178 Left ventricular volume and viability but not transmural extent of scar determine LV remodeling and exercise capacity responses to revascularization and medical therapy in patients with LV dysfunction

Abstract

Myocardial revascularization (RVS) is known to improveLV remodeling and exercise capacity in selected pts. Wesought the relative impact of baseline LV volume, viablemyocardium (VM) and transmural extent of scar (TME) onthese phenomena.Methods: We recruited 84 pts with LV dysfunction aftermyocardial infarction. At baseline, VM was identified ascontractile reserve with dobutamine echo and TME wasmeasured by the proportion of the LV wall showing lateuptake on gadolinium MRI, also expressed as as TMEscore (sum of segmental scores ranging from 0 [0%] to 4[100%]). Baseline measurements of MRI volume and VO2were compared with 12 month follow-up.Results: In 33 pts (63±10 years, 27 with VM) undergoingRVS, baseline EDV was 180±39 and decreased by5±18%; reverse remodeling was predicted by VM segtsand baseline EDV (Table). In RVS, baseline VO2 was13±4 ml/kg/min, and increased by 2±27%; change infunctional capacity was associated with extensive (>25%)viable segts. Medical therapy was continued in 51 pts(63±10 years, 43 with VM), in whom baseline EDV was191±70 ml. Remodeling was predicted by VM segts andbaseline EDV (Table). In the medical group, baseline VO2was 15±5 ml/kg/min, and deteriorated by 12±21%. TMEwas not predictive of remodeling.Conclusions: Although RVS and medical therapy haveopposite effectsonvolumechange, increasingEDVis associatedwith less viability and greater baseline EDV but notdependent on scar extent. Changes in exercise capacityare dependent on revascularization of extensive VM.