Correspondence

A Holter Hazard

N Engl J Med 2005; 352:1389-1390March 31, 2005

Article

To the Editor:

A 52-year-old woman underwent Holter monitoring to evaluate palpitations. She did not report any other symptoms. Physical examination was unremarkable. An electrocardiogram obtained with the patient at rest was normal, with a rate of 90 beats per minute. The Holter monitor showed marked bradycardia throughout the period of monitoring (Figure 1Figure 1Representative Rhythm Strip Showing Marked Bradyarrhythmia.). In the hospital, cardiac monitoring showed a normal rhythm, with the rate between 70 and 100 beats per minute and no pauses or bradycardia. An electrocardiogram obtained by changing the speed of the paper to 100 mm per second reproduced the Holter findings. The patient's apparent bradyarrhythmia reflected mechanical problems with the Holter tape that somehow changed the speed of recording. Repeated Holter monitoring a week later was unremarkable. This case illustrates that when test results do not represent the patient's symptoms, mechanical or nonclinical factors should be considered in the differential diagnosis.

Malvinder S. Parmar, M.D.
Northern Ontario School of Medicine, Timmins, ON P4N 8P2, Canada
parmar@vianet.on.ca