Cardiovascular Disorders Flashcards
What is heart failure?
Heart unable to maintain adequate circulation for metabolic requirements of body
- Preserved ejection fraction (HFpEF): EF ≥ 50%, ↓ diastolic function (diastolic heart failure)
- Reduced ejection fraction (HFrEF): EF ≥ 40%, ↓ systolic function (systolic heart failure)
What causes diastolic heart failure?
Stiff heart muscle in left ventricle means smaller area for blood in it, so less blood fills ventricle- but still get reasonable amount pumped out which is why EF is preserved
So you get left ventricular hypertrophy
What causes systolic heart failure?
Left ventricle has weakened heart muscle and muscle is more dilated so less able to pump blood out of it thus reduced EF
What are some underlying causes of heart failure?
Secondary to cardiac damage (ischaemic, myopathy)
Hypertension
Valve disease
How can you test for heart failure?
Blood test: elevated brain natriuretic peptide (BNP)
Chest x-ray: cardiomegaly
What are treatment options for heart failure?
Drugs that reduce the exertional pressure on the heart
What is the main ECG finding in heart failure?
Bigger QRS complex due to increased muscle mass in heart so more electrical current- not always found in heart failure
What are examples of electrical transmission disorders?
Atrial arrhythmias
- atrial fibrillation
- Wolff-Parkinson-White (WPW)
Conduction blocks
What is atrial fibrilation?
Disorganised electric activity and contraction
What is Wolff-Parkinson-White?
syndrome causing tachycardia and abnormal cardiac electrical conductance
What is the underlying cause of atrial fibrilation?
spontaneously active cells throughout the atria
What is the underlying cause of Wolff-Parkinsion-White?
additional accessory conduction pathway (the bundle of kent) between the atria and ventricles
What are signs and symptoms of atrial fibrillation and Wolff-Parkinson-White?
palpitations and chest pain
What are ECG findings of atrial fibrilation?
absent p waves and irregularly irregular rhythm
What are ECG findings for WPW?
WRS pre-excitation and biphasic/ inverted T-wave of ECG
What are treatment options for atrial fibrillation?
Strategies to maintain sinus rhythm (e.g. cardioversion, anti-arrhythmics, catheter ablation)
What are treatment options for WPW?
benign, no treatment required
Why is there an absent P wave during atrial fibrillation?
Uncoordinated aberrant electrical activity and contraction due to pacemaker cells forming in regions outside of SA and AV node- this prevents smooth transition of electrical current from SA to AV node
Un-coordinated pacemaker currents in the atria
What causes the pre-excitation and Biphasic T-wave in WPW?
Accessory pathway (more common in left ventricle) causes a preexcitation of QRS complex, preventing current from solely going through the AV node as a gatekeeper. Additional pathway, so ventricular depolarisation earlier.
biphasic T-wave is due to the current not being stopped at the AV node and another depolarisation starting when a repolarisation is still occurring within the ventricles.
What is a first-degree conduction block?
slowing down of conduction through AV node