Asynergy of right ventricular wall motion in man.
Canine studies have shown a correlation between instantaneous segmental lengths in the right ventricular free wall and chamber volume, pressure, and stroke work. To determine whether such correlations exist in intact man, we studied the temporal relationships between chord dynamics in various regions of the right ventricle in 21 heart transplant recipients with apparently normal right ventricular function. Patients were examined by biplane radiography while performing various maneuvers (e.g., Valsalva maneuver). Computer-aided analysis of biplane radiograms of five surgically inserted radiopaque tantalum right ventricular myocardial markers was used to calculate interpoint chord lengths at 33 msec sampling intervals. Two patterns of right ventricular chord asynergy were defined: (1) An akinetic chord had an amplitude of less than 2.0 mm during the course of at least one beat; (2) an out-of-phase chord was more than a quarter period out of phase from the average curve (derived from all concurrently measured marker pairs during each maneuver) for at least one beat. Considering all chords (n = 978), 60 chords (6.1%) were akinetic and nine chords (0.9%) were out of phase. Excluding the outflow tract markers (n = 581), 33 chords (5.7%) were akinetic and five chords (0.9%) showed out-of-phase movement. During some maneuver, at least one akinetic chord occurred in 57% of patients and out-of-phase chords in 33% of patients. Most right ventricular regions were implicated in asynergic motion, including the right ventricular free wall, acute margin, and outflow tract. The frequency and distribution of asynergy in right ventricular chord dynamics observed in this study suggests that changes in a single right ventricular dimension may not accurately reflect global right ventricular events.
Chin
K W
KW
Department of Cardiovascular Physiology and Biophysics, Research Institute of the Palo Alto Medical Foundation, CA 94301.
Daughters
G T
GT
Alderman
E L
EL
Miller
D C
DC
D004562:Electrocardiography; D006439:Hemodynamics; D006801:Humans; D012016:Reference Values; D012119:Respiration; D014636:Valsalva Maneuver; D016276:Ventricular Function