[Evaluation of the time of appearance of myocardial ischemia during coronary angioplasty: comparison of the intracoronary electrogram and surface electrogram].
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Biomedical subjects
Publications and source records attributed to A Maresta.
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To define the risk of side branch occlusion during percutaneous transluminal coronary angioplasty (PTCA), 99 consecutive procedures, performed on 92 patients, were examined. In 77 of them side branches existed, originating from the stenosed segment; analysis was performed on 65 successful procedures (success rate = 84.4%). The 121 side branches were divided as follows: 53 (43.8%) originating from the stenosis itself (group A), of which 32 small in size (less than 1 mm) and 21 "moderate" (greater than or equal to 1 mm); 68 (56.2%) originating in the immediate vicinity of the stenosis (group B) of which 23 small and 45 moderate. After PTCA 3 side branches were occluded (2.5%): a small 1 of group A and 2 (1 small and 1 moderate) of group B. Three side branches (2.5%) all of group B, 1 small and 2 moderate, became stenotic in their take-off. In one only patient who had a side branch occlusion a slight CK-MB elevation (25 mU/ml) occurred together with a Q wave appearance in the aVL lead. In conclusion, side branches at risk are frequently present (in our population they account for 83.7% of the patients) but the real incidence of damage of these branches after PTCA is quite low, without any considerable difference between groups A and B, and significant clinical consequences are usually rare.
A randomized trial was performed in 22 patients with unstable angina to compare the efficacy of oral verapamil with nifedipine in reducing symptomatic ischaemic episodes. The trial consisted of a 48 h control period, a 96 h treatment period with nifedipine (20 mg every 6 h) or verapamil (120 mg every 6 h), and a follow-up period. Patients who had a minimum of four symptomatic ischaemic episodes during the control period were entered into the trial. Asymptomatic ischaemic episodes were evaluated by Holter monitoring. Coronary angiography was performed at the end of the treatment period. Both nifedipine and verapamil significantly reduced the mean number of daily symptomatic ischaemic episodes (p less than 0.01) and the total number of ischaemic episodes (p less than 0.03). This study confirmed the high degree of efficacy of both nifedipine and verapamil in reducing the number of ischaemic episodes during short-term treatment of unstable angina. Nevertheless, a significant number of myocardial infarctions occurred in these patients, and some required subsequent coronary bypass graft operations.
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Lidocaine (L) in still considered the drug of choice in the treatment of life threatening ventricular arrhythmias in the setting of acute myocardial infarction (A.M.I.): this is mainly due to its proved efficacy and high therapeutic index. Since however L has well defined electrophysiologic properties (class 1 B) and does not seem to be effective in all of these patients we compared its antiarrhythmic efficacy with the one of amiodarone (A), an antiarrhythmic agent provided of electrophysiologic properties quite different from L (class 4) and usually well tolerated. Twenty-five consecutive patients with A.M.I. without haemodynamic consequences, were randomly assigned to L (bolus of 1 mg/kg followed by an infusion of 10 mg/min for 20 minutes and thereafter of 1,5 mg/min) or A (bolus of 5 mg/kg and an eventual repeat dose of 150 mg followed by an infusion of 1,8 g/24 h) The baseline arrhythmia was classified as Lown class 2 ore more in all the patients. The ventricular arrhythmias were completely relieved in 47% of the patients assigned to L and in 60% of those treated with A (p = N.S.); a minor efficacy was found in 40% of the patients of both groups; in two cases ventricular fibrillation occurred after the acute infusion of L. The antiarrhythmic effectiveness kept fit with both drugs over a 24 hours period. A prolongation of QTc interval was found to occur both after the bolus and 24 hours of treatment with A. In addition A provoked a slight decrease of systolic blood pressure. No important side effects were observed with both drugs regimens.(ABSTRACT TRUNCATED AT 250 WORDS)
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A double-blind, cross-over study was performed in 23 consecutive patients with unstable angina at rest in order to compare the efficacy of verapamil (480 mg/day) and propranolol (240 mg/day) in reducing the number of anginal crises and nitroglycerin (NTG) consumption. Twenty patients, 15 men and five women, mean age 59.7 (range 45-68) years completed the study. The mean daily number of attacks was 3.1 in the two-day run-in period and 2.9 in a subsequent two-day placebo period immediately preceding the treatment periods. Propranolol reduced the number of attacks to 1.6 (P less than 0.01 compared to the run-in and placebo periods). Verapamil reduced the crises to 0.2/day (P less than 0.01 compared to the run-in placebo and propranolol periods). The NTG consumption behaved in a similar way. Adverse reactions to verapamil were observed in two patients. Although there are objective difficulties in performing correct trials in these kinds of patients, the results of this study indicate the efficacy of verapamil in preventing anginal pains during the "warm phase' of the unstable form and stress the superiority of this calcium antagonist when compared to propranolol.
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In a consecutive series of 297 patients prospectively evaluated at the time of admission for an acute myocardial infarction, the extension of necrosis was found to occur in 16,4% of the cases. The electrocardiographic site of extension was the same as during the initial episode in over 75% of cases suggesting the possibility of a similar pathogenetic mechanism and the involvement of the same coronary district. Patients in Killip class I were respectively 61% and 45% before and after the extension, in class II 33% and 14%, in class III 6% and 14%, in class IV 0 and 27% (p less than 0,001). In-hospital mortality was 16,1% without and 38,8% with extension (p less than 0,001). The peak level of CPK-MB was an average of 110 +/- 45 U/1 before and 96 +/- 34 after the extension (p = N.S.). It was not possible to recognize the patients at risk of extension according to the traditional clinical parameters (age, sex, site of necrosis, transmural involvement, residual angina, Norris index and Killip class before the extension). It is concluded that the protection of the myocardium at risk is of primary importance in the setting of acute myocardial infarction, regardless of the possibility of saving areas already compromised at the time of admission or the hypothetical "border zone".
Discriminant analysis was carried out in 83 patients with acute myocardial infarction who underwent hemodynamic monitoring, to obtain a prognostic index. The classification rate was satisfactory in over 80% of the patients both in a subset used to construct the prognostic index and in a pilot group in which the validity of the index was assessed. In decreasing order of importance the parameters in the function were: age, history of angina, pulmonary artery end-diastolic pressure, diastolic systemic pressure, sum of ST segment elevation, pulmonary vascular resistance, heart rate, history of hypertension and site of necrosis. A much less satisfactory classification rate was obtained using two well-established indexes, perhaps because of sampling, methodological and chronological differences. It thus seems desirable for each hospital to use prognostic indexes obtained from its own population. Such indexes should be updated whenever necessary.
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