RT Book, Section A1 Klein, George J. A2 Prystowsky, Eric N. A2 Klein, George J. A2 Daubert, James P. SR Print(0) ID 1176522629 T1 Bradycardia: Causes of Pauses T2 Cardiac Arrhythmias: Interpretation, Diagnosis, and Treatment, 2e YR 2020 FD 2020 PB McGraw Hill PP New York, NY SN 9781260118209 LK accesscardiology.mhmedical.com/content.aspx?aid=1176522629 RD 2024/03/29 AB Bradycardia or transient asystole can result from a wide variety of disorders of the sinus node and cardiac conduction system interacting with neural and humoral influences.1-2 Abnormalities may be discovered as incidental electrocardiographic (ECG) findings during screening or monitoring for other medical problems. Alternatively, they may be discovered after investigation for symptoms suggesting transient or persistent bradycardia. There is little difficulty when the abnormality is persistent and clearly related to presenting symptoms. Transient abnormalities, on the other hand, may be very difficult to demonstrate. A sudden and transient loss of consciousness or a feeling of impending unconsciousness (presyncope) are the major symptoms suggesting transient asystole. However, a wide variety of symptoms possibly reflecting chronic or intermittent hypoperfusion of the central nervous system or other organ systems may be caused by intermittent or chronic bradycardia, including dizzy or lightheaded spells, fatigue, cognitive disturbances, dyspnea, and so on. The diagnostic difficulties are compounded in the elderly, who frequently have multiple chronic medical disorders and conduction system abnormalities that may be difficult to relate to symptoms.