The influence of hypertrophy on myocardial function.
In patients with hypertrophy from long-standing left ventricle pressure (PL) and volume overload (VL) as well as in a group of controls basal left ventricular contractility was assessed by peak measured isovolumic velocity of shortening (Vpm), mean velocity of circumferential fiber shortening (mean VCF) and mean normalized systolic ejection rate (MNSER). The angiographically determined left ventricular muscle mass was elevated to a similar extent in PL and VL. As compared to the control group both hypertrophy had decreased contractile indexes. No significant differences of contractility existed between the groups with PL and VL. Hence it appears that in chronic mechanical overloading the extent of hypertrophy is probably more important for the decrease of contractility than the nature of the stimulis to hypertrophy. In 15 patients with aortic stenosis left ventricular muscle mass and isovolumic and ejection phase contractile indexes were determined preoperatively and 13.5 months after successful valve replacement by a tilting disc prosthesis. Postoperatively there was a significant (P less than 0.001) decrease of muscle mass from 182 to 114 g/m2. Mean VCF increased from 1.07 to 1.52 circ/sec (P less than 0.01); MNSER from 1.92 to 2.59 enddiastolic volumes/sec (P less than 0.01); Vpm from 1.17 to 1.60 ML/sec (P less than 0.001) and total pressure Vmax from 1.61 to 2.09 ML/sec (P less than 0.01). In 9 of 13 patients an abnormal or pathologic response to handgrip at the preoperative study became normal postoperatively. It is concluded that in aortic stenosis removal of the chronic pressure burden leads to regression of left ventricular hypertrophy associated with an improvement of resting and exercise contractile function. Pressure-deprived contractile indexes; ejection phase contractile indexes; chronic pressure load; chronic volume load; aortic valve replacement; postoperative hemodynamics.
D002312:Cardiomyopathy, Hypertrophic / Q000601:surgery*; D005260:Female; D006350:Heart Valve Prosthesis; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008946:Mitral Valve Stenosis / Q000601:surgery*; D009200:Myocardial Contraction; D011183:Postoperative Complications / Q000175:diagnosis