Discrimination of ventricular tachycardia and localization of its exit site using surface electrocardiography.

Figure 1.. Brugada algorithm for the differential diagnosis of WCTs. With modifications from Brugada, et al.[5] AV: atrioventricular; LBBB: left bundle branch block; RBBB: right bundle branch block; SVT: supraventricular tachycardia; VT: ventricular tachycardia; WCTs: wide complex tachycardias.

Figure 2.. Morphological criteria for diagnosis of ventricular tachycardias used by Brugada, et al.[5] With modifications from Eckardt L, et al.[7] LBBB: left bundle branch block; RBBB: right bundle branch block; SVT: supraventricular tachycardia; VT: ventricular tachycardia.

Figure 3.. Vereckei algorithm for the differential diagnosis of WCT. With modifications from Vereckei, et al.[6] AV: atrioventricular; BBB: bundle branch block; SVT: supraventricular tachycardia; VT: ventricular tachycardia; WCT: wide complex tachycardia.

Figure 4.. Schematic electrocardiogram representations. In lead V4 there are vertical lines denoting the onset of QRS complex, the initial and terminal 40 ms of the QRS complex is marked by small red points. During the initial 40 ms of the QRS, the impulse advanced vertically 0.8 mV, then the Vi = 0.8 and during the terminal 40 ms of the QRS, the impulse advanced vertically 0.2 mV, consequently the Vt = 0.2, and thus the Vi/Vt > 1 suggesting the diagnosis of SVT. In lead V3; Vi = 0.3 and Vt = 0.65 in this example, and therefore the Vi/Vt < 1 suggesting the diagnosis of VT. SVT: supraventricular tachycardia; VT: ventricular tachycardia.

Figure 5.. Vereckei algorithm for the differential diagnosis of wide QRS tachycardia based on the aVR lead. With modifications from Vereckei, et al.[8] SVT: supraventricular tachycardia; VT: ventricular tachycardia.

Figure 6.. Schematic electrocardiogram representations. Vi/Vt ratio criterion in the fourth step of the aVR algorithm. In the inferior part, most common lead aVR electrocardiogram patterns in SVT and VT.[8] SVT: supraventricular tachycardia; VT: ventricular tachycardia.

Figure 7.. Measurement of the RWPT in lead II. RWPT measured from the “isoelectric” line to the point of first change in polarity, was >50 ms (80 ms), with modifications from Pava LF, et al.[9] RWPT: R-wave peak time; SVT: supraventricular tachycardia; VT: ventricular tachycardia.

Figure 8.. Common characteristics found in outflow tract ventricular tachycardia (inferior axis deviation, positive QRS complexes in II, III and aVF). (A): RVOT tachycardia; (B): LVOT tachycardia. LVOT: left ventricular outflow tract; RVOT: right ventricular outflow tracts.

Figure 9.. Criteria for differentiating LVOT from RVOT. With modifications from Cheng D, et al.[19] LVOT: left ventricular outflow tract; RVOT: right ventricular outflow tract.

Figure 10.. Typical electrocardiograms for VT originating from the aortic root. With permission from Yamada T, et al.[20] L: left coronary cusp; LA: left atrium; N: non-coronary cusp; R: right coronary cusp; RA: right atrium; RV: right ventricle; VT: ventricular tachycardia.

Figure 11.. Schematic electrocardiogram representations. Differentiating the QRS morphology of LPFVT from RBBB and LAHB aberrancy, when 3 or 4 criteria are positive the diagnosis of left posterior fascicular VT is likely. LAHB: left anterior hemiblock; LPFVT: left posterior fascicular ventricular tachycardia; RBBB: right bundle branch block; VT: ventricular tachycardia.

Figure 12.. VT from the inferoseptal papillary muscle (A) and VT from the anteroseptal papillary muscle (B: schematic ECG representation). VT: ventricular tachycardia.