To the Editor: Portable electronic devices are in widespread use by the general public. We recently recorded an electrocardiographic (ECG) artifact simulating atrial flutter associated with use of such a device, a portable compact disk (CD) player. Although various medical conditions have been known to mimic atrial flutter on ECG, to our knowledge, this is the first report of such an artifact caused by a portable CD player. Report of a Case. The artifactual ECG (Figure 1, top) was recorded on a cardiograph (Hewlett-Packard M1700A, Andover, Mass). The tracing was obtained from a 20-year-old asymptomatic healthy female volunteer participant in a drug study. She had no history of cardiac disease, arrhythmia, or palpitations and had normal cardiac physical examination results and ECG both before and after the study. Standard laboratory screening tests for alcohol and drug abuse yielded negative results on the subject's entry into the clinical research unit. At the time of the ECG recording, she was listening to a personal CD player (Walkman, Sony Corp, Tokyo, Japan). The ECG shows apparent regular sawtooth flutter (f) waves at a rate of 333/min (f-f interval, 0.18 seconds) in all leads except for lead III. Lead III (the bipolar left leg-left arm lead), recorded simultaneously with leads I and II, clearly shows sinus rhythm with well-delineated P waves preceding each QRS complex and a PR interval of 0.13 seconds. On immediate recognition of the abnormality, the CD player was turned off, and ECG repeated 3 minutes later (Figure 1, bottom) was normal with confirmation of normal sinus rhythm in all leads. The artifactual extracardiac origin of the flutter waves is also indicated by their varying relationships to the regularly occurring R-R intervals of the QRS complex. In true atrial flutter with a fixed atrioventricular conduction ratio producing regular R-R intervals, the relationship between the flutter waves and QRS complexes (ie, f-R intervals) would be constant. The presence of the sinus P waves in lead III during the artifactual simulation of atrial flutter can be explained by the position of the CD player on the right side of the subject's bed,close to the right-arm ECG lead and distant from the bipolar left leg-left arm lead (III). Depending on the location of the track on the disk, the scanning rate of CD players ranges between 200 and 530 rpm, with slower scanning rates toward the outer portion of the disk and faster rates near the center. This ensures a constant rate of transferring data, 176 kb/s, conforming to a standard established in the 1970s.1Städje J The case of the exploding CD-ROM record.Available at: www.paintbug.com/cdexplode/Google Scholar On the basis of the rate of “flutter” waves of 333/min on our subject's ECG, we hypothesize that the music track being scanned was near the mid portion of the disk. Summary. Although other rhythmic artifactual conditions, such as parkinsonian tremor, have been known to mimic atrial flutter,2Marquez MF Colin L Guevara M Iturralde P Hermosillo AG Common electrocardiographic artifacts mimicking arrythmias in ambulatory monitoring.Am Heart J. 2002; 144: 187-197Abstract Full Text Full Text PDF PubMed Google Scholar, 3Rubenfire M Rosenzweig S Electrocardiographic artifacts simulating atrial flutter.JAMA. 1972; 220: 1130Crossref PubMed Scopus (7) Google Scholar, 4Koh TW A case of atypical atrial flutter induced during coronary angiography?.J Cardiovasc Electrophysiol. 2005; 16: 798-800Crossref PubMed Scopus (1) Google Scholar to our knowledge, based on a MEDLINE search, this observation has not been reported previously in association with the use of a personal portable CD player. Physicians should be aware of this potential cause of ECG artifacts. Safety While Swimming in a Sea of EnergyMayo Clinic ProceedingsVol. 82Issue 3PreviewHumans have always existed in an environment full of energy transmissions. For most of our history, this energy has been amorphous, coming from sources such as cosmic radiation and lightning. Since the introduction of electrical devices (eg, telegraph, light bulb, radio), humans have been exposed to increasing amounts of electromagnetic energy. Today, the variety of devices and their respective energy transmissions seem endless, yet modern life would not exist without these products. However, since the beginning of the electronic age, there have been concerns about the health consequences of exposure to electromagnetic energy. Full-Text PDF