Echocardiography, including stress echocardiography

Modalities

Modality	Use
TTE	First line - chamber size, EF, valves, pericardium, PASP
TOE	TTE inadequate, or the question is posterior or prosthetic
Stress echo	Inducible ischaemia, valve reserve, viability
Agitated saline contrast	Shunt detection - PFO, ASD
LV opacification contrast	Poor endocardial definition, apical thrombus
Strain (GLS)	Subclinical dysfunction - cardiotoxicity, amyloid

Velocity converts to pressure gradient by the simplified Bernoulli equation
- dP = 4v^2
- RV systolic pressure = 4 x (TR velocity)^2 + estimated RA pressure
Valve area from the continuity equation
Doppler is angle-dependent
- Off-axis interrogation underestimates velocity
- -> underestimates gradient
- -> underestimates severity

Mitral inflow E (early passive filling) and A (atrial contraction)
Tissue Doppler e' - mitral annular descent velocity, reflecting myocardial relaxation
E/e' correlates with left atrial pressure
Plus LA volume index and TR velocity

Oesophageal disease - varices, stricture, malignancy, prior surgery or radiotherapy
High sedation risk - severe respiratory disease, pulmonary hypertension
Poor dentition

Physical - bicycle or treadmill; preferred whenever the patient can exercise
Pharmacological - dobutamine (inotrope + chronotrope), dipyridamole (vasodilator), atropine as chronotropic adjunct
Also for low-gradient AS with reduced EF (dobutamine, to separate true severe from pseudo-severe) and for viability
Contraindications:
- Unstable angina
- Critical aortic stenosis
- Sustained ventricular arrhythmia
- Uncontrolled hypertension
- Decompensated heart failure
- Acute myocarditis or pericarditis
- High-grade AV block

Operator- and window-dependent
CMR is superior for RV volumes, tissue characterisation and infiltrative disease
Nuclear perfusion, CT coronary angiography and CT-FFR are alternatives for ischaemia
Serial studies are most reliable on the same machine with the same reader

12 more sections, plus exam facts

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