Related Experiment Videos
Doppler echocardiographic assessment of the pressure gradient during bicycle ergometry in hypertrophic cardiomyopathy
E Schwammenthal1, B Schwartzkopff, M Block
1Department of Cardiology and Angiology, Hospital of the Westfälische Wilhelms University, Münster, Germany.
Insights
Exercise significantly increases subvalvular pressure gradients in obstructive hypertrophic cardiomyopathy patients. This finding highlights the value of exercise Doppler echocardiography for assessing obstruction severity.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Obstructive hypertrophic cardiomyopathy (HCM) is characterized by a dynamic subvalvular pressure gradient.
- Assessing the hemodynamic significance of this obstruction during physiological stress is crucial for patient management.
Purpose of the Study:
- To evaluate the behavior of the subvalvular pressure gradient in patients with obstructive HCM during physical exercise.
- To determine the utility of exercise Doppler echocardiography in assessing obstruction severity.
Main Methods:
- 13 patients with obstructive HCM underwent upright bicycle ergometry with Doppler echocardiography.
- Right-sided cardiac catheterization was performed within 7 days for comparison.
- Systolic pressure gradient, mitral-septal contact duration, stroke volume, and systolic flow were measured.
Main Results:
- The Doppler-derived systolic pressure gradient significantly increased from 75 +/- 24 to 140 +/- 42 mm Hg during exercise (p < 0.0005).
- Mitral-septal contact duration also significantly increased (p < 0.0005), correlating well with the pressure gradient (r = 0.86).
- Outflow tract resistance increased significantly during exercise (p < 0.01).
Conclusions:
- Upright bicycle ergometry with Doppler echocardiography demonstrates a substantial increase in maximal pressure gradients in most obstructive HCM patients.
- Exercise Doppler echocardiography is valuable for assessing the hemodynamic significance of obstruction in a physiological setting.
- This method has potential for monitoring therapeutic intervention effects in HCM.
Abstract:
To assess the behavior of the subvalvular pressure gradient under physical exercise, 13 patients with obstructive hypertrophic cardiomyopathy were examined during upright bicycle ergometry by means of Doppler echocardiography. Additionally, right-sided cardiac catheterization was performed within 7 days. In 10 patients adequate Doppler tracings could be obtained during exercise. The Doppler-derived systolic pressure gradient increased from 75 +/- 24 to 140 +/- 42 mm Hg (p less than 0.0005). This was associated with an increase in the duration of the systolic mitral-septal contact from 59 +/- 21 to 136 +/- 28 ms (p less than 0.0005). Correlation between the pressure gradient and the duration of mitral-septal contact at rest and during exercise was good (r = 0.86), whereas correlation between the resting and exercise pressure gradient (r = 0.34) did not reach statistical significance. The increase in stroke volume during exercise, from 90 +/- 18 to 95 +/- 24 ml, was significant (p less than 0.05) but minimal. Therefore, only a moderate increase in systolic flow, from 205 +/- 54 to 268 +/- 78 ml/s (p less than 0.0005), was observed. Outflow tract resistance, defined as the ratio of the pressure gradient to systolic flow, increased from 0.38 +/- 0.11 to 0.57 +/- 0.24 mm Hg.s/ml (p less than 0.01). Thus, in a selected group of patients with hypertrophic cardiomyopathy a substantial increase in the maximal pressure gradient during upright bicycle ergometry was demonstrated in most patients. Exercise Doppler echocardiography may be valuable to assess the hemodynamic significance of obstruction in individual patients in a physiologic setting and has a potential to monitor the effect of therapeutic interventions.