Alternating Bundle Branch Block or Pyridostigmine-induced Mobitz Type II Block Masquerading as Acute Coronary Syndrome

Background “ST-T changes in the ECG!!” These words are enough to get the emergency doctor to spring into action. These changes can be diffuse and/or non-specific but we should rule out all emergent and urgent causes before shifting the patient to the specialist. To err on the side of dangerous etiology is the dictum. Introduction Out of all emergency department (ED) patients with undifferentiated chest pain, 7% will have ECG findings consistent with acute ischemia or infarction, and 6–10% of those in whom cardiac markers are ordered will have initially positive results. Of all patients with the possible acute coronary syndrome (ACS), 5–15% ultimately prove to have ACS.1 Shortness of breath with chest pain mostly has a cardiac origin in the presence of dynamic ECG changes. We had managed a patient with rapidly evolving ECG changes, chest pain, palpitations, and grade III–IV dyspnea. In the chaotic environment of a busy ED, the most probable diagnosis here will be ACS. Comorbid conditions like diabetes mellitus, hypertension, and prior coronary artery disease (CAD) are commonly enquired. However, other long-standing illnesses like myasthenia gravis (MG), as in our patient can be easily missed if a patient is not forthcoming with history. We experienced a similar confusion when in the cacophony of chest pain, dyspnea, and T wave inversions with bundle branch blocks, ACS protocol was initiated and a simple diagnosis was missed. The significance of the alternating bundle branch block (ABBB) will be presented to the readers. How to cite this article Hymavathi A, Uppaluri SC, Sharma A. Alternating Bundle Branch Block or Pyridostigmine-induced Mobitz Type II Block Masquerading as Acute Coronary Syndrome. J Med Acad 2020;3(2):63–66.