Paradoxical interatrial conduction recovery after cavotricuspid isthmus ablation: A case report.

We present a case of a patient with advanced interatrial block who was admitted for cavotricuspid isthmus ablation as treatment of typical atrial flutter. A baseline advanced interatrial block pattern turned into partial interatrial block pattern and prolonged PR interval after the procedure. We discuss the mechanism underlying that change.

Ivabradine for controlling heart rate in permanent atrial fibrillation: A translational clinical trial.

BACKGROUND: Pharmacological options for rate control in atrial fibrillation are scarce. Ivabradine was postulated to reduce the ventricular rate in this setting. OBJECTIVES: The objectives of this study were to evaluate the mechanism of inhibition of atrioventricular conduction produced by ivabradine and to determine its efficacy and safety in atrial fibrillation. METHODS: The effects of ivabradine on atrioventricular node and ventricular cells were studied by in vitro whole-cell patch-clamp experiments and mathematical simulation of human action potentials. In parallel, a multicenter, randomized, open-label, phase III clinical trial compared ivabradine with digoxin for uncontrolled permanent atrial fibrillation despite ß-blocker or calcium channel blocker treatment. RESULTS: Ivabradine 1 µM inhibited "funny" current and rapidly activating delayed rectifier potassium channel current by 28.9% and 22.8%, respectively (P < .05). The sodium channel current and L-type calcium channel current were reduced only at 10 µM. Ivabradine slowed the firing frequency of a modeled human atrioventricular node action potential by 10.6% and induced a minimal prolongation of ventricular action potential. Thirty-five (51.5%) patients were randomized to ivabradine and 33 (49.5%) to digoxin. The mean daytime heart rate decreased by 11.6 beats/min (-11.5%) in the ivabradine arm (P = .02) vs 19.6 (-20.6%) in the digoxin arm (P < .001), although the noninferiority margin of efficacy was not met (Z = -1.95; P = .97). The primary safety end point occurred in 3 patients (8.6%) on ivabradine and in 8 (24.2%) on digoxin (P = .10). CONCLUSION: Ivabradine produced a moderate rate reduction in patients with permanent atrial fibrillation. The inhibition of funny current in the atrioventricular node seems to be the main mechanism responsible for this reduction. Compared with digoxin, ivabradine was less effective, was better tolerated, and had a similar rate of serious adverse events.

Right ventricle assessment in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation.

INTRODUCTION: Limited data are available regarding the evaluation of right ventricular (RV) performance in patients with aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). OBJECTIVE: To evaluate the prevalence of RV dysfunction in patients with severe AS undergoing TAVI and long-term changes. METHODS: Consecutive patients with severe AS undergoing TAVI from January 2016 to July 2017 were included. RV anatomical and functional parameters were analyzed: RV diameters, fractional area change, tricuspid annular plane systolic excursion (TAPSE), S-wave tissue Doppler of the tricuspid annulus (RV-S'TDI), global longitudinal strain (RV-GLS), and free wall strain (RV-FWS). Preprocedure and 1-year echo were analyzed. RESULTS: Final population included 114 patients, mean age 83.63 ± 6.31 years, and 38.2% women. The prevalence of abnormal RV function was high, variable depending on the parameter that we analyzed, and it showed a significant reduction 1 year after TAVI implantation: 13.9% vs 6.8% (TAPSE < 17mm), P = .04; 26.3% vs 20% (fractional area change < 35%), P = .048; 41.2% vs 29.2% (RV-S'TDI < 9.5cm/s), P = .04; 48.7% vs 39.5% (RV-GLS > [20]), P = .049; and 48.7% vs 28.9% (RV-FWS > [20]), P = .03. Significant differences were noted between patients with low-flow (LF) vs normal-flow (NF) AS in RV dysfunction prevalence as well as in RV function recovery which is less evident in LF compared with NF patients. CONCLUSIONS: RV dysfunction is high among symptomatic AS patients undergoing TAVI, with variable prevalence depending on the echocardiographic parameter used.