TGA + VSD + Valsalva + VT Flashcards
What is TGA?
- Transposition of the great arteries (TGA) is a form of cyanotic congenital heart disease.
- It is caused from the failure of the aorticopulmonary septum to spiral during septation.
- Children of diabetic mothers are at an increased risk of TGA.
What are the key features of TGA?
- Aorta leaves the right ventricle
- Pulmonary trunk leaves the left ventricle
- ‘Egg-on-side’ appearance on chest x-ray
What is the treatment for TGA?
Surgical correction is the definite treatment
What advice is given to patients with major risk factors for PE/DVT whilst travelling?
- Anti-embolism stockings
- These can either be bought by the patient or prescribed (class I)
- If risk is very high (e.g. a long-haul flight following recent major surgery) then consideration should be given to:
- delaying the flight
- specialist advice sought regarding the use of low-molecular weight heparin.
What is the valsalva manouevre?
- The Valsalva manoeuvre describes a forced expiration against a closed glottis.
- This leads to increased intrathoracic pressure which in turn has a number of effects on the cardiovascular system.
When is the valsalve manouvre used?
- To terminate an episode of supraventricular tachycardia
- Normalizing middle-ear pressures
What are the stages of the valsalva manouvre?
- Increased intrathoracic pressure
- Resultant increase in venous and right atrial pressure reduces venous return
- The reduced preload leads to a fall in the cardiac output (Frank-Starling mechanism)
- When the pressure is released there is a further slight fall in cardiac output due to increased aortic volume
- Return of normal cardiac output
Whare are ventricular septal defects associated with?
- Congenital VSDs are associated with chromosomal disorders (e.g. Down’s syndrome, Edward’s syndrome, Patau syndrome)
- Single gene disorders such as non-congenital causes include post myocardial infarction
What are features of VSD?
Classically a pan-systolic murmur which is louder in smaller defects
What are complications of VSD?
- Aortic regurgitation*
- Infective endocarditis
- Eisenmenger’s complex
- Right heart failure
- Pulmonary hypertension: pregnancy is contraindicated in women with pulmonary hypertension as it carries a 30-50% risk of mortality
*aortic regurgitation is due to a poorly supported right coronary cusp resulting in cusp prolapse
What is ventricular tachycardia?
- Broad-complex tachycardia originating from a ventricular ectopic focus
- Potential to precipitate ventricular fibrillation ==> urgent treatment.
What are the two main types of VT?
- Monomorphic VT: most commonly caused by MI
- Polymorphic VT: A subtype of polymorphic VT is torsades de pointes which is precipitated by prolongation of the QT interval
What is the management of VT?
- If the patient has adverse signs (systolic BP < 90 mmHg, chest pain, heart failure) then immediate cardioversion is indicated
- In the absence of such signs antiarrhythmics may be used
- If these fail, then electrical cardioversion may be needed with synchronised DC shocks
What is drug therapy is indicated for VT?
- Amiodarone: ideally administered through a central line
- Lidocaine: use with caution in severe left ventricular impairment
- Procainamide
Verapamil should NOT be used in VT
What should you do if drug therapy fails in VT?
- Electrophysiological study (EPS)
- Implant able cardioverter-defibrillator (ICD) - this is particularly indicated in patients with significantly impaired LV function
