Differentials
Acquired structural heart disease
SIGNS / SYMPTOMS
History of coronary artery disease (CAD), myocardial infarction (MI), or valvular heart disease requiring surgical correction.
INVESTIGATIONS
Echocardiographic changes consistent with CAD, previous MI, and valvular heart disease. Echocardiography may show regional left ventricular wall motion abnormalities suggestive of infarction and/or scarring. Valvular lesions such as regurgitant and/or stenotic valves in combination with left ventricular dysfunction may be identified by echocardiography.
ECG changes consistent with previous MI characterised by presence of Q waves.
Neurocardiogenic (vasovagal) syncope
SIGNS / SYMPTOMS
Triggers include cough, micturition, defecation, swallowing, upright posture, prolonged standing, heat, and hunger.
Premonitory symptoms include sweating, feeling hot, and nausea.
Recovery period: nausea and vomiting.
BP measurement may show orthostatic hypotension, particularly when provoked during a tilt table test.
INVESTIGATIONS
ECG shows normal QT interval.
Neurological syncope
SIGNS / SYMPTOMS
Triggers include anxiety and stress in panic attack; fatigue, stress, and missed meals in migraine.
Premonitory symptoms include hyperventilation, paraesthesiae in fingers and lips in panic attack; headache, visual disturbance, sensitivity to light and sound in migraine.
INVESTIGATIONS
ECG shows normal QT interval.
Catecholaminergic polymorphic ventricular tachyarrhythmias
SIGNS / SYMPTOMS
No differentiating signs or symptoms.
History extremely similar to that of LQTS, with arrhythmias triggered by physical activity and emotional stress.
INVESTIGATIONS
ECG is unremarkable at rest, with no significant prolongation of QT interval.
Exercise test provokes premature ventricular contractions with bidirectional ventricular tachyarrhythmias on ECG.
Genetic testing shows mutations in the RyR2 gene in autosomal dominant inheritance and mutations in the CASQ2 gene in autosomal recessive inheritance.
Epilepsy
SIGNS / SYMPTOMS
Triggers include inadequate sleep, alcohol, photic stimulation, drugs.
Premonitory symptoms: aura.
Syncopal episode: convulsive movement, tongue biting, and incontinence.
Recovery period: prolonged postictal state.
INVESTIGATIONS
EEG shows epileptiform abnormalities.
ECG shows normal QT interval.
Use of this content is subject to our disclaimer