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Acute filling pattern changes of the failing left ventricle after captopril as related to ventricular structure
P Barbier1, G Tamborini, G Alioto
1Istituto di Cardiologia dell'Università degli Studi, Centro di Studio per le Ricerche, Milano, Italia.
Insights
Captopril improves left ventricular filling patterns in heart failure by reducing heart workload. Left ventricular structural characteristics, specifically relative wall thickness, influence how effectively captopril normalizes filling patterns, distinguishing true normalization from pseudonormalization.
Area of Science:
- Cardiology
- Pharmacology
- Echocardiography
Background:
- Congestive heart failure (CHF) is often associated with altered left ventricular (LV) filling patterns.
- Captopril, an angiotensin-converting enzyme inhibitor, is known to improve cardiac function by reducing preload and afterload.
Purpose of the Study:
- To investigate if the structural characteristics of the left ventricle influence the acute effects of captopril on LV filling patterns in patients with hypertensive or idiopathic cardiomyopathy.
- To correlate changes in Doppler mitral flow and pressures with M-mode echocardiographic indices.
Main Methods:
- Evaluated pulsed Doppler mitral flow and systemic pressures in 20 patients (6 hypertensive, 14 idiopathic cardiomyopathy) before and 40 minutes after sublingual captopril (25 mg).
- Correlated hemodynamic and Doppler changes with baseline M-mode echocardiographic relative wall thickness index (h/r).
Main Results:
- Hypertensive patients had higher baseline mean arterial pressure and h/r compared to the idiopathic group.
- Captopril significantly reduced mean arterial pressure in hypertensive patients and reduced wedge pressure similarly in both groups.
- The hypertensive group showed a significant increase in early mitral flow and a decrease in late mitral flow, indicating true normalization. The idiopathic group showed minimal changes, suggesting pseudonormalization.
- A significant positive correlation was found between baseline h/r and the variation in the early/late mitral flow ratio across all patients.
Conclusions:
- Left ventricular structural characteristics, particularly relative wall thickness (h/r), play a crucial role in determining the response of LV filling patterns to captopril in CHF.
- A higher h/r is associated with true normalization of the filling pattern, while a lower h/r is linked to pseudonormalization, despite similar reductions in filling pressures.
Abstract:
In congestive heart failure captopril modifies the left ventricular filling pattern mainly by unloading the heart. We investigated whether the structural characteristics of the left ventricle may influence the acute effects of captopril on this pattern in patients with untreated hypertensive (H group, 6 patients) or idiopathic (I group, 14 patients) cardiomyopathy. We evaluated changes of pulsed Doppler mitral flow, of systemic arterial and wedge pulmonary pressures 40 min after 25 mg captopril administered sublingually, and correlated these changes with the M-mode echocardiographic relative wall thickness index (h/r). Baseline mean arterial pressure (H = 137 +/- 20 mm Hg, mean +/- SD, I = 95 +/- 19 mm Hg; p < 0.001), and h/r (H = 0.38 +/- 0.03, I = 0.28 +/- 0.09; p < 0.05) were greater in the high blood pressure group; wedge pressure, echocardiographic biplane ejection fraction, and Doppler indexes of the left ventricular filling were similar in the two populations. After captopril, ejection fraction did not change significantly, mean arterial pressure decreased significantly in hypertensive patients (H group, baseline = 137 +/- 20, captopril = 119 +/- 10, p = 0.02; I group, baseline = 95 +/- 19, captopril = 90 +/- 24, p = nonsignificant), and the wedge pressure was reduced by the same extent in both groups (H group, baseline = 27.7 +/- 3, captopril = 21 +/- 7, p < 0.05; I group, baseline = 20 +/- 12, captopril = 15 +/- 8, p < 0.05). In the H group early mitral flow increased [(E wave integral) x (mitral annulus area)] by 38 +/- 15%, and was almost steady in the I group (-1.3 +/- 30%; group H vs. I = p < 0.01); late mitral flow [(A wave integral) x (mitral annulus area)] showed a pattern exactly opposite to this (H = +0.4 +/- 40%, I = +38 +/- 19; p < 0.01). In the whole population there was a significant correlation between the early/late flow ratio variations and baseline h/r (r = 0.6, p < 0.05). In chronic congestive heart failure, changes in left ventricular filling with captopril are related to h/r: a higher index, as recorded in the H group, is associated with "true normalization' of the filling pattern after captopril; a lower index, as recorded in the I group, is associated with "pseudonormalization' despite a similar decrease of left ventricular filling pressure.