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Background: Left bundle branch area pacing (LBBAP) may be an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We sought to compare the acute hemodynamic and ECG effects of LBBAP, BVP, and left bundle-optimized therapy CRT (LOT-CRT) in CRT candidates with advanced conduction disease., Methods: In this multicenter study, 48 patients with either nonspecific interventricular conduction delay (n=29) or left bundle branch block (n=19) underwent acute hemodynamic testing to determine the change in left ventricular pressure maximal first derivative (LV d P /d t max ) from baseline atrial pacing to BVP, LBBAP, or LOT-CRT., Results: Atrioventricular-optimized increases in LV d P /d t max for LOT-CRT (mean, 25.8% [95% CI, 20.9%-30.7%]) and BVP (26.4% [95% CI, 20.2%-32.6%]) were greater than unipolar LBBAP (19.3% [95% CI, 15.0%-23.7%]) or bipolar LBBAP (16.4% [95% CI, 12.7%-20.0%]; P ≤0.005). QRS shortening was greater in LOT-CRT (29.5 [95% CI, 23.4-35.6] ms) than unipolar LBBAP (11.9 [95% CI, 6.1-17.7] ms), bipolar LBBAP (11.7 ms [95% CI, 6.4-17.0]), or BVP (18.5 [95% CI, 11.0-25.9] ms), all P ≤0.005. Compared with patients with left bundle branch block, patients with interventricular conduction delay experienced less QRS reduction ( P =0.026) but similar improvements in LV d P /d t max ( P =0.29). Bipolar LBBAP caused anodal capture in 54% of patients and resulted in less LV d P /d t max improvement than unipolar LBBAP (18.6% versus 23.7%; P <0.001). Subclassification of LBBAP capture (European Heart Rhythm Association criteria) indicated LBBAP or LV septal pacing in 27 patients (56%) and deep septal pacing in 21 patients (44%). The hemodynamic benefit of adding left ventricular coronary vein pacing to LBBAP depended on baseline QRS duration ( P =0.031) and success of LBBAP ( P <0.004): LOT-CRT provided 14.5% (5.0%-24.1%) greater LV d P /d t max improvement and 20.8 (12.8-28.8) ms greater QRS shortening than LBBAP in subjects with QRS ≥171 ms and deep septal pacing capture type., Conclusions: In a CRT cohort with advanced conduction disease, LOT-CRT and BVP provided greater acute hemodynamic benefit than LBBAP. Subjects with wider QRS or deep septal pacing are more likely to benefit from the addition of a left ventricular coronary vein lead to implement LOT-CRT., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04905290., Competing Interests: Dr Jastrzębski: speaker/consultant honoraria from Abbott, Biotronik, Boston Scientific, and Medtronic. Dr Foley: consultant to Medtronic, proctor for Medtronic. Dr Chandrasekaran: honoraria, consultancy fees and funding support from Medtronic, Biotronik, and Abbot. Dr Whinnett: speaker honoraria, consulting fees, and institutional fellowship/research support from Abbot, Boston Scientific, and Medtronic. Dr Vijayaraman: Medtronic: honoraria, consultant, research and fellowship support Abbott: honoraria, consultant Boston Scientific/Biotronik: honoraria; patent: HBP delivery tool. Dr Upadhyay: consulting and speaker honoraria from Abbott, Biotronik, Boston Scientific, GE Healthcare, Medtronic, Philips, Rhythm Science, and Zoll Medical. R.D. Schaller: speaking honoraria for Medtronic. Dr Richardson: consulting and speaking honoraria from Medtronic, Inc. Dr Herweg: fellowship support from Medtronic, speaker for Medtronic and Abbott. Dr Stadler, D. Kudlik, R. Waxman, Dr Zimmerman, J. Burrell, and Dr Cornelussen are Medtronic employees. The other authors report no conflicts

Background: Delivery of cardiac resynchronization therapy (CRT) requires left ventricular myocardial capture to achieve clinical benefits., Objective: We sought to determine whether ineffective pacing affects survival., Methods: Ineffective ventricular pacing (VP) was defined as the difference between the percentage of delivered CRT (%VP) and the percentage of effective CRT in CRT devices. Using the Optum de-identified electronic health record data set and Medtronic CareLink data warehouse, we identified patients implanted with applicable devices with at least 30 days of follow-up. Kaplan-Meier and Cox proportional hazards models assessed the impact of %VP and % ineffective VP on survival., Results: Among 7987 patients with 2.1 ± 1.0 years of follow-up, increasing ineffective VP was associated with decreasing survival: the highest observed survival was in the quartile with <0.08% ineffective VP and the lowest survival was in the quartile with >1.47% ineffective VP (85.1% vs 75.7% at 3 years; P < .001). As expected, patients with more than the median %VP of 97.7% had better survival than did patients with <97.7% VP (84.2% vs 77.8%; P < .001). However, patients who had >97.7% VP but >2% ineffective VP had similar survival to patients with <97.7% VP but ≤2% ineffective VP (81.6% vs 79.4%; P = .54). A multivariable Cox proportional hazards model demonstrated that <97.7% VP (adjusted hazard ratio 1.29; 95% confidence interval 1.14-1.46; P < .001) and >2% ineffective VP (hazard ratio 1.35; 95% confidence interval 1.18-1.54; P < .001) were both significantly associated with decreased survival., Conclusion: Ineffective VP is associated with decreased survival. In addition to maximizing the percentage of delivered CRT pacing, every effort should be made to minimize ineffective VP., Competing Interests: Disclosures Dr Mittal serves as a consultant to Boston Scientific and Medtronic. Drs Koehler, Stadler, Ghosh, and Klepfer are employees and shareholders of Medtronic. Dr Piccini is supported by R01AG074185 from the National Institutes of Aging. He also receives grants for clinical research from Abbott, the American Heart Association, Boston Scientific, iRhythm, and Philips and serves as a consultant to ABVF, Abbott, AbbVie, Boston Scientific, ElectroPhysiology Frontiers, Kardium, LivaNova, Medtronic, Milestone Pharmaceuticals, Sanofi, Philips, and UpToDate. The rest of the authors report no conflicts of interest., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The aim was to test the hypothesis that left ventricular (LV) and right ventricular (RV) activation from body surface electrical mapping (CardioInsight 252-electrode vest, Medtronic) identifies optimal cardiac resynchronization therapy (CRT) pacing strategies and outcomes in 30 patients. The LV80, RV80, and BIV80 were defined as the times to 80% LV, RV, or biventricular electrical activation. Smaller differences in the LV80 and RV80 (|LV80-RV80|) with synchronized LV pacing predicted better LV function post-CRT (p = 0.0004) than the LV-paced QRS duration (p = 0.32). Likewise, a lower RV80 was associated with a better pre-CRT RV ejection fraction by CMR (r =  - 0.40, p = 0.04) and predicted post-CRT improvements in myocardial oxygen uptake (p = 0.01) better than the biventricular-paced QRS (p = 0.38), while a lower LV80 with BIV pacing predicted lower post-CRT B-type natriuretic peptide (BNP) (p = 0.02). RV pacing improved LV function with smaller |LV80-RV80| (p = 0.009). In conclusion, 3-D electrical mapping predicted favorable post-CRT outcomes and informed effective pacing strategies., (© 2023. The Author(s).)

Background: Prolongation of the PR interval has long been considered a benign condition, particularly in the setting of nonstructural heart disease., Objective: The purpose of this study was to investigate the effect of PR interval on various well-adjudicated cardiovascular outcomes using a large real-world population data of patients with implanted dual-chamber permanent pacemakers or implantable cardioverter-defibrillators., Methods: PR intervals were measured during remote transmissions in patients with implanted permanent pacemakers or implantable cardioverter-defibrillators. Study endpoints (time to the first occurrence of AF, heart failure hospitalization [HFH], or death) were obtained between January 2007 and June 2019 from the deidentified Optum de-identified Electronic Health Record dataset., Results: A total of 25,752 patients (age 69.3 ± 13.9 years; 58% male) were evaluated. The average intrinsic PR interval was 185 ± 55 ms. In the subset of 16,730 patients with available long-term device diagnostic data, a total of 2555 (15.3%) individuals developed AF during 2.59 ± 2.18 years of follow-up. The incidence of AF was significantly higher (up to 30%) in patients with a longer PR interval (ie, PR interval ≥270 ms; P < .05). Time-to-event survival analysis and multivariable analysis showed that PR interval ≥190 ms was significantly associated with higher incidence of AF, HFH, or HFH or death when compared with shorter PR intervals ( P < .05 for all 3 parameters)., Conclusion: In a large real-world population of patients with implanted devices, PR interval prolongation was significantly associated with increased incidence of AF, HFH, or death., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Background: A screening tool to predict response to cardiac resynchronization therapy (CRT) could improve patient selection and outcomes., Objective: The purpose of this study was to investigate the feasibility and safety of noninvasive CRT via transcutaneous ultrasonic left ventricular (LV) pacing applied as a screening test before CRT implants., Methods: P-wave-triggered ultrasound stimuli were delivered during bolus dosing of an echocardiographic contrast agent to simulate CRT noninvasively. Ultrasound pacing was delivered at a variety of LV locations with a range of atrioventricular delays to achieve fusion with intrinsic ventricular activation. Three-dimensional cardiac activation maps were acquired via the Medtronic CardioInsight 252-electrode mapping vest during baseline, ultrasound pacing, and after CRT implantation. A separate control group received only the CRT implants., Results: Ultrasound pacing was achieved in 10 patients with a mean of 81.2 ± 50.8 ultrasound paced beats per patient and up to 20 consecutive beats of ultrasound pacing. QRS width at baseline (168.2 ± 17.8 ms) decreased significantly to 117.3 ± 21.5 ms ( P  <.001) in the best ultrasound paced beat and to 125.8 ± 13.3 ms ( P <.001) in the best CRT beat. Electrical activation patterns were similar between CRT pacing and ultrasound pacing with stimulation from the same area of the LV. Troponin results were similar between the ultrasound pacing and the control groups ( P = .96), confirming safety., Conclusion: Noninvasive ultrasound pacing before CRT is safe and feasible, and it estimates the degree of electrical resynchronization achievable with CRT. Further study of this promising technique to guide CRT patient selection is warranted., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Advanced stage heart failure patients can benefit from the unloading effects of an implantable left ventricular assist device. Despite best clinical practice, LVADs are associated with adverse events, such as pump thrombosis (PT). An adaptive algorithm alerting when an individual's appropriate levels in pump power uptake are exceeded, such as in the case of PT, can improve therapy of patients implanted with a centrifugal LVAD. We retrospectively studied 75 patients implanted with a centrifugal LVAD in a single center. A previously optimized adaptive pump power-tracking algorithm was compared to clinical best practice and clinically available constant threshold algorithms. Algorithm performances were analyzed in a PT group ( n = 16 patients with 30 PT events) and a thoroughly selected control group ( n = 59 patients, 34.7 patient years of LVAD data). Comparison of the adaptive power-tracking algorithm with the best performing constant threshold algorithm resulted in sensitivity of 83.3% vs. 86.7% and specificity of 98.9% vs. 95.3%, respectively. The power-tracking algorithm produced one false positive detection every 11.6 patient years and early warnings with a median of 3.6 days prior to PT diagnosis. In conclusion, a retrospective single-center validation study with real-world patient data demonstrated advantageous application of a power-tracking algorithm into LVAD systems and clinical practice.