Evaluation of ST-segment and T-wave changes associated with NSTE-ACS in patients with RBBB: a nested case-control...

Area of Science:

• Cardiology
• Emergency Medicine
• Diagnostic Imaging

Background:

• Acute coronary syndrome (ACS) diagnosis in the emergency department (ED) relies heavily on electrocardiogram (ECG) interpretation.
• Right bundle branch block (RBBB) can complicate ECG analysis for ACS, particularly non-ST-elevation ACS (NSTE-ACS).

Purpose of the Study:

• To evaluate the diagnostic utility of conventional ECG markers for NSTE-ACS in patients presenting with chest discomfort and RBBB.
• To identify specific ECG patterns associated with NSTE-ACS in the presence of RBBB.

Main Methods:

• A nested case-control study was conducted using data from 352 patients with suspected ACS and RBBB on ECG.
• Patients were categorized into NSTE-ACS (88 patients) and non-NSTE-ACS groups.
• Statistical analysis, including odds ratios and confidence intervals, was used to assess associations between ECG findings and NSTE-ACS.

Main Results:

• Isoelectric ST-segment and/or positive T-waves on ECG were significantly associated with NSTE-ACS in patients with RBBB (p < 0.05).
• The likelihood of NSTE-ACS increased with isoelectric ST-segments (OR 3.48), positive T-waves (OR 4.16), or both (OR 4.81).
• ST-segment depression and non-negative T-waves showed higher frequency in NSTE-ACS patients (OR 5.78), achieving an 80% correct classification rate.

Conclusions:

• In patients with RBBB, the presence of an isoelectric ST-segment and positive T-waves are significant indicators for NSTE-ACS.
• These ECG findings are crucial for emergency clinicians to consider when assessing cardiac ischemia in patients with RBBB.
• Close monitoring of these specific ECG changes can improve the accuracy of NSTE-ACS diagnosis in this challenging patient population.