| Background AMI with ventricular arrhythmia is one of the most acute diseases which endanger the victim's life, moreover, it is the independent risk factor which often leads to death. Therefore, the treatment of ventricular arrhythmia has magnificent meaning for people's life. But, as it has often been reported, it is a tough and complex job.It has long been customary for us to choose Ib medicine in the first place in the treatment of ventricular arrhythmia for many years. For instance, intravenous lidocaine is very popular in the treatment of ventricular arrhythmia for its low price, good effectiveness and fewer side-effects of low blood pressure. However, as the development of Evidence Based Medicine (EBM), it has been found that lidocaine may have many serious side-effects, such as, its proarrhythmic effects, often leading to the deterioration of heart failure. Besides, we only have intravenous lidocaine instead of oral lidocaine, and it seems that it can not reduce the incidence of cardiac event. Recently, heart physicians begin to use intravenous amiodarone to treat ventricular arrhythmia such as, ventricular premature beat. Amiodarone first came into being as the drug used in myocardial ischemia. In the 1970's, Singh discovered its electrophysiologic mechanisms and it has become so widespread as a kind of antiarrhythmic medicine of high potency and broad spectrum. People used to be so excited for its super-effect in the treatment of malignant ventricular arrhythmia. However, as time pass by, the application of amiodarone is great limited by side-effects on heart and other systems, especially irreversible pulmonary fibrosis. From the 1970's when its antiarrhythmic effects have been found, we have seen the development of amiodarone experienced the processes from crest, then to trough, then back to its starting point again. As soon as this new knowledge is acquired by more and more doctors, it is now turned to practical account. Moreover, it exerts an important part once more as antiarrhythmics medicine of broad spectrum. In spite of this, we should make the further intellectual effect needed to comprehend amiodarone in its full completeness, so that we can serve the patients better.Up to now, most of the domestic and foreign experiments of amiodarone focus on the study of its effectiveness to supraventricular tachycardia, atrial fibrilation, cardiopulmonary resuscitation. And there are fewer amiodarone studies about the efficacy of amiodarone in the treatment of AMI with ventricular arrhythmias and about other advantages compared with lidocaine. This study is a case-control study. Objective (1) The goal of this study was to investigate the efficacy of intravenous amiodarone in the treatment of AMI with ventricular arrhythmia and the comparison of therapeutic effects of lidocaine. (2) to investigate the side-effects of amiodarone and lidocaine on heart and other systemMaterial and methods1. Patients There were 62 patients with acute myocardial infarction complicated ventricular arrhythmia. All patients underwent physical examination, laboratory checkup 18-lead electrocardiogram (ECG), and 24h ambulatory ECG examinations before the study. Patients were excluded if they had hypokalemia. The 62 patients were divided into two groups randomly. The group of amiodarone (n=30) had 22 men and 8 women with mean age 53.6±6.4 years, There were 10 patients with extensive anterior wall acute myocardial infarction, 7 patients with septal acute myocardial infarction, 6 patients with inferior wall acute myocardial infarction, 4 patients with inferior and right ventricular acute myocardial infarction, 3 patients with high lateral acute myocardial infarction. There were 19 patients with frequent premature ventricular contractions (PVCs, mean PVCs>30 beats/hour). 3 patients with couple PVCs, 5 patients with multifocal PVCs, 6 patients with paroxysmal ventricular tachycardia. The group of lidocaine (n=32) had 20 men and 12 women with mean age 54.4±10.1 years. There were 8 patients with extensive anterior wall acute myocardial infarction, 10 patients with septal acute myocardial infarction, 6 patients with inferior wall acute myocardial infarction, 4 patients with inferior and right ventricular acute myocardial infarction, 4 patients with high lateral acute myocardial infarction. 20 patients with frequent PVCs, 3 patients with couple PVCs, 3 patients with multifocal PVCs, 3 patients with paroxysmal ventricular tachycardia. There was no significant difference between two groups, such as age, sex, location of AMI, and type of ventricular arrhythmias.2 Study Design A single-blind and crossover study was performed on each patient. The group of amiodarone was treated by intravenously 3mg/kg during the first 10 minutes. Supplemental infusion (150 mg) of intravenous amiodarone was given to treat breakthrough ventricular arrhythmias after 30 minutes. After that, intravenous amiodarone was given at the speed of 0.5-1mg/kg. At the same time, Oral amiodarone was given 0.2g, tid. The group of lidocaine was treated by intravenously 1mg/kg at first. Then was given 0.5mg/kg each 10 minutes until ventricular arrhythmias disappear or the total amount reached to 3-4mg/kg, and then supplemental infusions was given at the speed of 20-50μg/kg. The patients of two groups were observed for three days. Amiodarone and lidocaine were stopped or reduced does if heart rate was under 50 beats/min and QTc prolonged 30 percent. Cardioversion was applied if hemodynamic was instability. QT intervals and QT dispersions were determined before and after the treatment. The formula are QTd=QTmax-QTmin and QTc=QT/RR.3 Clinical observation The items of observation included: treatment effective rate, the effective rate of preventing atrial fibrillation, atrial flutter and paroxysmal supraventricular tachycardia, the relapse rate of chest pain, mortality, total incidence rate of side-effect, QTc and QTd.4 statistical method All results were expressed as meanlstandard deviation of the mean. Date was tested by t test, and X~2 examination. P <0.05 was considered a significant difference.Results The group of amiodarone: 28 cases were treated by amiodarone successfully, 2 cases were ineffective. Total treatment effectiverate of amiodarone was 93.3% (28/30 cases). Of 2 ineffective patients, synchro-direct current by amiodarone was used on one case with hemodynamic instable and got success, but frequnt paxoxysmal ventricular tachycaxdia. 1 case finally was developed to Ventricular fibrillation, after synchro-direct current worsten to death. Mortality was 3.3%(1/30 cases). The group of lidocaine: 20 cases were treated by lidocaine successfully. Total treatment effective rate of lidocaine was 62.5% (20/32 cases). 9 cases were treated by lidocaine were unsatisfied effectively. 2 cases with deteriorated cardiac function died of pump failure. 1 case with ventricular fibrillation was treated repeatedly with current diversion and even worsten to death at last. Mortality was 9.3 (3/32 cases). The treatment effective rate of amiodarone was higher than that lidocaine (P<0.05), which had statistical difference. But there was no statistical difference in their mortality (P>0.05). While the total incidence rate of side-effect of group of lidocaine was higher than that of amiodarone (P<0.05). Two groups had significant statistical difference. The relapse rate of chest pain of amiodarone group was lower than that of lidocaine group (6.6% vs 40.6%) (P<0.05); Amiodarone group had better effect on preventing Af and SVT. Occurrences of Af and SVT were (amiodarone) 3.3% vs (lidocaine) 28.1% (P<0.05). Two groups had significant difference in statistical. The variation of QTc had no statistical difference between the two groups. In the same time after the treatment QTd was obviously decreased on amiodarone group (34±12 vs 21±9) (P<0.05). The variation of QTd on lidocaine group after the treatment had no statistical difference (32±11vs 29±14)(p>0.05).Conclusion Compared with traditional antiarrhythmic drug-lidocaine, amiodarone has better treatment effect: on acute myocardial infarction complicated ventricular arrhythmia (ventricular premature beats, ventricular tachycardia and ventricular fibrillation. Treatment effective rate is (amiodarone) 93.3% vs (lidocaine) 62.5% (P<0.05). It is better than lidocaine on preventing Af and SVT. The total incidence rate of side-effect of the amiodarone is lower than that of lidocaine.This clinical trial has indicated that amiodarone could be the first-selected, safe and effective drug for acute myocatdial infarction combined with ventricular arrhythmia. |
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