Biventricular pacing was associated with better quality of life and HF status in patients with atrioventricular block and systolic dysfunction compared with right ventricular pacing, according to new data from the BLOCK HF study.
Researchers analyzed 691 patients (mean age, 73 years; 75% men) with atrioventricular block, NYHA class I to III HF and left ventricular ejection fraction of less than 50% who were randomly assigned biventricular pacing or RV pacing.
In the main findings of BLOCK HF, patients assigned biventricular pacing had a lower rate of the composite endpoint of death, HF-related urgent care and adverse LV remodeling. In the present prespecified analysis, researchers assessed NYHA class, quality of life and clinical composite score based on clinical outcomes, HF status and patient symptoms at 6, 12, 18 and 24 months.
At 12 months, the biventricular pacing group had greater improvement in NYHA class than the RV pacing group, Anne B. Curtis, MD, from the department of medicine, University at Buffalo, New York, and colleagues wrote.
Anne B. Curtis
In the biventricular pacing group, 19% had improved HF class at 12 months, 61% were unchanged and 17% had worsened HF class, whereas in the RV pacing group, 12% had improved HF class, 62% were unchanged and 23% showed worsening, the researchers wrote.
Quality-of-life scores at 6 months and 12 months were more improved in the biventricular group than in the RV group (6 months, 5 vs. 0.3; posterior probability = 0.998; 12 months, 3.9 vs. 0.9; posterior probability = 0.964), but the differences were less significant at 18 months and 24 months. After adjustment for crossovers, the difference in improvement was significant at 6, 12 and 18 months but not 24 months.
At 6 months, clinical composite score was improved in 53% of the biventricular group vs. 39% of the RV group, unchanged in 24% of the biventricular group vs. 33% of the RV group and worsened in 24% of the biventricular group vs. 28% in the RV group (posterior probability = 0.998), and the differences were sustained at 12, 18 and 24 months, according to the researchers.
“The findings with biventricular pacing may reflect prevention of future dyssynchrony and [HF] as well as treatment of currently existing dyssynchrony,” Curtis and colleagues wrote.
In a related editorial, Frieder Braunschweig, MD, PhD, and Cecelia Linde. MD, PhD, both from the department of medicine, Karolinska Institutet, and the department of cardiology, Karolinska University Hospital, Stockholm, wrote that the new findings “are important parameters to take into account in the largely elderly population concerned. However ... the results seem not to be clear enough to close the book on biventricular pacing in patients with [atrioventricular] block and LV dysfunction.” – by Erik Swain
Disclosure: BLOCK HF was funded by Medtronic. Curtis reports serving on advisory boards for Daiichi Sankyo, Janssen Pharmaceuticals, Pfizer, Sanofi and St. Jude Medical, consulting for Medtronic and Sanofi, and speaking for Medtronic and St. Jude Medical. Please see the full study for a list of the other researchers’ relevant financial disclosures. Braunschweig reports financial ties with Biotronik, Boston Scientific, Medtronic and St. Jude Medical. Linde reports financial ties with AstraZeneca, Biotronik, Cardio3, Medtronic, Novartis, St. Jude Medical and Vifor.