SAQ 386 – Cardiology – syncope with Mobitz type II heart block

Cardiology – syncope with Mobitz type II heart block.

a. Non-cardiac syncope causes

• Reflex syncope: vasovagal, situational, or carotid sinus syncope.
• Orthostatic hypotension from blood or fluid loss, or Addison disease.
• Vascular causes such as aortic dissection, pulmonary embolism, or subclavian steal.
• Neurological causes including subarachnoid haemorrhage, TIA, migraine, or autonomic failure.
• Medications including beta-blockers, calcium-channel blockers, nitrates, ACE inhibitors, diuretics, antipsychotics, antidepressants, antiparkinsonian drugs, cocaine, sildenafil, alcohol, or volatile nitrites.
• Psychogenic causes.
• Hypoglycaemia.
• Anaemia.

b. Risk tools

• Canadian Syncope Risk Score.
• San Francisco Syncope Rule.
• ROSE rule.
• Simplified Boston Syncope Rule.
• STePS.

c. ECG

• Mobitz type II second-degree atrioventricular block.

d. Causes

• Anterior or septal myocardial infarction.
• Idiopathic conduction-system fibrosis such as Lenegre-Lev disease.
• Cardiac surgery close to the septum.
• Inflammatory disease such as myocarditis or rheumatic fever.
• Autoimmune disease such as SLE or systemic sclerosis.
• Infiltrative myocardial disease such as amyloid, haemochromatosis, or sarcoidosis.
• Hyperkalaemia.
• Drugs including beta-blockers, calcium-channel blockers, digoxin, or amiodarone.

e. Management

• Admit with telemetry.
• Treat any identified underlying cause.
• Arrange permanent pacemaker placement.