Palpitations
Document the rhythm, then use echo to find the substrate that changes prognosis and therapy.
Echo approach, step by step
Echo does not diagnose an arrhythmia. It identifies the structural substrate: normal heart versus cardiomyopathy, valve disease, congenital disease or scar. The substrate determines prognosis, anticoagulation and ICD decisions. Echo is recommended in documented AF, SVT with suspected structural disease, and ventricular arrhythmias [38,182,213].
- LVSize, LVEF and GLS. Is there tachycardia-induced or PVC-induced cardiomyopathy? [38]
- HypertrophyLook for HCM (asymmetric, SAM) or hypertensive LVH [13].
- RVLook for dilatation and regional wall-motion abnormality (ARVC) [145].
- AtriaLA volume (AF risk and recurrence); RA size [182].
- ValvesMitral stenosis (AF, embolism), MR, mitral valve prolapse with annular disjunction (arrhythmic MVP) [6,38].
- CongenitalASD (atrial arrhythmias), Ebstein anomaly (accessory pathways) [25,213].
- ScarWall thinning, aneurysm, regional dysfunction → re-entrant VT substrate [38].
- Pericardium and thyroid cluesHyperdynamic LV with high output → thyrotoxicosis or anaemia [201].
- LVEF, GLS
- LV wall thickness pattern
- RV regional motion
- LA volume index
- Mitral valve (MS, MVP, MAD)
- Congenital (ASD, Ebstein)
- Scar / aneurysm
Causes & echo clues
| Rhythm or cause | Echo substrate | Next step |
|---|---|---|
| Atrial fibrillation / flutter | LA enlargement, MS or MR, HFpEF, LVH | CHA₂DS₂-VA, rate or rhythm control [182] |
| SVT (AVNRT, AVRT) | Usually normal; Ebstein anomaly in AVRT | EP study and ablation [213] |
| Frequent PVCs | Normal, or LV dysfunction if the burden is high | Holter burden; ablation if cardiomyopathy [38] |
| Ventricular tachycardia | Scar, aneurysm, HCM, ARVC, DCM, sarcoid | CMR, EP study, ICD [38] |
| Tachycardia-induced cardiomyopathy | Reduced LVEF that recovers with rate control | Repeat echo after control [38,182] |
| Thyrotoxicosis | Hyperdynamic LV, high output, AF | TSH, fT4 [201] |
| Arrhythmic MVP | Bileaflet prolapse, mitral annular disjunction, inferolateral wall | Holter, CMR [38] |
Clinical pathway to the diagnosis
- Capture the rhythmAn ECG during symptoms is the single most useful test. Use Holter, event recorder, smartwatch strips or an implantable loop recorder according to symptom frequency [182,213].
- 12-lead ECG at restPre-excitation, long or short QT, Brugada pattern, epsilon waves, Q waves, LVH [38].
- Blood testsTSH, electrolytes (K, Mg), haemoglobin, and drugs or stimulants.
- EchoAssess structure and function [38,182].
- CMRIf echo or ECG suggests cardiomyopathy, scar or VT [38].
- Treatment by rhythmAF → stroke prevention and rate or rhythm control [182]; SVT → vagal manoeuvres, adenosine, ablation [213]; VT → see the ventricular tachycardia presentation [38].
Clinical pearls & pitfalls
Practical tipReduced LVEF with a fast rhythm? Control the rate or rhythm, then repeat the echo in 1–3 months. A large recovery points to tachycardia-induced cardiomyopathy [38,182].
- LVEF measurement in AF needs averaging over several beats [1].
- TTE cannot exclude LA appendage thrombus. TOE is needed before cardioversion when the patient is not anticoagulated for ≥3 weeks and AF has lasted >24 hours [182].
- Young patient with SVT and a large RA and apically displaced tricuspid valve → Ebstein anomaly with an accessory pathway [25].
- PVC burden above about 10% warrants LV assessment and follow-up [38].
- A normal echo does not exclude channelopathies (long QT, Brugada, CPVT). The ECG and family history are key [38].
Red flags
- Palpitations with syncope or presyncope [196]
- Palpitations on exertion
- Family history of sudden death or cardiomyopathy [14,38]
- Known structural heart disease or reduced LVEF [38]
- Wide-complex tachycardia recorded