Left bundle branch block with sinus tachycardia

ECG Quiz 3

Left bundle branch block with sinus tachycardia
Left bundle branch block with sinus tachycardia

Wide QRS is due to left bundle branch block as evidenced by the negative QRS complex in lead V1 and slurred R waves in I, aVl and V5, V6. Secondary ST segment and T wave changes are also seen, opposite in direction to the dominant QRS – ST elevation with upright T waves in right precordial leads and ST segment depression with inverted T waves in left precordial leads. If the ST segment and T waves are concordant, it will indicate a primary T wave abnormality as in myocardial ischemia. Left ward axis is considered by some authors as evidence of additional left anterior fascicular block.