Rationale: Atrial fibrillation occurs in up to 15% of patients with hyperthyroidism compared to 4% of people in the general population. Silent myocardial ischemia may occur in the absence of chest pain. Silent myocardial ischemia would carry serious sequelae in delayed diagnosis and the appearance of complications. Atrial fibrillation is the most commonly encountered clinical arrhythmia, often complicating acute myocardial infarction. It contributes to high rates of in-hospital adverse events. Anemia may be a risk factor for tachycardia.
Patient concerns: A 65-year-married male, worker, and Egyptian, patient was presented to the critical care unit with atrial fibrillation, silent myocardial infarction, and thyrotoxicosis.
Diagnosis: A 65-year-married male, worker, and Egyptian, patient was presented to the critical care unit with atrial fibrillation, silent myocardial infarction, and thyrotoxicosis.
Interventions: Electrocardiography, oxygenation, blood transfusion, and. abdominal ultrasound
Outcomes:Dramatic electrocardiographic and clinical stabilization was the result.

Lessons:The mind orientation for the physician in atypical presentation of silent myocardial infarction in some subgroups such as the elderly, diabetes mellitus, women, obstructive sleep apnea, and critically ill patients is critical and pivotal. The elderly is a significant risk factor for silent myocardial infarction. Silent myocardial infarction, subsequent left ventricular dysfunction, thyrotoxicosis, and elderly constellation risk factors atrial fibrillation.

Keywords:Silent coronary heart disease; Infarction; Arrhythmia; Anemia; Thyrotoxicosis; Atrial fibrillation; Elderly

Abbreviations:AF: Atrial Fibrillation; AMI: Acute Myocardial Infarction; DCC; Cardioversion; ECG: Electrocardiogram; HR; Heart Rate; ICU: Intensive Care Unite; MI: Myocardial Infarction; NSR: Normal Sinus Rhythm; O2: Oxygen; SGOT: Serum Glutamic-Oxaloacetic Transaminase; SGPT: Serum Glutamic- Pyruvic Transaminase; SMI; Silent Myocardial Ischemia; STEMI: ST-Segment Elevation Myocardial Infarction; VR: Ventricular Rate