M. Chimienti

Treatment of angina at rest with nifedipine: A short-term controlled study

The effectiveness of nifedipine in treating angina pectoris at rest was evaluated in 14 patients with frequent ischemic episodes associated with S-T segment elevation or depression. The trial consisted of (1) a 48 hour control period; (2) a placebo period and a period of treatment with nifedipine of 48 hours each; and (3) a second placebo period and a second period of treatment with nifedipine of 24 hours each. The efficacy of treatment was evaluated by continuous electrocardiographic recording to detect painless ischemic episodes. During coronary angiography coronary spasm was demonstrated in five patients. The ergonovine maleate test was positive in seven of eight patients. No statistically significant difference was found in the mean daily number of ischemic episodes between the control period and the first placebo period, or between the control and the second placebo periods. Nifedipine produced a highly significant reduction in the mean daily number of episodes compared with the response to placebo during the first as well as the second period. Nifedipine is effective in angina at rest caused by coronary arterial spasm. The prevention of ischemia may be related to the ability of nifedipine to decrease calcium-dependent coronary muscle tone and to prevent coronary spasm.

Ventricular tachyarrhythmias in prinzmetal's variant angina: Clinical significance and relation to the degree and time course of S-T segment elevation

Fifty-six patients with active Prinzmetals variant angina were studied to determine the incidence and clinical significance of ventricular tachyarrhythmias and the correlation between arrhythmias and degree and time course of S-T segment changes during the ischemic attacks. Twenty-nine patients (Group I) had no ventricular arrhythmias in any of the 1,083 recorded episodes, while 27 patients (Group II) developed arrhythmias in 18% of the attacks. No significant differences in clinical, electrocardiographic, angiographic, or hemodynamic findings could be found between the 2 groups. In 23 of the 27 Group II patients, ventricular arrhythmias developed during maximal S-T segment elevation (occlusion arrhythmias), while in 10 they occurred during resolution of S-T segment changes (reperfusion arrhythmias); 6 of the latter patients also had occlusion arrhythmias. Eight of the 23 patients with occlusion arrhythmias and 6 of the 10 with reperfusion arrhythmias had ventricular fibrillation or ventricular tachycardia. Maximal S-T segment elevation was significantly greater (p less than 0.001) in patients with occlusion arrhythmias than in those without arrhythmias. The episodes with reperfusion arrhythmias were significantly longer (p less than 0.001) and showed a significantly greater S-T segment elevation (p less than 0.001) than those without arrhythmias in Group I patients. This study shows that significant ventricular tachyarrhythmias develop during ischemic attacks in about 50% of patients with active variant angina; clinical and angiographic features are not useful in distinguishing patients with arrhythmias from the others. Our findings suggest that in variant angina ventricular arrhythmias may be due to the effects of both coronary artery occlusion and reperfusion; both types of arrhythmias are correlated with the severity of ischemia, as measured by the degree of S-T segment elevation. Reperfusion arrhythmias also appear to be correlated with the duration of ischemia.

Hyperventilation and ergonovine tests in Prinzmetal's variant angina pectoris in men.

Hyperventilation and ergonovine tests were carried out in a group of 30 patients with variant angina to assess the sensitivity of the 2 tests and to correlate the response with spontaneous disease activity. Hyperventilation produced a positive response in 83% (25 of 30) and ergonovine in 93% (28 of 30) of the patients. After hyperventilation 22 of 25 showed ST-segment elevation, 2 ST depression and 1 T-wave pseudonormalization; after ergonovine ST-segment elevation developed in 23 patients, ST depression in 4 and T-wave pseudonormalization in 1. In all cases the electrocardiographic changes occurred in the same leads as during the spontaneous attacks. The incidence of chest pain and ventricular arrhythmias was similar during both tests; spontaneous remission of ischemia, however, was more frequent (48 vs 14%) after hyperventilation than after ergonovine. Acute ischemia developed at a mean of 218 +/- 112 seconds after the end of hyperventilation in 19 of 25 positive tests; at that time double product was not significantly different from basal values. The sensitivity of hyperventilation was similar (95 vs 100%) to ergonovine in the patients with greater than or equal to 1 daily attack, while in those with less than 1 daily attack the sensitivity of hyperventilation decreased to 55% compared to 77% with ergonovine. Thus, in variant angina the sensitivity of both tests correlates with disease activity. Hyperventilation is a safe provocative test with a sensitivity similar to ergonovine in patients with active disease; however, in patients with sporadic attacks hyperventilation has a lower sensitivity than ergonovine and therefore a limited diagnostic value.

Safely of long-term flecainide and propafenone in the management of patients with symptomatic paroxysmal atrial fibrillation: Report from the flecainide and propafenone Italian study investigators

To compare the relative safety of flecainide acetate to propafenone HCl during long-term treatment (12 months), we conducted a randomized, open-label, comparative, parallel, multicenter trial in 200 patients with paroxysmal atrial fibrillation (AF) and no history of heart disease. Initial daily doses were flecainide 200 mg (n = 97) or propafenone 450 mg (n = 103). Dose escalations up to a maximum of flecainide 300 mg/day or propafenone 900 mg/day were permitted after > or = 2 attacks of paroxysmal AF. Patients were assessed for safety and drug tolerance at designated intervals over the 12-month study unless discontinued for adverse experience or inadequate response. Ten patients on flecainide reported 14 cardiac adverse experiences; 4 discontinued the drug. Seven propafenone patients reported 8 cardiac adverse experiences; 5 discontinued the drug. Three proarrhythmic events occurred: 1 propafenone patient developed ventricular tachycardia and 2 flecainide patients experienced AF with a rapid ventricular response. An intention-to-treat analysis showed that the probability of safe and effective treatment after 12 months was 77% for flecainide-treated patients and 75% for the propafenone-treated patients. There was an acceptable risk-benefit profile in patients with paroxysmal AF and no evidence of clinically significant heart disease who were treated with flecainide or propafenone for 12 months. Further, there was no statistically significant difference in safety or efficacy between flecainide and propafenone in this study.

Dipyridamole Test in Angina Pectoris: Diagnostic Value and Pathophysiological Implications

The value of the dipyridamole test (0.75 mg/kg i.v.) in the diagnosis of angina pectoris was studied in 54 patients with angina pectoris (35 with angina on effort associated or not associated with rest angina and 19 with angina only at rest) and in 12 control subjects. The test induced electrocardiographic signs of ischemia (positive test) in 74% of patients with angina on effort, while it was negative in all cases with angina only at rest and in control subjects. All anginal patients with normal coronary arteries or less than 50% stenosis had a negative test; a positive response was observed in 36, 79 and 60% of cases with one-, two-or three-vessel disease, respectively. Hemodynamic changes with a marked arteriolar vasodilatation were observed both in the negative and in the positive tests. In the positive tests no significant change of double product, blood pressure and left ventricular end-diastolic pressure occurred before ischemia appeared. The results of the study show that dipyridamole as a diagnostic test in angina pectoris has a high specificity but a lower sensitivity than exercise test. The hemodynamic and eletrocardiographic findings in the positive tests suggest that dipyridamole-induced ischemia is due to a flow maldistribution with selective subendocardial ischemia secondary to the coronary arteriolar dilatation caused by the drug.

Time-related decrease in sensitivity to ergonovine in patients with variant angina.

Eighteen patients with variant angina, a positive ergonovine test, and a favorable response to calcium antagonists were studied by serial ergonovine tests and Holter monitoring to assess the long-term changes in response to ergonovine and the relationship with the spontaneous activity of the disease. The number of patients with a positive test decreased from 18 of 18 in the acute phase to 12 of 18 (66%) at 3 months, 10 of 17 (59%) at 6 months, and five of 17 (29%) at 12 months. The mean dose level of ergonovine associated with a positive response and the percentage of positive tests with ST segment depression increased progressively during follow-up. The results of the ergonovine test were well correlated with the spontaneous activity of the disease in 94%, 83%, 76%, and 71% of the patients at initial observation and at 3, 6 and 12 months, respectively. Thus in patients with variant angina and a favorable response to calcium antagonists, a time-related decrease in sensitivity to ergonovine develops during follow-up. In most patients the response to ergonovine is well correlated with the spontaneous activity of the disease; thus the ergonovine test may be a useful tool in the assessment of the natural evolution of vasospastic angina.

Treatment of vasospastic angina pectoris at rest with nitroglycerin ointment: A short-term controlled study in the coronary care unit

The effectiveness of nitroglycerin ointment in vasospastic angina pectoris at rest was evaluated in 10 patients selected for study. The study was performed after a 24 hour control period, and a randomized single-blind crossover experimental design was followed. Two percent nitroglycerin ointment (15 mg) or placebo ointment was administered every 6 hours for a period of 48 hours each; the first treatment period was followed by a second in which each preparation was used for a 24 hour period. All patients were hospitalized in the coronary care unit; an objective evaluation was carried out using a multichannel electrocardiographic recording to assure recognition of the painless ischemic episodes. Coronary angiography showed critical stenosis of one or two vessels in 9 of the 10 patients; spasm was demonstrated in 3. Results of the ergonovine test were positive in nine of nine patients. Nitroglycerin ointment produced a significant reduction in the mean daily number of episodes during the first (12.5 +/- 3.9 versus 0.5 +/- 0.4, p less than 0.02) as well as the second treatment period (10.6 +/- 3.8 versus 0.6 +/- 0.4, p less than 0.02). These results demonstrate that nitroglycerin ointment provides effective, long-lasting protection against angina due to coronary spasm.

Spontaneous remission of variant angina documented by Holter monitoring and ergonovine testing in patients treated with calcium antagonists

Twenty-four patients with Prinzmetals variant angina showing a favorable initial response to calcium antagonist treatment were studied to assess the evolution of the disease and the frequency and time course of spontaneous remission. At 3, 6 and 12 months from the acute phase, patients underwent in-hospital control studies, with 48-hour Holter monitoring and ergonovine testing carried out during treatment and after its interruption. During calcium antagonist therapy complete protection from spontaneous attacks was documented in 22 of 24 patients at 3 months, in 19 of 21 at 6 months and in all 21 at 12 months; ergonovine test results were negative in 16 of 23 patients at 3 months, in 16 of 20 at 6 months and in all 20 studied at 12 months. After stopping treatment spontaneous attacks did not reappear in 7 of 24 patients (29%), 14 of 21 (66%) and 16 of 21 (76%) at 3, 6 and 12 months respectively, while the ergonovine test response remained negative in 6 of 21 (28%), 7 of 18 (39%) and 13 of 20 (65%) of the patients controlled at 3, 6 and 12 months. Thus, complete remission of angina documented by both Holter recording and ergonovine testing occurred in 5 of 24 patients (21%) at 3 months, in 7 of 21 (33%) at 6 months and in 12 of 21 (57%) at 12 months. Patients with remission of angina had a shorter duration of symptoms and more often showed normal or not critically diseased coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of Isoproterenol and Exercise Tests in Asymptomatic Subjects with Wolff-Parkinson-White Syndrome

In order to evaluate the effects of increases of sympathetic tone in ventricular response during atrial fibrillation and in the relationship between the accessory pathway effective refractory period (ERP) and ventricular rate during atria] fibrillation, 20 male subjects, aged 19 ± 6 years, were studied electrophysiologically in basal conditions, after isoproterenol infusion (2–4 μ/min) and during submaximal bicycle exercise test, at a constant workload equal to that which increases the sinus rate to the same extent (140 beats/min) induced by isoproterenol infusion. Accessory pathway ERP was evaluated at the same driven rate (150 beats/min) in both instances. In the control study as during both tests atrial fibrillation paroxysms were induced by burst stimulation. In control conditions the rate increase from 100 to 150 beats/min induced a reduction of accessory pathway ERP from 266 ± 27 msec to 244 ± 22 msec (P < 0.005). At the same driven rate of 150 beats/min, isoproterenol infusion and exercise test induced a more marked shortening of accessory pathway ERP to 211 ± 28 msec (P < 0.005) and to 214 ± 29 msec (P < 0.005), respectively. Atrial fibrillation paroxysms lasting more than 10 seconds were induced in 20/20 cases in the control study, in 15/20 during isoproterenol infusion and in 13/19 cases during exercise test. The shortest cycle length during atrial fibrillation was reduced from a basal value of 253 ± 72 msec to 204 ± 27 msec (P < 0.05) during isoproterenol infusion and to 236 ± 32 msec (NS) during exercise test. Similar behavior was observed in the mean cycle length during atrial fibrillation (from 372 ± 67 to 291 ± 36 and to 329 ± 70 msec, respectively). In conclusion, isoproterenol and exercise test, when exerting the same effect on sinus rate, induce the same accessory pathway ERP decrease, mainly due to a direct electrophysiological effect, which overcomes that secondary to increase in heart rate. Isoproterenol reduces the shortest and mean RR intervals during atrial fibrillation more than exercise test, probably because other determinants in addition to the accessory pathway ERP may influence heart rate during atrial fibrillation. The increase of sympathetic tone seems to reduce atrial fibrillation electrical inducibility.

A modified ajmaline test for prediction of the effective refractory period of the accessory pathway in the wolff-parkinson-white syndrome

Patients with the Wolff-Parkinson-White syndrome in whom the atrioventricular accessory pathway has a short anterograde effective refractory period (ERP) are considered at risk of sudden death if atrial fibrillation occurs. 1 Administration of ajmaline during sinus rhythm (50-mg intravenous bolus over 3 minutes) has been suggested as a test for identifying patients with an accessory pathway ERP shorter than 270 ms; in such patients the drug usually does not block anterograde conduction over the accessory pathway. 2 This study evaluates (1) the relation between dose of ajmaline, injected at a constant rate of 10 mg/min, blocking conduction over the accessory pathway, and duration of the accessory pathway ERP; (2) the reproducibility of the test, so modified; and (3) the possibility of predicting accessory pathway ERP on the basis of the dose of ajmaline blocking conduction over the accessory pathway. Thirty-two consecutive patients (21 men, 11 women), mean age 34 4- 15 years, with Wolff-ParkinsonWhite syndrome were studied. During continuous 6lead (I, II, III, V1,V~ and V6) electrocardiographic recording, ajmaline was administered intravenously at a constant rate of 10 mg,/min up to conduction block of the accessory pathway or a maximum total dose of 100 mg. The next day, after the patient gave informed written consent, electrophysiologic study was performed; the anterograde accessory pathway ERP was determined as the longest atrial premature beat interval not followed by anterograde conduction over the accessory pathway, at a driven rate 10 beats/rain faster than sinus rate. In 15 patients the ajmaline test was repeated after 24 to 72 hours. In 6 of the first 22 patients treated, ajmaline did not block conduction aver the accessory pathway: in 2 of them the accessory pathway ERP could not be determined because it was less than atrial refractoriness (250 and 200 ms, respectively) and in 4 the mean acces