Effects of acute angiotensin-converting enzyme inhibition on diastolic ventricular interaction in the dilated heart.
BACKGROUND
The normal and dilated heart behaves as a single functional unit during preload reduction: volume unloading in the setting of diastolic ventricular interaction allows for increased left ventricular (LV) filling.


OBJECTIVE
We hypothesized that reduction of venous return induced by a physiologic stimulus (tilting) or by acute angiotensin-converting enzyme (ACE) inhibitors in dilated heart is likely to have a marked and similar effect on ventricular chamber geometry and filling. This study was designed to assess how the normal and dilated heart adapts to preload reduction.


METHODS
Twenty normal subjects and 20 patients with moderate heart failure due to dilated cardiomyopathy were studied with two-dimensional and Doppler echocardiography in supine position (B) and after 40 degrees of head-up tilting (T). The following day, patients repeated supine (C) and tilting test (TC) after administration of captopril (25 mg s.l.). Right ventricular (RV) and LV dimensions, LV geometry, and tricuspid, mitral, and pulmonary venous flow patterns were recorded at each step of the study.


RESULTS
In the two groups, T was associated with reduction of RV area and LV volumes; C and TC produced a similar effect on RV and LV. Changes in LV septal-lateral diameter and anterior-posterior diameter were different at each step of the study: during T (both groups) and after C and TC, the septallateral diameter increased slightly while the anterior-posterior diameter decreased. During T, mitral and tricuspid peak flow velocities decreased, peak late velocities were unchanged, and the deceleration time of mitral flow increased; the systolic forward flow of pulmonary venous flow decreased, the diastolic forward flow did not change, and the difference in duration between reverse pulmonary flow and mitral peak late flow decreased: C and CT induced similar changes.


CONCLUSIONS
Preload reduction induced by tilting or by ACE inhibitors induces profound and similar effects on LV and RV dimensions, LV geometry, and biventricular filling. Reduction of RV dimension is associated with adaptation of LV geometry and decrease of LV diastolic pressure, which facilitates LV filling and pulmonary venous drainage: ACE inhibition associated with tilting exerts an additional effect on these changes. These data confirm the role of ventricular interaction in modulating LV filling in heart failure.
Pepi
Mauro
M
Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia dell'Università degli Studi, Milan, Italy. mpepi@cardiologicomonzino.it
Tamborini
Gloria
G
Maltagliati
Anna
A
Guazzi
Marco
M
Berna
Giovanni
G
Susini
Francesca
F
Muratori
Manuela
M
Celeste
Fabrizio
F
D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002216:Captopril / Q000627:therapeutic use; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000503:physiopathology; D003971:Diastole / Q000187:drug effects / Q000502:physiology; D015150:Echocardiography, Doppler; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D007558:Italy; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D015588:Observer Variation; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D013223:Statistics as Topic; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology; D013599:Systole / Q000187:drug effects / Q000502:physiology; D018667:Tilt-Table Test; D013997:Time Factors; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy / Q000503:physiopathology
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril