Introduction: Patients presenting with cardiac symptoms such as chest pain, palpitations, dyspnea, and arrhythmias are often initially evaluated for cardiovascular conditions, leading to admission under cardiology care. However, non-cardiac conditions can sometimes mimic these presentations, posing diagnostic challenges for clinicians (1, 2).

Case series: The first patient presented with general weakness and fatigue. She did not experience chest pain, palpitations, or loss of consciousness. She had a known history of arterial hypertension but had recorded lower blood pressure values over the past few days. An electrocardiogram (ECG) showed sinus bradycardia with a prolonged PR interval, raising suspicion of sick sinus syndrome. Further investigation revealed reduced thyroid hormones as well as low cortisol levels, leading to the diagnosis of secondary hypothyroidism due to hypopituitarism. The second patient was admitted due to palpitations, exercise intolerance, and leg edema. An ECG revealed atrial flutter with a rate of 150 beats per minute. Echocardiography confirmed mildly reduced systolic function of the left ventricle, leading to a diagnosis of the first manifestation of heart failure. Further testing showed significantly elevated thyroid hormones with low TSH, leading to the diagnosis of thyroid storm. The third patient was admitted due to nausea accompanied by chest and upper abdominal pain on the day of admission. Both the ECG and laboratory results were normal, while a chest X-ray indicated only a hiatal hernia. Due to prolonged chest pain the patient was hospitalized and underwent coronary angiography, which yielded normal results. The patient later experienced an episode of syncope, which led to a CT pulmonary angiography being performed, ruling out pulmonary embolism but confirming a large hiatal hernia. The patient underwent surgery on the same day.

Conclusion: These cases highlight the importance of considering a broad differential diagnosis in patients with cardiovascular complaints, as well as the need for interdisciplinary collaboration to ensure accurate diagnosis and treatment. By recognizing non-cardiac causes of cardiac-like symptoms, clinicians can avoid diagnostic pitfalls and optimize patient care.