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Disturbance of Cardiac Rate and Rhythm III.As in previous diagrams, only the audible heart sounds are the physical signs of these disorders.A.Normal
rhythm is interspersed with two random premature beats: If such beats are very frequent, the ear may not be able to distinguish them from atrial fibrillation
unless some maneuvers are employed. The rhythm becomes regular as the rate accelerates to approximately 120 beats per minute.B. Atrial
fibrillation:The ventricular rhythm is grossly irregular and continues to be irregular when the rate is accelerated by exercise to more than 120/min.C.
Bigeminy:A normal beat is followed by a premature beat and this pattern repeats many times. The premature beats tend to fall out when exercise
accelerates the rate to more than 120/min.D. Dropped beats in second-degree AV block:Each successive impulse going through the AV node produces a
Source: Chapter 4. Vital Signs, Anthropometric Data, and Pain, DeGowin's Diagnostic Examination, 9e
longer interval until one fails to induce ventricular contraction. In contrast to premature beats, exercise tends to increase the number of dropped beats.
Citation: LeBlond RF, Brown DD, DeGowin RL. DeGowin's Diagnostic Examination, 9e; 2009 Available at: http://mhmedical.com/ Accessed:
May 10, 2017
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