Cardiovascular conditions 1 Flashcards
Arrhythmias and intrinsic conditions
What is Atrial fibrillation/flutter?
Supraventricular tachyarrhythmias, characterised by uncoordinated atrial activity on the surface ECG with fibrillatory waves of varying shapes, amplitudes and timing associated with an irregularity irregulat ventricular response when atrioventricular conduction is intact
What causes atrial fibrillation/flutter?
Cronary artery disease Heart failure Valvular disease Diabetes Thyroid disorders COPD Obstructive sleep apnoea advanced age
What are the risk factors for atrial fibrillation/flutter?
Increasing age Diabetes mellitus Hypertension Congestive heart failure Valvular heart disease Coronary artery disease Other atrial arrhythmias Cardiac or thoracic surgery Hyperthyroidism Hypoxic pulmonary conditions Alcohol intoxication Obesity Smoking Inflammatory disorders
What are the symptoms of Atrial fibrillation/flutter?
Palpitations Dizziness SOB Syncope Chest discomfort
What are the signs of atrial fibrillation/flutter?
Irregular pulse rate Hypotension Elevated JVP Added heart sounds (Gallop rhythm in HF, pericardial rub in pericarditis) Rales (Present in HF) Evidence of stroke
What investigations are done for Atrial fibrillation/flutter?
ECG (diagnostic - could be not detected)
TFTs (Raised)
FBC (Anaemia)
U&Es (Abnormal K+ can potentiate arrhythmias, especially if on digoxin)
TTE, do a TOE in those with an abnormality on TTE
How do you manage Atrial fibrillaiton/flutter?
Control arrhythmia and thromboprophylaxis to prevent strokes
Treat underlying cause
Treatment associated with heart failure
Need lifestyle changes e.g. avoid precipitating factors
Rate/ rhythm control
Left atrial ablation if drugs cant control it
What is used to maintain Rate in atrial fibrillaiton/flutter?
Standard Beta blocker or a rate-limiting CCB (ditliazem/verapamil)
Consider digoxin for those with paroxysmal AF if sedentary
Combo of: Beta-blocker, ditliazem, digoxin
DO NOT offer amiodarone for long-term rate control
What drugs are used for rhythm control in atrial fibrillaiton/flutter?
Cardioversion if lasts longer than 48 hrs
Amiodarone for 4 weeks, before cardioverson and up to a year after
Long term:
Beta blocker
Dronedarone for maintenance of sinus rhythm after successul cardioversoin in people with paroxysmal or persistent AF
Amiodarone for those with left ventriuclar impairment or heart failure
What scoring system is used to assess stroke risk in those with AF or at risk of arrhythmia?
CHA2DS2-VASc score
What is the CHA2DS2-VASc score?
1 point for each: - Heart failure - Diabetes - Hypertension - Vascular disease - Aged >65 - Female 2 points for: - Prior TIA/Stroke/thromboembolism - >/= 75 years old Males: Score 1 or more - oral anticoagulation Females: Score of 2 or more - consider oral anticoagulation
What anticoagulation is used in atrial fibrillation/flutter?
Apixaban (Prevent stroke and systemic embolism in people with non-valvular AF who have had a stroke or TIA)
Rivaroxaban (Congestive heart failure, HTN, 75+, DM, stroke or TIA)
How would someone manage acute atrial fibrillaiton/flutter?
Emergency electrical cardioversion without delay if haemodynamic instability
If use cardioversion: offer flecainide or amiodarone with evidence of structural heart damage
If >48 hrs, delay cardioversion until on therapeutic anticoag for minmum 3 weeks
Do not offer magnesium or CCB for pharmacological cardioversion
Anticoagulation (heparin)
Other management options: Cryoablation or high intensity focused ultrasound ablation
What are the complications of atrial fibrillation/flutter?
Acute stroke
Myocardial infarction
Congestive Heart failure
What is cardiac arrest?
Sudden cardiac arrest is a sudden state of circulatory failure due to a loss of cardiac systolic function.
What are the 4 cardiac rhythm disturbances?
Ventricular fibrillation
Pulseless ventricular tachycardia (Torsades de pointes is a sub-group of polymorphic VT)
Pulseless electrical activity
Asystole
What causes cardiac arrest?
Ischaemic heart disease, cardiovascular disease, cardiomyopathy/dysrhythmia
VT, VF most commonly IHD and acute MI
Most common cause of PEA = Myocardial ischaemia/infarction, hypovolaemia, hypoxia and PE
What are the Risk factors for cardiac arrest?
Coronary artery disease Left ventricular dysfunction Hypertrophic cardiomyopathy Arrhythmogenic left ventricular dysfunction Long QT syndrome Meds that prolong QT interval Acute medical or surgical emergency Illicit substances Brugada syndrome Valvular heart disease Smoking History of eating disorders
What is Brugada syndrome?
A rare, dangerous condition affecting potassium and sodium cell entry in cardiac cells - causing very fast heart beats
What are the signs and symptoms of Cardiac arrest?
Unresponsive patients
Absence of normal breathing
Absence of circulation
Disturbed rhythm disturbance
What investigations are done for cardiac arrest?
Continuous cardiac monitoring FBC (Low Hct in haemorrhage) Serum electrolytes (Hyper/hypokalaemia) ABG Cardiac biomarkers (positive/elevated) Echo (valvular abnormalities)
What are the reversible causes of cardiac arrest?
4H's and 4T's Hypoxia (Give oxygen) Hypovolaemia (Correct with IV fluids) Hypothermia (Consider in those drowning) Hyperkalaemia Tension pneumothorax Tamponade Toxins Thromboembolism
How do you manage cardiac arrest?
If responsive: Call ambulance If unresponsive: ABCD and call ambulance A: Airway - head tilt, chin lift B: Breathing - Look for chest movements C: Circulation (30:2) D: Defibrillation!
Further considerations:
- Amiodarone (150mg followed by infusion of 900mg, lidocaine if no amiodarone)
- Consider Ca2+ in case of PEA (hyperkalaemia, hypocalcaemia, OD on CCBs or magnesium)
- Consider magnesium sulphate
- Bicarbonate, 50mmol in arrests with hyperkalaemia or tricyclic antidepressants
Transfer to ITU for monitoring of breathing, circulation and ventilation
What are the complications of Cardiac arrest?
Death - highly likley Rib and sternal fractures Anoxic brain injury Ischaemic liver injury Renal acute tubular necrosis Recurrent cardiac arrest
What is Heart block?
It is a cardiac electrical disorder defines as impaired (delayed or absent) conduction from the atria to the ventricles
What are the classifications of heart block?
First degree Second degree (Mobitz I and Mobitz II) Third degree (complete) block
What causes heart block?
Fibrosis and calcification of the conduction system, CAD and medication such as:
AV-nodal blocking agents (beta blockers, CCBs, digitalis, adenosine), Anti-arrhythmics (sotalol and amiodarone)
Others include: Vagal tone, cardiomyopathy, calcification from valvular calcification
What are the Risk factors for heart block?
Age-related degenerative changes Increased vagal tone AV-nodal blocking agents Chronic stable CAD Acute coronary syndrome Chronic heart failure Hypertension Cardiomyopathy Left ventricular hypertrophy Recent cardiac surgery Myocarditis Sarcoidosis Infective endocarditis Blunt cardiac injury
What are the symptoms of heart block?
1st degree - asymptomatic
Mobitz I - asymptomatic
Mobitz II and 3rd degree cause stokes-adams attacks (syncope caused by ventricular asystole)
- May cause: Dizziness, palpitations, chest pain and heart failure
What are the signs of heart block?
Often normal
Complete heart block: Slow large volum pulse, JVP shows cannon A waves
Reduced CO
What investigations are done for heart block?
ECG Serum troponin (Raised) Serum potassium (Very low or very high) Serum calcium (very low or very high) Serum pH (Very low or very high) Serum digitalis (Normal to high)
What is seen on ECG for first degree heart block ?
Prolonged PR interval but prolonging is the same
What is seen on ECG for second degree heart block (Mobitz type I)?
Progressive prolonging PR until there is a P wave without a QRS
What is seen on ECG for second degree heart block (Mobitz type II)?
PR interval same but regular/intermittent lack of QRS
What is seen on ECG for third degree heart block?
Total dissociation of P wave and QRS complexes
- QRS initiated in: Bundle of His (narrow complex) or More distally (Wide complex and slow rate)
How do you manage heart block?
1st degree or Mobitz I Asymptomatic: - Monitoring Symptomatic: 1st: Discontinue Medications 2nd: Infrequently PPM or cardiac resynchronicsation therapy
Mobitz II or 3rd-degree
Asymptomatic:
- 1st: Condition specific management and discontinuation of AV node-blocking drugs
- 2nd: PPM or cardiac resynchronisation therapy +/- ICD placement
Symptomatic:
- 1st: Condition-specific management, discontinuation of AV nodal blocking drugs, and temporary
- 2nd: PPM or cardiac resynchronisation therapy +/- ICD placement
What are the complications of Heart block?
Pacemaker implantation sequelae
Asystole
Cardiac arrest
Heart failure
What is Supraventricular tachycardia?
SVT is any tachydysrhythmia arising from above the level of the bundle of His, usually the atria or AV node. These typically produce a narrow complex tachycardia.
There are 2 main types: Atrioventricular nodal re-entry tachycardia and Atrioventricular re-entry tachycardia
What causes AVNRT?
The most common type of SVT, due to a reentry that forms around the AV node, which conducts to the ventricles faster than normal conduction pathways
What is AVNRT?
Reentrant tachycardia with an anatomically defined circuit that consists of 2 distinct pathways
What causes AVRT?
Occurs when normal AV conduction is present as well as accessory pathways. Forming a re-entry between atria and ventricles
What are the risk factors for SVT?
Nicotine Alcohol Caffeine Previous MI Digoxin toxicity
What are the symptoms of SVT?
May have minimal symptoms or may present with syncope
Palpitations
Light-headedness
Polyuria (due to increased atrial pressure causing ANP release)
Abrupt onset and termination of symptoms
Other symptoms: Fatigue, chest discomfort, dyspnoea, syncope
What are the signs of SVT?
Normal except tachycaridia
What investigations are done for SVT?
ECG
24hr ECG monitoring required with paroxysmal palpitations
Cardiac enzymes (Check for MI)
Electrolytes (Can cause arrhythmias)
Digoxin level
Echocardiogram (check for structural disease)
What can be seen on ECG for AVNRT/AVRT?
Tachycardia
Narrow QRS
No P waves
Decreased PR interval
How can you tell the difference between AVNRT and AVRT?
Acutely you cannot tell the difference!
Once tachycardia has resolved, you can see delta waves on ECG in AVRT
What is the management of SVT?
Unstable:
DC cardioversion
Stable:
Vagal manouevres (valsalva, carotid massage)
If valsalva doesnt work:
- Adenosine 6mg bolus (increase to 12) [contraindicated in asthma, use verapamil insted]
- Wait 2 mins, no change adenosine 12mg
- Same again after 2 mins
- wait 2 more mins, no change, IV metoprolol/amiodarone/digoxin/ DC cardiovert
If unresponseive to chemical cardioversion or tachycardia or adverse signs (low BP, heart failure, low consciousness) - sedate and synchronised / DC cardioversion
- Ongoing management: Radiofrequency ablation of slow apathy, beta blockers, alternatives: Fleicanide, propafenone, verapamil
What are the complications of SVT?
Haemodynamic collapse
DVT
Systemic embolism
Cardiac tamponade
What is vasovagal syncope?
Loss of consciousness due to a transient drop in blood flow to the brain caused by excessive vagal discharge
What causes vasovagal syncope?
Very common cause of fainting
Precipitated by: Emotions (e.g. fear, severe pain, blood phobia) and Orthostatic stress (e.g. prolonged standing, hot weather)
What are the symptoms of vasovagal syncope?
Loss of consciousness lasting a short time
Patients may experience vagal symptoms (Sweating, dizziness, light-headidness) before passing out
There may be twitching of limbs during blackout
Recovery is normally quick
What are the signs of vasovagal syncope?
None
What are the investigations for vasovagal syncope?
ECG (Check for arrhythmia)
Echo (Check for outflow obstruction)
Lying/standing blood pressure (Check for orthostatic hypertension)
Fasting blood glucose (check for DM/hyperglcaemia)
What is Ventricular fibrillation?
Cause of cardiac arrest and sudden cardiac death. Ventricular muscle fibres contract randomly causing a complete failure of ventricular function.
What causes Ventricular Fibrillation?
Ventricular fibres contract randomly causing complete failure of ventricular function
Most cases occur in patients with underlying heart disease
What are the Risk factors for ventricular fibrillation?
Coronary artery diseae AF Hypoxia Ischaemia Pre-excitation syndrome Drugs Electrolyte imbalance
What are the signs and symptoms of Ventricular fibrillation?
History of: Chest pain, fatigue and palpitations Known pre-existing conditions: - CAD - Cardiomyopathy - Valvular heart disease - Long QT syndrome - Wolff-Parkinson white syndrome - Brugada syndrome
What investigations are done for ventricular fibrillation?
ECG (Chaotic irregular deflections of varying amplitude)
Cardiac enzymes (troponin)
Electrolytes (Derangements cause arrhythmias)
Drug levels and toxicology screen
TFTs
Coronary angiography
How do you manage ventricular fibrillation?
Defibrillation and cardioversion
Full assessment of LVF, myocardial perfusion and electrophysiological stability
Most need an ICD
Beta blockers
May be treated with radiofrequency ablation
CABG prevents recurrent VF if ejection fraction is normal and ischaemia was the cause of the arrest
What are the complications of Ventricular fibrillation?
CNS Ischaemic injury Myocardial injury Post-defibrillaiton arrhythmias Aspiration pneumonia Defibrillation injury to self or others Injuries from CPR and resuscitation Skin burns Death
What is Ventricular tachycardia?
A broad complex tachycardia originating from a ventricular ectopic focus.
What defines ventricular tachycardia?
3 or more ventricular extrasystoles in succession at a rate of more than 120bpm
Accelerated idioventricular rhythm refers to ventricular rhythms with rates of 60-100 bpm
What are the types of VT?
Monomorphic VT
Non-sustained VT (<30secs)
Sustained VT
What is Sustained VT associated with?
Late phasemyocardial infarction Cardiomyopathy Right ventricular dysplasia Myocarditis Drugs (flecainide and disopyramide)
What are the types of VT?
Fascicular tachycardia
Right ventricular outlflow tract tachycardia
Torsades de pointes
Polymorphic ventricular tachycardia
What is Fascicular tachycardia?
Not usually associated with underlying structural heart disease
Originates from left bundle branch
Produces QRS complexes of short duration (often misdiagnosed as SVT)
QRS has right bundle branch block pattern
What is Right ventricular outflow tract tachycardia?
Originates from right ventricular outflow tract
ECG typically shows right axis deviation, with a LBBB pattern
Tachycardia provoked by catecholamine release, sudden changes in heart rate and exercise
Responds to alpha blockers or calcium anatagonists
What is polymorphic ventricular tachycardia?
Same ECG as torsades de pointes but in sinus rhythm
ECG tract similar to AF with pre-excitation
Less common than torsades de pointes
Leads to cardiogenic shock
Occur in acute MI and deteriorate into VF
What causes ventricular tachycardia?
Ischaemic heart disesae
Underlying non-ischaemic cardiomyopathy
Chagas disease
What are the Risk factors for ventricular tachycardia?
Coronary artery disease Acute MI Left venrticular systolic dysfunction Hypertrophic cardiomyopathy Long/Short QT syndrome Brugada syndrome Ventricular pre-excitation Arrhythmogenic right ventricular cardiomyiopathy Electrolyte imbalance Drug toxicity Chagas disese Family history of sudden death Mental or phsyical stress
What are the symptoms of Ventricular tachycardia?
Chest pain
Palpations
Dyspnoea
Syncope
What are the signs of Ventricular tachycardia?
Respiratory distress Bibasal crackles Raised JVP Hypotension Anxiety Agitation Lethargy Coma
What investigations are done for Ventricular tachycardia?
ECG Electrolytes Level of therapeutic drugs (e.g. digoxin) Evaluate for MI CXR Arrhythmia
What is seen on ECG on Ventricular tachycardia?
Rate >100 bpm Wide QRS complex Presence of AV dissociation Fusion beats Retrograde ventriculoatrial conduction
How do you manage ventricular tachycardia?
ABCs of resuscitation and provide basic and advanced life support
Pulseless VT - treat as if VF
Unstable VT (Reduced cardiac output) - Unsychronised defibrillaiton, respond to low levels of energy. Amiodarone often used for haemodynamically unstable VT, replenish electrolyte imbalance
Refractory VT - after 300mg amiodarone, followed by infusion of 900mg over 24hrs
When is an implantable cardiac defibrillatory used for?
Sustained VT causing collapse
Sustained VT with ejection fraction <35%
Previous cardiac arrest due to VT/VF
MI complicated by non-sustained VT
