sinus bradycardia
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Introduction
Sinus bradycardia refers to a rhythm generated by a slowed pattern of initial depolarization in the sinus node.
Etiology
- physiologic
- pathologic
- increased vagal tone
- antiarrhythmic agents
- myocardial ischemia
- acute inferior myocardial infarction
- sick sinus syndrome
- increased intracranial pressure
- hypothermia
- myxedema
- recovery from infection
Clinical manifestations
- patients may be asymptomatic
- lightheadedness
- breathlessness
- angina
- weakness
- syncope & near-syncope
- inability to increase heart rate with exercise[3]
Diagnostic procedures
- electrocardiogram
- atrial rate <60/min
- p waves with normal configuration & axis
- normal or prolonged PR interval
- normal QRS pattern
- exercise stress test[3]
Management
- asymptomatic patients require no therapy
- treatment of symptomatic patient is directed towards specific etiology
- atropine 0.5-2.0 g IV
- transcutaneous pacemaker vs permanent pacemaker
- bradycardia refractory to atropine & transcutaneous pacemaker not available
- dopamine 5-20 ug/kg/min
- epinephrine 2-20 ug/min
- isoproterenol 2-10 ug/min
More general terms
More specific terms
Additional terms
- sick sinus syndrome; atrial fibrillation with bradyarrhythmia; tachycardia-bradycardia syndrome
- sinoatrial exit block
References
- ↑ Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 139
- ↑ Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 271
- ↑ 3.0 3.1 3.2 3.3 Medical Knowledge Self Assessment Program (MKSAP) 18, 19 American College of Physicians, Philadelphia 2018, 2022