cardiac arrthmias 4 Flashcards
what is the purpose of rhythm control
restore & maintain sinus rhythm
what ways can you restore sinus rhythm?
electrical cardioversion- DC
Pharmacological cardioversion-amiodarone
flecainide
propafenone
what do you do if the patient has haemodynamic instability?
electrical cardioversion
how do you maintain sinus rhythm and prevent cardiac AF?
Pharmacological therapy-β-blocker (other than sotalol)amiodarone, dronedarone flecainide, propafenone
non-pharm therapy :Non-Pharmacological therapy Left atrial catheter ablation –use of radiofrequency or cryoenergy to isolate pulmonary veins or other ectopic foci Surgical ablation –using the COX-Maze procedure
how do you control rate?
controlor slowing of the fast ventricular response via AV blockade
when is urgent control of ventricular rate needed?
during Paroxysmal & Persistent AF
what bb do you not use when managing AF?
sotalol
what drug would you give for rate control for heart failure?
β-blocker±Digoxin
what drug would you give for rate control for CAD?
β-blockerCalcium Channel Blocker Combination Rx
what treatment would give for AF if the patient didn’t have heart failure or CAD
β-blockerCalcium Channel Blocker Digoxin Combination Rx
what is an atrial flutter?
rapid, regular (or slightly irregular) & organised rhythm with atrial rate ~250-400/min, usually with 2:1 AV conduction
what is the main cause of atrial flutter?
usually due to a macro-reentrant mechanism in the right atrium involving the tricuspid valve annulus
what is atrial flutter very responsive to?
DC cardioversion
what is 1st line for restoration of sinus rhythm in atrial
RF catheter ablation
what is the two types of ventricular arrhythmias?
A wide spectrum of abnormal cardiac rhythms
Sustained Ventricular Arrhythmias
what is a ventricular tachyarrhythmias?
apid, regular run of 3 or more consecutive beats that originate from the ventricle
a150-250 beats/mint a rate of >100 beats/min
what are the underlying mechanisms for VT?
reentry
triggered activity
enhanced/abnormal automaticity
what does acute VT depend on?
depends on degree of haemodynamic compromise, type & duration of arrhythmia
what is the most lethal ventricular arrhythmias?
Ventricular Fibrillation
how many beats does a VF usually have per minute?
200
what is the underlying mechanism for VF?
random/ multiple wavelength reentry
what are the potential consequences of VF?
circulatory collapse death or irreversible brain damage
what ways do you manage VF?
electrical defibrillation (non-synchronisedcardioversion) cardiopulmonary resuscitation (CPR) pharmacological defibrillation amiodarone lidocaine implantable cardioverter defibrillator (ICD)
what is an atrioventricular block?
block of conduction through AV node and/or His-bundle or bundle branches
what are the possible causes of atrioventricular block?
functional/pharmacological block of AV nodal Ca channels
heightened vagal tone
hyperkalaemia
organic lesions –degenerative or fibrotic disease
what are the features of a first degree block?
prolonged PR interval > 0.2 seach atrial impulse is regularly transmitted to ventricles, but with delayusually due to impaired conduction in AV node
what are the features of a second degree block?
intermittent blocked beats
some atrial impulses are not transmitted to ventricles
block could be in AV node or His-bundle or bundle branch
what are the two types of second degree block?
Mobitztype I –progressively lengthening PR interval
Mobitztype II –constant PR interval
what is a 3rd degree block?
complete AV or heart block
no transmission of atrial impulses to the ventricles
emergence of ‘escape’ or idioventricular rhythm (30-50 bpm)
what may a 3rd degree block lead to?
asystolic cardiac arrest
‘Stokes-Adamssyndrome’
how do you manage atrioventricular block?
withdraw culprit drug
pacemaker implantation
