Evidence supporting a new rate threshold for multifocal atrial tachycardia.

Background: Exacerbation of chronic obstructive pulmonary disease (COPD) is overwhelmingly represented among patients presenting with multifocal atrial tachycardia (MAT) and has been used as a paradigm for such patients. The quasidiagnostic tachycardia threshold for MAT is conventionally set at 100 beats/min. Nevertheless, this threshold has not been demonstrated to be optimal.

Widely split P waves in the presence of interatrial block.

Interatrial block (IAB; P wave>or=110 milliseconds), conduction delay between the atria, is highly prevalent and is associated with atrial tachyarrhythmias, left atrial electromechanical dysfunction, as well as a potential risk for systemic embolism. However, much is still yet to be known of IAB's exact pathophysiology and how it may manifest in relation to medical disease. We present an unusual case of widely split P waves in the presence of IAB in a severely ill patient.

Acute right atrial strain: regression in normal as well as abnormal P-wave amplitudes with treatment of obstructive pulmonary disease.

Objective: To evaluate right atrial (RA) "strain" as reflected by changes in P-wave amplitude and vector in patients with COPD immediately before and immediately after beginning treatment of exacerbations.

Background: P-pulmonale (frequently temporary, reflecting acute RA strain) occurs under a variety of circumstances, including COPD. Emergency room (ED) ECGs in patients with acute exacerbations of COPD have suggested that P-pulmonale (P waves > or = 2.