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[Early detection of myocardial alterations in mitral insufficiency with the angiotensin test]
Insights
The angiotensin test effectively identifies early left ventricular dysfunction in patients with isolated mitral insufficiency by revealing impaired function under increased arterial resistance. This method aids in distinguishing patients with compromised cardiac performance.
Area of Science:
- Cardiology
- Physiology
- Pharmacology
Context:
- Isolated mitral insufficiency presents challenges in assessing early left ventricular (LV) dysfunction.
- Hemodynamic assessment at rest may not reveal subtle functional impairments.
- Systemic arterial resistance modulation offers a potential method for functional evaluation.
Purpose:
- To evaluate the utility of an angiotensin infusion test in assessing left ventricular function in patients with isolated mitral insufficiency.
- To differentiate between patients with preserved and impaired LV function under stress.
- To identify early signs of LV dysfunction that may not be apparent at rest.
Summary:
- Forty patients with isolated mitral insufficiency underwent assessment of left ventricular function at rest and during angiotensin infusion to increase systemic arterial resistance.
- Angiotensin infusion led to a significant decrease in systolic index (Fick's method) and ejection fraction, alongside an increase in regurgitant fraction, indicating impaired LV function.
- The angiotensin test identified two groups: one with induced LV dysfunction and another maintaining function, suggesting its utility in detecting early LV dysfunction even with normal resting hemodynamics.
Impact:
- The angiotensin test can serve as a valuable tool for the early detection of left ventricular dysfunction in isolated mitral insufficiency.
- This diagnostic approach may help stratify patients and guide timely therapeutic interventions.
- Understanding LV response to afterload stress provides insights into the pathophysiology of mitral regurgitation.
Abstract:
Left ventricular function was assessed at rest and after increasing systemic arterial resistance by angiotensin in 40 patients with isolated mitral insufficiency. Angiotensin was administered intravenously at a dose of 0,4 micrograms/mn until the systolic blood pressure rose by at least 30 mm Hg. Left ventricular and aortic pressures, cardiac index and left ventriculography in the 30 degree right anterior oblique projection (50 frames per second) were recorded before and during angiotensin infusion. The mean rise in systolic left ventricular pressure was 40 +/- 2,8 mm Hg; the heart rate increased slightly but significantly; left ventricular and diastolic pressure rose from 12,0 +/- 1,0 to 24,0 +/- 1,2 mmHg. The systolic index (Fick's method) was significantly decreased (37 +/- 1,6 ml/m2 to 26 +/- 1,6 ml/m2) though the angiographic systolic index remained unchanged. This is explained by an increase in the regurgitant fraction (51 +/- 2,5% ao 65 +/- 3%). The end diastolic volume index was unchanged; the ejection fraction was significantly decreased. The resting hemodynamic status was only slightly disturbed in 29 patients (mean capillary pressure less than 15 mm Hg, 8,8 +/- 0,52 mmHg). The left ventricular function curves with angiotensin distinguished two groups of patients: Group A (20 patients) with left ventricular dysfunction induced by angiotensin, Group B (9 patients) who maintained the systolic index despite the increase in left ventricular end diastolic pressure. These results suggest that the angiotensin test may be useful for detecting early left ventricular dysfunction in patients with isolated mitral insufficiency and virtually normal resting hemodynamic parameters.