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- Open Access
Fragmented QRS on 12-lead EKG is an independent predictor for myocardial scar: a cardiovascular magnetic resonance imaging study
© Tangcharoen et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Cardiovascular Magnetic Resonance
- Late Gadolinium Enhancement
- Left Ventricular Systolic Function
- Myocardial Scar
- Gadopentetate Dimeglumine
250 patients who underwent stress cardiac MRI were included. The 12-lead EKG was analyzed by two independent observers. Fragmented QRS was defined as the presence of an additional R wave (R') or notching in the nadir of R or S wave, or the presence of more than 1 R'. Patients whom EKG showed Q-wave were excluded. Cardiac MRI was performed under 1.5T magnetic resonance scanner (Philips Achieva release 3.2). Resting left ventricular systolic function and mass was acquired with steady-state free precession sequence in short-axis view. All patients were given either Gadopentetate dimeglumine or Gadobenate demeglumine (total 0.2 mmol/kg) for late gadolinium enhancement sequence. Images were analyzed by 2 observers using Extended MR WorkSpace release 2.6. Impaired cardiac function was defined as left ventricular ejection fraction less than 50%. Myocardial scar was defined as hyper-enhanced area within left ventricular myocardium. Statistical analysis was done by SPSS.
Total 164 patients were finalized included (age, 63 + 11 years ; male, 42%; diabetes mellitus, 28.7%; hypertension, 64.6 % ; hyperlipidemia, 57.3%). Fragmented QRS was found in 49 patients (29.9%). Of 164 patients, 26 patients (15.9%) had myocardial scar whereas 23 patients (14%) had poor LV function. Although the LV mass, LVEDV and LVEF between the patients with fQRS and without fQRS was not significantly different, the patients with fQRS had more prevalence of myocardial scar than patients without fQRS (24.5% vs. 12.2%, p < 0.05). The sensitivity, specificity and negative predictive value of fQRS for detection of myocardial scar were 46 %, 73%, 88% respectively. Using multivariable regression analysis, the fQRS was a strong independent predictor for myocardial scar detection (OR 4.26, p = 0.026 ) after adjusted for other cardiovascular risk factors.
Fragmented QRS is an independent factor for myocardial scar, therefore, patients with this abnormal EKG findings should have cardiac imaging investigation irrespective of conventional coronary risk factors or history of ischemic heart disease.
Multivariate regression analysis for myocardial scar detection
Myocardial scar detected by late gadolinium enhancement MRI
0.97 - 1.09
0.26 - 4.12
0.06 - 1.35
0.32 - 5.36
History of ischemic heart disease
0.11 - 3.72
1.19 - 17.09
LV mass (gm)
1.001 - 1.026
LV ejection fraction (%)
0.85 - 0.94
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