Cardiology Flashcards
Define…
1) Preload
2) Afterload
3) Contractility
4) Elasticity
1) The volume of blood in the ventricles just before contraction (end diastolic volume).
2) The pressure against which the heart must work to eject blood in systole.
3) The inherent strength + vigour of the heart’s contraction during systole.
4) Myocardial ability to recover its original shape after systolic stress.
Define…
1) Compliance
2) Diastolic distensibility
3) Resistance
4) Starling’s law
1) How easily a chamber of the heart expands when it’s filled with blood.
2) The pressure required to fill the ventricle to the same diastolic volume.
3) A force that must be overcome to push blood through the circulatory system.
4) Increased EDV leads to increased stroke volume + so increased cardiac output leading to more forceful contraction as the sarcomeres are stretched more.
What are the equations for…
1) Stroke volume
2) Mean arterial pressure
3) Cardiac output
4) Poiseuille’s
5) Ohm’s law
6) Pulse pressure
7) Blood pressure
1) SV = EDV - ESV
2) MAP = DP + 1/3PP
3) CO = HR x SV
4) Flow = vessel radius^4
5) Flow = pressure gradient ÷ resistance
6) PP = SP - DP
7) BP = CO x PVR
How can the vascular system activate RAAS?
A reduction in CO means there is reduced renal perfusion + so there’s little/no arteriolar stretch which initiates RAAS.
Explain the RAAS process.
- Juxtaglomerular cells located in the afferent arterioles are stimulated to release the enzyme renin.
- Renin enters the blood where it cleaves angiotensinogen produced in the liver into angiotensin I.
- Angiotensin I is a biologically inactive peptide which undergoes further cleavage by angiotensin converting enzyme (ACE) produced in the lungs to form the active agent angiotensin II.
What effects does angiotensin II have on the body?
Angiotensin II
- Stimulates zona glomerulosa of adrenal cortex to secrete aldosterone.
- Stimulates thirst + vasopressin release causing water retention.
- Increases Na+ reabsorption in the proximal convoluted tubule + so water retention.
- Vasoconstrictor + so increases GFR (esp. in efferent arterioles).
What effects does aldosterone have on the body?
- Acts on principal cells of the collecting duct + stimulates transcription of epithelial sodium channels (ENaCs) causing Na+ reabsorption + so water reabsorption into the principal cells which causes more K+ excretion due to ENaC mechanism.
What is the counter mechanism to RAAS within the heart?
- The atrial natriuretic + brain natriuretic peptide hormones (ANP/BNP).
- They are released in response to stretching of the atrial + ventricular muscle cells as a result of raised atrial/ventricular pressures/volume.
What are the main effects of the ANP/BNP hormones?
- Increased renal excretion of Na+ + water.
- Relax vascular smooth muscle (renal vasodilator in afferent arterioles to increase GFR to increase Na+ excretion).
- Increased vascular permeability.
- Inhibits the release/actions of aldosterone, angiotensin II, endothelin + vasopressin.
What enzyme metabolises ANP/BNP?
- Neutral endopeptidase (NEP) like neprilysin.2
What do the following represent…
1) P wave.
2) PR interval.
3) QRS complex.
4) QT interval.
5) ST segment.
6) T wave.
7) J point
1) Atrial depolarisation.
2) Time taken for atria to depolarise + electrical activation to get through the AVN (120-200ms).
3) Ventricular depolarisation (120ms)
4) Correlates to plateau phase of cardiac action potential + should be 350-450ms, heart rate can make it vary.
5) Interval between depolarisation + repolarisation.
6) Ventricular repolarisation.
7) Where the QRS complex becomes the ST segment, should be isoelectric.
ECG questions
1) In what leads should the QRS complex be dominantly upright?
2) In what lead are all waves negative?
3) What is the rule for R + S wave progression in the chest leads?
1) I + II.
2) aVR.
3) R grows from V1-4, S must grow V1-3 + disappear in V6.
ECG questions
1) Where might the ST segment not be isoelectric?
2) In what leads must P + T waves be upright + there be no/small Q waves?
1) Only V1-2 it may be elevated.
2) Leads I-II, V2-6.
How can you determine rhythm from an ECG?
- Regular rhythm = 300 ÷ number of big boxes between two QRS complexes.
- Irregular rhythm = number of beats present in 10 seconds x 6
What is the QRS axis of the heart?
- Represents the overall direction of the heart’s electrical activity.
- Normal axis is -30 to 90 degrees.
- -30 to -90 degrees is left axis deviation.
- 90 to 180 degrees is right axis deviation.
What ECG changes are seen in…
1) Right atrial enlargement?
2) Left atrial enlargement?
3) Abnormal T waves?
1) Tall pointed P waves (P pulmonale).
2) Notched/bifid (‘M’ shaped) P waves (P mitrale).
3) Symmetrical, tall + peaked, biphasic or inverted.
Define…
1) Atherosclerosis.
2) Atherogenesis.
3) Ischaemia.
4) Infarction.
1) Atherosclerosis is the pathology of the arteries characterised by the deposition of fatty material in the intima (inner wall), it’s an inflammatory process.
2) Atherogenesis is the development of an atherosclerotic plaque.
3) Ischaemia is reversible damage to tissues as a result of impaired vascular perfusion depriving tissues of vital nutrients + oxygen.
4) Infarction is irreversible necrosis of tissue due to ischaemia.
What is the effect of an atheromatous plaque? What causes the inflammation in atherosclerosis?
- It thins the media of an artery + it’s distributed in the peripheral + coronary arteries with focal distribution along the artery length.
- Endothelial cell injury leads to chemoattractants to be released which signal to leukocytes that accumulate + migrate into the vessel walls causing cytokine release (IL-1, 6) causing inflammation.
Why does atherosclerosis have such a major disruption to flow?
Poiseuille’s equation…
- Flow = vessel radius^4
What are the features in the first step in atherosclerosis progression?
Fatty streaks…
- Earliest lesion of atherosclerosis, appears very early (<10y/o).
- Consist of aggregations of lipid-laden macrophages (foam cells) + T lymphocytes within the intimal layer of the vessel wall.
What are the features in the second step in atherosclerosis progression?
Intermediate lesions…
- Foam cells.
- Vascular smooth muscle cells.
- T lymphocytes.
- Adhesion + aggregation of platelets to vessel wall.
- Isolated pools of extracellular lipid.
What are the features in the third step in atherosclerosis progression?
Fibrous plaques/advanced lesions…
- Fibrous cap that overlies lipid core + necrotic debris.
- Foam cells + macrophages.
- Smooth muscle cells.
- T lymphocytes.
- Can impede blood flow + prone to rupture.
What are the features in the fourth step in atherosclerosis progression?
Plaque rupture…
- Plaques are constantly growing + receding. The fibrous cap has to be resorbed + redeposited in order to be maintained. If balance shifted in favour of inflammatory conditions, the cap becomes weak + the plaque ruptures leading to thrombus formation + vessel occlusion.
What is plaque erosion and what can it lead to?
- Lesions tend to be small ‘early lesions’ where the fibrous cap does not disrupt.
- Can lead to an NSTEMI.
What are the complications with atherosclerosis?
- Myocardial infarction.
- Stroke.
- Aortic aneurysms.
- Peripheral vascular disease (gangrene, intermittent claudication).
What are the constituents in an atherosclerotic plaque?
- Lipid.
- Necrotic core with dead cells, debris.
- Connective tissue.
- Fibrous cap – layers of smooth muscle.
- Lymphocytes – chronic inflammation.
What are the risk factors with atherosclerosis?
- Smoking – due to free radicals, nicotine + CO.
- HTN – due to shearing forces on the endothelial cells.
- Hyperlipidaemia – due to direct damage to endothelial cells.
- Diabetes mellitus.
- Increasing age.
What is the treatment for atherosclerosis?
- Percutaneous coronary intervention (PCI).
ANGINA PECTORIS
What is the pathophysiology of angina pectoris?
- Angina is a symptom of oxygen supply/demand mismatch to the heart experienced on exertion.
- Typically, an atheroma causes a narrowing of the coronary vessels meaning that at times of increased oxygen demand like exertion, there is symptomatic reversible myocardial ischaemia leading to anginal pain.
ANGINA PECTORIS
Explain the difference between physiological + pathological state in angina pectoris?
- In the physiological state, blood vessels try to compensate for increased myocardial demand by reducing microvascular resistance to increase flow.
- In the pathological state, at rest epicardial resistance is already high + so microvascular resistance has to fall at rest to supply myocardial demand so on exertion microvascular resistance can’t reduce any more so the flow can’t increase to meet metabolic demand.
ANGINA PECTORIS What is... 1) Stable angina? 2) Unstable angina? 3) Decubitus angina? 4) Prinzmetal angina?
1) Induced by effort, relieved by rest.
2) Crescendo angina; angina of increasing frequency or severity, occurs on minimal exertion or at rest; associated with higher risk of MI.
3) Precipitated by lying flat.
4) Vasospastic angina; caused by coronary artery spasm (may coexist with fixed stenoses, rare though), occurs at rest.
ANGINA PECTORIS
What is the aetiology of angina pectoris?
- Atherosclerosis.
- Increased distal resistance (LVH).
- Reduced oxygen carrying capacity (anaemia).
- Coronary artery spasm.
- Thrombosis.
ANGINA PECTORIS
What are the modifiable/non-modifiable risk factors of angina pectoris?
Modifiable... - Smoking. - Diabetes mellitus. - Hypercholesterolaemia (LDL). - Obesity/sedentary lifestyle. - HTN. Non-modifiable... - Increasing age. - Gender (male bias). - Family history.
ANGINA PECTORIS
What is the clinical presentation of angina pectoris?
- Constricting/heavy discomfort to the chest/jaw/neck/shoulders/arms.
- Symptoms brought on by exertion.
- Symptoms relieved with 5 mins rest or glyceryl trinitrate (GTN) spray.
- All 3 = typical angina, 2 = atypical angina, 0-1 = non-anginal chest pain.
- Accessory symptoms of breathlessness.
ANGINA PECTORIS
What are the differential diagnoses of angina pectoris?
- Pulmonary embolism.
- Pericarditis/myocarditis.
- Musculoskeletal.
- Gastro-oesophogeal reflux, ulceration.
- Psychological.
ANGINA PECTORIS
What are the investigations for angina pectoris?
- Stress ECG.
- Coronary angiogram (high NPV, low PPV so good at excluding disease).
- ECG may show signs of ischaemia (ST depression, flat/inverted T waves).
- Can use pre-test probability of coronary artery disease, takes into account gender, age + typicality of pain.
ANGINA PECTORIS
What is the primary prevention for angina pectoris treatment?
Modify risk factors…
- Smoking cessation.
- Dietary + exercise advice.
- Get conditions like HTN, hypercholesterolaemia, T2DM controlled.
ANGINA PECTORIS
What is the secondary prevention for angina pectoris treatment?
Pharmacological…
- Reduce CV events (aspirin, statins).
- Reduce symptoms (GTN spray, CCBs, ACEi, BBs).
Interventional…
Interventional…
- Revascularisation via PCI/CABG if there are large amounts of myocardial ischaemia.
- This in turn will help to reduce symptoms caused from stenotic coronary vessels.
ACS
What are acute coronary syndromes (ACSs)?
- ACS encompasses a spectrum of acute cardiac conditions including unstable angina, non-ST elevation myocardial infarction (NSTEMI) + ST elevation myocardial infarction (STEMI).
ACS
What is the pathophysiology of ACS?
- An atherosclerotic plaque ruptures causing platelet aggregation to occur leading to thrombus formation which completely occludes the artery.
- This leads to irreversible ischaemia causing infarction + so necrosis of the cells that results in permanent heart muscle damage.
- MI means there’s necrosis of cells which causes release of troponin – a marker of cardiac muscle injury which does not present in unstable angina as there’s only myocardial ischaemia without cell necrosis.
ACS
What’s the difference between type 1 and type 2 MI?
- Type 1 is spontaneous MI with ischaemia due to plaque rupture.
- Type 2 is MI secondary to ischaemia due to increased oxygen demand.
ACS
What are the common/uncommon aetiologies of ACS?
Common... - Rupture of atherosclerotic plaque leading to arterial thrombosis. Uncommon... - Coronary vasospasm. - Drug abuse. - Coronary artery dissection.
ACS
What complications are there with ACS?
May develop Dressler’s syndrome 2-10 weeks after an MI…
- Myocardial injury stimulates the formation of autoantibodies against the heart, secondary form of pericarditis.
- Presents with fever, chest pain + pericardial rub.
ACS
What are the modifiable/non-modifiable risk factors of angina pectoris?
Modifiable... - Smoking. - Diabetes mellitus. - Hyperlipidaemia. - Obesity/sedentary lifestyle. - HTN. - Cocaine use. Non-modifiable... - Increasing age. - Gender (male bias). - Family history.
ACS
What’s the clinical presentation of unstable angina?
- Constricting/heavy discomfort to the chest/jaw/neck/shoulders/arms at rest.
- Pain with crescendo patterns (pain becomes more frequent + more easily provoked).
- No significant rise in troponin.
ACS
What are the symptoms of MI?
- Acute central crushing chest pain that may radiate to chest/jaw/neck/shoulders/arms.
- Sweating.
- Dyspnoea.
- Palpitations.
- Nausea/vomiting.
- Third occur in bed at night.
ACS
What are the signs of MI?
- Distress/anxiety/sweatiness.
- Pallor.
- Increased/decreased pulse + BP.
ACS
What are the differential diagnoses of ACS?
- Stable angina.
- Pulmonary embolism or pneumothorax.
- Peri/myocarditis.
- Musculoskeletal.
- Gastro-oesophageal reflux.
ACS
What are the complications with ACS?
- Heart failure.
- Rupture of infarcted ventricle or interventricular septum.
- Mitral regurgitation.
- Arrhythmias.
- Heart block.
ACS
What investigations are there for ACS?
ECG…
- ST elevated, hyperacute T waves or new LBBB w/ T-wave inversion of pathological Q waves later (STEMI).
- ST depression + T-wave inversion (NSTEMI + unstable angina).
Bloods…
- Serum troponin.
Echocardiogram.
Coronary angiogram.
ACS
What is the initial treatment for MI?
MONA…
- Morphine for pain relief.
- Oxygen to prevent hypoxia.
- Nitrates for vasodilation.
- Aspirin 300mg.
- Get into hospital ASAP, call PCI centre if STEMI.
ACS
What is the hospital treatment for ACS?
- PCI immediately or if not possible then thrombolysis with streptokinase.
ACS
What is the primary prevention for ACS?
Modify risk factors…
- Smoking cessation.
- Dietary + exercise advice.
- Get conditions (HTN, hyperlipidaemia, T2DM) controlled.
ACS
What treatments optimise cardioprotective medications for ACS?
Antiplatelets - Aspirin 75mg once daily. - P2Y12 inhibitor like clopidogrel. Beta blocker to reduce myocardial oxygen demand. High dose statin. - Atorvastatin 80mg. ?ACEi.
CARDIAC FAILURE
What is cardiac failure and what happens when the heart fails?
- Cardiac output is inadequate for the body’s requirements suggesting the efficiency of the heart as a pump is impaired, heart cannot deliver blood at a rate that meets metabolic demand.
- Compensatory mechanisms attempt to maintain CO but as the cardiac failure progresses, mechanisms are exhausted + become pathophysiological.
CARDIAC FAILURE
What are the 4 compensatory methods in cardiac failure?
- Sympathetic system.
- RAAS.
- Natriuretic peptides.
- Ventricular dilation/hypertrophy.
CARDIAC FAILURE
Explain how the sympathetic system acts as a compensatory method + the consequence of this.
- Improves ventricular function by increasing HR + contractility.
- BUT causes arteriolar constriction which increases load + so myocardial work.
CARDIAC FAILURE
Explain how RAAS acts as a compensatory method + the consequence of this.
- Reduced CO leads to reduced renal perfusion; activates RAAS leading to fluid retention + so increased preload.
- BUT it also causes arteriolar constriction which increases load + myocardial work.
CARDIAC FAILURE
Explain how the natriuretic peptide system acts as a compensatory method + the consequence of this.
- Atrial + brain natriuretic peptide hormones have diuretic, hypotensive + vasodilating properties.
CARDIAC FAILURE
What are the 2 broad categories for cardiac failure?
Systolic failure…
- Inability of ventricle to contract normally, results in reduced CO, ejection fraction <40%.
Diastolic failure…
- Inability of ventricle to relax + fill normally, causing increased filling pressure, typically EF >50% – heart failure with preserved ejection fraction (HFPEF).
CARDIAC FAILURE
What are the 2 types of cardiac failure and where does blood back up to?
- Left cardiac failure = pulmonary circulation.
- Right cardiac failure = systemic circulation.
CARDIAC FAILURE
What is the New York Heart Association’s classification of cardiac failure?
- Class I = no limitation (asymptomatic).
- Class II = slight limitation (mild cardiac failure.
- Class III = marked limitation (symptomatically moderate cardiac failure).
- Class IV = inability to carry out any physical activity without discomfort (symptomatically severe cardiac failure).
CARDIAC FAILURE
What’s the aetiology of cardiac failure?
Systolic failure... - IHD. - MI. - Cardiomyopathy. Diastolic failure... - Cardiac tamponade. - Ventricular hypertrophy. - Cor pulmonale + obesity.
CARDIAC FAILURE
Why are men more likely to be affected by cardiac failure?
Oestrogen acts as a protective factor in menstruating women.
CARDIAC FAILURE
What are the symptoms of left cardiac failure?
- Nocturnal cough ± pink frothy sputum.
- Paroxysmal nocturnal dyspnoea, exercise intolerance.
- Cold peripheries.
CARDIAC FAILURE
What are the symptoms of right cardiac failure?
- Peripheral oedema.
- Ascites.
- Nausea.
CARDIAC FAILURE
What two initial investigations are crucial in determining if someone has cardiac failure?
Bloods – BNP raised levels indicates heart failure.
ECG – may indicate cause.
- NICE say if ECG + BNP levels are normal then cardiac failure unlikely so search for alternative diagnosis.
- If either abnormal – echocardiography required as it’s diagnostic, can confirm presence of LV dysfunction.
CARDIAC FAILURE
What could you see on the CXR of someone with cardiac failure?
- Cardiomegaly.
- Alveolar oedema “Bat’s wings”.
- Dilated prominent upper lobe vessels.
- Pleural effusion.
- Kerley B lines (interstitial oedema).
CARDIAC FAILURE
What is the generic treatment for cardiac failure?
Generic lifestyle advice…
- Smoking + alcohol cessation.
- Optimise weight, nutrition + exercise.
CARDIAC FAILURE
What is the medical treatment for cardiac failure?
Symptomatic…
- Loop diuretics like furosemide for oedema.
- Switch to K+-sparing diuretic like spironolactone if hypokalaemic.
Disease-altering…
- ACEi (ARBs if C/I) in all those with LV systolic dysfunction as improves symptoms + prolongs life
- Beta blockers like bisoprolol to decrease mortality.
- Calcium glycoside like digoxin.
COR PULMONALE
What is the pathophysiology and prognosis of cor pulmonale?
- Right cardiac failure due to right ventricular hypertrophy caused by chronic pulmonary arterial HTN.
- Poor, 50% die in 5 years.
COR PULMONALE
What is the aetiology of cor pulmonale?
- Chronic lung disease like COPD, pulmonary fibrosis.
- Pulmonary emboli, sickle-cell disease.
- Neuromuscular disease like myasthenia gravis, MND.
COR PULMONALE
What are the symptoms of cor pulmonale?
- Dyspnoea.
- Fatigue.
- Syncope.
COR PULMONALE
What are the signs of cor pulmonale?
- Cyanosis.
- Tachycardia.
- Raised JVP.
COR PULMONALE
What blood tests can you do for cor pulmonale and what do they show?
- FBC – Hb + haematocrit increased (secondary polycythaemia).
- ABG – Hypoxia ± hypercapnia.
COR PULMONALE
What would the ECG + CXR show for cor pulmonale?
ECG... - Right axis deviation. - Right ventricular hypertrophy. - P pulmonale (tall pointed P waves). CXR... - Enlarged RA + RV. - Prominent pulmonary arteries.
COR PULMONALE
What is the treatment for cor pulmonale?
- Treat underlying cause.
- Treat respiratory failure with oxygen.
- Treat cardiac failure with diuretics like furosemide.
- Consider venesection or heart-lung transplantation in young patients.
HYPERTENSION
What are the four types of HTN?
- Primary/essential.
- Secondary.
- Malignant.
- White coat.
HYPERTENSION
Explain what primary/essential HTN is.
- No known aetiology, typically older patients.
- Usually asymptomatic, ?headache.
- Always check for end organ damage/signs of renal disease, check for retinopathy, proteinuria.
HYPERTENSION
Explain what secondary HTN is.
HTN secondary to…
- Renal disease.
- Endocrine disease like Cushing’s + Conn’s syndromes, hyperparathyroidism, acromegaly, pheochromocytoma.
- Others like pregnancy, cocaine.
HYPERTENSION
Explain what malignant HTN is.
- Rapid rise in BP leading to vascular damage, commonly fibrinoid necrosis + bilateral retinal haemorrhages + exudates ± papilloedema.
- Severe HTN >200/130mmHg.
- Commonly symptoms like headache ± visual loss in younger, black patients.
- URGENT TREATMENT.
HYPERTENSION
Explain what white coat HTN is.
- Elevated clinical BP with a normal ambulatory blood pressure monitoring (ABPM) BP.
HYPERTENSION
What is suspected HTN in clinic and how do you confirm this?
- Suspected is clinical BP ≥140/90mmHg.
- Confirmed by using ambulatory blood pressure monitoring or multiple home BP measuring.
- Helps with white coat HTN/borderline.
HYPERTENSION
How is HTN classified?
Clinical BP... Stage 1 = 140/90mmHg. Stage 2 = 160/100mmHg. Severe = 180/110mmHg. ABPM... Stage 1 = 135/85mmHg. Stage 2 = 150/95mmHg.
HYPERTENSION
What is the first line treatment for HTN?
Primary prevention…
- Smoking + alcohol cessation.
- Low-fat + reduced salt intake.
- Increased exercise, weight loss.
- Treat underlying cause.
HYPERTENSION
What two systems are targeted in anti-hypertensive medications?
- RAAS + sympathetic nervous system.
HYPERTENSION
What BP reading would mean you have to treat this patient immediately with anti-hypertensives, even before lifestyle advice?
- BP >160/100mmHg.
- Only consider starting medication if >140/90mmHg.
HYPERTENSION What are the clinical/ABPM blood pressure targets for... i) Under 80. ii) Over 80. iii) Diabetics
i) CBP = <140/90mmHg, ABPM = <135/85mmHg.
ii) CBP = <150/90mmHg, ABPM = <145/85mmHg.
iii) CBP = <130/80mmHg.
HYPERTENSION What is the first line medication for... i) Under 55s. ii) Over 55s. iii) Afro-Caribbean any age.
i) ACEi or ARB if C/I like lisinopril or candesartan.
ii) CCB like amlodipine.
iii) CCB like amlodipine.
HYPERTENSION
What are the second + subsequent treatments for HTN?
- 2nd step = Add ACEi/ARB or CCB.
- 3rd step = add thiazide-like diuretic.
- Consider addition of any other medications like beta blockers, K+-sparring diuretics.
SINUS TACHYCARDIA What is the... i) Pathophysiology ii) Aetiology iii) Treatment
of sinus tachycardia?
i) HR >100bpm with a normal P wave, followed by a normal QRS complex – not an arrythmia.
ii) Physiological response to exercise + excitement.
Can be due to fever, anaemia, thyrotoxicosis, acute PE.
iii) Treat underlying cause, beta blockers used to slow sinus rate.
SUPRAVENTRICULAR TACHYS
What is the pathophysiology of Atrioventricular re-entrant tachycardia (AVRT)?
- Due to presence of an accessory pathway where congenital myocardial fibres connecting the ventricles + atria, which can lead to pre-excitation of ventricles.
- Wolff-Parkinson-White syndrome is best-known type of aVRT in which there is an accessory pathway (Bundle of Kent) between atria + ventricles.
SUPRAVENTRICULAR TACHYS
What is the pathophysiology of Atrioventricular node re-entrant tachycardia (AVNRT)? What are the risk factors that can aggravate the arrhythmia?
- Commonest supraventricular tachycardia.
- Circuits form within AVN causing narrow complex tachycardias.
- Atrial impulse carried by slow pathway to ventricles but can also travel back up fast pathway to signal back down slow pathway.
- Exertion, emotional stress, caffeine.
SUPRAVENTRICULAR TACHYS
What are the symptoms of AVRT/AVNRT?
- Rapid regular palpitations with abrupt onset/offset.
- Dyspnoea.
- Chest pain.
- Jugular venous pulsation.
SUPRAVENTRICULAR TACHYS
What does the ECG show in…
i) Wolff-Parkinson-White syndrome?
ii) AVNRT?
i) Short PR, broad QRS, delta waves (slurred upstroke to QRS).
ii) P waves hidden as embedded in QRS, QRS normal or wide.
SUPRAVENTRICULAR TACHYS
What is the acute treatment for AVRT/AVNRT?
- Increase vagal stimulation of sinus node by Valsalva manoeuvre (ask patient to blow into 20mL syringe with enough force to push plunger back).
- Adenosine (short acting AVN blocking drug that will terminate most junctional tachycardias).
SUPRAVENTRICULAR TACHYS
What is the long term treatment for AVRT/AVNRT?
- Radiofrequency ablation of accessory pathway via a cardiac catheter.
- Flecainide, verapamil + amiodarone commonly used.
SUPRAVENTRICULAR TACHYS
What is the treatment for haemodynamically unstable patients?
- Emergency DC cardioversion.
SUPRAVENTRICULAR TACHYS
What is the pathophysiology of atrial fibrillation?
- AF is a chaotic, irregular atrial rhythm at 300-600bpm where the AVN responds intermittently as it’s unable to keep up, hence an irregular ventricular rhythm.
- CO drops by 10–20% as ventricles aren’t primed reliably by atria contributing to heart failure.
SUPRAVENTRICULAR TACHYS
What is the aetiology of atrial fibrillation?
- HTN.
- IHD.
- Thyrotoxicosis.
- Mitral valve disease.
SUPRAVENTRICULAR TACHYS
What are the symptoms of atrial fibrillation?
- Palpitations.
- Dyspnoea.
- Syncope.
- Chest pain.
SUPRAVENTRICULAR TACHYS
What are the signs of atrial fibrillation?
- Irregularly irregular pulse.
- 1st heart sound of variable intensity.
- Signs of LVF.
SUPRAVENTRICULAR TACHYS
What is the main complication with atrial fibrillation and how is this calculated?
- Embolic stroke caused by stagnation of blood in atria due to ineffective mechanical action of atria leading to thrombus formation.
- Calculated initially by the CHADS2 score + if score >2 then CHA2DS2-VASc score.
SUPRAVENTRICULAR TACHYS
What are the components of the CHA2DS2-VASc score?
Congestive cardiac failure (1) HTN (1) A2 (≥75 = 2 or 1 in first system, 64-75 = 1) Diabetes(1) S2troke/TIA (2) Vascular disease (1) Sex Category female (1)
SUPRAVENTRICULAR TACHYS
What CHA2DS2-VASc score warrants anti-coagulation?
1 = consider, 2 = anti-coagulate.
SUPRAVENTRICULAR TACHYS
What investigations would you do in someone with atrial fibrillation?
ECG.
- Absent P waves, irregular QRS complexes, F waves, irregularly irregular.
SUPRAVENTRICULAR TACHYS
What is the main goals in treatment of atrial fibrillation?
- Rate control + anti-coagulation.
SUPRAVENTRICULAR TACHYS
How can rate control be achieved in atrial fibrillation?
- Beta blocker or rate-limiting calcium channel blockers (verapamil, diltiazem).
- Digoxin.
SUPRAVENTRICULAR TACHYS
How can anti-coagulation be achieved in atrial fibrillation?
- Warfarin whilst maintaining international normalised ratio (INR) 2.0–3.0.
- DOACs like apixaban, no INR testing.
SUPRAVENTRICULAR TACHYS
How can rhythm control be achieved in atrial fibrillation?
- Elective DC cardioversion.
- Elective pharmacological cardioversion with amiodarone (if underlying heart disease) or flecainide (if no underlying heart disease).
SUPRAVENTRICULAR TACHYS
What is the long term treatment of atrial fibrillation?
- Catheter ablation.
- Pacemaker.