A 47-year-old man with known coronary artery disease arrives at the ER with chest pain, sweating, and palpitations. His symptoms started suddenly 2 hours ago while he was at work. The patient had right coronary artery percutaneous angioplasty six months ago. Anxiety and panic attacks are also part of the patient's medical history. The blood pressure is 180/90 mm Hg, and the pulse rate is 110 beats per minute with a regular rhythm. An esmolol infusion relieves symptoms quickly and slows the heart rate. with a regular rhythm. An esmolol infusion produces rapid symptom relief and heart rate slowing. Which of the following portions of the ECG will be affected most significantly by the medication?

Question

A 47-year-old man with known coronary artery disease arrives at the ER with chest pain, sweating, and palpitations. His symptoms started suddenly 2 hours ago while he was at work. The patient had right coronary artery percutaneous angioplasty six months ago. Anxiety and panic attacks are also part of the patient's medical history. The blood pressure is 180/90 mm Hg, and the pulse rate is 110 beats per minute with a regular rhythm. An esmolol infusion relieves symptoms quickly and slows the heart rate. with a regular rhythm.  An esmolol infusion produces rapid symptom relief and heart rate slowing.  Which of the following portions of the ECG will be affected most significantly by the medication?

Quizplus · Accepted Answer

Eductional Objective: The P wave on an ECG represents atrial depolarization, while the QRS complex represents ventricular depolarization. The PR interval is the time elapsed between the start of atrial depolarization (the P wave) and the start of ventricular depolarization (start of QRS complex). The longer the PR interval, the longer an electrical stimulus takes to travel from the SA node to the ventricles via the AV node, His bundle, and fascicular branches. Beta blockers and other drugs that slow AV nodal conduction will increase the PR interval. Beta blockers (with the exception of sotalol, which also has class III properties) have no effect on QRS or QT interval durations.

A 47-Year-Old Man with Known Coronary Artery Disease Arrives at the ER