No abstract

Background: Impaired coronary flow reserve (CFR) is a significant predictor of poor prognosis in patients with idiopathic dilated cardiomyopathy (IDC). Nebivolol reduces mortality and morbidity in patients with heart failure and left ventricular dysfunction, including cases caused by IDC. Objective: To assess the effects of nebivolol on CFR in patients with IDC. Methods: CFR was measured in 21 clinically stable patients with IDC (mean (SD) ejection fraction 35.7 (6.2)) at baseline and after 1 month of treatment with nebivolol once daily. A control group of apparently healthy subjects who were matched for age and sex was used for comparison. Resting and hyperaemic coronary flows were measured using transthoracic second-harmonic Doppler echocardiography. None of the subjects had any systemic disease. Results: After 1 month of treatment, heart rate was reduced significantly (p,0.001). The blood pressure was decreased significantly (p,0.001). The left ventricular end-diastolic diameter and stroke volume were not changed significantly, but end-systolic diameter was decreased significantly (p,0.05). Resting rate-pressure product was lower after treatment with nebivolol, but dipyridamole-induced change was not influenced by the treatment. Nebivolol treatment reduced significantly coronary velocities at rest (p,0.02) and also caused a significant increase in coronary velocities after dipyridamole (p,0.02), leading to a greater CFR (2.02 (0.35) vs 2.61 (0.43), p,0.001). Nebivolol induced an absolute increase of 6% in the CFR in 17 of 21 patients (80.9%). Conclusions: In patients with IDC, 1 month of treatment with nebivolol induces a marked increase in CFR.

SummaryObjective: Although the cardiovascular system is highly sensitive to thyroid hormones, the cardiovascular effects of subtle thyroid dysfunction such as subclinical hypothyroidism (SHT) remain unclear. Therefore, we investigated coronary flow reserve (CFR) reflecting coronary microvascular function in patients with SHT.Methods: Fifty subjects with SHT and 30 control subjects with normal serum thyroid hormones and TSH levels were included in this study. Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity.Results: Age, gender, diastolic and systolic blood pressure, body mass index (BMI), serum lipid parameters, and thyroid hormone levels were similar between the groups. Heart rate was significantly lower in the SHT group. Left ventricular diastolic filling parameters were significantly different in the SHT group while other echocardiographic parameters were similar. CFR values were significantly lower in subjects with SHT than in the control group (2.38 ± 0.44 vs. 2.98 ± 0.47, p<0.0001).Conclusions: These findings suggest that CFR, which reflects coronary microvascular function, is impaired in patients with SHT.

Aortic elastic properties are significantly and LV diastolic function is slightly impaired in subjects with PHT, and impairment of aortic elasticity is as severe as that in hypertension.

Left ventricular remodeling and diastolic function were similar in patients with non-dipper and dipper hypertension. However, aortic elastic properties were slightly impaired in non-dipper hypertensives than those were in dipper ones, but these differences did not reach statistically significance.