From the Guidelines
Management of intermittent complete heart block during a non-ST elevation myocardial infarction (NSTEMI) requires prompt intervention with temporary pacing and definitive treatment of the underlying coronary issue. Initially, a temporary transvenous pacemaker should be placed to maintain adequate heart rate and cardiac output. Atropine (0.5-1mg IV) may be used for emergent management of symptomatic bradycardia while preparing for pacing. The patient should receive standard NSTEMI treatment including antiplatelet therapy (aspirin 325mg loading dose followed by 81mg daily, plus a P2Y12 inhibitor such as ticagrelor 180mg loading dose followed by 90mg twice daily), anticoagulation (typically unfractionated heparin or low molecular weight heparin), and high-intensity statin therapy, as recommended by the guidelines 1. Early coronary angiography with revascularization of the culprit vessel is crucial, as the heart block is likely due to ischemia affecting the conduction system. If the heart block persists after revascularization, permanent pacemaker implantation is typically recommended, usually after a waiting period of 3-7 days to determine if conduction recovers once ischemia resolves, as suggested by the guidelines 1. The persistence of heart block after revascularization suggests significant damage to the conduction system and carries a poor prognosis without permanent pacing support. Key considerations in the management of these patients include:
- Bed rest with continuous ECG monitoring, as recommended by the guidelines 1
- Supplemental oxygen for patients with arterial saturation less than 90% or other high-risk features for hypoxemia, as recommended by the guidelines 1
- Avoidance of nonsteroidal anti-inflammatory drugs (NSAIDs) except for aspirin, due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture associated with their use, as recommended by the guidelines 1
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Treatment of Intermittent Complete Heart Block in NSTEMI
- The treatment of intermittent complete heart block in the context of a non-ST-segment elevation myocardial infarction (NSTEMI) is not directly addressed in the provided studies.
- However, study 2 suggests that the timing of invasive strategy (early vs. delayed) does not appear to influence the rate of pacemaker placement in NSTEMI complicated by high degree atrioventricular block (HDAVB).
- Study 3 reports a case of complete heart block in a patient with late presentation inferior STEMI, which was successfully treated with percutaneous coronary intervention (PCI), avoiding the need for a permanent pacemaker.
- Study 4 and 5 discuss the treatment of NSTEMI in general, including the use of beta-blockers and invasive strategies, but do not specifically address the treatment of intermittent complete heart block.
- Study 6 compares the use of ACE inhibitors and ARBs in patients with NSTEMI who underwent PCI, but does not address the treatment of intermittent complete heart block.
Invasive Strategy
- Study 2 found that early invasive strategy (<24 hours) was associated with lower length of stay and total hospitalization cost, but did not significantly reduce the rate of pacemaker implantation or in-hospital mortality.
- Study 5 recommends an invasive strategy with cardiac catheterization and revascularization when clinically appropriate, regardless of whether the patient receives revascularization.
Medical Management
- Study 4 found that acute beta-blocker use was associated with lower in-hospital mortality and improved clinical outcomes in patients with NSTEMI.
- Study 6 suggests that ACE inhibitors may be more effective than ARBs in reducing major adverse cardiac events (MACEs) in patients with NSTEMI who undergo PCI.