Estudo de perfusão miocárdica em portadores de bloqueio de ramo direito / Myocardial perfusion study in patients with right bundle branch block

PURPOSE: To evaluate the sensitivity and specificity of myocardial perfusion scintigraphy in the detection of coronary artery disease in patients with right bundle branch block (RBBB). METHODS: Thirty one patients (24 male, 62.3 +/- 10.5 years) with RBBB, submitted to myocardial perfusion scintigraphy associated with exercise (n = 7) or dipyridamole (n = 24) and previous cinecoronariography were studied retrospectively. Left ventricle scintigraphic image was divided in three segments corresponding to the three main epicardic coronary territories in a total of 93 segments. Cineangiographic and scintigraphic data were then compared according to the different artery territories. RESULTS: Twenty three patients had significant lesions (> or = 60) in one or more coronary arteries and eight had no obstruction. Forty nine segments were irrigated by normal coronary arteries and 44 were related to arteries that had significant lesions. Twenty out of twenty three patients showed alterations in perfusion (sensitivity = 87). All patients without coronary obstructions showed normal perfusion scintigraphy (specificity = 100). One of the segments perfused by normal coronaries showed abnormal scintigraphy. Scintigraphy showed perfusion defects in 29 out of 44 segments with coronary obstructions. Sensitivity and specificity of the method for each arterial territory were 72and 100(left descending coronary artery), 67and 94(right coronary artery), 55and 100(circunflex coronary artery), respectively. CONCLUSION: The presence of RBBB does not modify the sensitivity and specificity of the method in the detection of coronary artery disease.

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.

Estudo da viabilidade miocárdica através do SPECT-Tálio-201: redistribuiçäo convencional versus reinjeçäo / Myocardial Viability Assessed by Tl-201 SPECT. Redistribution Versus Reinjection

Objetivo - Verificar se uma 3ª série de imagens obtidas pela reinjeçäo do tálio-201, 24h após tomografia convencional de perfusäo miocárdica com esse radioisótopo, melhora a identificaçäo de áreas de viabilidade miocárdica. Métodos - Foram estudados 30 pacientes masculinos, com idade média de 57,7 + ou - 9,4 anos, com infarto do miocárdio antigo através de SPECT (single-photon-emission computed tomography) - tálico-201, obtendo-se 3 séries de imagens (estresse, redistribuiçäo após 4h e reinjeçäo após 24h). As imagens foram interpretadas, dividindo-se o coraçäo em 5 paredes(apical, lateral, anterior, septal e inferior(, atribuindo-se a cada uma delas um valor, através de sistema de escore de 4 pontos (0= captaçäo normal; 1=hipocaptaçäo discreta; 2=hipocaptaçäo moderada; 3=hipocaptaçäo acentuada ou ausência de cpataçäo). Foi considerado miocárdio viável quando houve melhora em pelo menos um poto no escore total da parede, em pelo menos duas projeçöes no território relacionado ao infarto (determinado pelo eletrocardiograma de repouso). Resultados - Se (23,3 por cento) pacientes mostraram melhora de captaçäo do radiofármaco, exclusivamente durante a reinjeçäo, denotando melhora na eficácia do método. Nove (30 por cento) apresentaram hipocaptaçäo persistente em todos os momentos, sugerindo fibrose na área relacionada ao infarto. Apresentaram melhora da captaçäo já na redistribuiçäo 14 (46,7 por cento) pacientes e, destes, 6 obtiveram melhora ainda maior na reinjeçäo. Esta condiçäo foi interpretada como processo isquêmico regional crônico, ou seja, miocárdio hibernante. Conclusäo - Imagens de redistribuiçäo hipocaptantes, sem alteraçöes significativas em relaçäo às imagens de estresse, näo necessariamente indicam fibrose. A técnica de reinjeçäo foi superior ao SPECT convencional na detecçäo de miocárdio viável, o que permitiu melhor orientaçäo terapêutica

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

Cintilografia de perfusäo miocárdica associada ao estresse farmacológico com dipiridamol / Scintigraphy of myocardial perfusion combined with pharmacologic stress with dipyridamole

PURPOSE--To analyze adverse reactions (AR), hemodynamic and electrocardiographic changes and thallium scintigraphy (TS) results, during pharmacological stress with dipyridamole (SD), correlating these data to the presence and extension of coronary artery disease (CAD). METHODS--We studied 126 patients, 66 had no evidence of cardiovascular disease (G1) and 60 had critical occlusive CAD > or = 70 per cent stenosis (G2). Most of them were male, mean age 56.5 +/- 10.9 years old. All patients were submitted to TS after receiving 0.56 mg/kg of dipyridamole intravenously (0.14 mg/min during 4 min) followed by 111MBq of thallium-chloride-201. Conventional ECG was recorded before and after SD; heart rate (HR) and arterial pressure (AP) were monitored during dipyridamole infusion. All signals and/or symptoms were observed. RESULTS--Cine-coronarography showed 22 patients (37 per cent ) with one vessel disease (VD) (G2a), 26 (46 per cent ) with two VD (G2b) and 12 (20 per cent ) with three VD (G2c). Of the 126 patients 63 per cent did not present symptoms. Flushing (25 per cent ) and sick-headache (12 per cent ) were most frequent AR. Typical angina was reported by one G1 patient (1.5 per cent ) and six G2 patients (10 per cent ) (p < 0.05). HR increased 18.09 +/- 12.27 per cent and 12.40 +/- 4.90 per cent , systolic blood pressure varied -5.2 +/- 7.5 per cent and -4.3 +/- 6.5 per cent in G1 and G2, respectively. These parameters are not correlated to CAD presence and extension. ST depression and ectopic beats occurred in 5 per cent and 11 per cent of G1 patients, in 15 per cent and 30 per cent of G2 patients, respectively (p < 0.05). Typical angina was more common in G2a and G2b; ST changes in G2b and G2c; and arrhythmia in G2c (not significant). Sensitivity of TS associated to SD was 84 per cent , comparable to stress exercise thallium test. CONCLUSION--TS associated to SD, a noninvasive, safe with low morbidity and few collateral effects method is an option to patients with limitations to physical exercise tests

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.-