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A prolonged QRS duration on surface electrocardiogram is a specific indicator of left ventricular dysfunction [see
R L Murkofsky1, G Dangas, J A Diamond
1Zena & Michael A. Wiener Cardiovascular Institute, and the Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029, USA.
Insights
A prolonged QRS duration on an electrocardiogram (ECG) is a specific indicator of reduced left ventricular (LV) systolic function. Further QRS prolongation increases specificity for predicting abnormal LV ejection fraction (EF).
Area of Science:
- Cardiology
- Diagnostic Imaging
- Electrophysiology
Background:
- The 12-lead electrocardiogram (ECG) is a standard tool for cardiac assessment.
- Existing LV systolic function scoring systems lack direct correlation with QRS duration alone.
Purpose of the Study:
- To investigate the association between prolonged QRS duration and diminished left ventricular (LV) systolic function.
- To determine if QRS duration is an independent predictor of reduced LV systolic function.
Main Methods:
- Analysis of 12-lead ECGs and radionuclide ventriculography in 226 patients.
- Exclusion of patients with confounding cardiac conditions or medications.
- Correlation of QRS duration with LV ejection fraction (EF) and volume indices.
- Multivariate analysis incorporating QRS duration, R-wave score, and clinical variables.
Main Results:
- Significantly longer QRS duration in patients with abnormal EF (0.102s vs. 0.091s, p < 0.0001).
- QRS duration >0.10s showed high specificity (83.6%) but moderate sensitivity (43.8%) for abnormal EF.
- Increased QRS duration thresholds (e.g., >0.12s) enhanced specificity and positive likelihood ratios for predicting decreased LV function.
- Prolonged QRS duration and low R-wave score were independent predictors of reduced LV systolic function.
Conclusions:
- Prolonged QRS duration (>0.10s) on a standard ECG is a specific, though not highly sensitive, marker for decreased LV systolic function.
- Increasing QRS duration thresholds improve predictive specificity for abnormal LV EF.
- QRS duration is a valuable, independent predictor of LV systolic dysfunction.
Objective:
We sought to determine whether a prolonged QRS-interval duration is associated with decreased left ventricular (LV) systolic function.
Background:
The 12-lead electrocardiogram (ECG) is a routine test for suspected cardiac disease. Although several scoring systems have been devised to estimate LV systolic function, no studies have examined the direct relationship between QRS duration alone and LV systolic function.
Methods:
We analyzed the standard 12-lead surface ECG of 270 consecutive patients, referred for radionuclide ventriculography. Patients (n = 44) with bundle branch blocks, atrial flutter or fibrillation, pacemaker rhythm, recent myocardial infarction or bypass surgery, and patients on antiarrhythmic drugs were excluded. In the remaining patients (n = 226), we correlated the QRS duration on standard resting ECG, and the resting LV ejection fraction (EF), end-systolic and end-diastolic counts (ESC and EDC, respectively; LV volume indices), as obtained by radionuclide angiography. We used a multivariate analysis to identify independent predictors of reduced ventricular function entering QRS duration, the previously described R-wave score and clinical variables in our model.
Results:
The QRS duration in the abnormal EF group was significantly longer than in the normal EF group (0.102 vs. 0.091 s, p < 0.0001). A QRS duration >0.10 s was highly specific (83.6%), but modestly sensitive (43.8%), for the prediction of abnormal EF. Furthermore, an abnormal EF was predicted with incrementally increased specificity (83.6% to 99.3%) and a corresponding decrease in sensitivity (43.8% to 13.8%) for each 0.01-s increase in the definition of prolonged QRS (from >0.10 to >0.12 s). Accordingly, the positive likelihood ratio for the prediction of decreased LV function was increased from 2.67 to 19.7 as the definition of prolonged QRS duration was increased from >0.10 to >0.12 s. In the multivariate analysis, a prolonged QRS duration and a low R-wave score were the only independent predictors of decreased LV systolic function.
Conclusions:
Prolonged QRS duration (>0.10 s) obtained from a standard resting 12-lead ECG is a specific, but relatively insensitive indicator of decreased LV systolic function. Further prolongation of the QRS had a higher specificity for decreased LV EF and a higher positive likelihood ratio for predicting abnormal LV EF.
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