Prediction of cardiac death in patients with a very low ejection fraction after myocardial infarction: a Cardiac Arrhythmia Suppression Trial (CAST) study.

The Cardiac Arrhythmia Suppression Trial (CAST) database was analyzed with a Cox proportional hazards regression model to predict the mortality of patients with very poor left ventricular systolic function (ejection fraction < or = .20). Predictors of total death or cardiac arrest were (relative risk), QRS duration (1.10/10 msec increase), coronary artery bypass grafting (0.38), basal heart rate (1.26/10 min-1 increase), diastolic blood pressure (0.79/10 mm Hg increase), diabetes mellitus (1.59), EF (0.94/1 U increase), and ease of suppression (the ability to suppress ambient ventricular ectopy on the lowest dose of the first randomly chosen CAST drug) (0.64). Predictors of arrhythmic death or arrhythmic cardiac arrest included thrombolysis (0.44), coronary artery bypass grafting (0.38), diuretic use (1.71), heart rate (1.21/10 min-1 increase), calcium channel blocker use (1.69), and QRS duration (1.10/10 msec increase). Thus easily measurable clinical and laboratory variables help predict prognosis in this clinically important subgroup. The pathophysiologic basis for and the clinical implications of the ease of ventricular arrhythmia suppression correlating with prognosis requires further study.

ST segment tracking for rapid determination of patency of the infarct-related artery in acute myocardial infarction.

OBJECTIVES: This study was designed to test the hypothesis that monitoring the ST segment on a single electrocardiographic (ECG) lead reflecting activity in the infarct zone provides sensitive and specific recognition of reperfusion within 60 min of initiation of therapy in acute myocardial infarction. BACKGROUND: Infarct-related arteries that fail to recanalize early may benefit from immediate rescue angioplasty. Hence, detection of reperfusion has important practical clinical implications. METHODS: Of 41 patients with acute myocardial infarction who had ambulatory ECG (Holter) monitors placed, 38 had adequate ST segment monitoring for 3 h; 35 of the 38 were treated with thrombolytic agents and 3 with primary angioplasty. All patients underwent early coronary angiography and were classified into two groups: Group P (22 patients) had angiographic patency (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow), the Group O (16 patients) had persistent occlusion (TIMI grade 0 or 1 flow) of the infarct-related vessel at 60 min from initiation of therapy. The initial ST segment level was defined as the first ST segment level recorded; the peak ST segment level was defined as the highest ST segment level measured during the 1st 60 min. To assess the optimal ST segment recovery criteria for reperfusion, the presence or absence of a > or = 75%, > or = 50% and > or = 25% decrement from initial and peak ST segment levels, sampled and analyzed at 2.5-, 5-, 10-, 15-and 20-min intervals, was correlated with patency of the infarct-related artery at 60 min. RESULTS: ST segment recovery of > or = 50% reduction from peak ST segment levels with sampling rates at < or = 10-min intervals provided the optimal criterion for recognizing coronary artery patency at 60 min (sensitivity 96%, 95% confidence interval [CI] 77% to 99%; specificity 94%, 95% CI 69% to 99%, p < 0.0001). The subgroup of 13 patients in Group P with TIMI grade 3 reperfusion flow all met this criterion (sensitivity 100%, 95% CI 75% to 100%). The use of the initial ST segment level as the baseline for determining the presence of a > or = 50% reduction in ST segment levels within 60 min was less sensitive. Prediction of coronary reperfusion within 60 min of therapy on the basis of a > or = 75% decrement from peak ST segment levels was less sensitive, and the use of a > or = 25% decrement was less specific. CONCLUSIONS: ST segment monitoring of a single lead reflecting the infarct zone provides a reliable method for assessing reperfusion within 60 min of acute myocardial infarction. Optimal criteria for ECG reperfusion include a > or = 50% decrease from peak ST segment levels, with ST segment measurements recorded continuously or at least every 10 min.

Coronary-subclavian steal: a cause of recurrent myocardial ischemia.

Coronary-subclavian steal through an internal mammary artery (IMA) graft is a rare cause of myocardial ischemia in patients who have previously undergone coronary artery bypass surgery. Two patients presented with upper extremity ischemic symptoms and recurrent angina pectoris 3 to 4 years following coronary artery bypass with in situ IMA grafts. Diagnosis of coronary-subclavian steal was confirmed by brachiocephalic arteriography, which showed tight stenosis or occlusion of the proximal subclavian artery. Coronary arteriography showed retrograde filling of the IMA with steal from the coronary circulation. Both patients were successfully treated by carotid-subclavian bypass.

Randomized placebo-controlled trial of amlodipine in vasospastic angina. Amlodipine Study 160 Group.

OBJECTIVES: This study was designed to assess the efficacy and safety of amlodipine, a long-acting calcium channel blocker, in patients with vasospastic angina. BACKGROUND: Previous studies have established the value of short-acting calcium channel blockers in the treatment of coronary spasm. METHODS: Fifty-two patients with well documented vasospastic angina were entered into the present study. After a single-blind placebo run-in period, patients were randomized (in a double-blind protocol) to receive either amlodipine (10 mg) or placebo every morning for 4 weeks. Twenty-four patients received amlodipine and 28 received placebo. All patients were given diaries in which to record both the frequency, severity, duration and circumstances of anginal episodes and their intake of sublingual nitroglycerin tablets. RESULTS: The rate of anginal episodes decreased significantly (p = 0.009) with amlodipine treatment compared with placebo and the intake of nitroglycerin tablets showed a similar trend. Peripheral edema was the only adverse event seen more frequently in amlodipine-treated patients. No patient was withdrawn from the double-blind phase of the study because of an adverse event. Patients who completed the double-blind phase as responders to amlodipine or as nonresponders to placebo were offered the option of receiving amlodipine in a long-term, open label extension phase. During the extension, the daily dose of amlodipine was adjusted to 5 or 15 mg if needed and the rate of both anginal episodes and nitroglycerin tablet consumption showed statistically significant decreases between baseline and final assessment. CONCLUSION: This study suggests that amlodipine given once daily is efficacious and safe in the treatment of vasospastic angina.

Anomalous coronary arteries: angiographic findings in 80 patients.

Among 13010 adults who underwent coronary arteriography, 80 (0.61%) patients had a total of 83 anomalous coronary arteries. Thirty-three (41%) of the patients were of Hispanic origin, while out of the entire population studied 30% were Hispanic. The right coronary artery was the most common anomalous vessel. It was identified in 50 (62%) patients, arising in 35 from the left aortic sinus, in 14 from the posterior sinus, and in 1 from the left coronary artery. An anomalous circumflex artery was recognized in 22 (27%) patients. Nine (11%) patients presented an anomalous left anterior descending artery, 1 patient an anomalous left main coronary artery, and another an anomalous septal perforator artery. Twenty-three (29%) patients had concomitant congenital heart abnormalities, most commonly. bicuspid aortic valve and mitral valve prolapse. In each of 5 patients with complex congenital heart disease the course of the anomalous vessel could have interfered with a surgical procedure. In 4 cases anomalous coronary arteries were associated with either anomalous systemic venous circulation or anomalous cardiac veins. In 5 (6%) patients only, the anomalous coronary artery was solely responsible for a clinical event. Coronary atherosclerosis of the anomalous arteries was found in 28% of the patients, while the overall incidence of the disease in this series was 65%. Thus, anomalous coronary arteries are associated with a high incidence of congenital heart diseases, but do not appear to be associated with an increased risk for development of coronary atherosclerosis. The angiographic recognition of these vessels is important in patients who undergo coronary angioplasty or cardiac surgery. Variations in the frequency of congenital coronary anomalies as reported herein may be attributed to a genetic background.

The calcium antagonists in vasospastic angina.

Coronary vasospasm is an important pathophysiologic mechanism of angina at rest. Because the calcium antagonists are potent vasodilators, they have become widely used and are now considered the treatment of choice for vasospastic angina. Practically all currently available calcium antagonists in the United States have been shown to be efficacious and safe for the therapy of vasospastic angina. However, because spontaneous remissions are common and angina attacks can frequently occur during the nighttime, considerations such as the duration of action of a given agent, the duration of treatment, and patient compliance have become important in the selection of the most appropriate therapy. Amlodipine is a long-acting dihydropyridine derivative that is suitable for use as a once-daily calcium antagonist. There is preliminary evidence that amlodipine is efficacious and well tolerated in vasospastic angina. Amlodipine, therefore, has the potential to become the preferred calcium antagonist for this condition.

Acute ventricular septal rupture. Angiographic-morphologic features and clinical assessment.

Twenty patients with acute ventricular septal rupture underwent cardiac catheterization. Prior to catheterization, 17 patients were in Killip class 3-4. Mean cardiac index and cardiac output were 2.03 +/- 0.81 L/min/m2 and 3.55 +/- 1.33 L/min, respectively. Based on a recent pathologic description of septal rupture, we encountered by angiography and during surgery, two morphologic types of rupture: simple type which appears as a direct through-and-through communication between the ventricles, and complex type which presents hemorrhagic tracts in the septum with the opening into the ventricles at different levels. Considering the management of patients with septal rupture and the clinical outcome in our series, it is suggested that there is a need to minimize invasive angiographic procedures prior to early surgical correction of the ruptured septum.

Cardiac arrhythmias associated with prophylactic pacing during coronary angiography.

Data from 518 consecutive cardiac catheterizations were analyzed to test the value of prophylactic pacemaker insertion during coronary angiography and to compare the incidence of arrhythmic complications in patients with and without pacemakers. In patients without pacing (n = 273), 1 episode of ventricular fibrillation occurred, which responded promptly to defibrillation. Sinus bradycardia (fewer than 30 beats/min for 10 seconds) was recorded in 74 patients (27%) and required treatment in 30 (11%). No patient required or would have benefited from pacemaker placement. Of the 245 patients with prophylactic pacemakers, there was an increased incidence of all ventricular (9 vs 1; p less than 0.013) and supraventricular (5 vs 0; p less than 0.046) arrhythmias. Pacemaker-associated induction of ventricular fibrillation occurred in 2 patients and was clearly related to electrical stimulation during a normally non-vulnerable period of the cardiac cycle. In conclusion, routine prophylactic pacemaker insertion during coronary angiography is not warranted in patients with normal sinus rhythm and normal atrioventricular conduction. More information is needed to determine if pacing is needed in patients with conduction system disease.

Coronary artery spasm. What is its role in ischemic heart disease?

Knowledge of the pathophysiology of myocardial ischemia has been greatly enhanced recently by new information on coronary artery spasm. This phenomenon accounts for the mechanism underlying the attacks of resting chest pain in Prinzmetal's angina and plays a role in almost all aspects of ischemic heart disease. The diagnosis of coronary artery spasm can be made presumptively with noninvasive methods, but definitive documentation is usually obtained in the cardiac catheterization laboratory. The nitrate derivatives and the calcium antagonists provide a safe and effective approach to therapy.

The diagnosis of coronary artery spasm in the cardiac catheterization laboratory.

Coronary artery spasm can now be well documented in the cardiac catheterization laboratory. At present, reliable criteria are available for the diagnosis of severe episodes that are characteristic of patients with Prinzmetal's variant angina. Newer criteria for the diagnosis of milder episodes of spasm are gradually being developed. Optimal criteria may become available with further progress of quantitative angiography. Provocation techniques for the induction of an attack of spasm in the cardiac catheterization laboratory are widely available. Of these, ergonovine testing is the most popular. The tests can usually be performed by experienced angiographers with impressive safety and provide a high degree of sensitivity and specificity when used in patients with the clinical diagnosis of variant angina. Although the research applications of such techniques are extremely broad, their practical clinical indications are somewhat limited to the work-up of patients with infrequent chest pains and normal or near-normal coronary arteriograms. There are other indirect methods for the diagnosis of coronary spasm, but the ideal technique is not available yet. Further expansion of newer modalities for the diagnosis of coronary artery spasm will certainly enhance our understanding of myocardial ischemia and will improve our ability to manage patients with ischemic heart disease.