Effect of closed loop stimulation versus accelerometer on outcomes with cardiac resynchronization therapy: the CLASS trial

• Published in: Journal of interventional cardiac electrophysiology 2021-09, Vol.61 (3), p.479-485
• Main Authors: Hsu, Jonathan C., Darden, Douglas, Alegre, Maylene, Birgersdotter-Green, Ulrika, Feld, Gregory K., Hoffmayer, Kurt S., Han, Frederick, Krummen, David, Raissi, Farshad, Ho, Gordon, Taub, Pam R., Urey, Marcus A., Adler, Eric
• Format: Article
• Language: English
• Subjects: Accelerometers; Accelerometry; Aged; Cardiac Resynchronization Therapy; Cardiology; Closed loops; Congestive heart failure; Ejection fraction; Female; Heart failure; Heart Failure - therapy; Heart rate; Humans; Intolerance; Male; Medicine; Medicine & Public Health; Patients; Physical training; Quality of Life; Stimulation; Stroke Volume; Vanadium oxides
• ISSN: 1383-875X; 1572-8595
• DOI: 10.1007/s10840-020-00829-4

Purpose Chronotropic incompetence (CI) in patients with heart failure is common and associated with impaired exercise intolerance and adverse outcomes . This study sought to determine the effects of closed loop stimulation (CLS) rate-adaptive pacing on functional capacity in patients with heart failure with reduced ejection fraction (HFrEF) and CI implanted with cardiac resynchronization therapy (CRT) devices. Methods A randomized, blinded, cross-over designed trial enrolled patients with HFrEF and CI implanted with a Biotronik CRT-D to complete a quality of life questionnaire, 6-min walk distance (6MWD), and cardiopulmonary exercise testing after two programmed periods: 1-week period of CLS and 1-week period of standard accelerometer (DDDR). Results Nine patients (6 males, mean age 71.4 years, 7 with New York Heart Association Class III, mean ejection fraction 39 ± 8%) were enrolled. Quality of life trended higher in CLS as compared to DDDR (550.8 ± 123.9 vs 489.3 ± 164.9, p  = 0.06). There were no differences between CLS and DDDR in 6MWD (293.1 ± 90.2 m vs 315.1 ± 95.5 m, p  = 0.52), peak heart rate (HR) 110.7 ± 14.7 bpm vs 109.7 bpm ± 14.1, p  = 0.67), or peak VO2 (12.3 ± 4.9 ml/kg/min vs 12.9 ± 5.9, p  = 0.47). As tests were submaximal as indicated by low respiratory exchange ratios (0.98 ± 0.11 vs 1.0 ± 0.8, p  = 0.35), VE/VCO 2 slope also showed no difference between CLS and DDDR (35.8 ± 5.6 vs 35.4 ± 5.7, p  = 0.65). Five patients (56%) preferred CLS programming ( p  = 1.0). Conclusions In patients with HFrEF and CI implanted with a CRT-D, peak HR, peak VO2, and 6MWD were equivalent, while there was a trend toward improved quality of life in CLS as compared to DDDR. Clinical trial registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT02693262.