Differential Diagnosis for LAFB with Raised Troponin I

• Single most likely diagnosis:
  • Acute Coronary Syndrome (ACS), specifically Non-ST-Elevation Myocardial Infarction (NSTEMI): This is the most likely diagnosis because LAFB (Left Anterior Fascicular Block) can be a sign of underlying coronary artery disease, and raised troponin I is a marker of myocardial injury, which together point towards an acute coronary event.
• Other Likely diagnoses:
  • Unstable Angina: Although troponin levels are elevated, which typically indicates myocardial infarction, unstable angina can sometimes present with minor troponin elevations, especially if there's ongoing ischemia without full infarction.
  • Cardiac Contusion: If there's a history of trauma, cardiac contusion could lead to both ECG changes (including LAFB) and elevated troponin due to direct myocardial injury.
• Do Not Miss diagnoses:
  • Pulmonary Embolism (PE): Although less common, a large PE can cause acute right heart strain, which might lead to ECG changes, including LAFB, and troponin elevation due to right ventricular strain. Missing this diagnosis could be fatal.
  • Aortic Dissection: This is a life-threatening condition that can cause acute chest pain, ECG changes (including LAFB if the dissection involves the coronary arteries), and elevated troponin if there's coronary involvement.
• Rare diagnoses:
  • Myocarditis: Inflammation of the heart muscle can cause ECG abnormalities, including LAFB, and elevated troponin levels. It's less common but should be considered, especially in younger patients or those with a recent viral illness.
  • Cardiac Sarcoidosis: This condition can cause various ECG abnormalities, including conduction defects like LAFB, and can lead to elevated troponin levels if there's active inflammation or scarring of the myocardium.