Cardiology Flashcards
Definition of heart failure?
Failure of the body to maintain a cardiac output that can accommodate metabolic demands.
5 main causes of heart failure?
Coronary artery disease Hypertension Valvular heart disease Cardiomyopathy Cor Pulmonale
How to calculate Cardiac Output?
Heart Rate x Stroke Volume
Three main components of the neurohormonal component of cardiovascular regulation?
RAAS system
Sympathetic nervous system
Vasopressin (ADH)
Role of the sympathetic nervous system in Heart Failure?
Increased cardiac sympathetic activity activates β₁ β₂ and α₁ leads to increased cardiac toxicity and arrhythmias.
Increased sympathetic activity to the kidneys leads to stimulation of α₁, and β₁ (Leading to activation of RAAS) Increased BP
What is hBNP?
Brain Natriuretic Peptide
Predominantly found in cardiac ventricles
vasodilatory and Diuretic properties.
Effects of hBNP?
Dilation of veins and arteries
Decreased Noradrenaline and aldosterone
Increased Diuresis & Natriuresis
Some endothelium derived Vasodilators?
NO
Bradykinin
Prostacyclin
Endothelium derived vasoconstrictor?
Endothelin I
Symptoms (NOT SIGNS) of Left Ventricular Failure?
Dyspnoea on exertion
Nocturnal Dyspnoea
Orthopnoea (SOB when lying flat)
Cough
Haemoptysis (coughing up blood)
Signs (NOT SYMPTOMS) of Left ventricular
Basal Lung Crackles
Tachycardia
S3 Gallop (heart sound)
Pleural effusion
Right ventricular failure Symptoms (not signs)?
Abdominal pain
Anorexia
Nausea
Bloating
swelling
Right Ventricular failure Signs (not symptoms)?
Peripheral oedema
Jugular venous distension
Hepato-jugular reflex
Hepatomegaly
Ascites
Class I, II, II and IV classifications of heart failure?
I: No symptoms with ordinary activity
II: Slight limitation with physical activity
III: Marked limitation with physical activity
IV: Unable to carry out any physical activity with discomfort, symptoms may be present at rest.
5 year mortality rate after heart failure diagnosis?
50%
Diagnostic techniques used to evaluate New onset heart failure?
ECG
Chest X-Ray
Blood-Test
Echocardiography
Uses of Diuretics in heart failure?
Used to Relieve fluid retention
Decrease Bloop Pressure
Improved exercise tolerance
Facilitate the use of other drugs used for heart failure
Drugs to use in Heart failure?
Diuretics
ACE inhibitors
Angiotensin Receptor Blockers
Beta-Blockers
Aldosterone antagonists
Digitalis Glycosides
What is automaticity in pacemaker cells?
A pacemakers cell’s ability to spontaneously depolarise, and propagate an Action potential.
Where do sympathetic and parasympathetic innervation act in the heart?
SA node, pretty much no effect on lower pacemakers.
What are the three pacemakers of the heart?
SA node (normal) - 60-100 min-1
AV node
- 40-60 min-1
Purkinje fibres
- 20-40 min-1
Three main mechanisms leading to the generation of arrhythmias?
Enhanced automaticity
Re-Entry
After depolarisation
How can enhanced automaticity generate an arrhythmia?
If a lower pacemaker becomes faster than a higher pacemaker then this one will start to take over and the heart will not contract rhythmically.
How can re-entry generate an arrhythmia?
- Slow conduction causes a short refractory period and this means the myocyte is able to receive new impulses
- There is rapid conduction and a long refractory period meaning the myocyte cannot receive new impulses
If there are two pathways next to each other firstly the beat cannot gain entry to the rapid conduction pathway as it has not recover and so will travel down the slow one, when it reaches the end of the slow it can now travel back up the rapid one and will cause a circular pathway of contraction.
Examples of re-entry arrhythmias?
Macro-reentry: Wolf-Parkinson White
Micro-reentry: Atrial fibrillation
What can arrhythmias present with?
Syncope (blackouts)
Palpitations
Angina
Dyspnoea
What four things do you use to clinically classify arrhythmias?
Heart rate (tchy/bradycardic)
Rhythm (regular/irregular)
Site (supraventricular/ventricular)
QRS complex of an ECG (narrow/broad)
How can you tell whether an arrhythmia is supraventricular or ventricular?
Supraventricular if the QRS is narrow.
Types of atrial ectopic beats?
Isolated ectopic beat
Atrial tachycardia
Atrial flutter (atria not really beating)
Atrial fibrillation (atria not contracting at all)
What does it mean in an ECG if the p-wave is negative?
That the AV node is depolarising from the bottom up
Examples of ventricular ectopic beats?
Ventricular tachycardia
Ventricular fibrillation (dead unless defibrillated)
Heart block
Types of heart Block?
First Degree: AV node very slow to conduct resulting in very long PR interval
Second degree:
- Mobitz I: Some P waves are generated but not conducted
- Mobitz II: This is pathological, not every P-wave is conducted but there is a rhythm to which ones are and a set PR interval.
Third degree heart block: No conduction to ventricles at all, the purkinje fibres become the pacemakers
What’s asystole?
No heart contraction.
Four main anti-arrhythmic drug classes?
Sodium channel blockers
Beta adrenoceptor blockers
Potassium channel blockers
Calcium channel blockers
Mechanism of action of beta-adrenoceptor blockers?
Suppression of abnormal pacemakers
Mechanism of action of potassium channel blockers?
Tissue remains in refractory period for longer
Mechanism of calcium-channel blockers?
Decrease automaticity in supraventricular tissues.
5 things to look out for during a CV examination, when measuring someone’s pulse?
Volume Rate Character Rhythm Quality
What are the changes to the ECG in a STEMI?
ST elevation
Deep Q wave
Negative T wave in late STEMI
