Congestive heart failure: differential adaptation of the diaphragm and latissimus dorsi

Diaphragm and latissimus dorsi muscle functions, histochemistries, and morphometries were studied in anesthetized male Yucatan minipigs with congestive heart failure (CHF) induced by supraventricular tachycardia (n = 5). Sham-operated animals served as a control group (n = 5). In CHF animals, transdiaphragmatic pressure measured during supramaximal phrenic stimulation was reduced by 40% at low frequencies ( or = 30 Hz. The cross-sectional area of latissimus dorsi type IIb fibers was decreased, but twitch characteristics, fiber type co...