Henry DeMots

Protective effects of aspirin against acute myocardial infarction and death in men with unstable angina. Results of a Veterans Administration Cooperative Study.

We conducted a multicenter, double-blind, placebo-controlled randomized trial of aspirin treatment (324 mg in buffered solution daily) for 12 weeks in 1266 men with unstable angina (625 taking aspirin and 641 placebo). The principal end points were death and acute myocardial infarction diagnosed by the presence of creatine kinase MB or pathologic Q-wave changes on electrocardiograms. The incidence of death or acute myocardial infarction was 51 per cent lower in the aspirin group than in the placebo group: 31 patients (5.0 per cent) as compared with 65 (10.1 per cent); P = 0.0005. Nonfatal acute myocardial infarction was 51 per cent lower in the aspirin group: 21 patients (3.4 per cent) as compared with 44 (6.9 per cent); P = 0.005. The reduction in mortality in the aspirin group was also 51 per cent--10 patients (1.6 per cent) as compared with 21 (3.3 per cent)--although it was not statistically significant; P = 0.054. There was no difference in gastrointestinal symptoms or evidence of blood loss between the treatment and control groups. Our data show that aspirin has a protective effect against acute myocardial infarction in men with unstable angina, and they suggest a similar effect on mortality.

Natural history of "high-risk" bundle-branch block: final report of a prospective study.

We conducted a prospective study in which 554 patients with chronic bifascicular and trifascicular conduction abnormalities were followed for an average of 42.4 +/- 8.5 months. Heart block occurred in 19 patients, and 17 were successfully treated. The actuarial five-year mortality from an event that could conceivably have been a bradyarrhythmia was 6 per cent (35 per cent from all causes). Of the 160 deaths 67 (42 per cent) were sudden; most of these were not ascribable to bradyarrhythmia but to tachyarrhythmia and myocardial infarction. Mortality was higher in patients with coronary-artery disease (P less than 0.01) and congestive heart failure (P less than 0.05). Patients in whom syncope developed before or after entry into the study had a 17 per cent incidence of heart block (2 per cent in those without syncope)(P less than 0.05); however, no single variable was predictive of which patients were at high risk of death from a bradyarrhythmia. The predictors of death were increasing age, congestive heart failure, and coronary-artery disease; the predictors of sudden death were coronary-artery disease and increasing age. The risks of heart block and of death from a bradyarrhythmia are low; in most patients, heart block can be recognized and successfully treated with a pacemaker.

Failure of Antiplatelet and Anticoagulant Therapy to Improve Patency of Grafts after Coronary-Artery Bypass

Fifty patients who underwent aortocoronary saphenous-vein bypass-graft surgery were randomly assigned to one of three groups to determine the effects of antiplatelet or anticoagulant therapy on graft patency. Twenty-four patients served as controls; 13 patients received aspirin (325 mg three times a day) and dipyridamole (75 mg three times a day); and 13 patients received closely regulated warfarin therapy. Medications were begun on the third post-operative day. Six months after surgery, all patients underwent coronary angiography to assess graft patency. There were no statistically significant differences between groups in various clinical, hemodynamic and angios, 27 of 33 grafts (82 per cent) with aspirin and dipyridamole and 29 of 37 grafts (78 per cent) with warfarin (P less than 0.5), all patients had at least one patent graft. Postoperative treatment either with aspirin and dipyridamole or with warfarin failed to improve the patency of the grafts.

Preoperative criteria predictive of late survival following valve replacement for severe aortic regurgitation

Forty-five patients underwent aortic valve replacement (AVR) for severe isolated aortic regurgitation from 1973 to 1979. There were two (4.4%) hospital deaths, both functional class IV. Six patients with mechanical prosthesis not receiving anticoagulants were excluded from further analysis. These data relate to 39 patients; the two operative deaths, 35 patients with mechanical prosthesis receiving anticoagulants, and two with bioprosthesis. There were three late cardiac deaths with 5-year survival 85%; average annual mortality rate of 3%. The 5-year survival with pre-AVR left ventricular (LV) ejection fraction greater than or equal to 0.45 was 87% vs 54% less than 0.45, (p less than 0.04); cardiac index greater than or equal to 2.5 L/min/m2 92% vs 66% less than 2.5 (p less than 0.04); mean VCF greater than or equal to 0.75 vs less than 0.75 circ/sec (p less than 0.09); end-diastolic pressure less than or equal to 20 vs greater than 20 mm Hg (p less than 0.08). Late survival was not significantly different between pre-AVR functional class I and II vs class III and IV; LV end-diastolic volume index greater than or equal to 210 vs less than 210 ml/m2; LV end-systolic volume index greater than or equal to 110 vs less than 110 ml/m2; and LV mass greater than or equal to 240 vs less than 240 gm/m2. With ejection fraction greater than or equal to 0.50 there was only one operative death (functional class IV) and no late cardiac deaths. Thus late survival following aortic valve replacement for severe isolated aortic regurgitation is better predicted preoperatively by the LV systolic pump function variables of ejection fraction and cardiac index than by LV diastolic parameters and clinical status.

Left main coronary artery disease: Risks of angiography, importance of coexisting disease of other coronary arteries and effects of revascularization

To elucidate the determinants of the poor prognosis of patients with left main coronary artery disease and to assess the efficacy of diagnostic and therapeutic interventions the angiographic features and clinical course of 58 patients with left main coronary artery disease studied between September 1967 and June 1974 were analyzed. Eighty-three coronary arteriograms were obtained in these 58 patients using the Judkins technique; there were no immediate complications although one patient died 3 days after study. Previously cited predictors of left main coronary artery, unstable or nonexertional angina and marked S-T segment depression with exercise were found in a minority of patients; thus, the presence of the disease could not reliably be predicted before arteriographic study. Coexisting disease was found in either two or three other coronary arteries in 46 of 58 patients; only 2 patients had isolated left main coronary artery disease. Because the criteria for operability have changed in recent years, current criteria without knowledge of the treatment actually given or its outcome. The condition of 10 of 58 patients was judged inoperable in retrospect because of severe coexisting distal coronary artery disease (8 patients) or ventricular dysfunction (2 patients). Of 19 patients whose condition was judged operable in retrospect but who were treated without surgery, 9 died, 8 within 18 months; 10 have survived 12 to 83 months. Another 27 patients with a condition judged operable in retrospect had received saphenous vein bypass grafts. In this group, there were four operative and three late deaths. The severity of angina decreased in survivors treated surgically but was unchanged in survivors treated without surgery. The improvement in survival rates of surgically treated patients was not statistically significant. The data indicate that coronary arteriography can be performed at low risk with the Judkins technique even though preangiographic prediction of left main coronary artery disease is unreliable. Coexisting disease in oter major coronary arteries is an important determinant of the poor prognosis of patients with left main coronary artery disease and precludes surgery in 13 percent. Isolated left main coronary artery disease is uncommon. Surgical therapy relieves symptoms more effectively than nonsurgical therapy.

A Prospective Study of Sudden Death in High-Risk Bundle-Branch Block

We prospectively followed 257 patients with bifascicular and trifascicular conduction-system disease and intact atrioventricular conduction who had undergone His-bundle studies. Forty-seven per cent had associated coronary-artery disease, and 23 per cent primary conduction-system disease. His-ventricular interval was moderately prolonged in 43 per cent and markedly prolonged in 12 per cent. During an average follow-up period of 25 months 50 patients died. However, death was sudden in only 27, and 17 of the sudden deaths were not due to bradyarrhythias. Actuarial analysis showed an overall mortality rate (mean +/- S.E.) of 19 +/- 2.6 per cent at two years, mortality from sudden death being 10 +/- 2.6 per cent. Permanent heart block occurred in 12. No clinical symptoms (including syncope), electrocardiographic findings, electrophysiologic data or their combination identified patients at high risk of sudden death. Sudden death due to bradyarrhythmia is uncommon in patients with bundle-branch block and intact atrioventricular conduction. Therefore, routine prophylactic use of permanent pacemakers in all such patients is inappropriate. Pacemaker implantation should be reserved for those with documented symptomatic bradyarrhythmias.

Effects of Ouabain on Coronary and Systemic Vascular Resistance And Myocardial Oxygen Consumption in Patients Without Heart Failure

The effect of digitalis glycosides on vascular resistance varies from one vascular bed to another and is also related to the hemodynamic state of the patient. To determine whether the rate of infusion is also a determinant of the vasoactive response the effect of various infusion rates of ouabain on the coronary and systemic beds was examined and the associated changes in myocardial oxygen consumption in patients without heart failure were quantitated. A 10 second and 2 minute infusion of ouabain (15 μg/kg body weight) produced 18.1 ± 5.6 percent and 7.5 ± 1.7 percent increases in mean arterial pressure and 23.7 ± 9.8 percent and 17.6 ± 7.5 percent increases in systemic vascular resistance, respectively (P <0.05 for each). A 15 minute infusion produced no statistically significant change in either variable. Coronary vascular resistance increased 13.4 ± 5.2 percent (P <0.05) after a 10 second infusion but did not change during or after a 15 minute infusion. The 10 second infusion was also associated with transient deterioration of myocardial lactate metabolism. Thirty minutes after ouabain administration mean arterial pressure had returned to control levels, but myocardial oxygen consumption remained increased by 12.5 ± 3.9 percent (P <0.025), indicating that ouabain produces a net increase in myocardial oxygen demand in patients without heart failure. Rapid intravenous administration of ouabain produces systemic and coronary arteriolar constriction that may lead to clinical deterioration. These effects can be avoided by slower delivery of the drug. Even in patients without heart failure, the increase in myocardial oxygen consumption with full digitalization is small.

The statistical analysis of graft patency data in a clinical trial of antiplatelet agents following coronary artery bypass grafting

Because most coronary artery bypass patients receive more than one graft at surgery, it is most important to determine whether statistical analysis of graft patency should be performed on the premise that the multiple grafts within patients are dependent or independent experimental units. Veterans Administration Cooperative Study No. 207 was a multicenter clinical trial comparing four different antiplatelet regimens to placebo in the prevention of graft occlusion following coronary artery bypass grafting. Using the results from the 1-week postoperative angiograms from the Veterans Administration Cooperative Study No. 207, in which there were 3.2 distal anastomoses per patient, we have tested the hypothesis that grafts within patients tend to act dependently with respect to patency or occlusion by comparing the graft patency data to a binomial distribution (i.e., that distribution that would have been manifest if grafts were independent). Because the graft patency results in Study No. 207 significantly deviated from the binomial distribution (p = 0.0003), a more appropriate analysis for graft patency data was applied using a ratio estimate as applied to cluster sampling. The statistical methods used in 11 previous clinical trials of antithrombotic therapy after coronary artery bypass grafting were examined. Only one of the previous studies used such an analysis, and three additional reports attempted to correct for dependency of grafts within patients in their analyses using other statistical methods. In seven of the studies the investigators did not address the potential problem of a dependent relationship between multiple grafts within patients. We conclude that grafts within patients act as dependent experimental units and that the ratio estimate as applied to cluster sampling may be appropriately applied to these data.

Echinococcus of the heart. An unusual tumor of the heart and liver.

Abstract Diagnostic and therapeutic techniques in the management of a young woman with hepatic and cardiac echinococcal cysts are discussed. Complications of these rare cardiac lesions, 1 of which occurred in this patient, are reviewed. The efficacy of angiographic procedures in diagnosis and localization of the cysts is discussed, and a sequential approach in the radiologic study is suggested.

Concealed Sinus Rhythm A Cause of Misdiagnosis of Digitalis Intoxication

A 47-year-old man with a long history of atrial fibrillation presented with a regular rhythm and absent P waves on the surface electrocardiogram. When this rhythm persisted after digitalis withdrawal His bundle electrocardiography demonstrated sinus rhythm. Recognition of concealed sinus rhythm prevents misdiagnosis of digitalis intoxication and inappropriate withdrawal of digitalis therapy.