Evaluation of a new treadmill exercise protocol to unmask type 1 Brugada electrocardiographic pattern: can we improve diagnostic yield?

AIMS: High precordial leads (HPL) on the resting electrocardiogram (ECG) are widely used to improve diagnostic detection of type 1 Brugada ECG pattern (Br1ECGp). A parasympathetic activation marks the initial recovery phase of treadmill stress testing (TET), and this can be useful for detecting the typical ECG pattern. Our study aimed to evaluate the role of a new HPL-treadmill exercise testing (TET) protocol in detecting Br1ECGp fluctuation compared to resting HPL-ECG. METHODS AND RESULTS: 74 out of 163 patients of a Brugada syndrome (BrS) Brazilian cohort (GenBra Registry) underwent exercise testing with HPL-TET protocol. Precordial leads were displayed in strategic positions in the right and left parasternal spaces. The step-by-step analysis included ECG classification (as presence or absence of Br1ECGp) in standard vs. HPL leads placement in the following sequences: resting phase, maximal exercise, and the passive recovery phase (including 'quick lay down'). For heart rate recovery (HRR) measurements and comparisons, a Student's t-test was applied. McNemar tests compared the detection of Br1ECGp. The significance level was defined as P < 0.05. Fifty-seven patients (57/74; 77%) were male, the mean age was 49.0 ± 14, 78.4% had spontaneous BrS, and the mean Shanghai score was 4.5. The HPL-TET protocol increased Br1ECGp detection by 32.4% against resting HPL-ECG (52.7% vs. 20.3%, P = 0.001) alone. CONCLUSION: Stress testing using HPL with the passive recovery phase in the supine position offers an opportunity to unmask the type 1 Br1ECGp, which could increase the diagnostic yield in this population.

Teste ergométrico após intervenção coronária percutânea e cirurgia de revascularização miocárdica / Stress testing after percutaneous coronary intervention and coronary artery bypass graft

No acompanhamento dos pacientes submetidos a revascularização do miocárdio por cirurgia ou intervenção coronária percutânea, algumas das preocupações são a oclusão das pontes, a presença de reestenose ou a progressão da doença, principalmente em pacientes assintomáticos. Desse modo, torna-se necessária a utilização de exames para detecção precoce desses eventos. O teste ergométrico é um dos métodos não-invasivos utilizados para esse fim, sendo fácil, seguro e, principalmente, de menor custo quando comparado aos métodos de imagem. Entretanto, quando estudado em grupos selecionados, como em pacientes com apenas um vaso doente e com eletrocardiograma de repouso sem alterações, o uso do teste ergométrico mostrou bons resultados. Além disso, alguns parâmetros do teste ergométrico têm valor significativo para avaliação de pacientes revascularizados ou após intervenção coronária percutânea. Mais especificamente, foi demonstrado que o tempo de duração do exercício é capaz de predizer a presença ou não de reestenose e/ou novas lesões. O teste ergométrico em indivíduos submetidos a intervenção coronária...

[Comparative study between the therapeutic effects of surgical myocardial revascularization and coronary angioplasty in equivalent ischemic situations: analysis through myocardial scintigraphy with 99mTc-Sestamibi]. / Estudo comparativo entre os efeitos terapêuticos da revascularização cirúrgica do miocárdio e angioplastia coronária em situações isquêmicas equivalentes: análise através da cintilografia do miocárdio com 99mTc-Sestamibi.

OBJECTIVE: To assess the myocardial ischemic load to previous and after myocardial revascularization. METHODS: Ninety-six randomized patients, carriers of multivessel coronary artery disease, stable angina, preserved left ventricular function, and exercise-induced myocardial ischemia treated with revascularization (SMR) or coronary angioplasty (TCA). Myocardial scintigraphy with 99mTc-Sestamibi was performed prior to and 6 months after myocardial revascularization. RESULTS: The SMR determined a significant greater index of complete revascularization (p=0.001), an increase in the number of maximum ergometric tests (p=0.001) and reduction in the number of positive ergometric tests with exercise angina (p=0.018). Both procedures provided an important improvement in the functional class of angina (p=0.001), an increase in the average value of double peak product (p=0.009), and the time of exercise tolerance (p<0.001), besides the reduction in the average value of the summed of exercise score (p<0.001) and the difference of the summed of scores (p<0.001) in both groups. CONCLUSION: TCA and SMR did not differ significantly concerning the reduction of myocardial ischemic load 6 months after the procedure. The myocardial revascularization was more complete with the SMR than the TCA, but it did not represent a significant factor for the reduction myocardial ischemic load.

Estudo comparativo entre os efeitos terapêuticos da revascularizacão cirúrgica do miocárdio e angioplastia coronária em situacões isquêmicas equivalentes: análise através da cintilografia do miocárdio com 99mTc-Sestamibi / Comparative study between the therapeutic effects of surgical myocardial revascularization and coronary angioplasty in equivalent ischemic situations: analysis through myocardial scintigraphy with 99mTc-Sestamibi

OBJETIVO: Avaliar a carga isquêmica do miocárdio prévia e ulterior à revascularizacão do miocárdio. MÉTODOS: Foram avaliados 96 pacientes randomizados, portadores de doenca arterial coronariana multivascular, angina estável, funcão do ventrículo esquerdo preservada e isquemia miocárdica esforco-induzida tratados com revascularizacão cirúrgica (RCM) ou angioplastia coronariana (ATC). Cintilografia do miocárdio com 99mTc-Sestamibi foi realizada antes e 6 meses após a revascularizacão do miocárdio. RESULTADOS: A RCM determinou índice significantemente maior de revascularizacão completa (p=0,001), aumento no número de testes ergométricos máximos (p=0,001) e reducão no número de testes ergométricos positivos com angina de esforco (p=0,018). Ambos os procedimentos ofereceram melhora importante na classe funcional da angina (p=0,001), aumento no valor médio do duplo produto de pico (p=0,009), e do tempo de tolerância ao esforco (p<0,001), além de reducão no valor médio da somatória do escore do esforco (p<0,001) e da diferenca da somatória dos escores (p<0,001) nos dois grupos. CONCLUSAO: ATC e RCM não diferiram significantemente quanto à reducão da carga isquêmica do miocárdio 6 meses após o procedimento. A revascularizacão do miocárdio foi mais completa com a RCM do que com a ATC, mas não representou fator significante para reducão da carga isquêmica do miocárdio.

Effect of enalapril on left ventricular diameters and exercise capacity in asymptomatic or mildly symptomatic patients with regurgitation secondary to mitral valve prolapse or rheumatic heart disease.

The effects of 12 months of therapy were evaluated in 47 mildly symptomatic patients with moderate to severe mitral valve regurgitation; 26 patients received enalapril and 21 received a placebo. Enalapril was associated with a significant reduction in left ventricular diameter and mitral regurgitation volume, with no evidence of change in systolic function indexes. However, enalapril did not hinder progressive aerobic impairment to effort.

Diagnóstico não-invasivo da doença vascular do enxerto após transplante cardíaco / Noninvasive diagnosis of allograft vascular disease after heart transplantation

OBJECTIVE: To determine the predictive values of noninvasive tests for the detection of allograft vascular disease. METHODS: We studied 39 patients with mean ages of 48Ý13 years and a follow-up period of 86Ý13 months. The diagnosis of allograft vascular disease was made by cine-coronary arteriography, and it was considered as positive if lesions existed that caused > or = 50 percent obstruction of the lumen. Patients underwent 24h Holter monitoring, thallium scintigraphy, a treadmill stress test, and dobutamine stress echocardiography. Sensitivity, specificity, and positive and negative predictive values were determined in percentages for each method, as compared with the cine-coronary arteriography results. RESULTS: Allograft vascular disease was found in 15 (38 percent) patients. The Holter test showed 15.4 percent sensitivity, 95.5 percent specificity...

Detecçäo do miocárdio viável: estudo de perfusäo, antes e após a cirurgia de revascularizaçäo em portadores de infarto do miocárdio / Detection of the viable myocardium: a perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients

Objective - To compare single-photon-emission computed tomography (SPECT) imaging scans using (201)Tl and (99m)Tc-MIBI in detection of viable myocardium, in regions compromised by infraction. Methods - Thirty-two (59.3+9.8 years old and 87 per cent male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50 per cent. They underwent coronary and left ventricle angiographies and SPECT before (including (201)Tl reinjection) and after coronary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. Results - Among 102 studied regions of the heart, there were 40 (39.2 per cent) areas of transient perfusion defects in the conventional protocol with (201)Tl and 52 (51.0 per cent) after reinjection. Therefore, 12/62 (19.4 per cent) more viable regions were identified by reinjection. Using (99m)Tc-MIBI, only 14 (13.7 per cent) regions with transient defects were identified, all of which were seen also in (201)Tl protocols. After surgery, 49 of total of 93 regions analyzed (52.7 per cent) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, (201)Tl SPECT scans-65.3 per cent, 90.9 per cent, 77.4 per cent, 88.9 per cent and 70.2 per cent, reinjection protocol with (201)Tl scans - 81.6 per cent, 81.8 per cent, 81.7 per cent, 83.3 per cent and 80.0 per cent; (99m)Tc-MIBI SPECT scans - 20.4 per cent, 90.9 per cent, 53.8 per cent, 71.4 per cent and 50.6 per cent. Logistic regression demonstrated that the reinjection protocol with (201)Tl was the best predictor of viability (P<0.001). Conclusion - Our data suggest the election of (201)Tl for viability studies, especially when using the reinjection protocol.

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.

Eletrocardiograma de alta resoluçäo na cardiopatia chagásica crônica / The signal average ECG in patients with chronic Chagas' heart disease

Foram estudados, por meio de eletrocardiograma de alta resoluçäo, 192 pacientes com cardiopatia chagásica crônica, sendo 96 (50 por cento) do sexo masculino. A idade variou entre 17 e 75 anso (média de 42,93.). O estudo objetivou estudar a prevalência de potencial tardio em portadores de cardiopatia chagásica crônica e sua relaçäo com taquicardia ventricular sustentada. De acordo com a presença ou a ausência de bloqueio de ramo e taquicardia ventricular sustentada foram constituídos 4 grupos. Admitiu-se a presença de potencial tardio, com filtro de 40H2, nos grupos sem bloquio de ramo, quando a duraçäo do QRS filtrado era . 110 ms, a duraçäo do sinal abaixo de 40 uV maior-igual 35ms e voltagem da raiz quadrada dos últimos 40 ms (VM40) maior-igual 20uV. Nos grupos com bloqueio de ramo considerou-se o VM 40 maior-igual 14UV como indicativo de potencial tardio. Resultados: nos grupos sem bloqueio de ramo o potencial tardio esteve presente em 21 (78 por cento) dos pacientes com taquicardia ventricular sustentada e em 22 (31 por cento) dos sem taquicardia ventricular sustentada (p < 0,001), com sensibilidade (S) 78 por cento, especificidade (E) 70 por cento e acurácia (Ac) 77 por cento. O potencial tardio esteve presente em 30 (48 por cento) dos pacientes sem taquicardia ventricular sustentada e em 20 (67 por cento) com taquicardia ventricular sustentada nos grupos com bloqueio de ramo (p=0,066), com S, 66 por cento; E, 52 por cento; e Ac, 57 por cento. No seguimento 12 (21 por cento) pacientes apresentaram recorrência de taquicardia ventricular sustentada: 91,6 por cento desses pacientes tinham potencial tardio. Ocorreram quatro óbtios sem relaçäo com eventos arrítmicos todos pertencentes ao grupo com bloqueio de ramo e sem taquicardia ventricular sustentada, e com potencial tardio ausente. Conclusöes: potencial tardio ocorreu em 77,7 por cento dos pacientes com taquicardia ventricular sustentada e sem bloqueio de ramo. Na ausência de bloqueio de ramo o eletrocardiograma de alta resoluçäo diferenciou pacientes com e sem taquicardia ventricular sustentada. nos grupos sem bloqueio de ramo observou-se S=70por cento e Ac=77 por cento. Nos grupos com bloqueio de ramo, em 66,6 por cento dos casos houve associaçäo entre potencial tardio e taquicardia ventricular sustentada. A recorrência de taquicardia ventricular sustentada esteve presente em 21 por cento dos casos e, desses, 91,6 por cento tinham potencial tardio.