
1. Broad Complex Tachycardia - QRS more than 0.12 seconds (3 seconds)
1.1. Ventricular Tachycardia
1.1.1. ECG - Absent P waves. Monomorphic broad QRS complex. Tachycardia
1.1.1.1. If unstable - Syncronised DC Cardioversion/ Shock. Amiodarone IV
1.1.1.2. If stable - Amoidarone IV and lidocaine
1.1.1.2.1. If drug therapy fails: ICD - implantable Cardioverter- defibrillator. Electrophysiological study (EPS)
1.1.1.3. DO NOT use verapamil —> Precipitates cardiac arrest.
1.2. Torsades De Pointes
1.2.1. QRS complex twisting around the isoelectric line.
1.2.1.1. If unstable treat same as VT
1.2.1.2. If stable: IV magnesium sulphate 2g over 10mins. Stop drugs that prolong QT interval (clarithromycin, erythromycin. Correct electrolytes.
1.2.1.2.1. Consider permanent pacing and Isoprenaline infusion in recurrent cases.
2. Cardiac Arrest
2.1. Shockable
2.1.1. Ventricular Tachycardia
2.1.1.1. Broad Complex Tachycardia. HR >100bpm and QRS width >120.
2.1.1.2. Causes: Hypokalaemia, hypomagnesaemia, MI, hypertrophic obstructive cardiomyopathy, inherited channelopathies. Clarithromycin, Erythromycin
2.1.1.2.1. Monomorphic VT - Haemodynamically unstable Cardioversion- Synchronised shocks. CPR. IV adrenaline. Amoidarone.
2.1.1.2.2. Monomorphic VT - Haemodynamically stable - IV Amoidarone
2.1.1.3. AVOID VERAPAMIL - may precipitate cardiac arrest.
2.1.2. Ventricular Fibrillation
2.1.2.1. Quivering ventricles - no output, disorganised electrical activity. No clear QRS complex
2.1.2.1.1. Pulseless VT, Defibrillation Unsynchronised shocks. CPR. IV adrenaline. Amoidarone.
2.2. Non-shockable
2.2.1. Pulseless electrical activity
2.2.1.1. ECG shows electrical activity but no pulse
2.2.1.1.1. CPR, 1mg adrenaline
2.2.2. Asystole
2.2.2.1. Heart ceases to beat - no QRS on ECG.
2.2.2.1.1. CPR, 1mg adrenaline
3. Heart Block
3.1. Complete heart block - third degree Complete dissociation between P waves and QRS complexes. Regular bradycardia.
3.1.1. Troponin, potassium, calcium and pH to rule out cause.
3.1.2. Atropine 500mcg IV repeated. Temporary transcutaneous cardiac pacingPermanent pacemaker.
3.1.3. Anti-cholinesterase inhibitors (Donepezil) should be stopped.
3.1.4. Beta-blockers and non-dihydropyridine (verapamil /diltiazem) not given together as both -ve inotropic.
3.2. First-degree - delayed contraction. P waves followed by QRS (PR >0.2)
3.3. Second degree - do not make it to AV nodes. Some P waves not followed by QRS complex.
3.3.1. Mobitz Type 1 - conduction takes longer until it fails and then restarts
3.3.2. Mobitz 2 - intermittent failure of conduction with absent QRS
4. Narrow Complex Tachycardia - QRS less than 0.12 seconds (3 squares)
4.1. Sinus Tachycardia
4.1.1. Normal QRS, P and T wave. Not an arrhythmia - usually due to pain or sepsis.
4.2. Supraventricular tachycardia
4.2.1. Any Tachycardia that is not of ventricular origin. Paroxysmal. Regular rhythm (unlike AFib). No saw-tooth (like Aflutter)
4.2.1.1. Irregular SVT - treat as AF
4.2.1.2. Regular SVT - Valsalva Manoeuvre (blow into empty syringe - 1st line), carotid sinus massage = aim is to stimulate vagus nerve to slow down HR. IV adenosine 6mg rapid bolus = blocks AV node conduction. Use verapamil in asthmatic pts. If not work give 12mg, 18mg
4.2.1.3. AV re-entry (AVRT), AV nodal re-entry (AVNRT). Re-entry pathway allows electrical activity to re-enter the atria through the AV node again.
4.2.1.3.1. Wolff-Parkinson-White WPW syndrome. Congenital accessory AVRT pathway (bundle of Kent). Between atrial and ventricles bypassing AV node. Drinking caffeine. Asymptomatic, palpitation, dizziness, syncope
4.2.2. Asymptomatic: syncope, lightheadedness, palpitations, fatigue, dyspnoea.
4.2.3. Check ECG, digoxin levels, cardiac enzymes, CXR, TFTs
4.3. Atrial Fibrillation
4.3.1. Absent P waves and irregularly irregular rhythm
4.3.1.1. SMITH: sepsis, mitral valve pathology, Ischemic heart disease, thyrotoxicosis, hypertension.
4.3.1.2. Single waveform of JVP (atrial wave lost). Radial pulse less apical. Variable intensity in first heart sound.
4.3.1.3. Rate control (1st line). Bisoprolol (BB), Diltiazem / verapamil (CCB), digoxin
4.3.1.3.1. If a patient with AF has a stroke or TIA, the anticoagulant of choice should be warfarin or a direct thrombin or factor Xa inhibitor
4.3.1.3.2. A patient with AF + an acute stroke (not haemorrhagic) should have anticoagulation therapy started two weeks after the event
4.3.1.3.3. Use rhythm control to treat AF if there is coexistent heart failure, first onset AF or an obvious reversible cause
4.3.1.4. Unstable: cardioversion. If lasts <48hrs immediate. If more delayed (anticoag for 3 weeks before and 4 weeks after).
4.4. Atrial Flutter
4.4.1. Form of SVT. Succession of rapid atrial depolarisation up to 300bpm.
4.4.1.1. Re-entry circuit in right atrium near tricuspid valve.
4.4.1.2. Sawtooth pattern II,III,aVF, narrow QRS. Regular rhythm.
4.4.1.3. Treatment Similar to AF but more sensitive to cardioversion.