Arrhythmias Flashcards
What is the only way pulses from the sinus node can get to the ventricles?
via the AV node
How is an arrhythmia named?
anatomical site or chamber of origin
mechanism eg fibrillation
d: fibrillation
heart going so fast its quivering, cant fill properly low CO
Name the Supraventricular Arrhythmias
Supraventricular tachycardia Atrial Fibrillation Atrial Flutter Ectopic atrial tachycardia
Bradycardia
Sinus bradycardia
Sinus pauses
Name the Ventricular Arrhythmias
Ventricular ectopics or Premature Ventricular Complexes (PVC) Ventricular Tachycardia (VT) Ventricular Fibrillation (VF)
Asystole
Name the Atrio-ventricular Node Arrhythmias
AVN re-entry tachycardia (AVNRT)
AV reciprocating or AV Reentrant tachycardia (AVRT)
AV block :
1st degree
2nd degree
3rd degree
Name some of the causes of Arrhythmias
abnormal anatomy ANS Metabolic Inflammation Drugs Genetic
What is the abnormal anatomy that causes them?
left ventricular hypertrophy
accessory pathways
congenital HD
What is the ANS that causes them?
Sympathetic stimulation: stress, exercise, hyperthyroidism
Increased vagal tone causing bradycardia
What are the meatbolic changes that causes them?
Hypoxia: chronic pulmonary disease, pulmonary embolus
Ischaemic myocardium: acute MI, angina
Electrolyte imbalances: K+, Ca 2+, Mg2+
Name an inflammatory condition that causes arrhythmias
viral myocarditis
how do drugs cause arrhythmias?
direct electrophysiologic effects or via ANS
Name some genetic causes of arrhythmias?
mutations of genes encoding cardiac ion channels e.g. the congenital long QT syndrome
Name the 2 electrophysiological mechanisms that cause A?
Ectopic beats: Beats or rhythms that originate in places other than the SA node
Altered automaticity e.g. ischaemia, catecholamines
Triggered activity, e.g. digoxin, long QT syndrome
Re-entry : requires more than one conduction pathway, with different speed of conduction (depolarization) and recovery of excitability (refractoriness):
accessory pathway tachycardia (Wolf Parkinson White syndrome), previous myocardial infarction, congenital heart disease.
Name some abnormal physiologies that increase HR?
hyperthermia Hypoxia Hypercapnia Cardiac Dilation Hypokalaemia, prolongs repolarization
Name some abnormal physiology that cause bradycardia/Heart block
Hypothermia
Hyperkalaemia
Symptoms of Arrhythmias
Palpitations, ”pounding heart” Shortness of breath Dizziness Loss of consciousness; ”Syncope” Faintness: “presyncope” Sudden cardiac death Angina, heart failure
Name the Investigations for Arrhythmias?
12 lead ECG (in tachycardia , during SR) CXR Echocardiogram Stress ECG Look for myocardial ischaemia, exercise related arrhythmias 24 hour ECG Holter monitoring Event recorder: (capture the arrhythmia) Electrophysiological (EP) study Induce clinical arrhythmia to study mechanism and map arrhythmia
Name some types of arrhythmiae?
normal sinus arrhythmia sinus bradycardia sinus tachycardia Atrial Ectopic Beats Regular Supraventricular tachycardia
How do ectopic beats cause an arrhythmia?
origninates in places other than SA node
Are ectopic beats a physiological/pathological cause?
physiological
How is re entry a cause of arrhythmias?
requires more than one conduction pathway, with different speed of conduction (depolarization) and recovery of excitability (refractoriness)
how many re entry be caused?
WPW previous MI or CHD
Name the 4 H’s that INcrease HR? and the C
Hyperthermia, Hypoxia, Hypercapnia, Cardiac dilation, Hypokalaemia 4H’s.
Name the 2 things that decrease HR and cause Heart Block/
Hypothermia
Hyperkalaemia
describe triggered activity of an arrhythmia/
In terminal phase a small depolarization may occur (if big enough) may cause sustained train of depolarisations.
symptoms of arrhythmias?
Palpitations, SOB, Dizziness, Syncope (pre-syncope), Cardiac death, Angina, HF.
Name the investigations for arrhythmias?
ECG (24 hr), CXR, Echo, Stress ECG,
What is sinus bradycardia treated with and what is it?
<60bpm, - treat with Atropine (acute), or pacing
when is pacing used to treat sinus bradycardia?
if haemodynamic compromise
what is sinus tachycardia + treated with?
> 100bpm, Treat underlying cause, B-blockers
If you have Atrial Ectopic Beats, what are the symptoms and treatment?
asymptomatic – palpitations, no treatment
What are the causes of regular supraventricular tachycardia?
caused by AV nodal re-entrant tachycardia (AVNRT), AV reciprocating tachycardia (AVRT), Ectopic atrial tachycardia (EAT)
what are the effects of acute reg supraventricular tachycardia?
Increase vagal tone, slow AVN conduction [IV adenosine, IV verapamil]
what is the advice given for chronic reg supraventricular tachycardia?
avoid sti mulants, B-Blockers, Anti-arrhythmic Drugs, Radiofrequency ablation
How is VT treated if pulsing and if pulseless?
DC cardioversion if haemodynamically unstable, Pulseless VT requires Defibrillation
What happens to the heart in VF?
loss of ability to pump
How is VF treated?
Cardioversion if unstable, If stable use Anti-Arrhythmic drugs.
What is the most common sustained arrhythmia?
atrial fibrillation
what is paroxysmal AF?
sudden spasm <48hrs
when is AF persistent?
> 48hrs and cardioverter to NSR
when is AF permanent?
inability to restore NSR
What congenital syndrome can cause polymorphic VT ( torsades des pointes), what is it triggered by and what are the symptoms?
Congenital Long QT syndrome
adrenergic stimulation
syncope and sudden death
what does brugada syndrome pose a risk of?
Risk of polymorphic VT, VF, AF common, St elevation + RBBB in V1-3.
What is Brugada syndrome triggered by?
Triggered by sleep, fever, excess alcohol.
what is the advice for those with brugada syndrome?
Avoid anti-arrhythmics, psychotropics, analgesics, anaesthetics
