The Epidemic of Inadequate Bi-Ventricular Pacing in Patients with Persistent or Permanent Atrial Fibrillation and Its Association with Mortality
Background—We classified patients' atrial fibrillation (AF), assessed its impact on bi-ventricular pacing (BIVP%), and determined if AF classification or BIVP% independently correlate with mortality in Cardiac Resynchronization Therapy Defibrillator (CRT-D) patients.
Methods and Results—CRT-D patients were classified as Permanent (daily mean AF burden ≥23 hours), Persistent (≥7 consecutive days of AF ≥23 hours/day), Paroxysmal (≥1day with AF ≥6 hours), or No/Little AF (all others) using device-detected AF during the 6 months post-implant. We evaluated subsequent all-cause mortality using a multivariable Cox proportional hazards regression. Among 54,019 patients (age 70±11, 73% male, follow-up 2.3±1.2 years), 8% of patients each had Permanent (N=4,449), Persistent (N=4,237), and Paroxysmal AF (N=4,219). A high proportion of patients with Permanent (69%) and Persistent (62%) AF did not achieve high BIVP (>98%). Relative to No/Little AF, patients with AF had increased mortality after adjusting for age, gender, BIVP, and shocks (Permanent: hazard ratio(HR)=1.28 [1.19-1.38], p < 0.001; Persistent: HR=1.51 [1.41-1.61], p < 0.001). Relative to patients with BIVP>98%, patients with reduced BIVP had increased mortality after adjusting for age, gender, AF, and shocks (90-98%: HR=1.20 [1.15-1.26], p<0.001; <90%: HR=1.32 [1.23-1.41], p<0.001). High BIVP% was associated with the greatest mortality improvement in Permanent AF among the AF classifications.
Conclusions—High BIVP% wasn't achieved in two-thirds of 8,686 Persistent or Permanent AF patients and these patients had an increased risk of death. A shift toward more aggressive rate control and/or more pacing may be necessary in patients with AF to maximize the benefits of CRT.
- Received October 26, 2013.
- Revision received April 7, 2014.
- Accepted April 15, 2014.