A 72-year-old man comes to the office due to occasional lightheadedness over the last 3 months. It occurs both during exertion and at rest and lasts about 2 minutes. The patient has no chest pain, dyspnea, or syncope. Other medical issues include hypertension, hyperlipidemia, and a right hemicolectomy 8 years ago for colon cancer. Medications include low-dose aspirin, hydrochlorothiazide, lisinopril, and rosuvastatin. The patient quit smoking 20 years ago and usually drinks 2 or 3 beers on weekends. He does not participate in any regular exercise program.
Physical examination is unremarkable. A treadmill exercise stress test is performed. The patient exercises for 7 minutes and 20 seconds and achieves a workload of 7.0 metabolic equivalents at 90% of his maximal age-predicted heart rate. No symptoms except fatigue are reported during the exercise. ECG shows no ST-segment changes suggestive of myocardial ischemia. During the last minute of exercise and the recovery period, he has a transient episode of third-degree atrioventricular block noted on the rhythm strip. Coronary angiogram shows 70% stenosis in the distal left anterior descending artery.
Which of the following is the most appropriate next step in management of this patient?

Question

A 72-year-old man comes to the office due to occasional lightheadedness over the last 3 months.  It occurs both during exertion and at rest and lasts about 2 minutes.  The patient has no chest pain, dyspnea, or syncope.  Other medical issues include hypertension, hyperlipidemia, and a right hemicolectomy 8 years ago for colon cancer.  Medications include low-dose aspirin, hydrochlorothiazide, lisinopril, and rosuvastatin.  The patient quit smoking 20 years ago and usually drinks 2 or 3 beers on weekends.  He does not participate in any regular exercise program.
Physical examination is unremarkable.  A treadmill exercise stress test is performed.  The patient exercises for 7 minutes and 20 seconds and achieves a workload of 7.0 metabolic equivalents at 90% of his maximal age-predicted heart rate.  No symptoms except fatigue are reported during the exercise.  ECG shows no ST-segment changes suggestive of myocardial ischemia.  During the last minute of exercise and the recovery period, he has a transient episode of third-degree atrioventricular block noted on the rhythm strip.  Coronary angiogram shows 70% stenosis in the distal left anterior descending artery.
Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

This patient has no symptoms or ECG changes to indicate myocardial ischemia; however, he developed transient complete (third-degree) atrioventricular (AV) block during exercise. In the absence of myocardial ischemia or another potentially reversible cause (eg, medication effect), permanent pacemaker (PPM) placement is recommended for any complete AV block. This applies regardless of whether the complete AV block is symptomatic or asymptomatic, is persistent or transient, or occurs at rest or with exercise. Other indications for PPM placement include: Advanced second-degree AV block (block of ≥2 consecutive P waves)Mobitz type II second-degree AV block (symptomatic or asymptomatic)Mobitz type I second-degree AV block (only if symptomatic)Symptomatic sinus bradycardia (heart rate usually <40/min)Exercise chronotropic incompetence (inability to achieve 85% of age-predicted maximum heart rate) Advanced second-degree AV block (block of ≥2 consecutive P waves) Mobitz type II second-degree AV block (symptomatic or asymptomatic) Mobitz type I second-degree AV block (only if symptomatic) Symptomatic sinus bradycardia (heart rate usually <40/min) Exercise chronotropic incompetence (inability to achieve 85% of age-predicted maximum heart rate) (Choice A) Tilt table testing is indicated for evaluating syncope and can differentiate between reflex and orthostatic syncope. It is unlikely to be helpful in this patient with presyncope that is likely related to complete AV block. (Choice B) Holter monitor can allow further investigation of suspected arrhythmias; however, this patient already meets criteria for PPM placement and does not need further cardiac rhythm testing. (Choice C) This patient is at high risk for recurrent complete AV block and meets class I indications for PPM placement. Reassurance and follow-up are not appropriate. (Choice D) The AV node is usually supplied by the right coronary artery and less commonly by the left circumflex artery; therefore, in this patient, the presence of 70% stenosis in the left anterior descending artery lesion is not a cause of AV block and does not require percutaneous coronary intervention given the lack of clinical, stress test, or ECG manifestations of myocardial ischemia. Educational objective: In the absence of a reversible cause (eg, myocardial ischemia), patients with complete (third-degree) atrioventricular block require permanent pacemaker placement regardless of whether the block is symptomatic or asymptomatic, is persistent or transient, or occurs at rest or with exercise. __________ References: 2012 ACCF/AHA/HRS focused update of the 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. (http://www.ncbi.nlm.nih.gov/pubmed/22965336)

A 72-Year-Old Man Comes to the Office Due to Occasional