QT Interval Dispersion Behavior in Patients With and Without Obstructive Coronary Artery Disease Undergoing Exercise Test

Abstract Background: Stress test is used to detect coronary artery disease (CAD). The QTc interval dispersion (dQTc) is an electrocardiographic index of ventricular repolarization heterogeneity. Some researchers have linked transient myocardial ischemia induced by physical exertion with increased heterogeneity of ventricular repolarization measured by dQTc. Objectives: To study the patterns of dQT in patients with and without chronic obstructive CAD and to define a reliable cutoff point for dQT that could become a diagnostic criterion for myocardial ischemia. Methods: We retrospectively analyzed the electrocardiogram in resting and in exercise of 63 patients submitted to exercise test and cardiac catheterization. We divided the patients into three groups: true negative (VN), true positive (VP) and false positive (FP). VN: patients with coronary lesion lower than 70% and exercise test without myocardial ischemia; VP: individuals with stenosis greater than 70% in coronary arteries and a test suggestive of myocardial ischemia; FP: people with stenosis lower than 70% in the coronary arteries and stress test with ischemia criteria. Values of p < 0.05 were considered statistically significant. Results: Resting dQTc was not different among the three groups. However, for the dispersion of the QTc interval in exercise was, respectively, 47 ± 17 ms, 72 ± 42 ms, and 61 ± 31 ms for VN, VP and FP (p = 0.003). Conclusions: Obstructive chronic coronary disease patients have an increase in dQTc during exercise. Measurement of dQTc may be helpful in the diagnosis of myocardial ischemia in the stress test.

Endocardite infecciosa por Streptococcus bovis em paciente com carcinoma colônico / Infectious endocarditis due to Streptococcus bovis in a patient with colon carcinoma / Endocarditis infecciosa por Streptococcus bovis en paciente con carcinoma colónico

Descrevemos o caso de uma paciente de 66 anos de idade, com endocardite infecciosa por Streptococcus bovis e adenocarcinoma colônico, que desenvolveu insuficiência aórtica grave aguda. Foi submetida à cirurgia de troca valvar aórtica e posteriormente à ressecção tumoral (hemicolectomia direita). É importante ressaltar a necessidade de complementação do estudo do cólon, mesmo em indivíduos assintomáticos, quando diagnosticamos endocardite infecciosa por S. bovis.

We report the case of a 66 year-old female patient with infectious endocarditis due to Streptococcus bovis and adenocarcinoma of the colon that developed acute aortic insufficiency. She was submitted to aortic valve replacement surgery and later to tumor resection (right hemicolectomy). It is important to emphasize the need for complementing the study of the colon, even in asymptomatic individuals, when infectious endocarditis due to S. bovis is diagnosed.

Describimos el caso de una paciente de 66 años de edad, con endocarditis infecciosa por streptococcus bovis y adenocarcinoma colónico, que desarrolló insuficiencia aórtica grave aguda. Fue sometida a cirugía de reemplazo valvular aórtico y posteriormente a resección tumoral (hemicolectomía derecha). Es importante destacar la necesidad de complementación del estudio del colon, aun en individuos asintomáticos, cuando diagnosticamos endocarditis infecciosa por S. bovis.

Síndrome do QT longo e torsades de pointes pós-parto / Postpartum torsades de pointes and long QT syndrome

Relatamos o caso de uma paciente puérpera, internada com diagnósticos de infecção do trato urinário e insuficiência cardíaca que evoluiu com arritmias ventriculares do tipo torsades de pointes, após hipopotassemia e uso de Ciprofloxacin. Não apresentou supressão das arritmias ventriculares após reposição de potássio e magnésio, mas após implante de marca-passo provisório. Recebeu alta hospitalar com QTc de 490 ms, em uso de Propranolol.

This article reports the case of a puerperal patient admitted with diagnosis of urinary tract infection and heart failure. This condition evolved with torsades de pointes ventricular arrhythmias, then, hypokalemia, and use of Ciprofloxacin. Ventricular arrhythmias did not present any improvement after potassium and magnesium replacement, but after implantation of temporary pacemaker, this condition showed signs of improvement. The patient was discharged with QTc at 490 ms, taking Propranolol.