The effect of angiotensin-converting enzyme inhibitors of left atrial pressure in dogs with mitral valve regurgitation.
BACKGROUND
Despite many epidemiological reports concerning the efficacy of angiotensin-converting enzyme (ACE) inhibitors in dogs with mitral regurgitation (MR), the hemodynamic effects of ACE inhibitor administration have not been fully evaluated.


OBJECTIVE
To document left atrial pressure (LAP) in dogs with MR administered ACE inhibitors, in order to obtain interesting information about daily LAP changes with administration of ACE inhibitors.


METHODS
Five healthy Beagle dogs weighing 9.8 to 14.2 kg (2 males and 3 females; aged 2 years).


METHODS
Experimental, crossover, and interventional study. Chordae tendineae rupture was induced, and a radiotelemetry transmitter catheter was inserted into the left atrium. LAP was recorded for 72 consecutive hours during which each of 3 ACE inhibitors--nalapril (0.5 mg/kg/d), temocapril (0.1 mg/kg/d), and alacepril (3.0 mg/kg/d)--were administered in a crossover study.


RESULTS
Averaged diurnal LAP was significantly, but slightly reduced by alacepril (P = .03, 19.03 +/- 3.01-18.24 +/- 3.07 mmHg). The nightly drops in LAP caused by alacepril and enalapril were significantly higher than the daily drops (P = .03, -0.98 +/- 0.19 to -0.07 +/- 0.25 mmHg, and P = .03, -0.54 +/- 0.21-0.02 +/- 0.17 mmHg, respectively), despite the fact that the oral administrations were given in the morning. Systolic blood pressure (122.7 +/- 14.4-117.4 +/- 13.1 mmHg, P = .04) and systemic vascular resistance (5800 +/- 2685-5144 +/- 2077 dyne x s/cm5, P = .03) were decreased by ACE inhibitors.


CONCLUSIONS
ACE inhibitors decrease LAP minimally, despite reductions in left ventricular afterload. ACE inhibitors should not be used to decrease LAP.
Ishikawa
T
T
Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Tokyo, Japan.
Tanaka
R
R
Suzuki
S
S
Miyaishi
Y
Y
Akagi
H
H
Iino
Y
Y
Fukushima
R
R
Yamane
Y
Y
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D016279:Atrial Function, Left / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000031:analogs & derivatives / Q000627:therapeutic use; D002940:Circadian Rhythm; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004656:Enalapril / Q000627:therapeutic use; D005260:Female; D008297:Male; D008944:Mitral Valve Insufficiency / Q000188:drug therapy / Q000662:veterinary*; D013841:Thiazepines / Q000627:therapeutic use
D000806:Angiotensin-Converting Enzyme Inhibitors; D013841:Thiazepines; D004656:Enalapril; C055603:temocapril hydrochloride; D002216:Captopril; C046835:alacepril