RESUMEN
Background: Atrioventricular node ablation (AVNA) with right ventricular or biventricular pacing (conventional pacing; CP) is an effective therapy for patients with refractory atrial fibrillation (AF). Conduction system pacing (CSP) using His bundle pacing or left bundle branch area pacing preserves ventricular synchrony. Objective: The aim of our study is to compare the clinical outcomes between CP and CSP in patients undergoing AVNA. Methods: Patients undergoing AVNA at Geisinger Health System between January 2015 and October 2020 were included in this retrospective observational study. CP or CSP was performed at the operators' discretion. Procedural, pacing parameters, and echocardiographic data were assessed. Primary outcome was the combined endpoint of time to death or heart failure hospitalization (HFH) and was analyzed using Cox proportional hazards. Secondary outcomes were individual outcomes of time to death and HFH. Results: AVNA was performed in 223 patients (CSP, 110; CP, 113). Age was 75 ± 10 years, male 52%, hypertension 67%, diabetes 25%, coronary disease 40%, and left ventricular ejection fraction (LVEF) 43% ± 15%. QRS duration increased from 103 ± 30 ms to 124 ± 20 ms (P < .01) in CSP and 119 ± 32 ms to 162 ± 24 ms in CP (P < .001). During a mean follow-up of 27 ± 19 months, LVEF significantly increased from 46.5% ± 14.2% to 51.9% ± 11.2% (P = .02) in CSP and 36.4% ± 16.1% to 39.5% ± 16% (P = .04) in CP. The primary combined endpoint of time to death or HFH was significantly reduced in CSP compared to CP (48% vs 62%; hazard ratio 0.61, 95% confidence interval 0.42-0.89, P < .01). There was no reduction in the individual secondary outcomes of time to death and HFH in the CSP group compared to CP. Conclusion: CSP is a safe and effective option for pacing in patients with AF undergoing AVNA in high-volume centers.
RESUMEN
A newly described bacterial isolate, Acinetobacter sp. HM746599, has been obtained from leatherback sea turtle hatchling blood. The implication is that the hatchling was infected during development in the egg, which is substantiated by other studies to be reported by us in the future. The 16S rRNA gene sequence of the bacterium (GenBank accession number: HM746599) showed the greatest similarity to the identified species, Acinetobacter beijerinckii (97.6-99.78%) and Acinetobacter venetianus (99.78%). Acinetobacter sp. HM746599 are gram-negative, rod-shaped coccobacilli and are hemolytic/cytotoxic to human and sea turtle red blood cells (RBCs). Hemolysis is not the result of any detectable soluble toxin. Acinetobacter beijerinckii and A. venetianus hemolyze sheep RBCs while Acinetobacter sp. HM746599 does not, and unlike A. venetianus, the growth of Acinetobacter sp. HM746599 and A. beijerinckii is not supported by l-arginine. Many Acinetobacter species, especially hemolytic ones, are pathogenic to immunologically compromised humans and it is possible that, in addition to sea turtles, this bacterium might also be a danger to susceptible humans who handle infected hatchlings. The bacteria are available from CCUG (Culture Collection, University Gothenburg, Göteborg, Sweden) and from NRRL (Agricultural Research Service Culture Collection, Peoria, IL).