Dizziness & presyncope
Most dizziness is not cardiac — echo is useful when the story, ECG or examination point to the heart.
Echo approach, step by step
Dizziness covers vertigo (vestibular), presyncope (reduced cerebral perfusion), disequilibrium and non-specific light-headedness. Only presyncope is likely to be cardiac. The approach mirrors syncope, with a lower pre-test probability [196].
- Aortic valve and LVOTLook for AS and HCM with obstruction (provoke) [5,13].
- LV functionLow output (low EF, low SVI) [1].
- RV and PA pressurePH: exertional dizziness [8].
- VolumeIVC and LV cavity size; hyperdynamic LV → dehydration [3].
- Masses and valvesMyxoma, MS, prosthetic dysfunction [167,176].
- AV and LVOT
- LVEF and SVI
- PASP / RV
- Volume status
Causes & echo clues
| Cause | Echo clue | Next step |
|---|---|---|
| Orthostatic hypotension, dehydration | Small hyperdynamic LV, collapsing IVC | Lying and standing BP [196] |
| Bradycardia, conduction disease | Usually normal | ECG monitoring [205] |
| Tachyarrhythmia | Substrate (LA, LV) | Ambulatory ECG [182,213] |
| AS / HCM | Gradient | Echo grading; provocation [5,13] |
| Pulmonary hypertension | High TR velocity | PH work-up [8] |
| Vestibular or neurological | Normal echo | Clinical examination, neurology |
Clinical pathway to the diagnosis
- Characterise the symptomSpinning (vertigo) → vestibular or neurological; light-headedness when standing → orthostatic; with palpitations → arrhythmia; on exertion → obstruction or ischaemia.
- ExaminationOrthostatic BP, murmurs, neurological examination.
- ECG and monitoringEspecially in patients over 60 or with conduction disease [205].
- EchoWhen there is a murmur, abnormal ECG, heart failure or exertional symptoms [196].
- Drug reviewAntihypertensives, alpha-blockers, nitrates, diuretics.
Clinical pearls & pitfalls
Practical tipA systolic murmur that gets louder on standing suggests dynamic LVOT obstruction. Measure the gradient standing [13].
- Drug-induced orthostatic hypotension is the commonest reversible cause in older patients [196].
- A normal echo with dizziness does not exclude intermittent arrhythmia [196].
Red flags
- Presyncope on exertion [196]
- Palpitations, bradycardia or conduction disease on ECG [205]
- Systolic murmur (AS, HCM) [6,13]
- Known cardiomyopathy [38]