Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ Sinus tachycardia, nonspecific ST-T changes. Precordial T-wave inversions. Prominent S wave in lead I, Q wave in lead III, and inverted T wave in III (S1/Q3/T3). Incomplete or complete RBBB, P pulmonale (lead II). Rightward axis. ST-segment elevation (especially in leads V1, aVR) and ST-segment depression may occur in cases of large pulmonary emboli. +++ Pearls ++ No ECG pattern is diagnostic for pulmonary embolism. Small-to-moderate emboli may not affect the ECG. With large emboli, increased resistance to pulmonary arterial flow produces right ventricle overload and dilation. Increased right atrial pressures may produce P pulmonale (tall P waves > 2.5 mm in lead II) or atrial dysrhythmias. ++ FIGURE 23.50A Sinus Tachycardia and S1Q3T3 Pattern in a Patient with Acute Pulmonary Embolism. (ECG contributor: James V. Ritchie, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.50B S wave is apparent in lead I (blue arrowhead), Q wave in lead III (black arrowhead), and inverted T wave in lead III (blue arrow). 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 click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. 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 Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth