Introduction Several single‐center short‐term studies have demonstrated the feasibility, safety, and positive clinical outcomes of permanent His bundle pacing (HBP). We performed a retrospective study to evaluate long‐term technical and safety performances of HBP in a large population of pacemaker patients from two different centers. Methods and Results The analysis includes 844 patients (345 female, mean age = 75 ± 9 years) who underwent successful permanent HBP for pacemaker indications from 2004 to 2016. The main endpoints were long term electrical performances including pacing threshold, sensing, impedance, and freedom from pacing related complications. The pacing indication was AV Block in 348 (41.2%) patients, sinus node disease in 147 (17.4%), any bradycardia indication in patients with atrial fibrillation in 335 (39.7%) patients and need for cardiac resynchronization therapy in 14 (1.7%) patients. Mean pacing capture thresholds and sensed R waves were 1.6 V and 5.8 mV, respectively at implant and 2.0 V and 6.1 mV at chronic follow‐up. During the median follow up of 3 years (interquartile range = 1‐6 years), HBP was free of any complication in 91.6% of patients. In the first 368 patients, HBP was achieved using a deflectable curve delivery system, while in 476 using the fixed curve sheath. A significant difference was found in the thresholds (2.4 ± 1.0 V and 1.7 ± 1.1 V, P < .001, respectively) and complications (11.9% and 4.2%, P < .001, respectively) between the two groups. Conclusions Permanent HBP was safe and effective during long‐term follow‐up. The fixed curved delivery sheath offered significantly better electrical parameters and reliability over time. The results of this multicenter study are consistent with recent studies.

Background-One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site. Methods and Results-Thirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dt max at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dt max coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dt max in all patients at each site (AR1 ρ=0.98; P<0.001). A Q-LV value >95 ms corresponded to a >10% in LV dP/dt max . An inverse correlation between paced QRS duration and improvement in LV dP/dt max was seen in 24 patients (75%). Conclusions-Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dt max . A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dt max of ≥10%. (Circ Arrhythm Electrophysiol. 2014;7:377-383.)Key Words: cardiac resynchronization therapy ◼ cardiomyopathies ◼ heart failure ◼ hemodynamics Received July 11, 2013; accepted March 14, 2014. interval-the interval from the onset of the intrinsic QRS on the surface ECG to the first large peak of the LV electrogram) and hemodynamics was derived from single measurements in each patient and, therefore, cannot be extrapolated to the use of Q-LV interval within an individual patient. The aims of our study were to investigate acute hemodynamic improvement during LV pacing from all available sites within a patient, as well as to test the hypothesis that the region with the longest electric delay provides the best hemodynamic response. MethodsWe analyzed the relationship between LV dP/dt max increase and LV electric delay in a CRT population. The study was approved by the local ethics board, and all patients provided written informed consent.In accordance with our standard implantation procedure, the right ventricular and atrial leads were positioned in conventional sites in all patients. Specifically, the right ventricular leads were implanted in the midseptum. The coronary sinus was cannulated via a telescopic approach, as previously described 18 ; coronary sinus angiography was performed, and all suitable collateral veins were subcannulated and visualized selectively. For the purpose of the present article, we def...

This feasibility study shows that DHBP can be accomplished with a new system consisting of a steerable catheter and an active fixation lead in 92% of the patients in whom it was attempted.

Compared with BiV pacing at any LV site, MPP yielded a small but consistent increase in hemodynamic response. A correlation between the increase in hemodynamics and Q-LV on MPP was observed for all measurements, including those taken at the best and worst sites. The MPP-induced improvement in contractility was associated with significantly greater narrowing of the QRS complex than conventional BiV pacing.

HA pacing compared with RVA or RVS pacing seems to be associated with a lower risk of persistent/permanent AF occurrence. The risk of persistent/permanent AF was similar in the RVA vs. RVS groups.