Diagnostic uses of intraatrial electrocardiography

Many tachyarrhythmias present difficult diagnostic problems. In patients with underlying cardiac disease, serious hemodynamic derangements can be the sequelae of uncontrolled or improperly treated arrhythmias. Our experience, illustrated by the case presentations, confirm that intraatrial electrocardiography is a safe and reliable technique for elaborating difficult tachyarrhythmias that are not conclusively diagnosed by noninvasive ECG techniques. Because misinterpretation of tachycardias can lead to incorrect therapeutic decisions, the minimal risk of such a procedure is far surpassed by the information obtained, which allows for correct diagnosis and aids in guiding effective therapy. Although careful, critical analysis of ECG and rhythm strips frequently allows a proper diagnosis, occasions often arise when the rhythm cannot be accurately defined. In such instances an intraatrial lead electrocardiogram can be utilized and is invariably of diagnostic aid in resolving the relationship of the P wave to the QRS complexes, which is usually the important key to a tachyarrhythmia diagnosis.