RESPONSE OF PLASMA ATRIAL-NATRIURETIC-FACTOR TO EXPERIMENTALLY INDUCED AORTIC AND MITRAL REGURGITATION IN DOGS

Study objective - The correlations between the plasma concentration of atrial natriuretic factor and right atrial or left atrial pressure were studied in experimentally induced aortic regurgitation and mitral regurgitation in dogs. Design - Aortic regurgitation was created by opening the tip of a basket wire catheter placed at the aortic annulus via the left ventricular wall, and terminated by pulling back the catheter. To create mitral regurgitation a basket catheter was inserted into the mitral annular position via a pulmonary vein. Regurgitation was induced by opening the tip of the catheter, and terminated promptly by closing it. Experimental material - Seven beagle dogs were prepared for the aortic regurgitation model and six for the mitral regurgitation model (weights 11.5 to 14.5 kg). Measurements and main results - The plasma concentration of atrial natriuretic factor was highly correlated with right atrial pressure (r = 0.78, SD = 0.07, n = 7) and left atrial pressure (r = 0.82, SD = 0.05, n = 7) in aortic regurgitation; and with right atrial pressure (r = 0.82, SD = 0.05, n = 6) and left atrial pressure (r = 0.84, SD = 0.05, n = 6) in mitral regurgitation. Further evaluation of the molecular forms of plasma atrial natriuretic factor revealed the alpha form in all 13 dogs and the gamma form in two (one with aortic and the other with mitral regurgitation); no evidence of the beta form was seen. Conclusions - Atrial natriuretic factor secretion responds rapidly to the circulatory changes caused by valvular incompetence.