bradycardia Flashcards
aetiology of bradycardia
can be physiological - high resting vagal tone eg in athletes
sinus bradycardia:
- drugs
- hypoxia
- pain
- hypothyroidism
- hypothermia
- cushing’s reflex - systemic response to high ICP
- MI
- sick sinus syndrome
- pericardial tamponade
- adrenal insufficiency
- severe obstructive jaundice
- pleural or peritoneal stimulation
- infection eg typhoid
- legionnaire’s disease
- anaerobic training
ectopic atrial rhythm
SAN block - ischemia, hyperkalaemia, excess vagal tine, negative chronotropes
AV block
drugs that cause sinus bradycardia
Betablockers.
Calcium-channel blockers.
Digoxin.
Amiodarone.
Clonidine.
Verapamil.
sick sinus syndrome
tachycardia-bradycardia syndrome
bursts of atrial tachycardia interspersed with periods of bradycardia;
paroxysmal atrial flutter or fibrillation possible
causes:
- SA and AV nodal fibrosis.
- Myocardial ischaemia.
- Congenital heart disease.
ECG - SA blcok, sinus or atrial bradycardia and bursts of tachy, usually AF
Ix for bradycardia
12 lead ECG - show rhythm, ischemic changes, myocardial infarction and conduction defects
ambulatory ECG
CHD investigation
electrolytes, glucose, ca, mg, TFTs and toxicology
FBC, UE, LFT inc albumin and total protein, creatinine, troponin, digoxin levels
Mx of bradycardia
rule out and treat underlying cause
dx and treat ischemia
resus if sx
atropine
if no response - repeat atropine or transcutaneous pacing
isoprenaline or adrenaline infusion
temporary/permenant pacing
