Clinical considerations for the allied professional: Programming issues in cardiac resynchronization therapy

Abstract

grammed? Answer: The basic premise in CRT programming is to maintain a wide range of atrial-synchronous biventricular pacing: low base rate in patients without sinus node dysfunction, high upper tracking rate per age-based predicted heart rate, and optimal AV interval in VDD or DDD mode. 2. Can AV delay be optimized empirically? Answer: Sensed AV (S-AV) delay averaging 100 ms may be optimal in the majority of patients but should be confirmed with subjective clinical response. Paced AV (P-AV) delay is programmed 30 ms longer than S-AV delay. If intrinsic intraatrial delay or latency (stimulus-to-P) is noted, P-AV delay is increased so that the P wave is not truncated and atrial depolarization is completed at the onset of ventricular activation. 1 Various formulas are used in approximating optimal AV delay based on intrinsic ECG intervals, e.g., optimal S-AV PR (ms) 0.50 (if QRS 150 ms) or PR (ms) 0.70 (if QRS 150 ms). 2,3 3. What are objective measures of AV optimization? Answer: The measures used in clinical trials include Doppler echocardiography for the Ritter method using mitral velocity, aortic velocity-time integral (VTI), and stroke