Study Design and Study Population
Consecutive patients in whom HBP was attempted, for any indication in accordance with the international guidelines, were recruited between August 2018 and December 2020 from three hospitals in Singapore—National University Heart Centre Singapore (NUHCS), Ng Teng Fong General Hospital (NTFGH), and Changi General Hospital (CGH).[8,9] Singapore is a multi-racial country in Southeast Asia with a population in excess of 5.7 million people. Healthcare is largely provided by a co-paying but heavily subsidized public healthcare system. Six public hospitals implant more than 90% of cardiac implantable electronic devices (CIED) of which NUHCS, CGH, and NTFGH were the earliest adopters of HBP. According to a 2017 national audit, 40% of pacemakers in Singapore were implanted at these three participating institutions. His bundle pacing was performed by five experienced electrophysiologists, each of whom has performed more than 300 CIED implants.
His bundle pacing was performed using a Medtronic SelectSecure 3830 lead (Medtronic, Minneapolis, MN, USA) via a fixed curve C315 sheath.[10,11] The 3830 lead was used to map for the His bundle potential which was displayed on an electrophysiology recording system whenever available and/or Medtronic analyser. Pace-mapping was performed if there was no detectable His electrogram. His bundle pacing was considered successful if the paced beats fulfilled the criteria for selective (S-HBP) or non-selective His bundle pacing (NS-HBP) as recommended by an international HBP collaborative group. Acute procedural success was arbitrarily defined as either selective or non-selective His bundle capture with a threshold of ≤3.5 V at the end of the implantation procedure. His bundle pacing capture threshold exceeding 3.5 V at 1 ms pulse width was considered as loss of HBP capture.
Data Collection and Follow-up
Baseline patient and electrocardiogram characteristics were collected from electronic medical records system and pacing databases. Chronic kidney disease was defined as a glomerular filtration rate of <60 mL/min/1.73 m2. His bundle pacing parameters including any loss of HBP capture were obtained at implantation and at the last clinically indicated follow-up. Procedural details and complications were also recorded. Ethics approval for this study was obtained from the respective institutional domain-specific review boards (NHG 2020/00211 and Singhealth 2019/2415).
Continuous variables are reported as mean ± standard deviation and categorical variables as percentages. Student's t-test and Fisher's exact t-test were used for continuous and categorical variables, respectively, to compare the differences between the subgroups of patients with successful vs. unsuccessful HBP and differences in HBP parameters between implant and last follow-up. A P-value of <0.05 was considered statistically significant. Univariable and multivariable logistic regression analyses were used to determine the significant predictors of successful HBP. To assess the impact of experience (measured as a number of cases performed by a single operator) on pacing parameters, regression models were constructed with a cubic spline. Statistical analysis was done using IBM SPSS Statistics Version 23 (IBM Corporation, Armonk, NY, USA) and GraphPad Prism Version 9.1.1 (GraphPad Software, San Diego, CA, USA).
Europace. 2022;24(4):606-613. © 2022 Oxford University Press
Copyright 2007 European Heart Rhythm Association of the European Society of Cardiology (ESC). Published by Oxford University Press. All rights reserved.