Brugada electrocardiographic pattern: reality or fiction?

In many cases, failure to perform an electrocardiogram according to established standards can lead to incorrect diagnosis. When this error involves a disease that can result in sudden death such as Brugada syndrome, diagnostic procedures are not without risk for the patient. A 20 year-old man visited his family doctor for atypical chest pain some time before. Electrocardiography (ECG) showed sinus rhythm of 47 bpm with striking ST-elevation in V1-V3 suggestive of the Brugada pattern. Sometimes, the different low-frequency components of the ECG, such as the ST segment, may be distorted by high cutoff filters resulting in diagnostic errors [Am J Cardiol 2012;110:318-320]. Faced with an apparent Brugada syndrome pattern on ECG, clinicians should ensure the recording was correctly made.

Technical mistakes during the acquisition of the electrocardiogram.

In addition to knowledge of normal and pathological patterns, the correct interpretation of electrocardiographic (ECG) recordings requires the use of acquisition procedures according to approved standards. Most manuals on standard electrocardiography devote little attention to inadequate ECG recordings. In this article, we present the most frequent ECG patterns resulting from errors in limb and precordial lead placement, artifacts in 12-lead ECG as well as inadequate filter application; we also review alternative systems to the standard ECG, which may help minimize errors.

Effects of inadequate low-pass filter application.

Some technical aspects in the ECG recording, although basic, are not well enough known. In this short communication we present two examples in which the low-pass filter attenuates or eliminates electrocardiographic signals which are important from the clinical point of view.