Severe sinus bradycardia Sinus pauses/sinus arrest Sinoatrial nodal exit block Chronotropic incompetence (failure of heart rate to increase during exercise) Clinical symptoms depend on the mechanism.

Less commonly, sinus arrhythmia may indicate an underlying medical problem, like heart disease or heart block. The heart's ..

comprises a variety of abnormalities consisting of sinus arrest, sinus bradycardia, sinoatrial block, and alternating episodes of tachycardia and bradycardia. [1] A large proportion of SND ...