The Palpitations That Weren’t Panic | Clinical Mysteries

A young adult had repeated episodes of sudden racing heartbeat and was repeatedly told it was anxiety. The timing held the clue.

The familiar label

The episodes began suddenly, often while resting, and ended just as abruptly. Between attacks the examination and routine ECG were normal. Because the patient looked anxious during symptoms, the label 'panic attack' followed.

The detail that did not fit

The patient described the pulse as 'like a switch turned on' rather than a gradual build-up. There was no consistent emotional trigger. One episode occurred while calmly watching television.

The twist

A rhythm strip captured during an attack showed a regular narrow-complex tachycardia—paroxysmal supraventricular tachycardia rather than primary anxiety.

Take-home message

A normal ECG between episodes does not exclude an intermittent arrhythmia. Sudden onset and sudden termination are valuable history clues; capture the rhythm during symptoms whenever possible.

Diagnostic principle: do not let the first plausible label stop the search when an important detail does not fit.

Educational note: This is a teaching composite, not a substitute for patient-specific diagnosis or treatment. Real patients require direct clinical assessment and appropriate investigations.