Impaired responsiveness of the ventricular sensory receptor in hypertensive patients with left ventricular hypertrophy.
We studied the control of forearm vascular resistance (FVR) by cardiopulmonary receptors in seven patients with hypertension and left ventricular hypertrophy (LVH) and in seven normotensive control subjects. Increasing levels of lower body negative pressure (LBNP) (-10 and -40 mm Hg) induced a progressive decrease in central venous pressure (CVP) and an increase in FVR. The changes in these two variables were correlated both in normal subjects and patients with hypertension (slope for normal subjects = -29.9, for patients with hypertension = -40.3, NS). After propranolol, there was a significant reduction in the increase in FVR induced by -40 mm Hg LBNP in normal subjects (+107 +/- 5 vs +129 +/- 15 mm Hg/ml/sec, p less than .05) but not in patients with hypertension. Consequently, the slope of the delta CVP/delta FVR regression was reduced in normal subjects (-20.6, p less than .01) but not in patients with hypertension. In another seven normal subjects and seven patients with hypertension and LVH we assessed the effects of -10 and -40 mm Hg LBNP on left ventricular filling pressure (LVFP). LBNP induced similar changes in CVP, LVFP, and total peripheral resistance both in normal subjects and in patients with hypertension. Propranolol failed to modify the effects of LBNP on CVP and LVFP in both groups and reduced the response of total peripheral resistance to -40 mm Hg LBNP only in normal subjects. Propranolol did not reduce the response of FVR to the cold pressor test and sustained handgrip or the arterial baroreflex response to the injection of phenylephrine and increased neck tissue pressure. Thus, hypertension-induced LVH seems to be associated with a selective impairment of the left ventricular sensory receptors.
D000328:Adult; D001794:Blood Pressure; D002302:Cardiac Output; D006332:Cardiomegaly / Q000503:physiopathology*; D002496:Central Venous Pressure; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D010656:Phenylephrine; D011311:Pressoreceptors / Q000503:physiopathology; D011433:Propranolol; D011669:Pulmonary Wedge Pressure; D012018:Reflex / Q000502:physiology; D011984:Sensory Receptor Cells / Q000503:physiopathology*; D014655:Vascular Resistance
D010656:Phenylephrine; D011433:Propranolol