Author + information
- Received March 19, 1985
- Revision received March 11, 1986
- Accepted March 21, 1986
- Published online August 1, 1986.
- George G.S. Sandor, MB, ChB, MRCP(Ed), FRCP(C)1,*,
- Martin L. Puterman, PhD1,
- Michael W.H. Patterson, MB, BS, MRCP, FRCP(C)1,
- Marion A. Tipple, MB, ChB, MRCP(UK), FRCP(C)1 and
- Dennis J. Vince, MD, FRCP(C)1
- ↵*Address for reprints: George G. S. Sandor, MB, Department of Pediatrics, University of British Columbia, 4480 Oak Street, Vancouver, British Columbia, Canada.
This study assessed the effect of pressure load, volume load and surgery on left ventricular chamber stiffness (b) and myocardial stiffness (k). A normal range for chamber stiffness and myocardial stiffness was also established. A total of 44 patients were studied: 8 were control subjects, 12 had volume load and 24 had pressure load. At cardiac catheterization simultaneous high fidelity pressures (P) and left ventricular volumes (V) were obtained in one diastolic cycle. From the relation P = aVb, operant chamber stiffness (b) was estimated for each patient. Similarly, the relation between stress (σ) and radius (B) was approximated by σ = cBfand the myocardial stiffness (k) derived for each patient. Mean values for chamber or myocardial stiffness for the diagnostic groups were not significantly different but differed within the operative groups. Mean values for b and k were greater in the post-open heart surgery group than in the post-closed heart surgery or nonsurgical group.
Although the mean values for chamber stiffness and myocardial stiffness for the diagnostic groups were not different, there were more abnormal patients in the pressure load group (9 of 24) than in the volume load group (2 of 8) when the normal range was obtained from the control group. Thus, left ventricular operant chamber and myocardial stiffness are often preserved with volume loading, less frequently with pressure loading and rarely after open heart surgery.
- Received March 19, 1985.
- Revision received March 11, 1986.
- Accepted March 21, 1986.
- American College of Cardiology Foundation