Contribution of the vectorcardiogram in the differential diagnosis of Brugada electrocardiographic pattern.

BACKGROUND: The electrocardiogram (ECG) is a powerful tool for differential diagnosis among a group of pathologies with different therapeutic approaches/prognoses, the so-called J-wave syndrome. The vectorcardiogram (VCG) can be used as a complementary method to the ECG in several dubious electrocardiographic alterations. OBJECTIVE: We carried out a VCG analysis after conceiving and measuring a novel parameter (JT-distance) that allows diagnosis of the Brugada ECG pattern. METHODS: A retrospective cohort study selected ninety-six ECGs with J-point elevation in V1/V2, ECG superior leads and VCGs, all performed on the same day. A new VCG measurement by Frank method (JT-distance) was conceived and designed in transverse and right sagittal planes by 3 lines drawn 1) at the final third of the QRS loop, comprehending the J-point; 2) at the initial portion of the T loop; 3) a parallel of the J-point line at the beginning of the T loop. JT measure was determined by the distance between parallels. A validation cohort was established in a new sample of thirty-five patients. RESULTS: JT-distance ≥1.5 mm (tranverse plane) and JT-distance >1.25 mm, in the sagittal plane, differentiated Brugada type-1 from Brugada type-2, early repolarization and others, with 95% sensitivity and 68% specificity. JT-distance <1.5 mm (transverse plane) and JT >1.25 mm (sagittal plane) had 100% sensitivity and 85% specificity for Brugada type-1 diagnosis. A validation cohort showed very similar Cohen's kappa levels (0.65 and 0.77, test and validation cohorts, respectively), with overlapping 95% confidence intervals. CONCLUSIONS: The novel vectorcardiogram measurement (JT-distance) presented a new diagnostic criterion to identify Brugada pattern. Nevertheless, prospective studies should be performed by other centers to confirm these findings.

[Intermittent antero-medial divisional block in patients with coronary disease]. / Bloqueio divisional ântero-medial intermitente em paciente com insuficiência coronária.

We report the case of a 69 year-old male who developed congestive heart failure functional class IV (NYHA). The admission electrocardiogram (EKG) revealed sinus rhythm, PR interval of 240 ms, QRS interval of 110 ms, the QRS vector of 0 degree, Q waves from V1 to V6, tall R waves from V1 to V4 that decreased to V5 and V6. The vectocardiogram had anteriorization of the electrical forces of QRS, with vector half area in the horizontal plane at +60 degrees. After two years the patient had a myocardial infarction, the EKG at the admission had the same pattern and after two days developed important changes: enlargement of QRS interval with length of 160 ms, QRS vector of +100 degrees, R waves at D2, D3 e AVF that increase from D2 to D3, QS at D1, AVL, AVR and V1, rS at V2 and V3, R wave is notched and thickened+ at V5 and V6, that return to the initial pattern after one day. The patient progressed to death in the eighth day after infarction. This case reported a intermitent pattern of EKG that is an uncontestable proof to the existence of the left middle fascicular block.

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

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.

UNLABELLED: 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 III (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%) of the patients with SVT and in 22 (31%) of the patients with SVT (p < 0.001), with Sensitivity (S) 78%; Specificity (SP) 70% and Accuracy (Ac) 72%. LP was present in 30 (48%) of the patients without and 20 (67%) of the patients with SVT, in groups III and IV. p = 0.066, with S = 66%; SP = 52%; and Ac = 57%. In the follow-up, there were 4 deaths unrelated to arrhythmic events, all of them did not have LP. Eight (29.6%) of the patients from group II and 4 (13%) from group IV presented recurrence of SVT and 91.6% of these patients had LP. CONCLUSIONS: LP occurred in 77.7% of patients with SVT and without BBB. In the groups with BBB, there was association of LP with SVT in 66.6% of the cases. The recurrence of SVT was patient in 21% of the cases from which 91.6% had LP.

[The electrocardiogram in endomyocardial fibrosis]. / O eletrocardiograma na endomiocardiofibrose.

PURPOSE: To detail the most common electrocardiographic findings on the endomyocardial fibrosis and to correlate with the ventricular form. METHODS: One hundred patients with endomyocardial fibrosis (68 female) with ages between 5 and 64 years old (mean 34 years). According to ventriculographic aspect the patients were divided in three groups: group I--11 patients with predominant right ventricular compromise; group II--58 patients with biventricular involvement, but not necessarily similar in intensity; group III--31 patients with predominant left ventricular compromise. RESULTS: On patients with predominant right ventricular compromise, the electrocardiographic pattern was of QRS complex of low voltage in the frontal plane, presence of incomplete right bundle block and QRS complex with low voltage and with qr or qs aspect in V1 contrasting with QRS complex of great amplitude on V2 and V3. Left anterior hemiblock, aspect of inactive area, and R waves of high voltage on left precordial leads were observed on patients with predominant left ventricular involvement. CONCLUSION: The electrocardiogram of endomyocardial fibrosis, in spite of inespecific, may help in the identification of ventricular involvement.