The influence of early repolarization variant on the exercise electrocardiogram: a correlation with coronary arteriograms

Sixteen adult patients with S-T segment elevation in their resting electrocardiograms characteristic of early repolarization variant (ERV) and chest pain syndromes of possible myocardial ischemia were evaluated with both treadmill exercise electrocardiography and coronary arteriography. Of 14 patients with normal coronary arteriograms, 13 had their resting S-T elevation return (“normalize”) to the isoelectric baseline with physical exercise, while one patient with normal arteriograms and normal left ventricular contractility but moderately elevated left ventricular end-diastolic pressure of unknown etiology developed significant S-T depression with exercise. Two patients with significant coronary atherosclerotic occlusive lesions developed “ischemic” S-T depression during treadmill testing. Symptoms developed during treadmill exercise did not distinguish patients with coronary artery disease from those without. Thus, while ERV at rest may be “normalized” by graded physical exercise in the absence of significant coronary atherosclerosis, the presence of ERV does not prevent the usual electrocardiographic manifestations of exercise-induced myocardial ischemia.     

Pacemaker pseudodysfunction with a coronary sinus pacemaker

A permanent transvenous coronary sinus pacemaker functioned effectively for 22 months both as an atrial and ventricular pacemaker. Slow atrial flutter resulted in failure of the pacemaker to capture the myocardium and thus incorrectly suggested pacemaker dysfunction. Transtelephonic evaluation of this phenomenon was particularly difficult and could have resulted in unnecessary replacement of the pacing unit     

Leukocyte intracellular cations in hypertension: Effect of antihypertensive drugs

Leukocyte (WBC) cations were determined in 32 normotensive control subjects and in 47 agematched patients with uncomplicated hypertension. The intracellular concentration of sodium (Na⁺) which averaged 25.5 mEq./Kg. wet cell weight (wcw) in the hypertensive patients was significantly higher (P <.01) than in the control subjects (average 19.7 mEq./Kg. wcw). Elevated WBC Na⁺ was observed only in the hypertensive patients under age 50 years. WBC potassium, magnesium, and percentage water content were not significantly different in hypertensive patients as compared to the control subjects. The finding of an increased intracellular Na⁺ content in hypertensive patients is consistent with recent observations relating the extracellular/intracellular Na⁺ gradient to vascular smooth muscle tension and to the control of the peripheral vascular resistance.WBC cations also were determined after treatment with hydrochlorothiazide, hydralazine, reserpine, or alpha methyldopa. Hydrochlorothiazide was associated with a reduction in WBC sodium content (P < .01). Reserpine also was associated with a lesser fall in WBC sodium (P < .05). Cell water content decreased slightly after hydrochlorothiazide (P < .05), but increased slightly following reserpine (P < .05). Changes in WBC, sodium, or water were not significant following alpha methyldopa or hydralazine. None of the drugs were associated with changes in WBC potassium or magnesium, although serum potassium concentration decreased significantly (P < .05) with hydrochlorothiazide.     

Open clinical studies at a referral center: Chronic maintenance tocainide therapy in patients with recurrent sustained ventricular tachycardia refractory to conventional antiarrhythmic agents

Chronic maintenance tocainide therapy was effective in controlling symptomatic, recurrent ventricular tachycardia in 11 of 15 patients. Patients were selected for tocainide therapy on the basis of refractoriness to conventional antiarrhythmic agents and responsiveness to the intravenous administration of lidocaine. Side effects were frequent but could usually be managed by taking the drug with meals or by more frequent administration of smaller doses. Survival, frequency of symptomatic tachycardia, frequency of asymptomatic ventricular tachycardia, and tolerance of the therapeutically effective dosage were the criteria used to assess therapeutic effectiveness. Factors common to the response group included primary and secondary Q-T prolongation before therapy, a paradoxical increase in ventricular ectopic activity with quinidine-like medications, and shortening of the Q-T interval with maintenance tocainide therapy. These factors may prove to be useful in identifying the patients who are most likely to benefit from chronic maintenance tocainide therapy.     

Compliance with isolation technique

We found that compliance with isolation precautions was less than optimal. It appeared that personnel were unaware of instances in which they had become contaminated. Increasing such awareness is indicated as an incentive to improve compliance. In addition, there were two areas in which education seemed to be indicated: for housekeeping staff to assure that they understood the need to contain infectious organisms within the isolation room as well as protecting themselves and for all personnel to identify the need for handwashing after removing gloves. Others have found that a careful monitoring program by an ICP can significantly reduce the overuse, but not underuse, of isolation. Such monitoring leads to considerable cost savings. We recommend that compliance with isolation technique be monitored on a periodic basis in other acute care institutions.     

Diagnostic and prognostic significance of electrocardiographic and CPK isoenzyme changes following coronary bypass surgery: correlation with findings at one year.

The incidence of ECG (14 per cent) indication of acute myocardial infarction complicating coronary artery bypass surgery is documented, corroborating the findings of prior series. An additional 32 per cent of patients had appearance of myocardial specific CPK-MB in serum during the immediate postoperative period. All patients surviving to 1 year following surgery (93 of 103) were asked to return for repeat cardiac catheterization to determine the presence and extent of interim ventricular contraction abnormalities. Sixty-five (70 per cent) of the group returned for evaluation. Preoperative and 1 year postoperative left ventriculograms were compared to determine if new contraction abnormalities would confirm the specificity of perioperative QRS and isoenzyme changes, and if the absence of new abnormalities would confirm their sensitivity. The majority of patients (65 per cent) had new areas of asynergy. However, 73 per cent of these were confined to the apex and thus could have been produced by the vent employed during cardiopulmonary bypass. QRS changes were 100 per cent specific and CPK-MB appearance was 78 per cent specific but they were only 20 and 54 per cent sensitive, respectively. Indeed, 46 per cent of those with new asynergy which was non apical had neither QRS change nor CPK-MB appearance. Thus QRS changes were always--and CPK-MB appearance was usually--associated with new asynergy but, in addition, many patients with no perioperative indication of infarction developed new areas of left ventricular contraction abnormality within the first postoperative year.     

Control of ventricular ectopic beats with intravenous lorcainide maintained by oral doses

We have investigated the feasibility of using oral lorcainide as maintenance therapy for patients with ventricular ectopic beats responsive to initial intravenous injections of lorcainide.     

Artifacts in portable electrocardiographic monitoring.

The development of portable ECG monitoring techniques has brought with it new insights into the electrical activity of the heart, and new problems in interpretation of artifacts. This article summarizes and classifies 15 different types of artifacts observed from dynamic electrocardiography. The artifacts appear partly as pseudo-arrhythmias mimicking supraventricular, ventricular, junctional, and dissociative rhythms. There are also non-arrhythmic artifacts which can be misleading in the interpretation of Q-waves, S-T-segments, and T-waves. Eight of the 15 artifacts have potentially serious consequences if not understood, and in 2 instances an artifact almost led to the unnecessary implantation of an artificial cardiac pacemaker.     

Myotonia dystrophica: ventricular arrhythmias, intraventricular conduction abnormalities, atrioventricular block and Stokes-Adams attacks successfully treated with permanent transvenous pacemaker.

In a patient with myotonia dystrophica multiple ventricular arrhythmias and high degree atrioventricular block requiring a permanent pacemaker developed. Patients with skeletal muscle disease may present with disproportionately advanced manifestations of associated cardiac disease. Early recognition of potential serious underlying cardiac disease is important in patients with this condition.