Document Detail

Rate Adaptive AV delay and Exercise Performance following Cardiac Resynchronization Therapy.
MedLine Citation:
PMID:  22772135     Owner:  NLM     Status:  Publisher    
BACKGROUND: Physiological shortening of the atrioventricular (AV) interval with increasing heart rate is well documented in normals, and an established component of dual chamber pacing for bradycardia. OBJECTIVES: To assess the effect of exercise on optimal AV delay and the impact of a patient specific rate adaptive AV delay on exercise capacity in heart failure (HF) patients following cardiac resynchronization therapy (CRT). METHODS: Phase 1: We performed iterative AV optimization at rest and exercise in 52 CRT patients in atrial sensed mode (mean age 71.6±9.2y, 25% female). Phase 2: Subsequently, 20 consecutive volunteers from this group (mean age 69.2±9.6y, 15% female), underwent cardiopulmonary exercise testing (CPET) with rate adaptive AV delay (RAAVD) individually programmed on (RAAVD-ON) or off (RAAVD-OFF). RESULTS: Phase 1: In 94%, there was a marked reduction (mean 50%) in optimal AV delay with exercise. The optimal resting versus exercise AV delay was 114.2±29ms at heart rate (HR) 64.4±7.1 bpm versus 57±31ms at HR 103±13 bpm, p<0.001. No patients required an increase in AV delay with exercise and 3 (6%) showed no change. Phase 2: With RAAVD-ON significantly better exercise times were achieved (8.7±3.2 minutes) compared with RAAVD-OFF (7.9±3.2 minutes; p = 0.003), and there was a significant improvement in VO2max (RAAVD-ON 16.1±4.0 versus RAAVD-OFF 14.9±3.7 ml/kg/min; p=0.024). CONCLUSIONS: There was a dramatic reduction in optimal AV delay with physiological exercise in the majority of this HF CRT cohort. Replicating this physiological response with a programmable rate adaptive AV delay translated into a 10% improvement in exercise capacity.
Nesan Shanmugam; Oscar Prada-Delgado; Ana Garcia Campos; Alex Grimster; Oswaldo Valencia; Aigul Baltabaeva; Sue Jones; Lisa Anderson
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-7-3
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  -     ISSN:  1556-3871     ISO Abbreviation:  -     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-7-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012. Published by Elsevier Inc.
St George's Healthcare NHS Trust, Department of Cardiology, London, United Kingdom.
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