Análise do bloqueio do ramo esquerdo pelo mapeamento eletrocardiográfico de superfície. Comparação com os achados eletro-vetorcardiográficos / Left bundle branch block analysis by body surface mapping. Comparison with electrocardiographic and vectocardiographic findings

PURPOSE: To compare the correlation between the departure areas (DA), negative or positive, in patients whose electrocardiogram showed left bundle branch block (LBBB) and association with left ventricular hipertrophy (LVH) and myocardial infarction (MI), to the electrocardiographic (ECG) and vectocardiographic (VCG) classic criteria. METHODS: The study was carried out with 46 patients (27 males) with LBBB. These patients had hypertension (19.5), coronary heart disease (34.7) and 21 patients with no heart disease (45.8). RESULTS: The statistic analysis using the Cluster method divided the patients in two groups. Group I (22 patients) showed an average rate for the DA (-2 SD) of 1091 for QRS and of 640 for ST-T. For the DA (+2 SD), the average rate was 618 for QRS and 881 for ST-T; group II (24 patients) showed an averaged for the DA (-2 SD) of 1063 for QRS and of 225 for ST-T. For the DA (+2 SD), the averaged rate was 428 for QRS and 600 for ST-T. CONCLUSION: In general the current ECG/VCG findings, can not differentiate the presence of the association of LBBB to LVH and MI. The DA of ST-T, mainly negative was the most efficient to separate the two groups and help in the differential diagnosis.

Signal-averaged electrocardiogram in chronic Chagas' heart disease

The aim of the study was to register the prevalence of late potentials (LP) in patients with chronic Chagas' heart disease (CCD) and the relationship with sustained ventricular tachycardia (SVT). 192 patients (96 males), mean age 42.9 years, with CCD were studied through a Signal Averaged ECG using time domain analysis. According to presence or absence of bundle branch block (BBB) and SVT, four groups of patients were created: Group I (n = 72): without SVT (VT-) and without BBB (BBB-): Group II (n = 27): with SVT (VT+) and BBB-; Group Ill (n = 63): VT- and with BBB (BBB+); and Group IV (N = 30): VT+ and BBB+. The LP was admitted, with 40 Hz filter, in the groups without BBB using standard criteria of the method. In the group with BBB, the root-mean-square amplitude of the last 40 ms (RMS) < = 14 microV was considered as an indicator of LP. Results: In groups I and II, LP was present in 21 (78 percent) of the patients with SVT and in 22 (31 percent) of the patients without SVT (p < 0.001), with Sensitivity (S) 78 percent; Specificity (SP) 70 percent and Accuracy (Ac) 72 percent. LP was present in 30 (48 percent) of the patients without and 20 (67 percent) of the patients with SVT, in groups Ill and IV. p = 0.066, with S = 66 percent; SP = 52 percent; and Ac = 57 percent. In the follow-up, there were 4 deaths unrelated to arrhythmic events, all of them did not have LP. Eight (29,6 percent) of the patients from group II and 4 (13 percent) from group IV presented recurrence of SVT and 91,6 percent of these patients had LP. Conclusions: LP occurred in 77.7 percent of the patients with SVT and without BBB. In the groups with BBB, there was association of LP with SVT in 66,6 percent of the cases. The recurrence of SVT was present in 21 percent of the cases from which 91,6 percent had LP.

Valor do teste de esforço computadorizado no diagnóstico diferencial entre fenômenos isquêmicos de origem obstrutiva e näo-obstrutiva / Value of Computadorized Exercise Stress Test in the Differentiation Among Ischemic Phenomena of Obstructive and Non-obstructive Origin

PURPOSE--To describe groups of patients who have obstructive and non-obstructive coronary artery disease, through computadorized exercise stress test. METHODS--The test was done in 121 patients, all male, divided into 3 groups: GN group, 50 patients with normal electrocardiographic response to exercise; GLO group, 40 patients with obstructive coronary artery disease and GNO group, 31 patients with normal coronary arteries, showing one or more of the following entities: intramural coronary traject, coronary tortuosity, slow flow, mitral valve prolapse or left ventricular hypertrophy. GLO and GNO groups presented with abnormal response of the ST segment during exercise. The quantitative variables registered by computer were particularly analyzed as follows: STL (point Y depression), slope, index and ST segment integral. The magnitude of ST vector was visually measured and quantified. The statistic study was made through ANOVA and multiples comparison by the Scheffe's method, Fisher's test, quisquare and sensibility, specificity and accuracy calculation. RESULTS--There was a significant statistic difference among the 3 groups relative to slope and index (p < 0.05). The integral variable of ST segment did not allow us to differentiate the GLO and GNO groups. In the association study between the ST vector magnitude and abnormal T loop, there was an increase in sensibility of 15//in the exercise stress test. CONCLUSION--The ST segment slope below zero values, define patients having obstructive disease, and the opposite, non-obstructive disease. Values of ST segment index lower than -2 are linked to obstructive disease and higher than -2 linked to non-obstructive. Values of ST segment lower than -7 microV. s separate individuals with normal exercise stress test from those with ischemic type response. The magnitude of ST vector equal to or lower than 0.20mV define normal vectorcardiographic response to the exercise

Ritmos ectópicos atriais: conceitos gerais, padröes eletrocardiográficos / Ectopic atrial rhytmis: general concepts; electrocardiography patterns

A finalidade deste trabalho é a de sistematizar os ritmos atriais, baseados na orientaçäo do vetor médio da despolarizaçäo atrial e, algumas vezes também, em alteraçöes da morfologia da onda P. Assim, foram estabelecidos padröes com características eletrocardiográficas próprias: o juncional A-V, em que AP está orientado para a esquerda e para cima; no atrial esquerdo alto AP se dirige para baixo e para a direita; quanto ao atrial esquerdo baixo o vetor de despolarizaçäo atrial aponta também para cima e para esquerda, mas com repercussäo em derivaçöes do plano horizontal; finalmente, o atrial direito baixo tem como características a orientaçäo de AP entre +20§ e -30§, associada a alteraçöes do contorno da onda P. Foram feitas referências ao ritmo do seio coronário. Foi efatizado que o mecanismo básico de cada padräo eletrocardiográfico näo tem, necessariamente, relaçäo com o que pode surgerir a denominaçäo atribuída a cada um deles. Algumas hipóteses da eletrogênese dessas arritmias säo apresentadas, com base em trabalhos referendados no final deste artigo

Bloqueios divisionais do ramo direito na miocardiopatia chagásica / Divisional block of the right branch in Chagas' cardiomyopathy

A análise do eletrocardiograma de 600 portadores de miocardiopatia chagásica revelou bloqueio divisional do ramo direito em 46 pacientes (7,6%), evidenciado por atraso final de conduçäo e confirmado pelo vetorcardiograma. Vinte e três pacientes (50%) apresentavam bloqueio divisional superior do ramo direito (BDSRD), 14 (30,4%) bloqueio divisional médio do ramo direito (BDMRD) e nove (19,5%) bloqueio divisional inferior do ramo direito (BDIRD). Enfatiza-se a importância do reconhecimento desses bloqueios habitualmente näo valorizados no eletrocardiograma convencional, permitindo o diagnóstico mais apurado e evolutivo dos distúrbios de conduçäo nas diferentes formas clínicas da miocardiopatia chagásica

Bloqueios divisionais do ramo direito na miocardiopatia chagásica / Divisional blocks of the right branch in Chagas' cardiomyopathy

A análise do eletrocardiograma de 600 portadores de miocardiopatia chagásica revelou bloqueio divisional do ramo direito em 46 pacientes (7,6%), evidenciado por atraso final de conduçäo e confirmado pelo vetorcardiograma. Vinte e três pacientes (50%) apresentavam bloqueio divisional superior do ramo direito (BDSRD), 14 (30,4%) bloqueio divisional médio do ramo direito (BDMRD) e nove (19,5%) bloqueio divisional inferior do ramo direito (BDIRD). Enfatiza-se a importância do reconhecimento destes bloqueios habitualmente näo valorizados no eletrocardiograma convencional, permitindo o diagnóstico mais apurado e evolutivo dos distúrbios de conduçäo nas diferentes formas clínicas da miocardiopatia chagásica

Bloqueios divisionais do ramo direito e áreas eletricamente inativas: diagnóstico diferencial eletro-vetocardiográico / Divisional block of the right bundle-branch and electrically inactive areas. Electrovectorcardiographic differential diagnosis

Estudam-se 100 pacientes assintomáticos (idade entre 13 e 56 anos), 82 homens, com características veto-eletrocardiográficos semelhantes, atraso final de conduçäo (AFC), na tentativa de caracterizar padröes no ECG e no VCG para o reconhecimento dos bloqueios divisionais do ramo direito. No bloqueio da divisäo superior do ramo direito (BDSRD), observa-se no ECG: 1) eixo de QRS orientado entre 30.- e 90.- ou indeterminado; 2) duraçäo de QRS normal; 3) onda S de D2 maior ou igual a onda S de D3; 4) onda R empastada em aVR; 5) ondas S presentes nas derivaçöes V5 e V6. No vetocardiograma, nota-se: 1) alça de QRS no plano frontal com orientaçäo inicial esquerda, para cima ou para baixo, rotaçäo anti-horária e morfologia afilada; 2) alça de QRS com rápida mudança de rotaçäo no momento 40 ms tanto no plano frontal quanto no horizontal, orientado para a direita; 3) AFC nos planos (horizontal, frontal e sagital) com 30 ms de duraçäo (12 cometas), orientado no PF entre 210.- e 260.-. Para bloqueio divisional inferior ou médio do ramo direito (BDIRD ou BDMRD) observou-se no ECG: 1) eixo de QRS orientado entre + 60.- - 150.-; 2) duraçäo do complexo QRS normal; 3) onda R em aVR empastada; 4) onda R nas derivaçöes D2 e D3 com baixa voltagem (näo maior que 10mm) e com entalhes na porçäo descendente; 5) ondas S presentes nas derivaçöes V5 e V6. No vetocardiograma, registra-se: 1) a alça de QRS, no PF, com orientaçäo inicial para esquerda, para baixo ou para cima e rotaçäo horária. 2) alça de QRS com rápida mudança de rotaçäo no 40.-, tanto no PF quanto no PH (da esquerda para direita) 3) AFC nos planos com duraçäo de 30 ms (12 cometas), orientado no PF, para o BDIRD, entre 120.- e 150.- para o BDMRD, entre 180.- e 200.-