Hypertension and CHD risk: whither alpha-1 blockers?

With the inclusion of alpha-blockers in the list of drugs recommended as firstline agents for managing hypertension, there has been a resurgence of interest in this group of drugs. The selective alpha-1 blockers reduce peripheral vascular resistance by blocking the alpha-1 receptors and preventing norepinephrine from reaching them. Their antihypertensive efficacy has been shown to be comparable to all other major classes of antihypertensive agents. They are also as well tolerated as the other currently used drugs, both facts being confirmed by the TOMHS. What differentiates them from the rest of the drugs is their beneficial effects on various other coronary heart disease (CHD) risk factors. While lowering blood pressure (a CHD risk factor by itself), the selective alpha-1 blockers also reduce serum total cholesterol and increase serum HDL cholesterol (yet another major CHD risk factor). These drugs have been shown to increase insulin sensitivity and lower blood glucose levels. In addition, they also cause regression of left ventricular hypertrophy. Given these added beneficial effects, the lipid- and glucose-friendly selective alpha-1 blockers are increasingly being used.

Silent myocardial ischaemia and cardiac autonomic neuropathy in diabetics.

Treadmill exercise electrocardiography was performed in 47 patients of diabetes to detect latent coronary artery disease. Eighteen patients (36.3%) were found positive on treadmill test. All forty seven subjects were evaluated for cardiac autonomic neuropathy. The incidence of cardiac autonomic neuropathy in treadmill positive group was 72.2% as compared to 31.0% in treadmill negative group, (p < 0.01). Nine patients from the positive group and 4 patients from the negative group were subjected for coronary angiography, which revealed significant CAD in 8 and 1 subjects in both groups respectively. It is concluded that the incidence of silent myocardial ischaemia in diabetics is very high and cardiac autonomic neuropathy seems to be the most probable reason for absence of pain.