Clinical Briefs
Meta-Analysis of Trials Comparing Beta-blockers, Calcium Antagonists, and Nitrates for Stable Angina
Despite many years of use of the three traditional classes of anti-anginal medications, none has emerged as distinctly superior. Because of demonstrated reductions in post-MI mortality with beta-blockers, consensus has generally suggested them as first-line therapy. Since some patients, especially those with bronchospastic lung disease, tolerate calcium channel blockade better than beta blockade, this class of agents also sometimes holds first-choice status. This study analyzed by meta-analysis all randomized trials (1966-1997) of at least one week duration, which compared at least two of the three different drug classes.
Most of the analyzed studies were beta blocker vs. calcium antagonists. Comparing outcomes of cardiac death, MI, angina episodes, use of nitroglycerin, and exercise time, neither class of drug emerged significantly superior. The only statistically significant difference between the classes was in respect to withdrawal for adverse events, for which beta blockers fared more favorably than calcium antagonists.
Studies comparing nitrates with calcium antagonists did not show any significant between-class differences; similarly, although comparisons between beta-blockers and nitrates were the least frequent, no clear advantage of either class emerged.
Since all three classes are equally efficacious, the fact that beta-blockers enjoyed more favorable withdrawal rates suggests that they remain first- choice therapy.
Heidenreich PA, et al. JAMA 1999; 281:1927-1936.
Effect of Cigar Smoking on the Risk of Cardiovascular Disease, COPD, and Cancer in Men
The general public does have the same perceptions about cigar smoking as cigarette smoking in reference to adversities such as COPD and cancer. Between 1993 and 1997, cigar sales increased almost 50%, predominantly due to use by young and middle-aged men. The current study examined the relationship between cigar smoking and cardiovascular disease among persons with no history of current or past cigarette smoking or current pipe smoking.
The population studied included 17,774 men, of whom 1546 were cigar smokers. The entire cohort was followed from 1971-1995. Cigar smokers were at increased relative risk for coronary heart disease and COPD. Cancers of the digestive tract and lung were twice as frequent among cigar smokers. There appears to be a dose-response relationship.
Consumption of large amounts of alcohol had a synergistic effect for relative risk of digestive and oropharyngeal cancer.
Other studies have implicated cigar smoking in a negative light, both in persons with and without preexisting cardiovascular disease. This study, as well as others, have failed to demonstrate a relationship between cigar smoking and cerebrovascular disease. Iribarren and associates conclude that cigar smoking causes substantial increases in COPD and cancer, despite the recent surge in the popularity of this habit.
Iribarren C, et al. N Engl J Med 1999; 340:1773-1780.
Ultrasound Therapy for Calcific Tendinitis of the Shoulder
Although not always symptomatic, calcification of the supraspinatus tendon of the shoulder is characterized by shoulder pain, often with associated rotator cuff dysfunction and limitation of motion. Surgical treatments usually alleviate pain and restore function, but patients will generally opt initially for noninvasive treatments, such as ultrasound.
Small, earlier trials of ultrasound have suggested that such treatment may cause shoulder calcifications to disappear. The purpose of this trial was to assess pulsed ultrasound in a large controlled trial for idiopathic calcific tendinitis.
Sixty-three patients were enrolled over 30 months, each demonstrating discrete radiographic evidence of calcific tendinitis, coupled with shoulder pain or restricted range of motion. Ultrasound treatment (and sham ultrasound = same device, same methodology, but generator turned off) was administered daily on weekdays for 15 minutes for three weeks, then thrice weekly for three weeks. At this level of intensity, sham ultrasound is not distinguishable from active by subjects. Radiographs were obtained at baseline, six weeks, and nine months.
Ultrasound treatment produced calcium deposit resolution in 19% of patients, and reduced calcification by half in 28% (vs 0% and 10% for placebo, respectively). At the post-treatment nine-month radiography, 65% of ultrasound recipients had resolved or reduced calcification, as compared with 20% of placebo recipients.
Ebenbichler and colleagues conclude that ultrasound is beneficial in resolving calcifications of shoulder tendinitis.
Ebenbichler GR, et al. N Engl J Med 1999;340:1533-1538.
Clinical Scenario. The ECG shown in the Figure was obtained from a previously healthy 56-year-old man with a history of gradually progressive fatigue. No chest pain. No history of prior infarction. The patient has never smoked. An echocardiogram was diagnostic and distinctly abnormal. Can you guess what the echo might show?
Interpretation. The rhythm is sinus bradycardia at a rate of 50 beats/minute. All intervals are normal. The mean QRS axis is indeterminate (QRS complexes are nearly equiphasic in all six limb leads). There is no ECG evidence of chamber enlargement. In the precordia leads transition occurs early; small q waves are seen in leads I, aVL, and V3 through V6; and there is nonspecific ST segment flattening with shallow T wave inversion in leads V2 to V4.
The overall ECG picture is nonspecific in nature. However, in view of the hints provided in the history (the patient was previously healthy, he does not smoke, and has no history of prior infarction)—the early transition with relatively prominent R waves in anterior precordial leads suggests prominent septal forces. The patient had nonobstructive hypertrophic cardiomyopathy with septal hypertrophy that was disproportionately enlarged compared to left ventricular wall thickness (asymmetric septal hypertrophy or ASH). It is likely that the small narrow q waves in leads V3 through V6 are also the reflection of prominent septal forces. Although the ECG will usually be abnormal in patients with hypertrophic cardiomyopathy, the changes seen are most often nonspecific and nondiagnostic. This would have been the case here had there not been the hints we have given.
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