ABSTRACT
Resumen Introducción: El ángulo QRS-T espacial es la diferencia entre el vector del QRS y la T. Se conoce el valor diagnóstico y pronóstico de este marcador en enfermedades cardíacas. Es prioritario determinar si estas mediciones son reproducibles con confiabilidad en nuestro medio. Métodos: En 30 adultos se obtuvieron electrocardiogramas, independientemente del diagnóstico. Las mediciones las realizaron dos estudiantes de Medicina de quinto año, un médico interno y un cardiólogo, posterior a un reentrenamiento sobre la medición del ángulo por el método de transformación visual. Con identificación cegada, ingresaron en un aplicativo web las mediciones del QRS y la T. El ángulo fue estimado a partir de la plantilla de Cortez y colaboradores. Sobre el 20% de las lecturas se estimó un acuerdo intraobservador y en el 100% de las lecturas un acuerdo interobservador. Los puntos de corte para estimar el acuerdo Kappa fueron < 105s (normal), 105° a 135° (limítrofe) y > 135° (anormal). Resultados: Se excluyó un ECG por calidad deficiente. El rango del ángulo estuvo entre 72.9° y 176.2°. El acuerdo interobservador entre los 4 evaluadores fue kappa = 0.786 (IC95% 0.728-0.823, p < 0.0001) y el intraobservador kappa = 1.0 (p 0.007). Conclusión: Es el primer estudio sobre el ángulo QRS-T espacial realizado en Colombia. Se logró un acuerdo inter- e intraobservador adecuado en la medición del ángulo por el método de transformación visual, en observadores con diferente experticia, con un kappa mayor de 0,75. Este resultado apoya la reproducibilidad de esta medición en estudios posteriores en Colombia.
Abstract Introduction: The spatial QRS-T angle is the difference between the QRS vector and T vector. The diagnostic and prognostic value of this marker in heart disease is well-known. It is essential to determine whether these measurements are reproducible and reliable in Colombia. Methods: Electrocardiograms (ECG) were obtained from 30 adults, regardless of the diagnosis. The measurements were made by two fifth-year medical students, a houseman/ intern, and a cardiologist. They were all re-trained on the measurement of the angle using the visual transformation method. With blinded identification, they entered the QRS and T measurements into a web application. The angle was estimated from the template of Cortez et al. About 20% of the readers showed an intra-observer agreement and an inter-observer agreement in 100%. The cut-off points to estimate the agreement Kappa were < 105° (normal), 105° a 135° (borderline), and >135° (abnormal). Results: One ECG was excluded due to poor quality. The range of the angle was between 72.9° and 176.2°. The inter-observer agreement between the 4 evaluators gave a kappa = 0.786 (95% CI; 0.728-0.823, P < .0001), and the intra-observer agreement a kappa = 1.0 (P = .007). Conclusion: This the first study on the spatial QRS-T angle performed in Colombia. A good inter- and intra-observer agreement was achieved in the measurement of the angle by the visual transformation method by observers with different levels of expertise, with a Kappa greater than 0.75. These results support the reproducibility of this measurement in subsequent studies in Colombia.
Subject(s)
Humans , Adult , Reproducibility of Results , Vectorcardiography , ElectrocardiographyABSTRACT
Objective: To analyze predictive value of plane QRS-T angle for postoperative malignant ventricular arrhythmia (MVA) of patients with acute myocardial infarction (AMI) who underwent PCI and the correlation between the predictive value and prognostic effect. Methods: The clinical data of 100 patients with AMI who underwent the treatment of percutaneous coronary intervention(PCI) were researched by using retrospective analysis. All of patients were divided into observation group (24 cases) and control group (76 cases) according to the angle of plane QRS-T after PCI. The plane QRS-T angle of observation group was more than 90°, and it was less than or equal to 90° in control group. The occurrence of MVA and clinical outcome of MVA between the two group were compared. Results: The age of observation group was significantly higher than that of control group (t=3.516, P<0.05). The interval of QTc of observation group was significantly higher than that of control group (t=2.131, P<0.05). And the percentage of left ventricular ejection fraction (LVEF) less than 45%, the occurrence rate of high blood pressure and the occurrence rate of MVA of observation group were significantly higher than those of control group (x2=3.922, x2=3.950, x2=5.942, P<0.05), respectively. The results of multi-factor Logistic regression analysis indicated that the angle of plane QRS-T of patients with AMI after PCI above 90° was the independent risk factor of MVA after PCI (OR=9.640, P<0.05). Conclusion: After the PCI of patients with AMI, the QRS-T angle> 90 ° was an independent risk factor of MVA.
ABSTRACT
Objective To analyze the value of plane QRS-T angle on prediction of malignant ventricular arrhythmia (MVA) occurred after emergency percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods The clinical data of 418 patients with STEMI who underwent PCI within 12 h of symptom onset were retrospectively analyzed, and the patients were divided into plane QRS-T angle ≤ 90° group (324 cases) and plane QRS-T angle>90° group (94 cases) according to the plane QRS-T angle after PCI. The clinical data were compared between 2 groups. Results Compared with patients in plane QRS-T angle ≤ 90° group, patients in plane QRS-T angle > 90° group was older: (67.4 ± 11.8) years vs. (63.6 ± 12.0) years, QTc interval was longer: (438.60 ± 34.97) ms vs. (425.24 ± 25.49) ms, rate of left ventricular ejection fraction (LVEF) 90° was an independent risk factor of MVA after PCI in STEMI patients (OR = 9.640, P =0.001), and using of beta-blockers was a protective factor (OR = 0.266, P = 0.028). Conclusions Plane QRS-T angle>90° is an independent risk factor of MVA after PCI in STEMI patients, while the use of beta-blockers is a protective factor. Paients with STEMI after PCI should be alert to the occurrence of MVA in the condition of plane QRS-T angle>90° and not taking beta-blockers.