ECG Interpretation Basics

A 62-year-old woman with a history of atrial fibrillation is found to have a prolonged PR interval (220 ms) on ECG. Which is the most common site of atrioventricular block in patients with acquired atrioventricular nodal disease?

A 58-year-old man with hypertension presents with palpitations. His ECG shows left axis deviation, tall R waves in aVL, and deep S waves in lead III. Regarding the ECG findings in left ventricular hypertrophy (LVH), all of the following are true EXCEPT:

A 58-year-old man with hypertension presents to the emergency department with acute onset chest pain radiating to the left arm. His vital signs are stable. The 12-lead ECG shows ST elevation in leads II, III, and aVF with reciprocal ST depression in leads I and aVL. What is the most appropriate immediate next step in management?

A 52-year-old woman with a history of palpitations is brought to the emergency department. Her 12-lead ECG shows a regular wide-complex tachycardia at 160 bpm with a rate of 2:1 atrioventricular (AV) block pattern. The QRS duration is 0.16 seconds. Blood pressure is 110/70 mmHg and she is alert. What is the most appropriate immediate next step in management?

Which ECG finding best distinguishes acute myocardial infarction (AMI) from left ventricular hypertrophy (LVH)?