Should patients with severe bradycardia (abnormally slow heart rate) requiring temporary pacing undergo an ischemic (reduced blood flow to the heart) workup?

From the Guidelines

Yes, patients with severe bradycardia requiring temporary pacing should generally undergo an ischemic workup. After stabilizing the patient with temporary pacing, an ischemic evaluation should be initiated as soon as the patient's condition allows. This typically includes a 12-lead ECG, cardiac biomarkers (such as troponin), and potentially urgent coronary angiography if acute coronary syndrome is suspected. The ischemic workup is crucial because bradycardia can be a manifestation of acute myocardial ischemia or infarction, particularly involving the right coronary artery which supplies the SA and AV nodes. Early identification of ischemia can guide further management, including potential revascularization. While the temporary pacing addresses the immediate threat of severe bradycardia, identifying and treating the underlying cause is essential for long-term management and preventing recurrence. However, the timing and extent of the ischemic workup should be tailored to the individual patient's clinical status, with the most urgent cases potentially proceeding directly to coronary angiography if indicated, as suggested by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.

Key Considerations

• The ischemic workup should be initiated as soon as the patient's condition allows, after stabilizing the patient with temporary pacing.
• The workup typically includes a 12-lead ECG, cardiac biomarkers, and potentially urgent coronary angiography if acute coronary syndrome is suspected.
• Early identification of ischemia can guide further management, including potential revascularization.
• The timing and extent of the ischemic workup should be tailored to the individual patient's clinical status.

Management Approach

• Temporary pacing can be implemented transcutaneously, via a transesophageal approach, or by insertion of a transvenous pacing electrode, as outlined in the 2018 ACC/AHA/HRS guideline 1.
• Atropine remains the first-line drug for acute symptomatic bradycardia, but its use should be cautious in the presence of acute coronary ischemia or MI, as noted in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.
• Transcutaneous pacing (TCP) may be useful for the treatment of symptomatic bradycardias, but it is at best a temporizing measure, and expert consultation should be obtained, as suggested by the 2010 American Heart Association guidelines 1.

From the Research

Temporary Pacing for Severe Bradycardia

• Patients with severe bradycardia requiring temporary pacing may undergo an ischemic workup to determine the underlying cause of their condition 2, 3.
• The need for temporary pacing is often determined by the presence of symptoms such as syncope, dizziness, and angina, as well as the patient's underlying heart rhythm and mechanism of bradycardia 2.
• Temporary cardiac pacing can be used to treat bradydysrhythmias and provide immediate therapy in acute situations 4, 5.

Ischemic Workup

• An ischemic workup may be necessary to determine if the patient's bradycardia is caused by reduced blood flow to the heart, such as in the case of acute myocardial infarction 2, 5.
• The workup may include tests such as electrocardiography (ECG) and cardiac enzyme assays to assess for signs of ischemia or infarction 3.

Management Strategies

• Management strategies for patients with severe bradycardia requiring temporary pacing may include the use of intravenous drugs to increase ventricular rate, as well as temporary transvenous or transcutaneous pacing 2, 4.
• In some cases, permanent pacemaker implantation may be necessary to provide long-term management of the patient's condition 2, 6.