Electrical delays in quadripolar leads with cardiac resynchronization therapy.

BACKGROUND: Pacing at sites of late intraventricular activation (QLV) or long interventricular conduction (right ventricle [RV]-left ventricular [LV]) have been associated with improved cardiac resynchronization therapy (CRT) outcomes. Quadripolar leads improve CRT outcomes by allowing for electrical repositioning to optimize pacing sites. However, little is known regarding the effect of such repositioning on electrical delay. OBJECTIVE: Determine the relationship between different electrical bipoles from a quadripolar lead and measures of electrical delay. METHODS: Forty-six patients underwent CRT with a quadripolar lead. The RV-LV and QLV intervals were measured for both the proximal and distal bipoles and the difference (Δ) between bipoles for each measure were calculated. Multivariate analyses were performed to identify predictors of electrical delays. RESULTS: This was a typical CRT population with a mean age of 65 years and ejection fraction of 27%, with left bundle branch block (LBBB) present in 70%. The regression model for ΔQLV was significant (p = .05), with both gender (p = .008) and LBBB status (p = .020) significant predictors. The overall regression model for ΔRV-LV was not significant. ΔQLV and ΔRV-LV were significant among LBBB patients. Among non-LBBB, only ΔRV-LV was significant (mean: 7.2 ms, p = .006). ΔRV-LV versus ΔQLV were strongly correlated in LBBB (R2 = .92) but not non-LBBB (R2 = .06). CONCLUSION: In LBBB, ΔRV-LV and ΔQLV are closely correlated suggesting that the proximal bipole and thus basal LV pacing sites should be selected when feasible. Greater variation in activation pattern is present in non-LBBB, so pacing sites should be individualized.

Higher initial weight-based heparin dosing is required with direct oral anticoagulants during catheter ablation for atrial fibrillation.

BACKGROUND: Heparin dosing of patients anticoagulated with direct oral anticoagulants (DOACs) undergoing atrial fibrillation (AF) ablation can be challenging as they require more heparin than those on warfarin therapy. We sought to compare periprocedural activated clotting times (ACTs) of patients on warfarin vs. DOAC and determine an optimal weight-based heparin dosage strategy. METHODS: Patients who underwent AF ablation over 28 months were reviewed for type of anticoagulation, intraprocedural heparin dosing, ACTs, and adverse outcomes. A heparin dosing strategy was then tested in a prospective validation cohort. RESULTS: There were 89 patients in the DOAC group and 43 in the warfarin group. Demographics, comorbidities, and complication rates were similar. Mean ACT and percentage of therapeutic ACTs were lower in the DOAC group, most significantly in those with a weight > 90 kg. In DOAC patients, a higher initial heparin bolus ≥ 150 units/kg yielded a higher percentage of therapeutic intraprocedural ACTs (49% ± 10 vs. 29% ± 7, p = 0.0008). In a prospective validation cohort of 25 patients administered an initial heparin bolus ≥ 150 units/kg, the mean ACT was 295 ± 33 and 49% of the ACTs collected were therapeutic, similar to findings of our high-dose retrospective subgroup. CONCLUSION: Patients on DOACs require more heparin during AF ablation to achieve therapeutic ACT. We suggest an initial heparin dose of at least 150 units/kg in this subset of patients, particularly in those with a weight > 90 kg.

Prophylactic pulmonary vein isolation during cavotricuspid isthmus ablation for atrial flutter: A meta-analysis.

BACKGROUND: Atrial arrhythmias (AA), including atrial fibrillation (AF), have been reported in patients after cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFL). Several studies have examined the effect of performing concomitant pulmonary vein isolation (PVI) with CTI on recurrent AA. These studies were analyzed to determine the overall effect of this approach on recurrent AA. METHODS: PubMed and Google Scholar were searched for randomized trials comparing the incidence of AA after CTI versus CTI + PVI until June 2018. Only patients without prior history of AF were included in the recurrent AA analysis. All patients were included in the analyses of other clinical outcomes. RESULTS: Four randomized control trials were included in the meta-analysis. In the recurrent AA analysis, a total of 314 patients were randomized in the studies (n = 158 CTI, n = 156 CTI + PVI). Freedom from AA at 1 year was significantly higher in the CTI + PVI group versus CTI alone (odds ratio [OR] 0.25 [0.14, 0.44] 95% confidence interval [CI], P < 0.00001). A total of 550 patients (n = 336 CTI, n = 214 CTI + PVI) were included in analyses for procedure time, fluoroscopy time, and complications rates. Procedure time and fluoroscopy time were significantly longer in the CTI + PVI group (mean difference [MD]: 103.31 min [94.40, 112.23] 95% CI, P < 0.00001) and (MD: 16.47 min [14.89, 18.05] 95% CI, P < 0.00001), respectively. Total complications were statistically similar between groups. CONCLUSION: This meta-analysis shows addition of a prophylactic PVI during CTI ablation significantly reduces recurrent AA at 1 year without significantly increasing major complications.

Use of antibiotic envelopes to prevent cardiac implantable electronic device infections: A meta-analysis.

INTRODUCTION: The rates of cardiac implantable electronic device (CIED) infections have risen over the past decade and are associated with increased hospitalizations and mortality. A number of preventative strategies have been developed including an antibiotic coated envelope, but it has yet to gain widespread use. METHODS: A meta-analysis was performed on controlled studies of the antibiotic envelope. PubMed and Google Scholar were searched for studies comparing infection rates with and without the use of an antibiotic envelope. Studies including both new implants and pulse generator replacements were included in the analysis. RESULTS: Five studies were included in the meta-analysis. A total of 4,490 patients underwent CIED implantation, 1,798 with an antibiotic envelope and 2,692 without an envelope. In the pooled cohort, the envelope was associated with a 69% relative risk reduction in CIED infection (0.31 [0.17, 0.58] 95% CI, P = 0.0002). Propensity matched data from three studies were analyzed to ensure accurate comparison. In the risk-matched cohort, infections were significantly lower in the envelope group (3 vs. 26, P < 0.0003). CONCLUSION: The use of antibiotic envelopes in CIED implant is associated with a significantly lower rate of infection.

The effect of the amiodarone-warfarin interaction on anticoagulation quality in a single, high-quality anticoagulation center.

Clinical trials have reported a low time in therapeutic range (TTR) in patients with atrial fibrillation treated with both warfarin andamiodarone. These trials included centers and countries with both high and low TTRs. What is the impact of amiodarone on the TTR in a single, high-quality anticoagulation clinic? TTR was assessed in amiodarone and nonamiodarone-treated patients from a University anticoagulation clinic. Baseline characteristics between patients ever-taking or never-taking amiodarone were similar, except more amiodarone patients were smokers (19.5 vs. 6.1%, P = 0.0031). The TTR calculated from 8901international normalized ratios (INRs) in 249 nonamiodarone patients with a mean follow-up of 34 ±â€Š20 months (mean INR 36 ±â€Š18) was 66 ±â€Š16.6% compared with 61.3 ±â€Š16.2% (P = 0.111) from 1455 INRs in 41 amiodarone-treated patients with a mean follow-up of 28 ±â€Š20 months (mean INR 35 ±â€Š22). Factors associated with a low TTR were male sex (P = 0.0013), smoker (P = 0.0048), and amiodarone use (P = 0.0374). A second on-treatment analysis, in which the TTR was calculated only during amiodarone therapy, resulted in similar findings; however, amiodarone did not emerge as a predictor of a low TTR. In 11 patients, the TTR prior to amiodarone (54.5 ±â€Š22.2%) was not significantly different in the first 3 months (54.6 ±â€Š33.4%) or after 3 months (67.2 ±â€Š33.7%) of amiodarone. In a single high-quality anticoagulation center, anticoagulation quality, as measured by the TTR, can be comparable in amiodarone and nonamiodarone-treated patients.

Cardiac stimulation with electronic control device application.

BACKGROUND: Electronic control devices (ECDs) are weapons used to incapacitate violent subjects. Subjects have died suddenly after ECD application, but because cardiac dysrhythmias have been inconsistently observed during ECD application in animals, the cause for death is uncertain. OBJECTIVES: The objective was to identify the factors contributing to cardiac stimulation during ECD application detected by transesophageal echocardiography. METHODS: Four Yorkshire pigs were anesthetized, paralyzed with vecuronium, and restrained in a supine position. A GE 6T echo probe was placed in the esophagus to directly visualize left ventricular function. M-mode echocardiography was used to estimate heart rate. Two dart locations, chest and abdomen, were assessed. ECD applications were delivered from one of five commercially available devices (Taser X26, Singer S200 AT, Taser M26, Taser X3, and Taser C2) in random order to each pig, four times in each orientation. RESULTS: Cardiac stimulation, characterized by multiple PVCs or the sudden increase in ventricular contraction rate during application, did not occur with abdominal dart location. With chest dart application in small pigs, cardiac stimulation occurred with all ECDs except with the Taser X3 (p < 0.0001). In large pigs, cardiac stimulation occurred only during chest application of the S200 AT (chest vs. abdomen: 207 beats/min, vs. 91 beats/min, p < 0.0001). CONCLUSION: Cardiac stimulation occurs during ECD application in pigs, and is dependent upon subject size, dart orientation, and ECD. The Taser X3 did not result in cardiac stimulation in small or large pigs.