Background Atrioventricular (AV) delay in cardiac resynchronisation therapy (CRT) recipients are typically optimised at rest. However, there are limited data on the impact of exercise-induced changes in heart rate on the optimal AV delay and left ventricular function.
Methods and results The authors serially programmed AV delays in 41 CRT patients with intrinsic sinus rhythm at rest and during two stages of supine bicycle exercise with heart rates at 20 bpm (stage I) and 40 bpm (stage II) above baseline. The optimal AV delay during exercise was determined by the iterative method to maximise cardiac output using Doppler echocardiography. Results were compared to physiological change in PR intervals in 56 normal controls during treadmill exercise. The optimal AV delay was progressively shortened (p<0.05) with escalating exercise level (baseline: 123±26 ms vs stage I: 102±24 ms vs stage II: 70±22 ms, p<0.05). AV delay optimisation led to a significantly higher cardiac output than without optimisation did during stage I (6.2±1.2 l/min vs 5.2±1.2 l/min, p<0.001) and stage II (6.8±1.6 l/min vs 5.9±1.3 l/min, p<0.001) exercise. A linear inverse relationship existed between optimal AV delays and heart rates in CRT patients (AV delay=241−1.61×heart rate, R2=0.639, p<0.001) and healthy controls (R2=0.646, p<0.001), but the slope of regression was significantly steeper in CRT patients (p<0.001).
Conclusions Haemodynamically optimal AV delay shortened progressively with increasing heart rate during exercise, which suggests the need for programming of rate-adaptive AV delay in CRT recipients.
Statistics from Altmetric.com
- optimal AV delay
- heart failure
- heart failure with normal ejection fraction
- atrial fibrillation
- imaging and atrial fibrillation
- imaging and cardiac resynchronisation therapy
- cardiovascular disease
- valvular heart disease
- tissue Doppler
- echocardiography (transoesophageal)
- cardiac resynchronisation therapy
Funding This project is sponsored by Medtronic International Ltd.
Competing interests None.
Patient consent Obtained.
Ethics approval Ethics approval was provided by the Cleveland Clinic Foundation and Emory University School of Medicine.
Provenance and peer review Not commissioned; externally peer reviewed.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.