Carvedilol for Post-MI Arrhythmia
Carvedilol has a “striking” antiarrhythmic effect after acute MI, suppressing both atrial and ventricular arrhythmias and benefiting even high-risk patients already taking an ACE inhibitor, reported John McMurray, M.D., of the Western Infirmary, Glasgow, Scotland, and his associates.
Their study, Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction (CAPRICORN), was a multinational trial of patients with acute MI and ventricular systolic dysfunction, followed an average of 1.3 years. Most subjects were taking ACE inhibitors; 975 were assigned to receive carvedilol and 984 to receive a placebo in the blinded trial.
Carvedilol cut the incidence of malignant arrhythmias by 70%. The combined rate of ventricular tachycardia, ventricular fibrillation, and ventricular flutter was 0.9% in the treatment group and 3.9% in the placebo group. The drug also markedly reduced the risk of atrial arrhythmias, an effect that has never been tested before in a blinded, placebo-controlled trial, the investigators said (J. Am. Coll. Cardiol. 2005;45:525-30).
These findings “reinforce the value of β-blockers as essential treatment in patients with acute infarction,” they noted. The Capricorn study was funded by GlaxoSmithKline and Roche Pharmaceuticals.
Disparities in Hypertension Care
Ethnic disparities in the diagnosis, treatment, and control of hypertension persist, with African Americans continuing to show a higher prevalence than other populations and with Mexican Americans having the lowest rates of treatment and blood pressure control, according to the Centers for Disease Control and Prevention, Atlanta.
The latest CDC analysis showed a prevalence of 40.5% among non-Hispanic blacks, 27.4% among non-Hispanic whites, and 25.1% among Mexican Americans. Overall, only 29% of hypertensive adults had controlled blood pressure. The rate of control was the same, 29.8%, in blacks and whites but substantially lower in Mexican Americans, at 17.3% (MMWR 2005;54:7-9).
“Public health officials and clinicians need to increase their efforts to treat and control BP levels … and promote physical activity, nutrition changes (e.g., reducing high salt/sodium) weight reduction or management, stress reduction, and routine BP screening,” the CDC said.
Statins Don't Cut Dementia Risk
Statins do not appear to decrease the risk of Alzheimer's disease and other dementias, as at least six observational studies have suggested, said Peter P. Zandi, Ph.D., of Johns Hopkins University, Baltimore, and his associates.
Three randomized trials have found no such protective effect. To shed light on the issue, Dr. Zandi and his associates analyzed data from a study of nearly 5,000 elderly residents of Cache County, Utah.
Initial analyses suggested that statin use lowered the risk of dementia, but that link disappeared after adjustment for age, sex, and other facators. The protective effect of statins seen in cross-sectional studies is an artifact of the study design and is not borne out by prospective analyses, they said (Arch. Gen. Psychiatry 2005;62:217-24).
Some researchers have called for randomized, controlled clinical trials to definitively determine whether statins protect against dementia. However, the results of this study suggest that “costly randomized prevention trials of statins [would be] premature,” Dr. Zandi and his associates commented.
Migraineurs at Higher CVD Risk
People who have migraine headaches, particularly those who experience auras, are at greater risk for early-onset cardiovascular disease than people without migraines, according to Ann I. Scher, Ph.D., of the National Institute on Aging, Bethesda, Md., and her associates.
The association between migraine and early ischemic stroke is well known, but the possible link with coronary heart disease before age 45 years “has not been definitively answered” until now, the investigators said (Neurology 2005;64:614-20).
They studied 620 migraineurs and 5,135 people without migraine. The average age of subjects was 42 years. Migraineurs had a higher prevalence of hypercholesterolemia, a low HDL cholesterol level, or a high ratio of total cholesterol to HDL cholesterol. They also had a higher prevalence of hypertension, existing coronary disease, and stroke. People who experienced migraine headaches with aura were at particular risk—“roughly twice or more as likely as the nonmigraine group to have a clinically relevant Framingham risk score,” the researchers said.
This study wasn't designed to determine why migraineurs are at higher CVD risk. But it did show that migraineurs were more likely to report that either their mothers or their fathers had an early MI. This “intriguing” finding “suggests the influence of genetic factors that predispose toward both migraine and CHD,” the authors noted.