Palpitations

arrythmia

pathophysiology

accelerated automaticity

increased sympathetic stimulation

triggered activity

myocardial infarction causing damage

forms "after depolarisation" which may reach threshold and produce arrythmias

examples

digitoxin overdose

electrolyte disturbance

long QT syndrome

re-entry

myocardial damage & fibrosis causing formation of a ring of cardiac tissue surrounding non-conductive fibrosed core

blockade of conduction in one limb of the 'ring'

retrograde conduction occurs

example:

paroxysmal tachycardia

types

bradycardic

sinus bradycardia

extrinsic

hypothyroid

hypothermia

neurologically mediated

Bezold Jerisch Reflex

vasovagal syncope

intrinsic

acute

damage due to AMI

chronic

degenerative damage

fibrosis

sick sinus syndrome (fibrosis of sinus)

heart block

bundle branch block

AV Block

tachycardic

supraventricular tachycardia

sinus tachycardia

exertional

inappropriate

persistent increase in resting heart rate unrelated to or out of proportion with level of physical/ emotion stress

due to sinaus node abnormalities

enhanced automaticity

abnormal autonomic regulation of heart

AV junctional tachycardia

paroxysmal SVT (re-entry tachycardia)

re-entry circuit involving AV node

AV nodal re-entry

AV reciprocating re-entry

atrial tachycardia

atrial fibrillation

common, esp in old patients

due to any cardiac condition causing:

raised atrial pressure

increased atrial muscle mass

atrial fibrosis

inflammation & infiltration of atrium

other systemic causes

phaeochromocytoma

thyrotoxicosis

hypokalemia

alcohol

syptoms & signs

decreased effort tolerance

cardiac failure

irregular pulse

regular pattern with ocassional irregularity (eg extrasystoles)

recurring irregular patterns (eg Weckebach

ECG

fibrillation waves

no clear P waves

Rapid & irregular QRS

management

acute

Defibrillation

Drugs

remove underlying cause

long term

rhythm control

antiarrythmic drug + defibrillation + warfarin

rate control

AV nodal slowing agent + warfarin

atrial flutter

milder form of atrial fibrillation

atrial tachycardia

uncommon

ventricular tachycardia

lif-threatening ventricular tachycardia

sustained VT

signs & symptoms

dizziness

syncope

hypotension

cardiac arrest

pulse b/w 120 & 220

treatment

defibrillation

drugs

amiodarone

lidocaine

ventricular fibrillation

rapid & irregular venticular activation w/o mechanical effect

sign & symptom

cardiac arrest

pulseless

cessation of respiration

LOC

ECG

shapeless, rapid oscillations

Brugada Syndrome

heritable idiopathic ventricular fibrillation

more common in young adult males in SEA

treatment

only effective treatment is defibrillation

pacemaker

Torsades de Pointes

arrythmia due to greatly prolonged ventricular repolarisation (QT wave)

causes of long QT syndromes

congenital

Jervell-Lange-Nielson syndrome

associated with deafness

Romano-Ward syndrome

cardiac

bradycardia

MVP

AMI

electrolyte derangement

hypokalemia

hypocalcemia

hypomagnesium

drugs

TCA

quinidine

amiodarone

causes palpitations & syncope but terminates spontaneously

complication: ventricular fibrillation & death

mitral valve prolapse

anemia

pulmonary embolism

hypotension