title: Doppler echocardiographic assessment of the pressure gradient during bicycle ergometry in hypertrophic cardiomyopathy.
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.
authors.affiliation: Department of Cardiology and Angiology, Hospital of the Westfälische Wilhelms University, Münster, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schwammenthal
authors.forename: B
authors.initials: B
authors.lastname: Schwartzkopff
authors.forename: M
authors.initials: M
authors.lastname: Block
authors.forename: J
authors.initials: J
authors.lastname: Johns
authors.forename: B
authors.initials: B
authors.lastname: Lösse
authors.forename: R
authors.initials: R
authors.lastname: Engberding
authors.forename: M
authors.initials: M
authors.lastname: Borggrefe
authors.forename: G
authors.initials: G
authors.lastname: Breithardt
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D006328:Cardiac Catheterization; D002302:Cardiac Output / Q000502:physiology; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology; D005082:Physical Exertion / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology; D013599:Systole; D014655:Vascular Resistance / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology