Rakesh Latchamsetty

Dabigatran vs warfarin for radiofrequency catheter ablation of atrial fibrillation

BACKGROUND It is not clear whether dabigatran is as safe and effective as uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). OBJECTIVE To compare the safety and efficacy of dabigatran by using a novel administration protocol and uninterrupted anticoagulation with warfarin for periprocedural anticoagulation in patients undergoing RFA of AF. METHODS In this case-control analysis, 763 consecutive patients (mean age 61±10 years) underwent RFA of AF using dabigatran (N = 191) or uninterrupted warfarin (N = 572) for periprocedural anticoagulation. In all patients, anticoagulation was started≥4 weeks before RFA. Dabigatran was held after the morning dose on the day before the procedure and resumed 4 hours after vascular hemostasis was achieved. RESULTS A transesophageal echocardiogram performed in all patients receiving dabigatran did not demonstrate an intracardiac thrombus. There were no thromboembolic complications in either group. The prevalence of major (4 of 191, 2.1%) and minor (5 of 191, 2.6%) bleeding complications in the dabigatran group were similar to those in the warfarin group (12 of 572, 2.1%; P = 1.0 and 19 of 572, 3.3%; P = .8, respectively). Pericardial tamponade occurred in 2 of 191 (1%) patients in the dabigatran group and in 7 of 572 (1.2%) patients in the warfarin group (P = 1.0). All patients who had a pericardial tamponade, including 2 in the dabigatran group, had uneventful recovery after perdicardiocentesis. On multivariate analysis, international normalized ratio (odds ratio [OR] 4.0; 95% confidence interval [CI] 1.1-15.0; P = .04), clopidogrel use (OR 4.2; 95% CI 1.5-12.3; P = .01), and CHA2DS2-VASc score (OR 1.4; 95% CI 1.1-1.8; P = .01) were the independent risk factors of bleeding complications only in the warfarin group. CONCLUSIONS When held for approximately 24 hours before the procedure and resumed 4 hours after vascular hemostasis, dabigatran appears to be as safe and effective as uninterrupted warfarin for periprocedural anticoagulation in patients undergoing RFA of AF.

Prevalence and Predictors of Complications of Radiofrequency Catheter Ablation for Atrial Fibrillation

Complications of Atrial Fibrillation Ablation. Introduction: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF.

Characteristics of Cavotricuspid Isthmus–Dependent Atrial Flutter After Left Atrial Ablation of Atrial Fibrillation

Background— Patients who have previously undergone ablation of atrial fibrillation may experience cavotricuspid isthmus (CTI)-dependent atrial flutter during follow-up. The effects of left atrial (LA) ablation on the characteristics of CTI-dependent flutter have not been described. Methods and Results— Fifteen patients underwent ablation of CTI-dependent flutter late after LA ablation of AF. The ECG, biatrial activation patterns, and LA voltage maps during flutter were analyzed. Thirty age- and gender-matched patients who underwent ablation of CTI-dependent flutter without prior LA ablation served as control subjects. Among the patients with prior LA ablation, mapping revealed counterclockwise activation around the tricuspid annulus in 12 of 15 patients (80%) and clockwise activation in 3 of 15 patients (20%). The flutter waves in the inferior leads were upright in 9 of the 15 patients (60%) with prior LA ablation and in none of the control subjects (P<0.001). The upright flutter waves in the inferior leads in patients with counterclockwise flutter corresponded to craniocaudal activation of the right atrial free wall. LA activation contributed little to the genesis of the flutter waves in these patients because of a significant reduction in bipolar LA voltage (0.44±0.20 versus 1.54±0.19 mV in patients with biphasic/negative flutter waves; P<0.001). Conclusions— CTI-dependent flutter that occurs after LA ablation of atrial fibrillation often has atypical ECG characteristics because of altered LA activation. In patients presenting with atrial flutter after LA ablation, entrainment mapping should be performed at the CTI even if the ECG is uncharacteristic of CTI-dependent flutter.

Recovery from left ventricular dysfunction after ablation of frequent premature ventricular complexes.

BACKGROUND Patients with frequent premature ventricular complexes (PVCs) and PVC-induced cardiomyopathy usually have recovery of left ventricular (LV) dysfunction postablation. The time course of recovery of LV function has not been described. OBJECTIVE To describe the time course and predictors of recovery from LV dysfunction after effective ablation of PVCs in patients with PVC-induced cardiomyopathy. METHODS In a consecutive series of 264 patients with frequent idiopathic PVCs referred for PVC ablation, LV dysfunction was present in 87 patients (mean ejection fraction 40%±10%). The PVC burden was reduced to<20% of the initial PVC burden in 75 patients. In these patients, echocardiography was repeated 3-4 months postablation. If LV function did not normalize after 3-4 months, a repeat echocardiogram was performed every 3 months until there was normalization or stabilization of LV function. RESULTS The ejection fraction normalized at a mean of 5±6 months postablation. The majority of patients (51 of 75, 68%) with PVC-induced LV dysfunction had a recovery of LV function within 4 months. In 24 (32%) patients, recovery of LV function took more than 4 months (mean 12±9 months; range 5-45 months). An epicardial origin of PVCs was more often present (13 of 24, 54%) in patients with delayed recovery of LV function than in patients with early recovery of LV function (2 of 51, 4%; P<.0001). The PVC-QRS width was significantly longer in patients with delayed recovery than in patients with recovery within 4 months (170±21 ms vs 159±16 ms; P = .02). In multivariate analysis, only an epicardial PVC origin was predictive of delayed recovery of LV function in patients with PVC-induced cardiomyopathy. CONCLUSIONS PVC-induced cardiomyopathy resolves within 4 months of successful ablation in most patients. In about one-third of the patients, recovery is delayed and can take up to 45 months. An epicardial origin predicts delayed recovery of LV function.

Impact of QRS duration of frequent premature ventricular complexes on the development of cardiomyopathy

BACKGROUND Patients with frequent premature ventricular complexes (PVCs) are at risk of developing reversible PVC-induced cardiomyopathy (rPVC-CMP). Not all determinants of rPVC-CMP are known. OBJECTIVE To assess the impact of the QRS duration of PVCs on the development of rPVC-CMP. METHODS In a consecutive series of 294 patients with frequent idiopathic PVCs referred for PVC ablation, the width of the PVC-QRS complex was assessed. The QRS width was correlated with the presence of rPVC-CMP. RESULTS The PVC-QRS width was significantly greater in patients with rPVC-CMP than in patients without rPVC-CMP (164 ± 20 ms vs 149 ± 17 ms; P < .0001). The site of origin of the PVC had an impact on the PVC-QRS width, with epicardial PVCs having the broadest QRS complexes. Patients with PVCs originating from the right ventricular outflow tract or the fascicles had the narrowest QRS complexes. After adjusting for PVC burden, symptom duration, and PVC site of origin, PVC-QRS width and an epicardial PVC origin were independently associated with rPVC-CMP. Based on receiver operator characteristics analysis, a QRS duration of >150 ms best differentiated patients with and without rPVC-CMP (area under the curve 0.66; sensitivity 80%; specificity 52%). The PVC burden for developing rPVC-CMP is significantly lower in patients with a PVC-QRS width of ≥150 ms than in patients with a narrower PVC-QRS complex (22% ± 13% vs 28% ± 12%; P < .0001). CONCLUSION Broader PVCs and an epicardial PVC origin are associated with the development of rPVC-CMP independent of the PVC burden.

Management and outcomes of cardiac tamponade during atrial fibrillation ablation in the presence of therapeutic anticoagulation with warfarin

BACKGROUND Cardiac tamponade (CT) is a possible complication of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Although the incidence of CT is not higher when RFCA is performed with a therapeutic international normalized ratio (INR), outcomes of CT are unclear. OBJECTIVE We compared outcomes among patients with and without a therapeutic INR who developed CT as a complication of RFCA of AF. METHODS The subjects of this retrospective study were 40 consecutive patients who developed CT during RFCA of AF at 3 centers. We divided the patients into 2 groups: RFCA performed with INR < 2 (group 1) and INR ≥ 2 (group 2). There were 23 patients in group 1 and 17 patients in group 2. RESULTS Baseline clinical and procedure characteristics were not different between the 2 groups. Heparin was reversed by protamine in 83% and 94% of patients (P = .37), and warfarin was reversed by fresh frozen plasma or factor VIIa in 17% and 35% of patients (P = .27) in groups 1 and 2, respectively. All patients were successfully treated by percutaneous drainage, and none required surgical intervention. There were no significant differences in the amount of initial pericardial drainage (523 ± 349 ml vs. 409 ± 157 ml, P = .22) or the duration of drainage (P = .14) between the 2 groups. All patients survived to hospital discharge. Median length of hospital stay was 2 days longer in group 1 (P <.01). CONCLUSION Cardiac tamponade is not more severe or difficult to manage in the presence of therapeutic anticoagulation with warfarin in patients undergoing RFCA of AF.

Meta-analysis of safety and efficacy of uninterrupted warfarin compared to heparin-based bridging therapy during implantation of cardiac rhythm devices.

Optimal management of perioperative anticoagulation in patients undergoing pacemaker or implantable cardioverter-defibrillator implantation is not yet established. We performed a meta-analysis of the published literature to assess the safety and efficacy of perioperative heparin-based bridging therapy versus uninterrupted warfarin therapy in patients undergoing pacemaker or implantable cardioverter-defibrillator implantation. We performed a systematic review of MEDLINE (1950 to 2012), EMBASE (1988 to 2012), Cochrane Controlled Trials Register (fourth quarter 2011), and reports presented at scientific meetings (1994 to 2011). Randomized controlled trials, case-control, or cohort studies comparing the safety and efficacy of uninterrupted warfarin therapy to heparin-based bridging therapy were eligible. Outcomes reported in eligible studies were rates of bleeding and thromboembolic events. Of 3,195 reports initially reviewed, we identified 8 studies enrolling 2,321 patients for the meta-analysis. Maintenance of therapeutic warfarin was associated with significantly lower bleeding postoperatively compared to heparin-based bridging therapy (odds ratio 0.30, 95% confidence interval 0.18 to 0.50, p <0.01). There was no significant difference in risk of thromboembolic events between these 2 strategies (odds ratio 0.65, 95% confidence interval 0.14 to 3.02, p = 0.58). In conclusion, strategy of uninterrupted warfarin therapy throughout pacemaker or implantable cardioverter-defibrillator implantation is associated with decreased risk of bleeding without increasing risk of thromboembolic events. This strategy is a viable alternative to heparin-based bridging therapy.

Predictive Value of Programmed Ventricular Stimulation After Catheter Ablation of Post-Infarction Ventricular Tachycardia

BACKGROUND A recent meta-analysis demonstrated a survival benefit in post-infarction patients whose ventricular tachycardia (VT) was rendered noninducible by catheter ablation. Furthermore, patients with noninducible VT had a lower VT recurrence rate than did patients whose VT remained inducible after ablation. OBJECTIVES The purpose of this multicenter cohort study was to assess whether noninducibility after VT ablation is independently associated with improved survival. METHODS Data from 1,064 patients who underwent VT ablation for post-infarction VT at seven international centers were analyzed. The ablation procedure was considered successful if no VT was inducible at the end of the procedure and unsuccessful if VT remained inducible or if programmed stimulation was not performed at the end of the ablation. RESULTS Median follow-up time was 633 days. Noninducibility was independently associated with lower mortality (adjusted hazard ratio: 0.65; 95% confidence interval: 0.53 to 0.79; p<0.001). Atrial fibrillation, diabetes, and age were other independent predictors of higher mortality. Ablation of only the clinical VT in patients who also had inducible, nonclinical VTs was not associated with improved survival. CONCLUSIONS Noninducibility after VT ablation in patients with post-infarction VT is independently associated with lower mortality during long-term follow-up.

Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly.

Stroke and Atrial Fibrillation Ablation. Introduction: Factors associated with cerebrovascular events (CVEs) after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF) have not been well defined in elderly patients (≥65 years). The purpose of this study was to determine the prevalence and predictors of CVEs after RFA in patients with AF ≥65 years old, in comparison to patients <65 years, and with or without AF.

Effect of radiation therapy on permanent pacemaker and implantable cardioverter-defibrillator function

BACKGROUND Radiation therapys (RTs) effects on cardiac implantable electronic devices (CIEDs) such as implantable cardioverter-defibrillators (ICDs) and pacemakers (PMs) are not well established, leading to device removal or relocation in preparation for RT. OBJECTIVE To determine the effect of scattered RT on CIED performance. METHODS We analyzed 69 patients--50 (72%) with PMs and 19 (28%) with ICDs--receiving RT at the University of Michigan. Collected data included device model, anatomic location, and treatment beam energies, treatment type, and estimated dose to the device. Patients were treated with either high-energy (16-MV) and/or low-energy (6 MV) photon beams with or without electron beams (6-16 MeV). The devices were interrogated with pre- and post-RT and/or weekly with either in-treatment or home interrogation, depending on the patients dependence on the device and the estimated or measured delivered dose. Outcomes analyzed were inappropriate ICD therapies, device malfunctions, or device-related clinical events. RESULTS The PMs were exposed to 84.4 ± 99.7 cGy of radiation, and the ICDs were exposed to 92.1 ± 72.6 cGy of radiation. Two patients with ICDs experienced a partial reset of the ICD with the loss of historic diagnostic data after receiving 123 and 4 cGy, respectively. No device malfunction or premature battery depletion was observed at 6-month follow-up from RT completion. CONCLUSIONS CIED malfunction due to indirect RT exposure is uncommon. Regular in-treatment or home interrogation should be done to detect and treat these events and to ensure that diagnostic data are preserved.