Altered elfect of the Valsalva maneuver on left ventricular volume in patients with cardiomyopathy

The failure of the blood pressure to fall during the late strain phase of the Valsalva maneuver in patients with heart failure may result from the left ventricle operating on a flat portion of its function curve or from maintenance of left ventricular volume despite decreased systemic venous return. To test these possibilities, we studied the effect of the Valsalva maneuver (40 cm H20 for 15 sec) on left ventricular volume in 12 normal subjects with a mean left ventricular ejection fraction of 0.65 ± 0.07 (± SD) and in eight patients with nonischemic cardiomyopathy, evidence of pulmonary congestion, and a mean left ventricular ejection fraction of 0.23 0.09. Left ventricular volume and right ventricular area were determined by apical two-dimensional echocardiography. In both groups the right ventricular end-diastolic area decreased during the late strain phase of the Valsalva maneuver. In normal subjects it decreased from 9.3 ± 1.5 to 5.6 ± 1.6 cm2 (p < .001) and in patients it decreased from 13 ± 2.2 to 10 ± 2.9 cm2 (p < .001). In normal subjects, left ventricular end-diastolic volume decreased from the control level during the Valsalva maneuver, and this was apparent in both the fourchamber (96 ± 21 to 68 ± 18 ml, p < .01) and two-chamber views (97 + 15 to 56 20 ml, p < .01). In the patients, left ventricular end-diastolic volume was not significantly different from control in either view (199 ± 70 to 195 + 78 and 214 ± 77 to 218 + 86 ml, respectively). In normal subjects, a decrease in stroke volume from control during the Valsalva maneuver was evident in both views (61 + 13to40 ± 11 ml,p< .01 and63 ± 9to33 ± 16ml,p< .01),butinthepatientstherewasnochange in stroke volume in either view during the Valsalva maneuver (45 ± 21 to 45 ± 23 and 49 + 12 to 49 + 17 ml). We conclude that in patients with pulmonary congestion and reduced left ventricular ejection fraction, left ventricular stroke volume does not fall during the strain phase of the Valsalva maneuver because left ventricular end-diastolic volume is maintained. Circulation 71, No. 2, 227-233, 1985. AN ALTERED RESPONSE to the strain of the Valsalva maneuver has been noted in patients with congestive heart failure`s and the maneuver has been suggested as a bedside technique to detect left ventricular dysfunction.3 Patients with congestive heart failure, in contrast to normal subjects, maintain mean arterial pressure and pulse pressure throughout the strain phase of the Valsalva maneuver, indicating a preserved left ventricular stroke volume.'I Two mechanisms have been suggested to explain this abnormal response in From the University of Texas Health Science Center at San Antonio and Audie Murphy Veterans' Administration Hospital, San Antonio. Supported in part by the Veterans Administration and NIH Training grant No. 5T32 HL 07350-05. Address for correspondence: William C. Little, M.D., The University of Texas Health Science Center, Medicine/Cardiology, 7703 Floyd Curl Dr., San Antonio, TX 78284. Received Oct. 10, 1984; accepted Nov. 8, 1984. Presented in part at the 56th Annual Scientific Sessions of the American Heart Association. Vol. 71, No. 2, February 1985 patients with congestive heart failure: (1) The depressed left ventricle may operate on the flat portion of its function curve, in which case, stroke volume would remain unchanged despite a decrease in left ventricular end-diastolic volume during the strain of the Valsalva maneuver.2' 3' 5 This effect may be augmented by a decreased effective afterload resulting from the increase in intrathoracic pressure.`8 (2) The left ventricular end-diastolic volume may be maintained in such patients during the strain and thus the stroke volume is unchanged.910 To test these possibilities we studied the effect of a standardized Valsalva maneuver on right ventricular end-diastolic cross-sectional area, left ventricular enddiastolic volume, and left ventricular stroke volume determined by two-dimensional echocardiography in normal volunteers and patients with nonischemic cardiomyopathy in whom clinical findings were consistent with congestive heart failure. 227 by gest on Jauary 5, 2018 http://ciajournals.org/ D ow nladed from