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
What is a second-degree conduction block?
reduced transmission of signal from atria to ventricles
What is a third-degree conduction block?
complete block of current from atria to ventricles
What is the underlying cause of a conduction block?
Damage, (fibrosis, calcification, necrosis) to the conduction system (AV node or His purkinje system)
What are ECG findings of a first degree block?
Increased PR interval
What are ECG findings of a second degree block?
increased P-R interval or ‘missing’ QRS complexes, depending on type of block
What are ECG findings of a third degree block?
p-waves not followed by QRS complexes
What are treatment options for conduction blockages?
Discontinuation of AV-blocking drugs (e.g. beta-blockers, calcium channel blockers) or pacemaker implantation in severe cases
What does the number of missing QRS complexes in second degree conduction block depends on?
The type of second degree conduction block (there are 3 types)
Which block is a medical emergency?
Third degree
What causes atrial fibrilation?
un-coordinated pacemaker currents in the atria
What are examples of vasculature disorders?
Hypertension
Acute coronary syndromes
What is hypertension?
Clinical BP ≥ 140/90 mmHg & ambulatory BP daytime average ≥ 135/85 mmHg for prolonged period
What are the underlying causes of hypertension?
Primary (essential): unknown
Secondary: resulting from another medical condition (e.g., kidney disease, adrenal disease)
How do you investigate hypertension?
blood pressure measurements
> 135/85 mmHg
What are treatment options for hypertension?
lifestyle changes followed by anti-hypertensive medication
What is the problem of hypertension?
Having prolonged hypertension
increases risk of stroke
increases risk of heart failure and myocardial infarction
increases risk of kidney disease
(these can also increase risk of hypertension, so vicious cycle)
What are the 3 types of acute coronary syndromes?
Angina
Non-ST-elevated myocardial infarction (NSTEMI)
ST-elevated myocardial infarction (STEMI)
What is an angina?
chest pain due to myocardial ischaemia caused by atherosclerosis
What is an NSTEMI?
Myocardial tissue damage due to prolonged ischaemia caused by atherosclerosis and artery blockage
What is a STEMI?
Serious myocardial tissue damage due to prolonged ischaemia caused by severe atherosclerosis and complete artery blockage
What is the underlying cause for anginas, NSTEMIs, STEMIs?
Atherosclerotic lesions of the coronary artery causing ischaemia (angina), artery blockage (NSTEMI) and then complete artery blockage (STEMI)
What are signs and symptoms of angina?
chest pain on exertion (stable) or at rest (unstable)
What are signs and symptoms of NSTEMI?
chest pain, sweating, nausea & vomiting
What are signs and symptoms of STEMI?
radiating chest pain, sweating, nausea & vomiting
What are ECG and blood finding for NSTEMI?
ST-depression/no changes & high troponin levels
What are ECG and blood finding for STEMI?
ST-elevation with reciprocal ST-depression & high troponin levels
What are treatment options for angina?
vasodilators
What are treatment options for NSTEMI and STEMI?
coronary stents, antiplatelets, vasodilators, antiemetics (nausea and vomiting), oxygen & pain-relief
What are the similarities and differences between NSTEMI and angina?
Small amount of occlusion of coronary arteries
Atheroma/ atherosclerotic lesion
Myocardial damage/ ischaemia during NSTEMI
less likely to see ECG changes in angina
Likely to see ST depression in NSTEMI
Why is STEMI more serious?
STEMI is more serious
Complete occlusion of lumen in coronary arteries
Often when atheroma burst and you get a platelet plug
ST elevation
Reciprocal ST depression in other leads
