Management of First-Degree AV Block in a 48-Year-Old Female with Chest Pain
The chest pain—not the first-degree AV block—is the primary concern requiring immediate evaluation for acute coronary syndrome (ACS), as women presenting with chest pain are at risk for underdiagnosis of cardiac causes. 1
Immediate Priorities
Address the Chest Pain First
The first-degree AV block is incidental and requires no specific treatment in this acute setting. 1, 2 Your focus must be on the chest pain evaluation:
Perform a focused cardiovascular examination immediately to identify ACS or other life-threatening causes (aortic dissection, pulmonary embolism, esophageal rupture). 1
Obtain a 12-lead ECG without delay to look for ST-segment changes, new Q waves, or T-wave inversions that would indicate ACS. 1
Emphasize accompanying symptoms more common in women with ACS, including dyspnea, palpitations, diaphoresis, lightheadedness, nausea, or upper abdominal discomfort—not just typical anginal chest pain. 1
Assess for anginal characteristics: gradual onset over minutes, triggered by exertion or emotional stress, and associated with the symptoms listed above suggest ischemia. 1
First-Degree AV Block Management
No treatment is required for isolated first-degree AV block in asymptomatic patients. 1, 2
The key clinical points about the AV block itself:
First-degree AV block (PR interval >0.20 seconds) is generally benign and does not cause acute symptoms or require intervention. 1, 2
It does not contraindicate standard ACS treatment if the chest pain proves cardiac in origin. 2
Use caution with AV nodal blocking agents (beta-blockers, calcium channel blockers, digoxin) if they become necessary for ACS management, but do not withhold them if clinically indicated. 2
Risk Stratification for the Chest Pain
Transport to the emergency department immediately if:
- The patient has signs of poor perfusion (hypotension, altered mental status, acute heart failure, diaphoresis). 1
- ECG shows ST-segment elevation, new left bundle branch block, or dynamic ST-T wave changes. 1
- Clinical suspicion for ACS remains moderate to high based on age, sex, and pain characteristics. 1, 3
Outpatient evaluation may be appropriate if:
- Low clinical suspicion for ACS based on atypical pain characteristics (fleeting seconds-duration pain, positional pain, pain localized to a small area). 1
- Normal or unchanged ECG. 3
- No hemodynamic compromise or concerning associated symptoms. 1
Common Pitfalls to Avoid
Do not attribute the chest pain to the first-degree AV block. First-degree AV block does not cause chest pain unless the PR interval is markedly prolonged (>300 ms) and causing pacemaker syndrome-like symptoms, which would present as exercise intolerance or dizziness, not chest pain. 2, 4
Do not delay ACS evaluation to investigate the AV block. The conduction abnormality is incidental in this acute presentation. 2
Do not withhold atropine if bradycardia develops, though use it cautiously in the setting of acute MI as increased heart rate may worsen ischemia. 1
Women are at particular risk for underdiagnosis of cardiac causes of chest pain—maintain high clinical suspicion even with atypical presentations. 1
Follow-Up Considerations for the AV Block
Only after excluding ACS, consider these points about the first-degree AV block:
No specific follow-up is needed for isolated, asymptomatic first-degree AV block with normal PR interval (<300 ms). 2
Consider ambulatory ECG monitoring if the PR interval is markedly prolonged (>300 ms), there is coexisting bundle branch block, or if there are risk factors for progression (neuromuscular disease). 2, 5
Permanent pacing is not indicated for isolated first-degree AV block unless the patient develops symptoms similar to pacemaker syndrome (exercise intolerance, dizziness) with marked PR prolongation. 2, 6