Left ventricular work and power: circumferential, radial and longitudinal components. Mathematical derivation and characteristic variation with left ventricular dysfunction.
Cardiac work and power, defined as the wall stress-velocity product per unit volume, have been derived with respect to a circumferential, radial and longitudinal component for the human left ventricle during a complete cardiac cycle. Thirty-nine patients, comprising five clinical groups, were evaluated using pressure and volume data acquired from single-plane cineangiography. The results indicate that work and power are divided into approximately 60% circumferential, 23% radial and 17% longitudinal components for normals. Characteristic variations from normal are presented for selected pathological case studies. With a compensated volume overload patient, diastolic work and power are uniformly reduced in all three directions and systolic radial power approximately equals longitudinal power. With a decompensated volume overload patient, systolic radial power is greater than longitudinal power. With a compensated pressure overload patient, systolic radial work and power are greatly elevated as compared to the normals and represent about 30% of the total work and power, while longitudinal work and power represent only about 8% of the total. With a congestive cardiomyopathy patient, systolic work and power are greatly reduced in all three directions as compared to normals.
D000328:Adult; D001696:Biomechanical Phenomena; D009202:Cardiomyopathies / Q000503:physiopathology; D002932:Cineangiography; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009200:Myocardial Contraction; D013318:Stroke Volume; D016276:Ventricular Function