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Question

Management of broad-complex tachycardia?

Answer 1

Regular > assume ventricular tachycardia (unless previously confirmed SVT with bundle branch block) > loading dose of Amiodarone 300mg over 20-60 mins, then followed by 900mg 24 hour infusion > if SVT with BBB - treat for regular narrow complex tachy Irregular > seek expert help. > Possibilities include: atrial fibrillation with bundle branch block - the most likely cause in a stable patient - treat as narrow complex > atrial fibrillation with ventricular pre-excitation > give Amiodarone > torsade de pointes

Answer 2

Narrow complex QRS, regular ventricular rhythm. P before every QRS. Rhythm originates in SAN. Causes = Physical deconditioning, hypoxia, PE, hypovolaemia, hyperthyroid, anaemia, caffeine, alcohol, nicotine, cocaine, amphetamines, aminophylline, atropine, clozapine, catecholamines. Inappropriate: persistent ↑HR, unrelated to/out of proportion to cause

Answer 3

``` SVT, atrial focus outside SAN. Mostly idiopathic HTN, heart disease, cardiomyopathy MI, infection, alcohol poisoning Congenital heart disease Catecholamine excess Drug toxicity: cocaine, digoxin, theophylline ``` ECG: Morphology of P waves depends on site origin but remains constant Regular rhythm ``` Management: Vagal manoeuvres If persists: IV adenosine, CCB (verapamil, diltiazem), BB blockers Catheter ablation Pacemaker ```

Answer 4

Multifocal origin of pacemaker activity Causes = COPD, theophylline, isoproterenol, ↓K, Mg, hypoxia, hypercapnia, acidosis, RA enlargement Typically in seriously ill patients with respiratory failure. Tends to resolve following Tx of underlying disorder. ``` ECG: HR > 100bpm Irregularly irregular P waves 3+ varying morphologies Narrow QRS SVT ``` ``` Management: Beta blockers CCB eg verapamil IV Mg Correct reversible causes ```

Answer 5

Abnormal automaticity or myocytes in AVN or proximal bundle of His a form of supraventricular tachycardia Narrow complex Regular P wave inverted in lead 2, can be hidden within QRS or immediately before QRS Short PR interval Prevention BB eg metoprolol CCB > verapamil Catheter ablation Acute management vagal manoeuvres: > Valsalva manoeuvre: e.g. trying to blow into an empty plastic syringe > carotid sinus massage intravenous adenosine rapid IV bolus of 6mg → if unsuccessful give 12 mg → if unsuccessful give further 18 mg contraindicated in asthmatics - verapamil is a preferable option > electrical cardioversion

Answer 6

first detected, recurrent, paroxysmal, persistent, permanent (cannot be cardioverted or deemed inappropriate) Palpitations, dyspnoea, chest pain Irregularly irregular pulse Rate/rhythm control - rate control except in coexistent HF, first onset AF or where obvious reversible cause Rate - BB or rate-limiting CCB (diltiazem). Can have combination of 2 of BB, diltiazem or digoxin if mono therapy doesn't control rate Rhythm - short duration of Sx (<48 hours) or anticoagulation prior

Answer 7

C - congestive HF - 1 H - hypertension (or treated HTN) - 1 A2 - age >75 = 2, age 65-74 = 1 D - diabetes - 1 S2 - prior stroke, TIA to thromboembolism = 2 V - vascular disease (including IHD, and PAD) = 1 S - sex (female) = 1 0 - no treatment 1 - males - consider anticoagulation, females- no Tx 2 - offer anticoagulation Choice of anticoagulation - warfarin and NOACs

Answer 8

a form of supraventricular tachycardia characterised by a succession of rapid atrial depolarisation waves. ECG findings > 'sawtooth' appearance > as the underlying atrial rate is often around 300/min the ventricular or heart rate is dependent on the degree of AV block. For example if there is 2:1 block the ventricular rate will be 150/min > flutter waves may be visible following carotid sinus massage or adenosine Management > is similar to that of atrial fibrillation although medication may be less effective > atrial flutter is more sensitive to cardioversion however so lower energy levels may be used > radiofrequency ablation of the tricuspid valve isthmus is curative for most patients

Answer 9

Accessory pathway between atria + ventricles. Allows signal to move backwards. More than 1 ventricular contraction can be stimulated from 1 impulse from SAN. Orthodromic: through AVN, ventricles contract, up through accessory pathway, atria contract, back down AVN etc. Antidromic: signal down through accessory pathway, ventricles contract, up through AVN atria contract, back down accessory. ``` Features: Palpitations Chest discomfort SOB Light-headed Syncope ``` Orthodromic: regular, narrow QRS tachy, p waves retrograde (after QRS) Antidromic: regular, wide QRS tachy. P waves often not visible, delta waves, short PR interval. Acute termination: vagal manoeuvre, carotid sinus massage, adenosine, electrical cardioversion. Chronic prevention: amiodarone, procainamide, sotalol, flecainide, radiofrequency catheter ablation.

Answer 10

Congenital accessory pathway (Bundle of Kent) conducts signal between A+V. Ventricles start to contract a bit early, pre-excitation. As accessory pathway does not slow conduction AF can degenerate rapidly to VF Signal takes longer through AVN, combines with single from BoK to contract ventricle. Set up re-entry loop, BoK propagate signals both ways. Come down AVN, go back up BoK, causing atria contraction + AVRT. ``` Tachyarrhythmias Palpitations Chest discomfort SOB Light headed Syncope Find physical activity exhausting ``` Short PR interval Delta wave: slurred upstroke of QRS Widening of QRS complex due to ventricular pe-excitation AF or flutter, very high >200-250 ``` Differentiating between type A and type B** type A (left-sided pathway): dominant R wave in V1 type B (right-sided pathway): no dominant R wave in V1 (in exams mostly type B with LAD) ``` ``` Associations of WPW HOCM mitral valve prolapse Ebstein's anomaly thyrotoxicosis secundum ASD ``` Management definitive treatment: radiofrequency ablation of the accessory pathway medical therapy: sotalol***, amiodarone, flecainide *** sotalol avoided if coexistent AF > can deteriorate to VF

Answer 11

Supraventricular tachycardia Accessory pathway within AVN. 2 pathways, form loop Slow-fast: typical, signal depolarisation down both pathways, reaches end of β path (fast) 1st. signal splits, travels. To ventricles (contraction), + travels up α path, meets slow signal, cancel each other out. Both go into refractory. α refractory shorter, ready 1st, signal from α exits to ventricles. Also travels up β, by time all way round, α out of refractory, re-entrant loop. Fast slow: atypical, anterograde conduction via fast pathway, retrograde via slow. RF: F>M, stress, alcohol, caffeine hyperthyroid, exercise, electrolyte disturbance ECG SVT 140-280bpm Absent p waves, signal getting through atria + ventricles almost same time p waves immediately before/ after QRS complex. P waves inverted/ retrograde R waves (small secondary R waves) Narrow QRS complexes Management: Adenosine Ca channel blockers eg verapamil, diltiazem Slow AVN: vagal manoeuvre (carotid sinus massage/ valsalva manoeuvre) > activates vagus nerve, blocks AVN temporarily. Electrical cardioversion Prevention Beta blockers eg metoprolol Radiofrequency catheter ablation: ablation of slow alpha pathway

Answer 12

broad-complex tachycardia originating from a ventricular ectopic focus. It has the potential to precipitate ventricular fibrillation and hence requires urgent treatment. monomorphic VT: most commonly caused by myocardial infarction polymorphic VT: A subtype of polymorphic VT is torsades de pointes which is precipitated by prolongation of the QT interval Non re-entrant/focal Abnormal automaticity of specific area of ventricle. Ventricular pacemaker cells fire at high rate, preventing SAN firing. Re-entrant VT More common Cardiomyocytes altered when stressed by stimuli eg drugs, changing conduction speed + refractory period Non-sustained: at least 3 beats, resolve spontaneously in <30s. Sustained: >30s, or requiring termination earlier due to haemodynamic instability. Adverse signs (SBP < 90, chest pain, HF) then immediate cardioversion. If not, then antiarrhytmics. if these fail, then electrical cardioversion may be needed. Drug therapy > amiodarone: ideally administered through a central line > lidocaine: use with caution in severe left ventricular impairment > procainamide If drug therapy fails > electrophysiological study (EPS) > implant able cardioverter-defibrillator (ICD) - this is particularly indicated in patients with significantly impaired LV function Electrical cardioversion: pulse delivered to heart on R wave, if delivered on T wave could induce VF

Answer 13

Congenital: > Jervell-Lange-Nielsen syndrome (includes deafness and is due to an abnormal potassium channel) > Romano-Ward syndrome (no deafness) ``` Drugs: > amiodarone, sotalol, class 1a antiarrhythmic drugs > tricyclic antidepressants, fluoxetine > chloroquine > terfenadine > erythromycin ``` electrolyte: hypocalcaemia, hypokalaemia, hypomagnesaemia acute myocardial infarction myocarditis hypothermia subarachnoid haemorrhage

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