Cardiac Imaging

Question 1

Chest X-ray - … heart

Answer 1

Normal heart

Question 2

What does an enlarged heart suggest? (Cardiothoracic ratio >0.5)

Answer 2

Congestive heart failure

Question 3

A globular heart on CXR indicates what?

Answer 3

A pericardial effusion

Question 4

Rib notching can be associated with what?

Answer 4

Inferior rib notching can be associated with aortic coarctation

Question 5

What is dextrocardia?

Answer 5

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).

Question 6

What is echocardiography?

Answer 6

a group of interrelated ultrasound applications used to examine the heart and great vessels.

Question 7

Echocardiography can be trans … or trans …

Answer 7

Transthoracic (TTE) or transoesophageal (TOE)

Question 8

CT angiography permits contrast-enhanced imaging of coronary arteries during a … with … radiation doses

Answer 8

CT angiography permits contrast-enhanced imaging of coronary arteries during a single breath hold with very low radiation doses

Question 9

Cardiac MR is a radiation- free method used as a first-line when imaging the …

Answer 9

Myocardium

Question 10

Check if a patient has a pacemaker before which scan?

Answer 10

MR - need to see if the pacemaker used is safe

Question 11

Nuclear imaging is used in cardio when?

Answer 11

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.

Question 12

Types of Echo:

Answer 12

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

Question 13

Uses of echo:

Answer 13

Quantification of global LV function
Estimating right heart haemodynamics
Valve disease
Congenital heart disease
Endocarditis 
Pericardial effusion

Question 14

Indications for cardiac catheterisation:

Answer 14

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

Question 15

Pre-procedure checks for cardiac catheterisation:

Answer 15

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

Question 16

Post-procedure checks:

Answer 16

Pulse, BP, arterial puncture site (for bruising or swelling), foot pulses
Investigations: FBC and clotting (if suspected blood loss), ECG

Question 17

Complications of cardiac catheterisation:

Answer 17

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.

Question 18

Mortality of cardiac catheterisation:

Answer 18

<1 in 1000 patients, in most centres.

Question 19

Intracardiac electrophysiology study (EPS) - what does this determine?

Answer 19

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.