Refractory ergonovine-induced coronary vasospasm: importance of intracoronary nitroglycerin

Recent experience has suggested that the ergonovine maleate test is a safe procedure for the diagnosis of variant angina pectoris, because ergonovine-induced coronary vasospasm has generally been reversible by sublingual nitroglycerin. This report describes five cases of ergonovine-induced coronary vasospasm that were refractory to sublingual nitroglycerin. Four of these patients had cardiac arrest. In two patients the vasospasm was responsive to intracoronary nitroglycerin administration. Three patients died as a reuslt of the test. The two survivors differed from the nonsurvivors in the total dose or ergonovine given (0.1 and 0.15 mg versus 0.17, 0.3 and 0.3 mg, respectively) and in the method of administration of ergonovine. The survivors were given serial doses of 0.05 mg each whereas the three nonsurvivors received either larger initial doses (0.1 followed by 0.07 mg) or progressive incremental doses (0.05, 0.1 and 0.15 mg serially). Sublingual nitroglycerin, given to all five patients, and intravenous nitroglycerin, given to three of the five, were ineffective in reversing vasospasm. Intracoronary nitroglycerin favorably altered the course of the survivors. Thus, the ergonovine maleate test is not benign and may cause severe coronary vasospasm that is unresponsive to sublingual and intravenous nitroglycerin, but may be reversed by intracoronary nitroglycerin.

Nifedipine in the treatment of Prinzmetal's (variant) angina

The clinical response to therapy with the calcium-blocking agent nifedipine was assessed in 12 patients with variant angina pectoris who were 44 to 67 years old. Five patients had vasospasm of the left anterior descending coronary artery, and seven had spasm of a dominant right coronary artery. Before nifedipine therapy, the frequency of anginal attacks per 24 hour period ranged from 1 to 12, with ventricular tachycardia accompanying ischemic episodes in 7 of 12 patients and high grade atrioventricular block occurring in 2 patients. After therapy with nifedipine, 11 of 12 patients had initial relief of symptoms, and 7 of the 11 had long-term relief. Withdrawal of nifedipine led to recurrence of angina on six occasions in four patients. Provocative testing in the cardiac catheterization laboratory by means of the cold pressor test in one patient and ergonovine maleate in another before and after nifedipine administration showed that this agent can block both alpha adrenergic- and regonovine-induced vasospasm. Nifedipine may have a significant role in the therapy of angina caused by coronary spasm.

Coronary hemodynamic and myocardial metabolic alterations accompanying coronary spasm

Arterial pressure, coronary sinus blood flow with the thermodilution technique and calculated coronary vascular resistance were measured and coronary arteriography performed at rest and after the administration of ergonovine in 14 patients with atypical chest pain (group 1) and 6 patients with variant angina (group II). Mild diffuse narrowing of the left coronary bed in group I was not accompanied by S-T segment shifts, and coronary vascular resistance did not change significantly. In contrast, severe focal spasm (greater than 90 percent narrowing) of the left anterior descending coronary artery in group II patients was accompanied by S-T elevation and a marked overall increase in coronary vascular resistance (from 0.65 +/- 0.07 to 1.14 +/- 0.10 mm Hg/ml per min) (P less than 0.005). In addition, the myocardial arteriovenous oxygen difference increased and net lactate extraction changed to lactate production in the two patients in group II in whom these measurements were made. Thus, thermodilution coronary sinus blood flow measurement may be a sensitive method for detecting primary increases in coronary vascular resistance due to a high grade focal spasm in the left anterior descending coronary artery.

Electrophysiologic characteristics of Ebstein's anomaly of the tricuspid valve

Electrophysiologic characteristics of five patients with Ebstein's anomaly of the tricuspid valve were defined with studies using luminal intracardiac electrode catheters. The diagnosis was made in each case from clinical data and confirmed at cardiac catheterization by the presence of an atrialized right ventricular chamber with atrial mechanical activity and ventricular electrical activity. In three cases intra-right atrial conduction was prolonged (P-A intervals of 50, 50, and 65 msec), a finding which reflected the presence of a characteristically large right atrium. The bundle of His electrogram was recorded in its usual anatomical location. Atrioventricular nodal conduction was prolonged in only one case. Intra-His delay was observed in two cases (bundle of His duration of 30 and 30 msec). Infranodal conduction was prolonged in four cases with H-V intervals of 60, 65, 65, and 80 msec. The anatomical abnormalities were least severe in the only patient with a normal H-V interval (50 msec). The prolonged H-V interval was thought to result from stretching of the conduction system over the atrialized right ventricle (ARV). The late depolarization during the splintered R' of the electrocardiogram found during intracardiac mapping of the ARV in three patients confirms the theory that the ARV produces the "second QRS" typically seen in this anomaly. The ARV was particularly irritable, and ventricular fibrillation was produced in two patients during catheter manipulation in this area. In one case the ARV had a shorter refractory period than the body of the right ventricle. Re-entrant supraventricular tachycardia was induced in the only patient with Wolff-Parkinson-White syndrome. In addition to the previously recognized electrophysiologic features reconfirmed here, patients with Ebstein's anomaly of the tricuspid valve usually have: normal position of the bundle of His, prolonged intra- right atrial conduction, prolonged infranodal conduction, and irritable ARV with delayed activation.

Sudden death due to coronary artery disease. A clinical, hemodynamic, and angiographic profile

The authors followed 536 medically managed patients with angiographically documented coronary artery disease for up to 4 years, and examined antemortem clinical, anatomical, and hemodynamic characteristics of the 29 patients who died suddenly during the follow-up period. These patients are compared in terms of hemodynamic characteristics to those who survived and those who died non-suddenly of coronary heart disease. Of the 29 patients who died suddenly, more than 80% had evidence of moderate to severe impairment of myocardial function many months prior to death. Only a single patient had the combination of relatively mild coronary artery disease and normal ventricular function. This single patient would be the ultimate target of a program designed to prevent sudden death. However, it has been necessary to follow 536 patients with angiographically documented coronary artery disease in order to find this one potential benefactor of sudden death prophylaxis. This study demonstrates that there are patients with coronary artery disease who die suddenly, despite relatively mild disease; however, these patients appear to represent only a small proportion of all sudden deaths.

Indices predicting long-term survival after valve replacement in patients with aortic regurgitation and patients with aortic stenosis

The long-term results of aortic valve replacement were reviewed in all 88 patients with isolated aortic regurgitation and all 103 patients with isolated aortic stenosis who were operated upon at the National Heart and Lung Institute from 1963 to 1971. Survival curves were compared to determine whether any of 30 preoperative clinical and hemodynamic findings correlated with long-term survival. The indices that were of predictive value in patients with aortic regurgitation were found to be different from those in aortic stenosis. Symptoms, cardiac index, and cardiothoracic ratio did not influence survival in patients with aortic regurgitation. In these patients, survival was inversely correlated with the level of left ventricular end-diastolic pressure (LVEDP): six-year survival was 74% in patients with LVEDP ≤ 10 mm Hg, 41% with LVEDP 11-20 ( P < .05), and 30% with LVEDP > 20 ( P < .01). Survival also was lower in patients with aortic regurgitation who had elevated pulmonary arterial and left atrial pressures, and in patients with electrocardiographic evidence of severe left ventricular hypertrophy (LVH). Using an LVH point score method (Romhilt-Estes), 56% of patients with a score ≤ 6 survived six years; 29% with a score > 6 survived ( P < .02). Survival in aortic stenosis did not relate to any of the above, but did correlate with preoperative functional class. Five-year survival was 70% in class II, but only 40% in class III-IV ( P < .02). Moreover, cardiothoracic ratio in patients with aortic stenosis correlated with survival in an unexpected way. Eleven of 31 patients with cardiothoracic ratio ≤ .45 had sudden unexplained death postoperatively, compared to only six of 72 patients with cardiothoracic ratio > .45 ( P < .01). This difference did not correlate with postoperative hemodynamic measurements, including magnitude of the transprosthetic gradient. We conclude that certain preoperative indices are of value in predicting long-term prognosis after valve replacement for aortic regurgitation and for aortic stenosis, but that the specific predictive indices for the two groups differ.

A method for evaluating computer programs for electrocardiographic interpretation. II. Application to version D of the PHS program and the Mayo Clinic program of 1968

A previously described method for evaluating computer programs for electrocardiographic (ECG) interpretation was applied to Version D of the Public Health Service (PHS) program and to the Mayo Clinic program of 1968. Staff cardiologists found agreement with the results of the PHS program in 45.5% of 1150 unselected tracings. Clinically significant disagreements based strictly on application of different criteria occurred in 29%, while disagreements based on program errors were found in 25.5%. The corresponding results for the Mayo Clinic program are: agreement in 47%, disagreements due to criteria differences in 30.9%, and disagreements due to program errors in 22.1%.

Both programs had serious deficiencies, particularly in the diagnostic categories of myocardial infarction and cardiac arrhythmias. PHS program errors resulted primarily from mismeasurements and deficient program logic, while Mayo Clinic program errors more frequently resulted from pattern recognition failures. Neither program appears suitable for routine clinical use at the present time.

A method for evaluating computer programs for electrocardiographic interpretation. I. Application to the experimental IBM program of 1971

A method for evaluating computer programs for electrocardiographic interpretation is described. This method allows a clinician to judge the usefulness of a program for his specific setting and needs. The method requires a significant proportion and variety of abnormal tracings, the application of specific fixed criteria, and the separation of disagreements between the computer program and the clinician into those resulting from criteria differences and those resulting from programming errors, viz., pattern recognition failures, mismeasurements, and/or deficient program logic. When applied to the experimental IBM program 1971, staff cardiologists found essential agreement with the program's results in 76% of 1150 unselected tracings. Clinically significant disagreements based strictly on the application of different criteria occurred in 20% of the tracings, whereas disagreements based on program errors were found in only 4%. Although this program requires some system of human overview and quality checking, its potential for clinical implementation is worthy of consideration.

Reduction in severity and extent of myocardial infarction when nitroglycerin and methoxamine are administered during coronary occlusion

The effects of treatment with nitroglycerin (TNG) and methoxamine on the degree of ischemic injury occurring during 5 hours of coronary occlusion were studied in 31 closed-chest sedated dogs. Acute coronary occlusion was produced by inflating a cuff previously implanted around the left anterior descending coronary artery. After 10 min of ischemia (assessed by intramyocardial electrodes), dogs were randomized into control and treated groups. Treated dogs received i.v. TNG during the remainder of the 5 hour occlusion. Arterial pressure was maintained at preinfusion levels with i.v. methoxamine. Six of 16 control dogs died; three of 15 treated dogs died. After 24 hours severity of infarct was assessed in survivors by gross inspection, and more quantitatively, by measurement of creatine phosphokinase (CPK) content of myocardium adjacent to each electrode. Transmural infarction was observed in all of the ten surviving control animals but in only two of the 12 treated animals. In control dogs, CPK was inversely related to ST segment elevation observed after 10 min of occlusion: the greater the ST elevation, the lower the myocardial CPK level. This relation was modified in the treated group: at comparable initial levels of ischemia (as judged by ST segment elevation prior to treatment), treated dogs had significantly less CPK depression than control dogs ( P < 0.025). Moreover, in controls, a significant reduction in CPK occurred at 48 of 57 electrode sites where ST elevation was observed after 10 min of occlusion. Only 19 of 69 such sites showed significant CPK reduction in the treated dogs ( P < 0.001). Thus, administration of TNG, with support of arterial pressure by methoxamine, markedly reduces the severity and extent of infarction occurring after 5 hours of coronary occlusion in the dog.

Postoperative assessment of patients with ventricular septal defect and pulmonary hypertension. Response to intense upright exercise

Circulatory function of patients with operatively closed ventricular septal defect and preoperative pulmonary arterial hypertension was evaluated in 11 asymptomatic subjects at rest and during intense treadmill exercise three to 15 years after operation. The pulmonary-to-systemic resistance ratio was normal or mildly to moderately elevated preoperatively. Postoperative mean pulmonary arterial pressure at the time of study was normal or mildly elevated at rest in 10 patients and moderately elevated in one (40 mm Hg). During intense upright exercise sufficient to lower pulmonary arterial oxygen saturation to 30%, cardiac output was below the normal range in five patients. Each of these patients had been operated upon after 10 years of age. The magnitude of the postoperative abnormality in cardiac output response to exercise was directly related to age at operation. Two of the five patients with impaired cardiac output response and two other patients manifested an abnormally elevated mean pulmonary arterial pressure during intense exercise. There was a positive correlation between pulmonary arterial pressure during intense exercise and age at operation. These results indicate that late postoperative cardiovascular function may be abnormal in patients with ventricular septal defect and preoperative pulmonary arterial hypertension, and that these abnormalities appear to be related to age at operation. Since all patients were asymptomatic, the long-term clinical significance of these hemodynamic abnormalities remains to be determined.

The Presence in Normal Serum of Inhibiting Substances Against Bacillus subtilis

Sera from 35 normal persons who had received no previous medication were tested for inhibiting substances against Bacillus subtilis and Staphylococcus aureus. Thirty of the sera (85 per cent) inhibited Bacillus subtilis in dilutions varying up to 1:32, but in no instance was Staphylococcus aureus inhibited. The data presented would indicate that Bacillus subtilis is not a suitable organism for use in the assay of antibiotics in the presence of serum.

The Effect of Colchicine and X-ray on a Transplantable Mammary Carcinoma in Mice

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