Cardiac Imaging Flashcards
Chest X-ray - … heart
Normal heart
What does an enlarged heart suggest? (Cardiothoracic ratio >0.5)
Congestive heart failure
A globular heart on CXR indicates what?
A pericardial effusion
Rib notching can be associated with what?
Inferior rib notching can be associated with aortic coarctation
What is dextrocardia?
Dextrocardia is a condition in which the heart is pointed toward the right side of the chest. Normally, the heart points toward the left. The condition is present at birth (congenital).
What is echocardiography?
a group of interrelated ultrasound applications used to examine the heart and great vessels.
Echocardiography can be trans … or trans …
Transthoracic (TTE) or transoesophageal (TOE)
CT angiography permits contrast-enhanced imaging of coronary arteries during a … with … radiation doses
CT angiography permits contrast-enhanced imaging of coronary arteries during a single breath hold with very low radiation doses
Cardiac MR is a radiation- free method used as a first-line when imaging the …
Myocardium
Check if a patient has a pacemaker before which scan?
MR - need to see if the pacemaker used is safe
Nuclear imaging is used in cardio when?
Perfusion is assessed at rest and with exercise or pharmacologically induced stress. It is useful for assessing whether myocardium distal to a blockage is viable and so whether stunting or CABG will be of value.
If hypoperfusion is ‘fixed’ i.e. present at rest and under stress, the hypoperfused area is probably scar tissue and so non-viable.
If hypoperfusion is ‘reversible’ at rest, the myocardium may benefit from improved blood supply.
Types of Echo:
M-Mode (motion mode) - single-dimension image
Two-dimensional (Real-time)
3D Echo - 4D if image is moving
Doppler and colour-flow echo - different coloured jets illustrate flow and gradients across valves and septal defects
Tissue Doppler imaging - this employed Doppler ultrasound to measure the velocity of myocardial segments over the cardiac cycle - useful for assessing longitudinal motion - and hence long-axis ventricular function - which is a sensitive marker of systolic and diastolic heart failure
Trans oesophageal echo - More sensitive than TTE, transducer is nearer to the heart. Indications - diagnosing aortic dissections; assessing prosthetic valves; finding cardiac source of emboli, and IE/SBE
Stress echo - used to evaluate ventricular function, ejection fraction, myocardial thickening, regional wall motion pre- and post-exercise, and to characterise valvular lesions. Dobutamine or dipyridamole may be used if the patient cannot exercise. Inexpensive and as sensitive/specific as a thallium scan
Uses of echo:
Quantification of global LV function Estimating right heart haemodynamics Valve disease Congenital heart disease Endocarditis Pericardial effusion
Indications for cardiac catheterisation:
Indications for coronary artery disease: diagnostic (Assessment of coronary vessels and graft patency); therapeutic (Angioplasty, stent insertion)
Valvular disease: diagnostic (pressures indicate severity), therapeutic valvulopasty (if the patient is too ill or declines valve surgery)
Congenital heart disease: diagnostic (Assessment of severity of lesions by measuring pressures and saturations); therapeutic (Balloon dilation or septostomy)
Other: cardiomyopathy, pericardial disease; endomyocardial biopsy
Pre-procedure checks for cardiac catheterisation:
Brief history/examination; NB: peripheral pulses, bruits, aneurysms
Investigations: FBC, U&E, LFT, clotting screen, CXR, ECG
Consent for procedure, including possible extra procedures, eg consent for angiography
IV access, ideally in the left hand
Patient should be nil by mouth (NBM) from 6h before the procedure
Patients should take all their morning drugs (and pre-medication if needed) but withhold oral hypoglycaemics
Post-procedure checks:
Pulse, BP, arterial puncture site (for bruising or swelling), foot pulses
Investigations: FBC and clotting (if suspected blood loss), ECG
Complications of cardiac catheterisation:
Haemorrhage: apply firm pressure over puncture site. If you suspect a false aneurysm, ultrasound the swelling and consider surgical repair. Haematomas are high risk for infections.
Contrast reaction: this is usually mild with modern contrast agents.
Loss of peripheral pulse: may be due to dissection, thrombosis, or arterial spasm. Occurs in <1% of brachial catheterisation. Rare with female catheterisation.
Angina: may occur during or after cardiac catheterisation. Usually responds to sublingual GTN; if not, give analgesia and IV nitrates.
Arrhythmias: usually transient, manage along standard lines.
Pericardial effusion: suspect if unexplained chest pain. May need drain depending on severity and haemodynamic status.
Pericardial tamponade: rare, but should be suspected if the patient becomes hypotensive and anuric. Urgent pericardial drain.
Infection: post-catheter pyrexia is usually due to a contrast reaction. If it persists for >24hr, take blood cultures before giving antibiotics.
Mortality of cardiac catheterisation:
<1 in 1000 patients, in most centres.
Intracardiac electrophysiology study (EPS) - what does this determine?
The catheter technique can determine types and origins of arrhythmias, and locate and ablate problem areas, eg aberrant pathways in WPW or arrhythmogenic foci. Arrhythmias may be induced, and the effectiveness if Citrix by drugs assessed.
