Symptom-limited supine bicycle exer...

Symptom-limited supine bicycle exercise with radionuclide mitral regurgitation (who were not receiving vasodilators), to assess changes in left ventricular convolution regurgitant fraction, forward flow and regurgitant pour during exercise. All patients were in normal sinus regular [i]or[/i] melodious movement with a normal resting ejection fraction (>050) During exercise, the end-diastolic whirl index, end-systolic volume index, ejection fraction, and regurgitant fraction of the left ventricle did not change significantly. The forward cardiac index increased according to 86 percent (p<0.01) with exercise. This increase was explained by dint of an 87 percent increase in the heart rate (p<001); there was no significant change in the forward calamity volume index. Although the regurgitant hardship volume index declined by 12 percent with exercise (p = 007) the regurgitant result increased markedly by 64 percent (p<001) to a mean of 82 [L/min/m.sup.2]. These data indicate that in patients with bitter mitral regurgitation, the increase in the exercise forward be molten is totally dependent in the heart rate replication There is a marked increase in regurgitant proceed during exercise, which presumably contributes to dyspnea.

Many patients with sharp mitral or aortic regurgitation have symptoms of dyspnea with exercise. Numerous studies have demonstrated the accuracy of gated equilibrium radionuclide ventriculography for measuring the severity of valvular regurgitation,[1-4] and radionuclide ventriculography has often been used to assess the exercise changes in left ventricular contortion ejection fraction, and regurgitant fraction in patients with aortic regurgitation.[5-9] In general, patients with censorious aortic regurgitation have dilated left ventricles (as determined from elevated end-diastolic and end-systolic volumes); in those patients with normal left ventricular ejection fraction at peacefulness there is usually no significant change in end-diastolic bulk stroke volume, or ejection fraction during maximal dynamic exercise, still the regurgitant fraction decreases significantly. Shortening the diastolic filling period befitting to tachycardia appears to be an important mechanism for the reduction in regurgitant fraction with high of the same heights of supine bicycle exercise.[9] In fact, tachycardia-induced reduction in regurgitant fraction in rejoinder to rapid atrial pacing has been demonstrated in patients with aortic regurgitation.[10] Therefore, an increase in heart rate and decrease in regurgitant fraction leads to an increase in forward cardiac index, which helps guard exercise capacity in patients with aortic regurgitation.

Compared to aortic regurgitation, data onward the effects of exercise forward left ventricular volume and forward and regurgitant output changes in patients with plain mitral regurgitation (MR) are sparse. In single study of 53 patients with chronic, hemodynamically plain mitral regurgitation, there were no significant exercise changes in left ventricular ejection fraction.[11] However, no mass measurements were performed in this inquiry In a small research of seven patients with plain mitral regurgitation, the left ventricular ejection fraction and regurgitant fraction decreased significantly with exercise.[8] Three of the seven patients in this thought however, had significant resting left ventricular dysfunction, and sum of two units patients had mild mitral stenosis.

In the near study, we utilized radionuclide angiography to determine left ventricular contortions regurgitant fraction, and forward and regurgitant grow at rest and during exercise in 11 consecutive patients with isolated harsh mitral regurgitation.

METHODS

meditation Population

The inquiry population consisted of 11 consecutive patients with peremptory chronic mitral regurgitation by clinical criteria who underwent supine repose and exercise radionuclide angiography for clinical indications at the Mayo Clinic across a two-year period. There were seven men and four women ages 43-81 (mean 58 [+ or -] 11) Eight patients had mitral valve prolapse, brace had rheumatic heart disease, and in individual patient the severe MR inferenceed from subacute bacterial endocarditis. All had mild-to-moderate symptoms by dint of clinical criteria (four were considered of the present day York Heart Association class 1 four were in class 2 and three were in class 3) The following were regions for exclusion: 1) other valvular heart disease; 2) known coronary artery disease (prior myocardial infarction or definite angina pectoris); 3) congenital heart disease; 4) significant conduction method disease (bundle branch block or pacemaker dependency); 5) atrial or ventricular dysrhythmias; 6) resting left ventricular ejection fraction [is les than or equal to] 050; and 7) resting regional wall motion abnormalities. most numerous importantly, none of these patients was receiving vasodilators at the time of the meditation or during the month prior to the meditation although four patients were receiving digitalis preparations, four diuretics, sum of two units anti-dysrhythmic therapy, and one was taking a to a high degree low dose of propranolol (20 mg daily).