Subclinical Cardiac Dysfunction in Sarcoidosis (13)
We further investigated the possible mechanism of the chronotropic abnormalities found in the patients with sarcoidosis by performing RNA to determine if the abnormal HRs were a result of impaired ventricular contractility. Systolic dysfunction, as demonstrated by low LVEF (<50 percent), was seen in 10 of 28 subjects with sarcoidosis and in only one of the normal subjects. With poor systolic function resulting from decreased ventricular contractility, stroke volume is reduced and the HR must increase excessively during exercise to maintain cardiac output. However, Figure 1 shows that high SHRs were found in patients with low and high LVEF and exercise performance, although impaired in both groups, was not different between patients with low or high resting ejection fractions. Hence, abnormal ejection fractions at rest did not seem to solely account for the poor exercise performance, and other explanations must be considered. buy yasmin online
Patients with tachycardiac response during exercise were more impaired in their exercise performance than patients with normal cardiac responses, regardless of ejection fraction at rest. Based on this observation, the following could be speculated. One group of patients, with the highest SHR and LVEF below 50 percent, have impaired contractility and the HR response is compensatory in order to maintain the cardiac output.