Relationship between electrocardiographic characteristics of left bundle branch block and echocardiographic findings

Background: Complete left bundle branch block (CLBBB) is an electrocardiographic (ECG) dromotropic disorder seen in patients with various structural heart diseases and sometimes is associated with poor prognosis. Its presence confounds the application of standard ECG criteria for the diagnosis of left ventricular hypertrophy (LVH), myocardial infarction (MI) in the chronic phase, and pathologies that produce changes on ST-T segment. The aim of this investigation was to establish the relationship between CLBBB and cardiac structural abnormalities assessed by echocardiography. Methods: This observational, cross-sectional study included ECG with CLBBB from 101 patients who also had transthoracic echocardiogram (TTE) performed within 6 months. Results: The prevalence of structural heart disease on TTE was 90%. No ECG criterion was useful to diagnose LVH since no relationship was observed between 9 different ECG signs and increased left ventricular mass index. QRS duration (p = 0.16) and left axis deviation (p = 0.09) were unrelated to reduced left ventricular ejection fraction (LVEF). Eight ECG signs proposed for the diagnosis of the chronic phase of MI demonstrated similar effectiveness, with high specificity and reduced sensitivity. Conclusions: CLBBB is associated with elevated prevalence of cardiac structural disease and hinders the application of common ECG criteria for the diagnosis of LVH, reduced LVEF, or chronic phase of MI. No ECG finding distinguished patients with structural heart disease from those with normal hearts. Electrocardiographic criteria for the diagnosis of MI in the chronic phase are useful when present, but when absent cannot rule it out.

Concordance between Carotid and Femoral Ultrasound for the Diagnosis of Subclinical Atherosclerosis in Patients with Low or Intermediate Cardiovascular Risk

Background: Approximately 50% of coronary events and sudden death occur in patients with low or intermediate cardiovascular risk, as determined by the Framingham risk score. Subclinical atherosclerosis in the carotid and femoral territories is a powerful predictor of cardiovascular events. Identifying patients with subclinical atherosclerosis allows reclassification of the cardiovascular risk in an individualized manner. Objective: The aim of this study was to investigate the prevalence of subclinical atherosclerosis in both territories in patients with low or intermediate cardiovascular risk, to evaluate the diagnostic agreement between carotid and femoral Doppler ultrasound, and to determine the independent predictors of subclinical atherosclerosis in both locations. Methods: Patients with low or intermediate risk of the Framingham risk score underwent carotid and femoral Doppler ultrasound for the diagnosis of subclinical atherosclerosis; patients with diabetes and those treated with statins were excluded. Results: A total of 207 patients were included: 50.2% were classified as low-risk patients, 50.2% were women, and mean age was 52±9 years. The prevalence of subclinical atherosclerosis was 42.5%. The concordance between carotid and femoral Doppler ultrasound was weak (kappa 0.28; 95% CI, 0.13-0.44). Age and sex were independent predictors of subclinical atherosclerosis in both territories, while smoking was an independent and powerful predictor only in the femoral arteries. Conclusions: Approximately 40% of patients with low or intermediate cardiovascular risk of the Framingham risk score have evidence of subclinical atherosclerosis. Concordance between the carotid and femoral Doppler ultrasound is weak, implying that the two methods identify subclinical atherosclerosis in different populations of patients.Introducción: Aproximadamente el 50% de los eventos coronarios y la muerte súbita tienen lugar en pacientes con riesgo cardiovascular bajo o intermedio del puntaje de Framingham. La aterosclerosis subclínica en los territorios carotídeo y femoral es un potente indicador de eventos cardiovasculares. La identificación de los pacientes con aterosclerosis subclínica permite reclasificar el riesgo cardiovascular de manera individual. Objetivos: Investigar la prevalencia de aterosclerosis subclínica en pacientes con riesgo cardiovascular bajo o intermedio, evaluar la concordancia entre el eco-Doppler carotídeo y el femoral para su diagnóstico y determinar los indicadores independientes en ambas localizaciones. Material y métodos: Se realizó eco-Doppler carotídeo y femoral a pacientes con riesgo bajo o intermedio del puntaje de Framingham para detectar aterosclerosis subclínica; se excluyeron los pacientes diabéticos y los tratados con estatinas. Resultados: Se incluyeron 207 pacientes; el 50,2% eran de riesgo bajo, el 50,2% eran mujeres y la edad media fue de 52 ± 9 años. La prevalencia de aterosclerosis subclínica fue del 42,5%. La concordancia entre el eco-Doppler carotídeo y el femoral fue débil (coeficiente kappa 0,28, IC 95% 0,13-0,44). La edad y el sexo fueron indicadores independientes de aterosclerosis subclínica en ambos territorios, mientras que el tabaquismo fue un poderoso indicador solo en las arterias femorales. Conclusiones: Aproximadamente el 40% de los pacientes con riesgo cardiovascular bajo o intermedio del puntaje de Framingham tienen evidencia de aterosclerosis subclínica. La concordancia entre el eco-Doppler carotídeo y el femoral es débil, lo que implica que ambos métodos identifican aterosclerosis subclínica en diferentes poblaciones de pacientes