[The relationship between conventional ECG and the culprit coronary artery in acute myocardial infarct]. / Relação entre o ECG convencional e a artéria coronária responsável no infarto agudo do miocárdio.

PURPOSE: To evaluate electrocardiogram (ECG) in detecting acute myocardial infarction (AMI) during the first 12 hours of symptoms and its relationship to the culprit coronary artery. METHODS: We studied 68 patients aged 55.6 (30 to 76) years, 61 males, with AMI confirmed by elevated CKMB isoenzyme and cinecoronariography (CINE). In all of them we obtained two ECG: first (i), with < 12 hours of symptoms and a second, > or = 5 days during evolution. ECG were analyzed in order to disclose up and downward ST-T segments > or = 1 mm, new Q waves > or = 0.04 s and R/S > or = 1 plus downward ST-T segment in leads V1 and V2. Then we have done correlation between these and the culprit coronary lesions at CINE. RESULTS: The culprit coronary lesions were: right coronary artery (RCA) in 16, left circumflex (LC) in 26 and left anterior descending (LAD) in 31 cases. According to the ECG, the RCA determined inferior AMI in all patients and the LC only in 62% of cases. Posterior AMI due to LC was seen in 81% of cases at ECG and, associated with lateral AMI, in 52%. Lone lateral AMI was seen in 5% and true posterior in 14% of cases, all of them due to LC. CONCLUSION: False negative ECG (i) in AMI is in fact due to LC occlusion which, frequently, causes posterior wall more then inferior wall myocardial infarction at ECG.

[Reproducibility of head-up tilt test in patients with neurocardiogenic syncope]. / Reprodutibilidade do teste de inclinação em pacientes com síncope neurocardiogênica.

PURPOSE: In order to identify the reproducibility of head-up tilt test, a second test one week later in 22 patients with a positive first test, was performed. METHODS: The test was performed in a fasting state during the morning. The heart rate and blood pressure were monitored during 20 minutes in the supine position and then at 60 degrees for up to 40 minutes. The test were considered positive if the patient experienced syncope or pre-syncope with fall in systolic blood pressure > 30mmHg. The following aspects were evaluated: reproducibility of the positive response; the type of response (hypotension, asystole or hypotension plus bradycardia) and the time interval between tilt and the beginning of symptoms. RESULTS: Eighteen (82%) patients had a second positive response; 14 (77.8%) of then had the same type of response; and 17 (94%) had syncope in similar time interval after tilt. CONCLUSION: The head-up tilt testing has good reproducibility, although its use in the therapeutic management needs a longer period of evaluation.

[Diagnostic value of the tilt test in the evaluation of syncope of unknown origin. Preliminary results]. / Valor diagnóstico do teste de inclinação na avalicção da síncope de origem indeterminada. Resultados preliminares.

PURPOSE: In order to identify neurally mediated syncope, head-up tilt testing was performed in patients with recurrent unexplained syncope. METHODS: The tests were performed in 125 patients in the fasting state, between 8:30 and 11:30 a.m. The blood pressure and heart rate were continuously monitored during 20 minutes in the resting state, and then, positioned at 60 degrees angle, for up to 40 minutes. A group of 20 patients with first negative test was submitted to intravenous isoproterenol in bolus of 2 micrograms every 2 minutes until symptoms occur or at a total dose of 8 micrograms. The test was considered positive when systolic blood pressure decreased at least 30 mmHg and the patient experimented syncope or pre-syncope. RESULTS: In 52 patients the test was positive (41.6%), 63.5% of which had hypotension exclusively; 7.7% asystole; and 28.8% had hypotension and bradycardia. Nine of the 20 patients submitted to isoproterenol test were positive (45%). All patients recovered spontaneously after returning to supine position. CONCLUSION: Head-up tilt testing is a safe and effective method for the identification of neurally mediated syncope.

[Catheter ablation of accessory pathways with low energy. Results in 40 consecutive patients]. / Ablação por cateter de vias acessórias com choques de baixa energia. Resultados em 40 pacientes consecutivos.

PURPOSE: To evaluate the results of direct current catheter ablation of accessory pathways by mean of a new low energy power source. METHODS: Catheter ablation was performed in 40 consecutive patients (23 male, mean age 31 +/- 11 years) with accessory atrioventricular pathways (AP) using a low energy DC power source. The electrophysiologic study and AP ablation were performed in the same procedure by endocardial approach using non-deflectable 6F bi, tri, or quadripolar electrodes. RESULTS: AP was located at left free wall (LFW) in 22 patients (55%), posteroseptal (PS) in 11 patients (27.5%), anteroseptal (AS) in 5 patients (12.5%) and right lateral (RL) in 2 patients (5.0%). A mean of 7.7 +/- 7 catodal shocks of 5-75 (20) joules (J) was delivered in 1.45 +/- 7 sessions, with a mean cumulative energy of 178 +/- 213J per patient. The mean values of number of shocks, number of sessions and cumulative energy per patient were lower in LFW AP ablation than in other positions (5 +/- 4 x 11 +/- 8 - p = 0.008; 1.1 +/- 0.3 x 1.8 +/- 0.9 - p = 0.008 and 118 +/- 150 x 260 +/- 245 - p = 0.03). The mean CK-MB rise was 18.5 +/- 7.8U/1. Three patients (7.5%) presented hemopericardium after PS AP ablation and in 1 patient (2.5%), a PS AP (paranodal pathway) ablation resulted in total atrioventricular block. During a follow-up of 9.5 +/- 4 months AP was absent in 28 (70%) patients; 18/22 (82%) with LFW AP, 6/11 (54%) with PS AP, 3/5 (60%) with AS AP and 1/2 (50%) with RL-AP, (p = 0.10). CONCLUSION: Low energy DC ablation is effective for AP ablation. The results are related with AP position.

[The surgical treatment of nodal reentry tachycardia. The late results]. / Tratamento cirúrgico da taquicardia por reentrada nodal. Resultados tardios.

PURPOSE: To analyze the long-term results of surgical treatment of atrioventricular nodal reentrant tachycardia (AVNT). METHODS: From March 1987 to March 1990, 20 patients with AVNT were submitted to surgical therapy, 14 female, aged 12 to 70 (42.8 +/- 17) years. All presented crisis of AVNT from 6 months to 60 (18.4 +/- 15.9) years. Ten of them had syncope or near syncope and two with cardiac arrest during reversion of AVNT with antiarrhythmic drugs. They used 1 to 6 (3.75 +/- 1.45) antiarrhythmic drugs before surgery. The electrophysiologic study (EPS) showed the common form of AVNT in all cases. The surgical procedure was anatomically directed to the posterior area of the AV node. Programmed atrial stimulation (PAS) were applied on 18 patients after surgery. The long-term results were analysed by clinical evaluation, EPS and Holter when they were necessary. RESULTS: The postoperative PAS was done in 18 patients and did not induce any AVNT, even after atropine IV. The PR interval was 153 +/- 50 ms before and 152 +/- 38 ms after surgery (p > 0.05). During follow up (26 +/- 10 m) there were not AVNT recurrence. Two patients developed chronic atrial fibrillation after 24 months of surgery. CONCLUSION: The perinodal dissection technique used was safe and successful to treat AVNT, preserving AV nodal conduction.