Fernando Santana Machado

Heart Rate Turbulence in Chagas Disease

RIBEIRO, A.L.P., et al.: Heart Rate Turbulence in Chagas Disease. Heart rate turbulence (HRT) quantifies the biphasic response of the sinus node to ventricular premature complexes (VPCs) and is a powerful electrocardiogram related risk predictor. VPCs are frequent in Chagas disease, a potentially lethal illness, and can hamper the analysis by conventional methods of autonomic heart control. The aim of the study was to examine HRT in patients with Chagas disease. Chagas disease patients and healthy controls (group 0, n = 11 ) without other diseases were submitted to a standardized protocol, including electrocardiogram, echocardiography, and 24‐hour Holter monitoring. Chagas disease patients were divided according to their left ventricular systolic function: normal (group 1, n = 103 ) and reduced ejection fraction (group 2, n = 23 ). Two HRT indices, turbulence onset (TO) and turbulence slope (TS), were calculated and compared among groups after adjustment for covariates like the prevalence of VPCs and the mean heart rate. Chagas disease patients had significantly altered TO (group 1: −0.0186, group 2: −0.0126) and TS (group 1: 10.844, group 2: 7.870) values in comparison with controls (TO − 0.0256, TS 19.829); P < 0.001 for both comparisons. In conclusion, HRT data may be useful in the electrocardiographic analysis of autonomic heart control in Chagas disease. Its prognostic value remains to be determined. (PACE 2003; 26[Pt. II]:406–410)

Doppler tissue imaging to assess systolic function in Chagas' disease

OBJECTIVE To assess the usefulness of Doppler tissue imaging (DTI) for evaluating the systolic function of chagasic patients with and without electrocardiographic abnormalities, in comparision with echocardiographic study. METHODS We studied 77 patients divided into 3 groups as follows: group 1 - control; group 2 - chagasic patients with normal electrocardiographic findings; and group 3 - chagasic patients with abnormal electrocardiographic findings. The following parameters were assessed: left ventricular dimensions and ejection fraction, left atrial dimensions and diastolic function on echocardiography. Systolic velocity and regional isovolumic contraction time (IVCTr) of the septal, anterior, lateral, posterior and inferior left ventricular walls were assessed on DTI. RESULTS Left ventricular cavitary dimensions, ejection fraction and DTI systolic wave showed significant differences between groups 1 and 3 and between groups 2 and 3, which were not found between groups 1 and 2. IVCTr allowed a statistically significant discrimination among the 3 groups. CONCLUSION DTI allowed discrimination among the different groups assessed, being superior to echocardiography in identifying early abnormalities of contractility, and, therefore, potentially useful for detecting incipient myocardial alterations in chagasic patients with normal electrocardiographic findings.

Minimally invasive coronary angiography using a multidetector CT

century, coronary thrombosis has been a known cause of death. In the 20 th century, this knowledge led to revolutionary treatment and prevention methods for acute myocardial infarction (AMI) 1 . The selective cineangiocardiography was introduced in 1958, and up to a few years ago was the only test available for coronary anatomical studies, in conjunction with autopsies. The non-invasive tests available were focused on analysis of the coronary function using physical or pharmacologic stress in an attempt to induce myocardial ischemia in order to detect it 2 . The advent of multidetector CTs, work stations with high processing capacity and the acquisition of images with isotropic resolution, made it possible to perform non-invasive coronary anatomical studies in vivo that are accurate and reproducible 3