The prognostic value of the duration of the ambulatory electrocardiogram after myocardial infarction

The purpose of this study was to examine the value of various durations of ambulatory ECG recording with regard to providing useful prognostic information. The authors explored a decision theoretic approach to determine the most useful period of monitoring for making a treatment decision based upon postulated benefit-to-risk ratios of antiarrhythmic therapies. They used data collected as part of the Beta-Blocker Heart Attack Trial (BHAT), a randomized clinical trial of propranolol versus placebo in 3,837 post-myocardial-infarction patients. In BHAT, 1,336 placebo-treated patients had a 24-hour ambulatory ECG that had at least 23 readable hours. Sensitivity and specificity were calculated for eight definitions of ventricular arrhythmia using either total mortality or sudden death (death within one hour of symptoms) as an endpoint. These indices were obtained using the first 1, 2, 4, 6, 12, and 24 hours plus a random hour, a random daytime hour, and a random nighttime hour of the 24-hour ECG of 1,336 placebo-treated patients. The study showed that in the case of high-risk, low-benefit therapies, no test is needed to make a treatment decision. No one should be treated. In the case of high-benefit, low-risk therapies, again, no test is required. Everyone should be treated. For therapies in the middle benefit-to-risk ratio range the most appropriate test for a treatment decision changes from the very specific to the most sensitive. Twenty-four hours of ambulatory monitoring is usually not necessary for a treatment decision, since four hours is likely to be sufficient.     

Long-term survival of patients with incomplete bundle-branch block complicating acute myocardial infarction.

Electrocardiograms and His bundle electrograms were reviewed in 28 patients with incomplete bilateral bundle-branch block complicating acute myocardial infarction. All had a His bundle electrogram at the time of pacemaker insertion; 10 had a second one. Of 23 patients with an initially abnormal HV interval (55 ms or greater), 15 died (65%), while only one died (20%) in the group of 5 with a normal HV interval. This difference is not statistically significant. Sequential His bundle electrograms were done in 6 of the 8 survivors with an initially abnormal HV interval, and 4 showed 10 to 15 ms decrease in HV interval. The disappearance of incomplete bilateral bundle-branch block occurred significantly more often in patients who survived (7 of 12) when compared with those who did not survive (2 of 16) (P less than 0.05). It is concluded that long-term survival is po-sible after incomplete bilateral bundle-branch block complicating acute myocardial infarction. The characteristics of the survivors include an initially normal HV interval, transient incomplete belateral bundle-branch block and a decreasing HV interval if it were initially abnormal.     

Nonprolapsing atrial myxoma; clinical, echocardiographic, and angiographic correlations

The auscultatory features typical of myxoma were absent in a patient with nonprolapsing left atrial myxoma. Angiocardiographic and echocardiographic findings including B-mode cross-sectional scanning are presented.     

Methemoglobin levels produced by organic nitrates in patients with coronary artery disease

To determine if ordinary doses of nitrates produce a significant increase in methemoglobin, methemoglobin levels were measured in 59 randomly selected patients with coronary artery disease and unstable angina pectoris who were receiving organic nitrate therapy. Patients were taking isosorbide dinitrate, 2% nitroglycerin ointment, or a combination of the two. Patients were subdivided according to whether they were using one (group A) or more than one (group B) organic nitrate preparations. These results were compared with 17 control patients. Mean methemoglobin levels in group B were 1.78 +/- 1.29%, and this differed significantly (P less than 0.05) from both group A mean methemoglobin, 1.13 +/- 0.92%, and controls, 0.99 +/- 0.55%. The proportion of patients with elevated methemoglobin concentration increased from the control to group A to group B. It is concluded that commonly used dosages of nitrates are capable of causing elevations of methemoglobin which are probably not of routine clinical significance. However, these elevations may be of import in certain patient populations such as those with coronary insufficiency or anemia.     

Ocular relaxation to reduce eye movements

Cognitive activities influence the rate and direction of eye movements, but the effect of various levels of eye activity on cognition has not been tested. Jacobson (1938) claimed to have reduced cognitive activity with some eye exercises by decreasing ocular motility. The current study assessed the effects of ocular relaxation eye exercises, adapted from Jacobson, on two subjects with a single-subject withdrawal design. Ocular relaxation brought about a 40% reduction in eye movements but was slightly less efficient at producing physiological and self-reported relaxation than autogenic relaxation. Utility of the procedure in cognition and imagery research and in clinical applications was discussed.