* Abnormal left axis deviation (usually between –45° and –60°) * qR pattern (small q, tall R) in the lateral limb leads I and aVL * rS pattern (small r, deep S) in the inferior leads II, III, and aVF * Delayed intrinsicoid deflection in lead aVL (> 0.045 s)<unk>  cannot be diagnosed when a prior inferior wall myocardial infarction (IMI) is evident on the ECG. IMI can also cause extreme left-axis deviation, but will manifest with Q-waves in the inferior leads II, III, and aVF. By contrast, QRS complexes in the inferior leads should begin with r-waves in<unk> . Effects of<unk>  on Diagnosing Infarctions and Left Ventricular Hypertrophy LAHB may be a cause of poor R wave progression across the precordium causing a pseudoinfarction pattern mimicking an anteroseptal infarction. It also makes the electrocardiographic diagnosis of LVH more complicated, because both may cause a large R wave in lead aVL. Therefore, to call LVH on an EKG in the setting of an LAHB you should see the presence of a “strain pattern” when you are relying on limb lead criteria to diagnose LVH
Left anterior fascicular block
Left posterior fascicular block
Bundle branch block
Intraventricular block
Left atrial appendage occlusion
Pre-excitation syndrome
Left bundle branch block
Sinoatrial arrest