Angiotensin converting enzyme inhibition restores cardiac and hormonal responses to volume overload in patients with dilated cardiomyopathy and mild heart failure.
BACKGROUND
Angiotensin converting enzyme (ACE) inhibition exerts a favorable effect on the response to exercise in heart failure. This study was planned to define the influence of ACE inhibition on the adaptation to volume overload.


RESULTS
We studied the hemodynamic, hormonal, and renal responses to acute volume expansion (sodium chloride, 0.9%, 0.25 ml.kg-1.min-1 for 2 hours) in patients with idiopathic or ischemic dilated cardiomyopathy and mild heart failure (New York Heart Association class I or II, ejection fraction < or = 50%). The patients were studied without any pretreatment (n = 14) or after 1 week of treatment with the oral ACE inhibitor quinapril at a dosage of 10 mg/day (n = 11). Seven patients were studied during constant intravenous infusion with nitroglycerin (0.1 micrograms.kg-1.min-1). The study groups had similar hemodynamic and clinical characteristics and hormonal profile at baseline evaluation. In the untreated patients, volume expansion did not increase left ventricular end-diastolic volume measured by echocardiography and was associated with a reduction in ejection fraction (p < 0.05) and with a paradoxical increase in forearm vascular resistance (p < 0.05) estimated by plethysmography. In addition, plasma atrial natriuretic factor did not change, and plasma norepinephrine was increased by saline loading. In contrast, in the patients treated with quinapril, volume expansion induced an increase of both left ventricular volumes (p < 0.001) without changing ejection fraction and reduced forearm vascular resistance (p < 0.05). In addition, in this group, plasma atrial natriuretic factor levels increased (p < 0.05) and plasma norepinephrine did not change during volume overload. During nitroglycerin infusion, volume expansion was associated with peripheral vasodilatation, increases of left ventricular volumes, and no change in ejection fraction. In this group, however, plasma atrial natriuretic factor levels did not change in response to volume overload.


CONCLUSIONS
We conclude that pretreatment with the ACE inhibitor quinapril significantly improves compromised responses to acute isotonic volume overload in patients with dilated cardiomyopathy and mild heart failure. The favorable influence of ACE inhibition on cardiovascular and hormonal responses to volume expansion seems to be related to the cardiac unloading produced by this treatment.
Volpe
M
M
Prima Clinica Medica, Seconda Facoltà di Medicina e Chirurgia, Università degli Studi di Napoli, Naples, Italy.
Tritto
C
C
DeLuca
N
N
Rubattu
S
S
Mele
A F
AF
Lembo
G
G
Enea
I
I
deCampora
P
P
Rendina
V
V
Romano
M
M
D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D001775:Blood Circulation / Q000187:drug effects; D001810:Blood Volume; D002303:Cardiac Output, Low / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006728:Hormones / Q000097:blood*; D006801:Humans; D007262:Infusions, Intravenous; D007546:Isoquinolines / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000627:therapeutic use; D010952:Plasma Substitutes / Q000627:therapeutic use; D000077583:Quinapril; D044005:Tetrahydroisoquinolines
D000806:Angiotensin-Converting Enzyme Inhibitors; D006728:Hormones; D007546:Isoquinolines; D010952:Plasma Substitutes; D044005:Tetrahydroisoquinolines; D005996:Nitroglycerin; D000077583:Quinapril