Abstract 2635: The Relation Between Axis Deviation On An Ecg And Left Ventricular Dyssynchrony
Background: Patients with end-stage left ventricular (LV) dysfunction and a wide QRS complex are considered prime candidates for cardiac resynchronization therapy (CRT). However, 18% to 30% of patients do not respond to CRT, because these patients may lack LV dyssynchrony. It is known that 27% to 43% of narrow QRS complex patients with heart failure already have LV dyssynchrony.
Objective: The purpose of this study was to evaluate the relation between axis deviation on an ECG and LV dyssynchrony.
Methods and results: 200 patients (103 males, 58.9 ± 8.2 years) with a narrow QRS complex and without structural heart disease (LV ejection fraction > 60%) were prospectively evaluated. All patients underwent echocardiogram with a tissue Doppler image (TDI) study to evaluate the LV dyssynchrony. Extensive LV dyssynchrony was defined as an electroanatomical delay found on the TDI between the LV septum and lateral wall, so called Ts (>60ms). Severe dyssynchrony was observed in 10% of patients with a significant left axis deviation (<-40 degrees: group L) and right axis deviation (>100 degrees: group R). Little dyssynchrony was observed in patients with a normal QRS deviation (-30 degrees to 100 degrees: group N).Ts is significant large in group L and R compared with group N respectively (Ts: 120 ± 10ms, 110 ± 15ms, 40 ± 5ms, both p<0.01 vs group N).
Conclusion: No patients with a normal QRS axis exhibited LV dyssynchrony. Alternatively, 10% of patients with left and right QRS axis deviation showed LV dyssynchrony. It is suggested that significant QRS axis deviation is a sign for LV functional change even in normal subjects.