Lecture 24 - Drugs and Arrythmia

Question 1

Common conditions?

Answer 1

normal rate: normal electrical activity, normal excitation-contractile coupling, ectopics; Bradycardias: AV/SND conduction disorders; Tachycardias: automaticity/triggered activity, re-entrant mechanisms

Question 2

Arrhythmias - bradycardias?

Answer 2

physiological, sinus node, AV node, neural mediated

Question 3

Arrhythmias - tachycardia?

Answer 3

atrial, junctional (SVT), ventricular (scar, ‘normal’ hearts)

Question 4

Cardiac devices?

Answer 4

single or dual chamber, Pacemaker vs ICD - rate support, AV synchrony, VV synchony (CRT device), other (vasovagal syncope devices, monitors)

Question 5

Indications for Device Support?

Answer 5

pacemaker: high grade AV block, symptomatic sinus node disease; Defribrillator: sustained VT, high/prior risk for SCD; CRT: cardiomyopathy and LBBB

Question 6

Sinus tachycardia?

Answer 6

appropriate (fever, thyrotoxicosis, pain) or inappropriate (no drivers, ?ST, ?Automaticity, ?SN reenty)

Question 7

Ectopy?

Answer 7

common, majority benign, symptomatic proportional to multiple factors (prematurity, disctraction/activity), examination through exclusion and ECG/echo, reassurance or suppressive Rx (B blockade, class I agents), severe symptoms + focus = ablation

Question 8

Considerations for drug therapy?

Answer 8

basic pharmacology, classes, efficacy, side effects, co-morbidity Rx, pro-arrhythmic effect, drug/device interactions`

Question 9

Class I drugs/Na channel agents - IA?

Answer 9

reduce Vmax, prolong AP, rapid onset/offset, e.g. quinidine, procainamide, disopyramide

Question 10

Class I drugs - IB?

Answer 10

no effect on Vmax, shorten AP, fast onset/offset, e.g. phenytoin, lidocaine, mexiletine

Question 11

Class I drugs - IC?

Answer 11

reduce Vax, slow conduction, slow onset/offset, e.g. flecainide, popafenone

Question 12

Class II?

Answer 12

beta blockers, e.g. metoprolol, atenolol, propanolol

Question 13

Class III?

Answer 13

K channel blockers -> increased repolarisation, e.g. sotalol, amiodarone, bretylium

Question 14

Class IV?

Answer 14

slow Ca channel blocker, e.g. verapamil, diltiazem, nifedipine

Question 15

Antiarrhythmic drug targets and function?

Answer 15

cell membranes, ANS, vagal tone; conduction velocity, refractory period length, automaticity of SA or AV node

Question 16

Effects of vagal tone?

Answer 16

increased: decreases HR, SA automaticity and slower conduction through AV node; decreased vagal tone does complete opposite

Question 17

AV nodal re-entrant tachycardia?

Answer 17

AV node duality, ectopic trigger, ‘safe’ SVT, medical or ablation therapy (

Question 18

Adenosine?

Answer 18

transient AV block, caution w transplant pts or persantin users

Question 19

AV reentrant tachycardia?

Answer 19

AP safety, medical or ablation therapy

Question 20

AF?

Answer 20

rate control: target AV node as SA node hindered, Class I, II, III, digoxin (V); treat rhythm: class III; ablation or devices later on; anticoagulation issues (use screening tools); co-morbidities

Question 21

VT?

Answer 21

reentry or automatic trigger around scar, not using normal His-Purkinje network, atria continue to activate and contract independently

Question 22

Treating VT /VF?

Answer 22

immediate resuscitation, then treating underlying pathology e.g. ischaemia, bradycardia, structural disease, metabolic or drug problem; other treatments V support, antiarrhythmetics, device, intervention

Question 23

Amiodarone?

Answer 23

large side effect profile, loading issues, maintenance (TFTs/LFTs, lung function), interacts w warfarin