Flecainide Versus Procainamide in Electrophysiological Study in Patients With Syncope and Wide QRS Duration.

OBJECTIVES: This study sought to compare the differences between procainamide and flecainide to stress the His-Purkinje system during electrophysiological study (EPS) in patients with syncope and bundle branch block (BBB). BACKGROUND: Patients with syncope and BBB are at risk of developing atrioventricular block. EPS is recommended including class I drug challenge to unmask His-Purkinje disease in cases with baseline normal His-ventricular interval. There is little data on differences between different class I drugs. METHODS: This was a prospective study of all consecutive patients undergoing EPS for syncope and BBB at a single center (January 1, 2012 to June 30, 2017). Of those patients with negative baseline EPS, 2 cohorts were compared: group A (historical cohort: procainamide) and group B (flecainide). RESULTS: During the study, 271 patients (age 73.9 ± 12.1 years, 64.9% male, QRS duration: 139.4 ± 13.9 ms) underwent EPS. In 166, baseline EPS was negative and class I drug challenge was performed (90 procainamide, 76 flecainide). The final value and percentage increase in the His-ventricular interval (76 ± 16 ms vs. 64 ± 10 ms and 22.5 ± 6.2% vs. 11.8 ± 5.3%; p < 0.001) and diagnostic yield (14.5% vs. 7.8%, p = 0.04) were higher with flecainide. No differences were found in baseline characteristics. During follow-up (25.8 ± 6.3 months), 39 patients (24.8%) with negative EPS (19.2% with flecainide vs. 30.1% with procainamide: relative risk: 5.1; 95% confidence interval: 2.6 to 10.2; p < 0. 001) received a pacemaker. CONCLUSIONS: Flecainide has a higher diagnostic yield than does procainamide in patients with BBB, syncope, and negative baseline EPS due to a greater increase of the His-ventricular interval. Additionally, there is a lesser need for pacemaker implantation in patients in whom the class I drug test using flecainide was negative.

Syncope, conduction disturbance, and negative electrophysiological test: Predictive factors and risk score to predict pacemaker implantation during follow-up.

BACKGROUND: Patients with syncope and bundle branch block (BBB) are at risk for atrioventricular block (AVB). Electrophysiological study (EPS) can help in identifying patients at higher risk for AVB, but the false-negative rate is remarkable. Few data on the predictors of the need for pacemaker implantation during follow-up have been reported. OBJECTIVE: The purpose of this study was to analyze the rate of patients who need pacemaker implantation after negative EPS and predictive factors. METHODS: A single-center prospective study of 159 consecutive patients (73.9 ± 12.1 years; male 64.9%) with syncope and BBB (January 2012-December 2016) and negative EPS was conducted. An implantable loop recorder was implanted. RESULTS: After 27.9 ± 10.8 months of follow-up, 39 patients (24.8%) underwent pacemaker implantation because of bradyarrhythmia. In the univariate analysis, bifascicular (right BBB + left fascicular block) block, bifascicular block + long PR interval, conduction disturbance different from isolated right BBB, HV ≥60 ms, and HV ≥70 ms after class I drug challenge were predictors of pacemaker implantation. In the multivariate analysis, only bifascicular block (hazard ratio 2.5; 95% confidence interval 1.4-4.8; P = .04) and HV interval ≥60 ms (hazard ratio 3.5; 95% confidence interval 1.8-6.2; P <.001) were statistically significant. A risk score according to the multivariate model identified 3 levels of pacemaker implantation rate (13.5%, 32.7%, and 66.7%; P <.001). No death or severe trauma related to bradyarrhythmia occurred. CONCLUSION: The strategy of an implantable loop recorder in patients with syncope and BBB is safe after negative EPS, but some patients might need pacemaker implantation during follow-up. A risk score based on HV ≥60 ms and bifascicular block can be useful in identifying patients at risk for advanced AVB after negative EPS.

Predictors of positive electrophysiological study in patients with syncope and bundle branch block: PR interval and type of conduction disturbance.

BACKGROUND: Electrophysiological study (EPS) is indicated in patients with syncope and bundle branch block (BBB). Data about predictors of positive EPS in these patients is scarce. OBJECTIVE: To assess clinical and electrocardiographic (ECG) predictors of positive EPS in patients with syncope and BBB. METHODS: Observational single-center study that included all consecutive patients with syncope and BBB that underwent EPS from January 2011 to June 2017. Results of EPS were considered positive according to current ESC syncope guidelines. RESULTS: During study period, 271 patients were included (64.9% male, age: 73.9 ± 12.2 years, number of syncopal episodes: 2.4 ± 2.5, LVEF: 56.1 ± 9.9%). Type of BBB: RBBB + LAFB/LPFB in 39.8%, isolated LBBB in 38.7% and isolated RBBB in 18.5% of the patients. Duration of QRS and PR interval were 141.9 ± 16.7 and 182.8 ± 52.2 milliseconds. EPS was positive in 41.7% of the patients. In multivariate analysis, conduction disturbance pattern and long PR interval (OR 8.6; 2.9-25; P < 0.0001) were predictors of positive EPS. Conduction disturbance patterns related with positive EPS were: BBB different than isolated RBBB (OR 15.2; 2.2-23.4; P = 0.005), LBBB or RBBB+long PR + left fascicular block (OR 4.5; 1.06-20.01; P < 0.042), and RBBB+left fascicular block compared with LBBB (OR 4.8; 1.2-16.7; P = 0.025). Clinical factors and syncope characteristics were not related with EPS result. CONCLUSIONS: Diagnostic yield of EPS in patients with syncope and BBB is moderate (41%). Type of conduction disturbance pattern and PR interval are associated with the electrophysiological (EP) test result. Patients with LBBB or bifascicular block have the highest rate of positive EP test. Long PR interval increases the proportion of positive EPS in all conduction disturbance patterns.

Predictors of acute inefficacy and the radiofrequency energy time required for cavotricuspid isthmus-dependent atrial flutter ablation.

PURPOSE: Although cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) ablation is a highly efficacious treatment, a bidirectional CTI block cannot be achieved in some patients. In this study, we sought to determine the predictors of acute inefficacy of CTI-AFL ablation and the predictors of the radiofrequency (RF) energy time required to achieve a complete bidirectional CTI block. METHODS: All consecutive patients who underwent stand-alone CTI-AFL ablation in our institution, except patients with congenital heart disease, were included in this retrospective study. Clinical, echocardiographic, and ablation data were collected from the Arrhythmia Unit and Imaging Unit databases and medical charts. RESULTS: Three hundred and fifty-five patients, with a mean age 63 ± 12 years, were included. The ablation was acutely inefficacious in 30 patients (9%). Tricuspid regurgitation was the only independent predictor of acute inefficacy of CTI-AFL ablation (OR 3.161, 95% CI 1.084-9.220, p = 0.035) and was associated with a longer RF time required to achieve CTI bidirectional block (p = 0.031). Age was inversely correlated with the RF time required to achieve a bidirectional CTI block (r = -0.133, p = 0.025). A previous CTI RF ablation, chronic obstructive pulmonary disease (COPD), the use of an irrigated catheter, and advanced age were the independent predictors for requiring less RF energy time to achieve a bidirectional CTI block. CONCLUSIONS: Tricuspid regurgitation is associated with less acute efficacy in CTI-AFL ablation. Prior CTI ablation, COPD, use of an irrigated catheter, and advanced age are independent predictors for needing less RF energy time to achieve a complete bidirectional CTI block.