Journal of the American College of Cardiology
Left ventricular shape, afterload and survival in idiopathic dilated cardiomyopathy
Author + information
- Pamela S. Douglas, MD, FACC∗,
- Robert Morrow,
- Alfred Ioli and
- Nathaniel Reichek, MD, FACC
- ↵∗Address for reprints:Pamela S. Douglas, MD, Cardiovascular Se ction, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104.
Abstract
Because idiopathic dilated cardiomyopathy is characterized by elevated wall stress and a more spherical left ventricle, the relations among shape, afterload and survival were examined. Thirty-six patients with cardiomyopathy were prospectively studied by two-dimensional echocardiography. Data included echocardiographic short- and long-axis cavity dimensions, their ratio and, with cuff systolic blood pressure, meridional and circumferential end-systolic stresses and their ratios. Survivors (n = 16) were followed up for 52 months (range 40 to 76); nonsurvivors (n = 20) died an average of 11 months after study.
Survivors had a smaller left ventricular end-diastolic short-axis dimension (6.4 versus 7.1 cm, p < 0.03) but a similar long-axis length (8.6 versus 8.3 cm). However, overall cavity shape or the ratio of short- to long-axis end-diastolic dimensions was more spherical in those with poorer survival (ratio 0.76 versus 0.68, p 0.02). Meridional and circumferential end-systolic stresses were similar in the two groups, but stress was more evenly distributed in the long- and short-axis planes in nonsurvivors (meridional/circumferential stress ratio 0.57 versus 0.52 in survivors, p < 0.05). Improved survival was associated with an end-diastolic short-axis dimension <7.6 cm, a short- to long-axis ratio <0.76 and a meridional to circumferential stress ratio <0.54. Life table analysis revealed a 28% mortality rate in patients with all three of these characteristics compared with 100% in patients with none. Survivors and nonsurvivors did not differ in systolic cavity dimension, wall thickness, relative wall thickness, cavity volume, percent posterior wall thickening or fractional shortening.
In conclusion, a poorer survival was associated with a more spherical ventricle and a more uniform distribution of afterload. In contrast, there was no association between survival and wall thickness, systolic function and endsystolic stress. Two-dimensional echocardiographic determinations of cavity dimension, shape and load distribution may provide useful prognostic information in dilated cardiomyopathy.
Footnotes
☆ We thank Evelyn Robles and Jeanette Forte for excellent secretarial support.
- Received May 9, 1988.
- Revision received June 10, 1988.
- Accepted September 15, 1988.
