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

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/VCO2 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.

Randomized controlled trial of Amigo® robotically controlled versus manually controlled ablation of the cavo-tricuspid isthmus using a contact force ablation catheter.

BACKGROUND: Radiofrequency catheter ablation (RFCA) of the cavo-tricuspid isthmus (CTI) is a common treatment for atrial flutter (AFL). However, achieving bi-directional CTI conduction block may be difficult, partly due to catheter instability. OBJECTIVE: To evaluate the safety and efficacy of the Amigo® Remote Catheter System (RCS) compared to manual catheter manipulation, during CTI ablation for AFL. METHODS: Fifty patients (pts) were prospectively randomized to robotically (25 pts) versus manually (25 pts) controlled catheter manipulation during CTI ablation, using a force-contact sensing, irrigated ablation catheter. The primary outcome was recurrence of CTI conduction after a 30-min waiting period. Secondary outcomes included total ablation, procedure, and fluoroscopy times, contact force measurement, and catheter stability. RESULTS: Recurrence of CTI conduction 30 min after ablation was less with robotically (0/25) versus manually (6/25) controlled ablation (p = 0.023). Total ablation and procedure times to achieve persistent CTI block (6.7 ± 3 vs. 7.4 ± 2.5 min and 14.9 ± 7.5 vs. 15.2 ± 7 min, respectively) were not significantly different (p = 0.35 and p = 0.91, respectively). There was a non-significant trend toward a greater force time integral (FTI in gm/s) with robotically versus manually controlled CTI ablation (571 ± 278 vs. 471 ± 179, p = 0.13). Fluoroscopy time was longer with robotically versus manually controlled CTI ablation (6.8 ± 4.4 min vs. 3.8 ± 2.3 min, p = 0.0027). There were no complications in either group. CONCLUSION: Robotically controlled CTI ablation resulted in fewer acute recurrences of CTI conduction compared to manually controlled CTI ablation, and a trend toward higher FTI. The longer fluoroscopy time during robotically controlled ablation was likely due to a steep learning curve. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02467179.