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Low‐intensity interval exercise training normalizes coronary blood flow‐O 2 demand coupling and improves cardiac efficiency in miniature swine with LV hypertrophy
Author(s) -
Emter Craig A
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1138.17
Subject(s) - cardiology , medicine , blood flow , heart rate , blood pressure , muscle hypertrophy , venous blood , coronary sinus , intensity (physics) , physics , quantum mechanics
We have previously reported low‐intensity interval exercise training prevents coronary vascular dysfunction in miniature swine with LV hypertrophy. The purpose of this study was to determine how changes in coronary vascular function impact metabolic and left ventricular (LV) function in aortic‐banded (AB) sedentary (AB‐S, n=5), AB exercise trained (AB‐TR, n=5) and control sedentary (CON, n=4) male Yucatan miniature swine. Pressure‐volume loops, myocardial oxygen consumption (MVO 2 ), and coronary blood flow (CBF) were measured simultaneously in vivo under varying afterloads by increasing MAP to 80, 90, 100, and 120 mmHg under anesthesia. Baseline MVO 2 (p=0.09) and heart rate across all pressure loads (p<0.05) were significantly elevated in AB‐S animals. For a given rate‐pressure product, CBF was decreased in AB‐S animals compared to AB‐TR and CON groups (p=0.057). Consequently, O 2 extraction was increased and venous O 2 pressure and saturation reduced for any given MVO 2 in AB‐S animals. O 2 extraction and venous O 2 content were the same in both AB‐TR and CON animals. Lactate metabolism was unaltered in all groups. LV stroke work (SW) was elevated in both AB‐S and AB‐TR groups, but cardiac efficiency (SW:MVO 2 ) was increased only in AB‐TR animals (p<0.05). In conclusion, low‐intensity interval exercise normalizes coronary blood flow‐O 2 demand coupling and improves LV efficiency in AB mini‐swine. NIH HL101332