![]() Moderate or large-sized pericardial effusions, pericardial thickening or fat, infiltrative cardiomyopathy, pulmonary hyperinflation, emphysema, obstructive lung disease, large and massive pleural effusions, and body mass index ≥ 30 kg/m 2 were defined as classic etiologies for LQRSV. Structural heart disease included LV systolic dysfunction, ischemic, or non-ischemic cardiomyopathy, and valvular heart disease. The diagnosis of obstructive pulmonary disease was confirmed if the FEV1/FVC ratio was less than 70% on pulmonary function test. Large to massive pleural effusion was defined to occur when it occupied more than two thirds of the hemithorax. Standard postero-anterior chest radiography was used for the diagnosis of pulmonary hyperinflation, emphysema, and pleural effusion. Demographics data were collected through careful reviews of electronic medical records. We identified patients with LQRSV isolated in limb leads from one hospital (LQRSV group) and selected all patients without LQRSV in both limb and precordial leads as a control group among corresponding patients from the other hospital ( Figure 1). We categorized patients according to LQRSV, which was defined as QRS complex voltages ≤0.5 mV in all limb leads or ≤1.0 mV in all precordial leads. All examinations were performed within a week. All patients routinely underwent ECG and echocardiography for cardiac screening and chest radiography, and pulmonary function for preoperative pulmonary risk evaluation. We screened consecutive patients aged over 60 who underwent preoperative risk evaluation for non-cardiac surgery between January 2016 and December 2016 in two tertiary university hospitals. We included patients undergoing standardized pre-operative examinations for non-cardiac surgery because they represent a relatively healthy population in which underlying cardiomyopathy or classic etiologies for discordant QRS voltage could be ruled out. Thus, we sought to find the etiologies of LQRSV limited to limb leads, a frequent form of discordant QRS voltage, and to investigate clinical significance of unexplained LQRSV in this study. ![]() However, none of the previous studies could explain why LQRSV is present only in limb or precordial leads, but not in both. These etiologies seem theoretically plausible because LQRSV can be a consequence of impaired voltage generation of ventricular myocardium and/or signal attenuation during electrical conduction. A small number of studies demonstrated that dilated cardiomyopathy and so-called classic etiologies including infiltrative cardiomyopathy, pericardial thickening or effusion, pulmonary diseases, or obesity, were associated with discordant QRS voltage. Discordant QRS voltage refers to when LQRSV is limited to either limb or precordial leads. Low QRS voltage (LQRSV) in surface electrocardiography (ECG) can be observed in various populations not infrequently. ECG voltage criteria may underestimate LVH in a relatively healthy population with LQRSV in limb leads. LQRSV in limb leads frequently occurs without apparent etiologies. Consequentially, diagnostic performance of precordial voltage criteria for LVH was particularly poor in patients with LQRSV in limb leads. Precordial QRS voltages were smaller, whereas left ventricular mass index and the prevalence of echocardiographic left ventricular hypertrophy (LVH) was higher in patients with LQRSV than in those without. Patients with LQRSV had a higher proportion of male and a greater body mass index. For primary analysis, patients with structural heart disease or classic etiologies of LQRSV were excluded. One-hundred and ninety-four without LQRSV were selected as the control from the 216 patients screened at the other hospital. Among the 9832 patients screened in one hospital, 292 (3.0%) showed LQRSV in limb leads. Patients with LQRSV isolated to limb leads and patients without LQRSV were selected from separate hospitals. Patients underwent pre-operative ECG, echocardiography, pulmonary function test, and chest X-ray. We reviewed patients aged over 60 who were scheduled for non-cardiac surgery in two hospitals. ![]() However, its clinical significance is obscure in healthy populations. Low QRS voltage (LQRSV) in electrocardiography (ECG) often occurs in limb leads without apparent cause.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |