Phasic left ventricular blood velocity alternans in man.
With the use of the Doppler ultrasonic flowmeter catheter, phasic instantaneous left ventricular blood flow velocity was measured by radiotelemetry in 28 subjects during pacemaker-evoked pulsus alternans. Blood velocity alternation was more manifest at faster pacing rates. Four patients demonstrated diastolic blood velocity alternans at the mitral valve. Discordant right heart pressure and left ventricular blood velocity alternation was recorded in three subjects. In one such patient, rate-related shifts of concordant and discordant left ventricular blood velocity alternans occurred. Intermediate or variant forms of alternation, comprising weak and strong beats in a ratio of 2:1, were noted in two subjects. This study provides the first comprehensive description of left ventricular blood velocity alternans in man. The observed phenomena may be related to an altered inotropic state or to beat to beat variations in end-diastolic fiber length.
D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D009202:Cardiomyopathies / Q000503:physiopathology; D003327:Coronary Disease / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D010701:Phonocardiography; D011674:Pulse