Differential diagnosis for palpitations
Common and important causes of palpitations for doctors and medical students
| Diagnosis | Evidence |
|---|---|
| Runs of supraventricular tachycardia (SVT) | Suggested by: abrupt onset, sweats and sustained dizziness. Confirmed by: baseline ECG or 24-hour ECG showing tachycardia with normal QRS complexes with absent or abnormal pulse waves >140/min. Exercise ECG to see if precipitated by exercise (and due to IHD). |
| Episodic heart block; Second-degree or third-degree atrioventricular (AV) block | Suggested by: onset over minutes or hours, slow and forceful beats. Loss of consciousness, pallor if significant loss of cardiac output. Confirmed by: non-conducted pulse waves associated with conducted pulse waves with fixed or progressive prolonged PR interval, P–R dissociation, and slow QRS rate on 12-lead or 24-hour ECG. |
| Sinus tachycardia (anxiety, pain, fever, caffeine, hypovolaemia, pulmonary embolism, hyperventilation) | Suggested by: gradual onset over minutes of regular palpitations and pulse. History of precipitating cause (usually). Confirmed by: 12 lead ECG or monitor strip and resolution by stopping precipitating factors or resolution of potential cause. |
| Atrial fibrillation | Suggested by: onset over seconds, irregularly irregular radial and apex pulse, apical–radial pulse deficit, and variable blood pressure. Confirmed by: ECG showing no pulse waves and irregularly irregular QRS complexes. |
| Ventricular ectopy unifocal (benign) or multifocal (may have underlying pathology) | Suggested by: palpitations felt as early or skipped beats occurring one at a time or in short bursts, noted over hours or days, sometimes associated with anxiety. Confirmed by: premature wide QRS complexes without preceding pulse waves on 12 lead ECG or 24-hour ECG. |
| Menopause | Suggested by: sweats, mood changes, irregular or no more periods, getting worse over weeks or months. Confirmed by: decreased serum estrogen, increased FSH/LH, and response to hormone replacement therapy. |
| Thyrotoxicosis | Suggested by: anxiety, irritability, weight loss, sweating, loose frequent stools, lid retraction and lag, proptosis, brisk reflexes, other signs and symptoms of hyperthyroidism. Onset over weeks or months. 12 lead ECG may show sinus tachycardia, atrial fibrillation, or ventricular arrhythmias. Confirmed by: increased FT4, and/or increased FT3 and decreased TSH. |
| Pheochromocytoma (rare) | Suggested by: abrupt episodes of anxiety, fear, chest tightness, sweating, headaches, and marked rises in blood pressure. Confirmed by: catecholamines (VMA, HMMA) or free metanephrine increase in urine and blood soon after episode. |