Cardiology Flashcards
What are the consequences of hypertension?
- chronic kidney disease
- hypertensive retinopathy
- aneurysms, atheroma and peripheral vascular disease
- left ventricular hypertrophy
- strokes and seizures
- acute cardiac ischaemia
Causes of hypertension?
- Sometimes not known - essential hypertension
- Non modifiable - genetics, age, ethnicity
- obesity - risk of diabetes, overweight
- alcohol - increased amounts of lipids in blood stream
- sodium - high salt diet retains more water and higher blood pressure
- stress - sympathetic flight or fight response
- smoking - chemicals impair vasodilation causing atherosclerosis
- kidney and endocrine disease - increased catecholamines in sympathetic nervous system (Conns syndrome), phaeochromocytoma prevents anti-hypertensives from being effective
- drugs - steroids, monoamine oxidase inhibitors, oral contraceptives
Drugs for hypertension?
- diuretics - increase water retention in kidneys, reduce circulating volume and lower BP.
- ACE inhibitors - inhibits formation of angiotensin II (done by ACE enzyme), leads to accumulation of bradykinin (vasodilator)
- Angiotensin receptor blockers (alternative to ACE inhibitors) - blocks angiotensin at the site of its action. Does not lead to the accumulation of bradykinin.
- Calcium channel blockers - prevents vasoconstriction and reduces rate and force of heartbeat.
- Beta blockers - causes stroke volume to not be as high by blocking sympathetic pathways, decreases renin release.
- Alpha blockers - vasodilation to reduce blood pressure. Clonidine and methyldopa reduce sympathetic nervous system but centrally - in the brain.
What is ventricular tachycardia?
Fast beat of ventricles, if irregular and chaotic pt can go into cardiac arrest - ventricular fibrillation
What is a heart block?
A conduction issue at the AV node of bundle of His - delay of contraction and conduction
What is ventricular escape?
If no electrical current can be generated ventricles make their own
What is supraventricular tachycardia?
Rhythm may start elsewhere in the atria or in the AV node, fast regular heartbeat indistinguishable from sinus tachycardia without having a ECG.
What is atrial fibrillation?
Rhythm originating somewhere in the atria but not SA node. Some electricity is conducted towards the ventricles but not all of it typically fast, time is needed for cells to repolarise leading to some but not all being conducted to ventricles. Flow of blood is ideal for clot formation in atrium, if clotted in left atrium passes to systemic circulation and can lead to the brain.
What are characteristics of atrial fibrillation?
- irregular pulse
- risk of stroke
What can you do for a patient who has atrial fibrillation?
Control heart rate
Anticoagulants
What are some anti-dysrhythmics?
Class I: stabilise membrane - procainamide, quinidine, lidocaine, flecainide
Class II: beta blockers
Class III: act on potassium channels - amiodarone
Class IV: calcium channel blockers
Glycosides: digoxin
What local anaesthetic is advised to avoid?
Bupivacaine - cardiotoxic
What is syncope?
Reduced temporary perfusion to the brain, type of unconsciousness that can be simple or vasovagal - upright, clear prodrome, provoking factors.
What types of red flags signify a red flag syncopal episode?
Family history, chest pain, fainting when lying flat, significant cardiac history
What is two types of valve disease?
Stenosis - stiff, amount of blood is limited as valves won’t open fully so heart has to beat faster and more forcefully to generate pressure
Regurgitation - floppy, blood goes backwards so blood has to be ejected twice through chamber, larger volumes of blood to beat - larger contraction
