Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ Irregularly irregular narrow-complex tachycardia at a rate > 100 bpm Multiple P-wave morphologies, with at least three distinct P-wave morphologies in the same lead Varying PP, PR, and RR intervals +++ Pearls ++ Multiple atrial foci are capable of acting as pacemakers. When irritated by stretching, medications, or certain acute medical conditions, these foci compete in pacing the atria. The different atrial foci produce P waves of different morphologies. Since the atrial foci vary in distance to the AV node, PR intervals vary. Multifocal atrial tachycardia (MAT) usually results from exacerbation of another condition that produces distention or irritation of the atria. The most common cause of MAT is chronic obstructive pulmonary disease (COPD) exacerbation. Treatment of the underlying condition should correct the arrhythmia. Even though MAT itself is not usually fatal, it is a poor prognostic sign. ++ FIGURE 23.30A Multifocal Atrial Tachycardia. (ECG contributor: James V. Ritchie, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.30B Multiple P morphologies (arrowheads), varying PR intervals (lower double arrows), and varying R-R intervals (upper double arrows) with heart rate greater than 100 bpm. Graphic Jump LocationView Full Size||Download Slide (.ppt) Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.