Sinus
Sinus rhythms
All sinus rhythms originate from the sinus node.
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Rate is between 60-100 bpm
Sinus bradycardia
Rate is between <60 bpm
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Causes
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high vagal tone (sleep, athletes, valsalva maneuvers, etc)
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drug related (beta blockers, calcium channel blockers, Digitalis toxicity etc)
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sinus node disease
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myocardial infarction
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hypothyroidism
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hypothermia
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hypoxia
Sinus tachycardia
Rate is between >100 bpm
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Causes
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​stimulants (coffee, alcohol, etc)
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increase in sympathetic tones (anxiety, pain, stress, etc)
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heart failure
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pulmonary embolism
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tamponade
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hypovolemia
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hypoxia
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hypotension or cardiogenic shock
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anemia
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myocardial infarction
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fever
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thyrotoxicosis
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Anticholinergic or sympathomimetic drugs (atropine, isuprel, etc)
Sinus arrhythmia
>10% variability in PP interval
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Mostly no clinical significance. Often associated with high vagal tone, respiration and age (seen more frequently in younger ages).
