"Reciprocal" depression of the ST segment in acute myocardial infarction

In acute myocardial infarction depression of the ST segment in leads distant from those showing ST elevation has been considered to be "reciprocal" but might reflect local ischaemia. To examine this possibility 103 consecutive patients who underwent exercise testing early after myocardial infarction were reviewed. Treadmill exercise testing was performed a mean of 12 (range 5-30) days after infarction using a limited Naughton protocol. Thirty five (34%) of the patients had had reciprocal change, defined as greater than or equal to 1 mm ST depression in leads remote from the site of the infarct, within 48 hours of infarction. Twenty two (63%) of the 35 patients developed exercise induced ST depression in the leads previously showing reciprocal change. Coronary artery disease was assessed in 10 of these patients by arteriography and in four at necropsy: all but one had stenosis of greater than or equal to 50% in a coronary artery supplying the reciprocal territory in addition to the disease in the vessel to the infarct site. Of patients with reciprocal ST depression, 23.5% experienced nonfatal reinfarction, pulmonary oedema after discharge, or death compared with only 9.5% of patients without reciprocal ST depression. Eight (23.5%) patients with reciprocal depression had ventricular fibrillation while in hospital compared with only two (3%) patients without. Reciprocal ST depression in acute myocardial infarction may reflect ischaemia in territory distant from the site of infarction and is associated with a high risk of fatal arrhythmias and late morbidity.

"Stress" hyperglycaemia during acute myocardial infarction: an indicator of pre-existing diabetes?

Hyperglycaemia occurring at admission in patients with suspected acute myocardial infarction is generally held to represent stress hyperglycaemia. 26 patients, not previously known to be diabetic, had blood glucose values greater than or equal to 10 mmol/l on admission to a coronary care unit. 16 survived for 2 months at which time a 75 g oral glucose tolerance test (OGTT) showed diabetes in 10 (63%) and impaired glucose tolerance in 1 (WHO criteria). All those with abnormal glucose tolerance at 2 months had had raised glycosylated haemoglobin (HbA1) (greater than 7.5%) on admission, indicating pre-existing diabetes. All those with a HbA1 level over 8% had abnormal glucose tolerance. 7 of the 10 who died or did not have an OGTT also had raised HbA1 at admission. An admission blood glucose greater than or equal to 10 mmol/l in patients with severe chest pain is more likely to indicate previously undiagnosed diabetes than "stress" hyperglycaemia. There is no evidence that myocardial infarction precipitates diabetes. The glycosylated haemoglobin concentration can be used to distinguish between stress hyperglycaemia and hyperglycaemia caused by diabetes.

A controlled trial of sotalol for 1 year after myocardial infarction

We carried out a double-blind, randomized study, based at The Academic Department of Cardiology in Newcastle upon Tyne, to compare the effect of sotalol 320 mg once daily with that of placebo in patients from 20 hospitals who survived an acute myocardial infarction. Treatment was started 5-14 days after infarction in 1456 patients; 60% were randomized to sotalol and 40% to placebo. This represented 45% of those evaluated for entry. All patients were followed for 12 months and the analysis was done on an "intention-to-treat" principle. Sixty-four patients (7.3%) in the sotalol group died, compared with 52 (8.9%) in the placebo group. Although the mortality rate was 18% lower in the sotalol group, the difference was not statistically significant. There was a significant reduction in confirmed reinfarction, but not in all suspected reinfarctions.

Can beta blockers be safely used in patients with recent myocardial infarction who also have congestive heart failure?

The indications for, and the contraindications to, therapy with beta-adrenoceptor drugs in acute myocardial infarction are still unclear. Earlier fears have been largely dispelled and these agents can probably be prescribed with comparative safety in affected patients without hypotension or evidence of cardiac failure. If, however, there is reason to suspect a raised end-diastolic pressure or a low cardiac output, they should only be used if the indications are strong and if careful hemodynamic monitoring is observed.

Fatal atheromatous embolization during coronary angiography

Multiple fatal embolism following left heart catheterization is described in two patients. Postmortem examination showed friable atheromatous aortic plaques as the likely source of emboli that clinically involved the heart, peripheral blood vessels, brain, gastrointestinal system and solid organs. Histologic examination showed widespread arterial embolism by atheromatous material.

Controlled trial of sotalol for one year after myocardial infarction

In a multicentre double-blind randomised study, the effect of sotalol 320 mg once daily was compared with that of placebo in patients surviving an acute myocardial infarction. Treatment was started 5--14 days after infarction in 1456 patients (60% being randomised to sotalol, and 40% to placebo) who represented 45% of those evaluated for entry. Patients were followed for 12 months. The mortality rate was 7.3% (64 patients) in the sotalol group and 8.9% (52 patients) in the placebo group. The mortality was 18% lower in the sotalol than in the placebo group, but this difference was not statistically significant. The rate of definite myocardial reinfarction was 41% lower in the sotalol group than in the placebo group (p less than 0.05). Although the differences in mortality were not significant, this trial supports the evidence that, in the year after myocardial infarction, beta adrenoceptor blocking drugs reduce mortality by 20--25%.

Effect of a highly purified hyaluronidase preparation (GL enzyme) on electrocardiographic changes in acute myocardial infarction

A highly purified preparation of hyaluronidase (GL enzyme) was given in a double-blind, placebo-controlled, randomised study to 192 consecutive patients within 12 h of suspected myocardial infarction. Compared with those receiving placebo, patients with definite myocardial infarction given GL enzyme had significantly less change in QRS complexes; in those with anterior infarction the development of Q waves was less prominent. At 4 months the overall mortality among those with definite and possible myocardial infarction receiving GL enzyme (6 out of 83 patients, 7.2%) was lower than that in those receiving placebo (11 out of 79, 14%); this difference was not significant. No adverse effects were observed.

The significance and management of ventricular arrhythmias. The Bradshaw Lecture 1979

Ventricular arrhythmias are the result of a variety of mechanisms that can occur in many different contexts. Although it would be, in principle, desirable to identify and treat the mechanism, therapy at present is best chosen for the particular context in which the rhythm disturbance develops. It seems probable that no one drug will ever be 'the best' and that the physician must be prepared to be familiar with many different drugs and be aware of the potential benefits of electrical therapy and surgery.

Measuring the effect of a mobile coronary care unit upon the community

A mobile coronary care unit working within a geographically defined area retrieved 20% of the estimated number of cases with myocardial infarction. These cases were similar to the population at risk in terms of age, sex, and previous history of ischaemic heart disease. Patients retrieved by the mobile unit had a lower overall case fatality ratio. This discrepancy was greater than could be explained by resuscitation or preventive treatment by the mobile unit teams. Reasons for this difference in mortality were explored. The benefits of the mobile coronary care unit were obvious in terms of the existing service but small in terms of the community. Any judgment on the effectiveness of a mobile unit must use both approaches to get a balanced view.

Mexiletine in the prophylaxis of ventricular arrhythmias during acute myocardial infarction

In a double-blind study involving 165 patients we examined the role of mexiletine, a new antiarrhythmic drug, for the prophylaxis of ventricular arrhythmias after acute myocardial infarction. Mexiletine or placebo was given orally to patients on arrival in the coronary care unit, and continuous electrocardiographic tape recordings were used to document arrhythmias. Ventricular tachycardia and R-on-T ventricular ectopic beats were significantly reduced in the mexiletine patients, but too few episodes of ventricular fibrillation occurred for statistical comment. When arrhythmias did occur in the mexiletine group, it was usually early in the study, at which time plasma drug levels were low. Adverse effects were uncommon. Patients who were given therapy, but in whom acute myocardial infarction could not be confirmed, suffered no serious consequences of taking mexiletine. The results demonstrate the benefit and limitations of prophylactic oral antiarrhythmic therapy for patients with acute myocardial infarction.

Antiarrhythmic action of lignocaine in early myocardial infarction. Plasma levels after combined intramuscular and intravenous administration

In an attempt to find a regimen suitable for pre-hospital prevention of arrhythmias following myocardial infarction, the antiarrhythmic and pharmacokinetic effects of combining intravenous and intramuscular lignocaine have been studied. In nine patients with acute myocardial infarction, 100 mg of lignocaine was administered intravenously and 300 mg into the deltoid muscle. The antiarrhythmic effect was observed by continuous tape monitoring of the patients' rhythm before and after treatment. Plasma levels above 2 microng/ml were achieved within 1 min and maintained for 1 h in all patients; in seven this level was maintained for 2 h. A marked reduction in the occurrence of ventricular ectopic beats was observed in the first 15 min after treatment and was maintained for 90 min, but a significant effect was still present at 3 h. No serious side-effects were noted.