has not been well studied. The purpose of this study was to determine whether RV pacing or biventricular pacing measurably affects acute hemodynamics in patients with an LVAD and a CRT device.METHODS AND RESULTS:Seven patients with CRT and LVAD underwent right heart catheterization. Pressures and oximetry were measured and LVAD parameters were recorded during 3 different conditions: RV pacing alone, biventricular pacing, and intrinsic atrioventricular conduction. Paired t tests were used to evaluate changes within subjects. There were no significant changes in right atrial pressure, pulmonary arterial pressures, pulmonary capillary wedge pressure, cardiac index, or any LVAD parameter (P > .05).CONCLUSIONS:Our data suggest that CRT probably has no acute hemodynamic effect in patients with LVADs, but further study is needed.

Thromboembolic cerebrovascular accident remains a rare but potentially devastating complication of catheter-based atrial fibrillation (AF) ablation. Uninterrupted oral anticoagulant therapy with warfarin has become the standard of care when performing catheter based AF ablation. Compared with warfarin, apixaban, a factor Xa inhibitor, has been shown to reduce the risk of stroke and major bleeding in nonvalvular AF. With an increase in apixaban use for stroke prophylaxis in patients with AF, there is an increased interest in the safety and efficacy of uninterrupted apixaban therapy during AF ablation. We compared the safety and efficacy of uninterrupted OA therapy with either warfarin or apixaban in all patients who underwent catheter-based AF ablation at the University of Alabama at Birmingham and at Augusta University Medical Center from January 7, 2013, to February 25, 2016. All patients underwent a transesophageal echocardiogram on the day of their ablation to assess for the presence of intracardiac thrombi. All complications were identified and classified as bleeding, thromboembolic events, or other. A total of 627 patients were analyzed as described earlier. There were 310 patients in the warfarin group and 317 patients in the apixaban group. There were 8 complications in the warfarin group and 5 complications in the apixaban group (p = 0.38). There were no thromboembolic complications in either group. In conclusion, the use of apixaban is as safe and effective as warfarin for uninterrupted,OA therapy during catheter-based ablation of AF. (C) 2017 Elsevier Inc. All rights reserved.

Discrepancy in Longevity Estimation in SJM ICDs. Background: Real-time estimated longevity has been reported in pacemakers for several years, and was recently introduced in implantable cardioverterdefibrillators (ICDs).Objective: We sought to evaluate the accuracy of this longevity estimate in St. Jude Medical (SJM) ICDs, especially as the device battery approaches depletion.Methods: Among patients with SJM ICDs who underwent generator replacements due to reaching elective replacement indicator (ERI) at our institution, we identified those with devices that provided longevity estimates and reviewed their device interrogations in the 18 months prior to ERI. Significant discrepancy was defined as a difference of more than 12 months between estimated and actual longevity at any point during this period.Results: Forty-six patients with Current/Promote devices formed the study group (40 cardiac resynchronization therapy [CRT] and 6 single/dual chamber). Of these, 34 (74%) had significant discrepancy between estimated and actual longevity (28 CRT and all single/dual). Longevity was significantly overestimated by the device algorithm (mean maximum discrepancy of 18.8 months), more in single/dual than CRT devices (30.5 vs. 17.1 months). Marked discrepancy was seen at voltages >= 2.57 volts, with maximum discrepancy at 2.57 volts (23 months). The overall longevity was higher in the discrepant group of CRT devices than in the nondiscrepant group (67 vs. 61 months, log-rank P = 0.03).Conclusions: There was significant overestimation of longevity in nearly three-fourths of Current/Promote SJM ICDs in the last 18 months prior to ERI. Longevity estimates of SJM ICDs may not be reliable for making clinical decisions on frequency of follow-up, as the battery approaches depletion.

Introduction: We previously reported the prevalence of externalized conductors (EC) in RiataTM and RiataTM ST silicone ICD leads at enrollment in the on-going Riata Lead Evaluation study. We here report the prospective follow-up results from this study evaluating the incidence of new EC and electrical dysfunction (ED). Methods: Patients previously implanted with a Riata or Riata ST silicone lead and a St. Jude Medical ICD/CRT-D pulse generator were enrolled. Fluoroscopy is performed at enrollment and annually thereafter in three views (AP, LAO, RAO). All fluoroscopic images are adjudicated for the presence of EC by a panel of experienced electrophysiologists. Leads are classified as having EC if either a conductor cable does not fit within the shock electrode shadow width or if the radius of curvature of the suspected region with EC is significantly different from the remainder of the lead body. Upon occurrence of a lead revision, electrical performance data are adjudicated by another physician panel to determine the presence of ED based upon predefined criteria. Patients will continue follow-up for a period of 3 years. Results: Time from implant was 9.9 ± 1.6 years for 8F leads and 8.3 ± 0.9 years for 7F leads. The incidence of new EC during the first year post-enrollment was 4.3% in 8F leads and 1.7% in 7F leads (p = 0.13, N = 544 adjudicated leads). The incidence of new EC during the second year post-enrollment was 7.8% in 8F leads and 2.2% in 7F leads (p = 0.03, N = 399 adjudicated leads). The incidence of new EC during the third year post-enrollment was 11.3% in 8F leads and 1.0% in 7F leads (p = 0.003, N = 255 adjudicated leads). Over a follow-up period of 40.9 ± 1.1 months from enrollment, a total of 28 of the 776 leads enrolled (10 with EC, 18 without EC) were identified as having ED. There was no significant difference in the proportion of ED in leads with and without EC (5.2% vs. 3.1%, respectively, p = 0.19). Conclusions: Through 3 years of follow-up, the annual hazard rate of new EC was 8.2% in 8F Riata and 1.6% in 7F Riata ST silicone leads. However, the presence of externalized conductors was not associated with a significant increased risk for electrical dysfunction.

Backgrounds— Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs. Methods and Results— Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied. The first ablation was performed at the site with the earliest local ventricular activation and best pace map on the endocardial or epicardial side. When the first ablation was unsuccessful, the second ablation was delivered on the other surface. If this sequential unipolar ablation failed, simultaneous unipolar ablation from both sides was performed. The first ablation was performed on the epicardial side in 9 VAs and endocardial side in 5 VAs. The intramural LVOT VAs were successfully eliminated by the sequential (n=9) or simultaneous (n=5) unipolar catheter ablation. Simultaneous ablation was most likely to be required for the elimination of the VAs when the distance between the endocardial and epicardial ablation sites was >8 mm and the earliest local ventricular activation time relative to the QRS onset during the VAs of <–30 ms was recorded at those ablation sites. Conclusions— LVOT VAs originating from intramural foci could usually be eliminated by sequential unipolar radiofrequency ablation and sometimes required simultaneous ablation from both the endocardial and epicardial sides.

V2S/V3R Index Distinguishes LVOT from RVOT OriginsIntroductionAlthough several ECG criteria have been proposed for differentiating between left and right origins of idiopathic ventricular arrhythmias (VA) originating from the outflow tract (OT‐VA), their accuracy and usefulness remain limited. This study was undertaken to develop a more accurate and useful ECG criterion for differentiating between left and right OT‐VA origins.Methods and ResultsWe studied OT‐VAs with a left bundle branch block pattern and inferior axis QRS morphology in 207 patients who underwent successful catheter ablation in the right (RVOT; n = 154) or left ventricular outflow tract (LVOT; n = 53). The surface ECGs during the OT‐VAs and during sinus beats were analyzed with an electronic caliper. The V2S/V3R index was defined as the S‐wave amplitude in lead V2 divided by the R‐wave amplitude in lead V3 during the OT‐VA. The V2S/V3R index was significantly smaller for LVOT origins than RVOT origins (P < 0.001). The area under the curve (AUC) for the V2S/V3R index by a receiver operating characteristic analysis was 0.964, with a cut‐off value of ≤1.5 predicting an LVOT origin with an 89% sensitivity and 94% specificity. In the AUC and accuracy, the V2S/V3R index was superior to any previously proposed ECG criteria in an analysis of all OT‐VAs. This advantage of the V2S/V3R index over the V2 transition ratio and other indices also held true for a subanalysis of 77 OT‐VAs with a lead V3 precordial transition.ConclusionThe V2S/V3R index outperformed other ECG criteria to differentiate left from right OT‐VA origins independent of the site of the precordial transition.

Cardiovascular Implantable Electronic Device Implantation with Uninterrupted DabigatranBackgroundWhile continuation of oral anticoagulation (OAC) with warfarin may be preferable to interruption and bridging with heparin for patients undergoing cardiovascular implantable electronic device (CIED) implantation, it is uncertain whether the same strategy can be safely used with dabigatran.Objective and MethodsTo determine the risk of bleeding and thromboembolic complications associated with uninterrupted OAC during CIED implantation, replacement, or revision, the outcomes of patients receiving uninterrupted dabigatran (D) were compared to those receiving warfarin (W).ResultsD was administered the day of CIED implant in 48 patients (age 66 ± 12.4 years, 13 F and 35 M, 21 ICDs and 27 PMs), including new implant in 25 patients, replacement in 14 patients, and replacement plus lead revision in 9 patients. D was held the morning of the procedure in 14 patients (age 70 ± 11 years, 4 F and 10 M, 5 ICDs and 9 PMs). W was continued in 195 patients (age 60 ± 14.4 years, 54 F, and 141 M), including new implant in 122 patients, replacement in 33 patients, and replacement plus lead revision or upgrade in 40 patients. Bleeding complications occurred in 1 of 48 patients (2.1%) with uninterrupted dabigatran (a late pericardial effusion), 0 of 14 with interrupted D, and 9 of 195 patients (4.6%) on W (9 pocket hematomas), P = 0.69. Fifty percent of bleeding complications were associated with concomitant antiplatelet medications.ConclusionsThe incidence of bleeding complications is similar during CIED implantation with uninterrupted D or W. The risks are higher when OAC is combined with antiplatelet drugs.

BACKGROUND:Idiopathic ventricular arrhythmias (VAs) can be rarely ablated from the noncoronary cusp (NCC) of the aorta. OBJECTIVE:The purpose of this study was to investigate the prevalence and the clinical, electrocardiographic, and electrophysiologic characteristics of idiopathic NCC VAs. METHODS:We studied 90 consecutive patients who underwent successful catheter ablation of idiopathic aortic root VAs (left coronary cusp [LCC] 33, right coronary cusp [RCC] 32, junction between LCC and RCC 19, NCC = 6). RESULTS:NCC VAs occurred in significantly younger patients (all <40 years old) and exhibited a shorter QRS duration (all but one <150 ms), smaller R-wave amplitude ratio in leads II and III (III/II), earlier ventricular activation in the His bundle (HB) region (all but one preceded QRS onset by >25 ms), and larger atrial to ventricular electrogram amplitude ratio (A/V) at the successful ablation site (all but one >1) than the other VAs. QRS morphology of the NCC VAs was similar to that of RCC VAs, but NCC VAs always exhibited a left bundle branch block and left superior (n = 1) or inferior axis (n = 5). All NCC VAs exhibited ventricular tachycardias, although premature ventricular contractions were dominant in the other VAs. CONCLUSION:NCC VAs were very rare (7%) and occurred in significantly younger patients than those among the other aortic root VAs. In a limited set of six patients, the ECG and electrophysiologic characteristics of NCC VAs were similar to those of RCC VAs but were characterized by narrower QRS duration, smaller III/II ratio, earlier ventricular activation in the HB region, and A/V ratio >1 at the successful ablation site.

Introduction: Conflicting data exists for congenital long QT syndrome (LQTS) treated with a combination of beta blockade and continuous pacing. High risk patients are usually treated with an implantable cardiac defibrillator (ICD) exposing them to the risk of inappropriate shocks and potentially more frequent generator replacements. Appropriate therapy also has been shown to trigger ICD storm in many cases due to increased sympathetic discharge. We sought to examine the outcome of a cohort of patients at our institution treated with the combination of a beta blocker and atrial based pacing at a higher rate than previously described. Methods: The long term clinical course of patients with LQTS treated with beta blockers and atrial pacing were examined to identify recurrent syncope, cardiac arrest, sudden cardiac death or the need to upgrade to a defibrillator. Results: A total of 30 patients with LQTS (age 26.8 ± 21.3 years; 21 females) were identified with varying presentations - syncope (n=16); torsade de pointes (n=7); cardiac arrest (n=6); family history (n=1). All patients had a pacemaker implanted and arrhythmia diagnostics turned on. Lower rate was set to a mean of 89 ± 9 bpm [ ≥ 90 (n=20); ≥80 (n=9); 70 (n=1)]. 21 patients were programmed in the AAI mode, with the rest in the DDD (n=6) or DDI (n=3) modes. Over a mean follow up of 9.7 ± 6.6 years, no patient had recurrent syncope, cardiac arrest or sudden cardiac death. None of the patients required upgrade to an ICD. 4 patients died during follow up from known unrelated causes. Conclusion: A combination of beta blocker therapy and atrial based pacing at a high rate is highly effective in preventing sudden death in patients with congenital LQTS. This approach may be particularly beneficial in the young population, in whom, implantation of a pacemaker rather than an ICD may enhance device longevity and avoid inappropriate ICD therapies.