title: Diastolic potentials recorded by surface electrocardiographic signal averaging during sustained ventricular tachycardia: possible origin from the reentrant circuit.
abstract: ECG signal averaging can detect low amplitude diastolic potentials in sinus rhythm. We, therefore, recorded signal-averaged ECGs during eight episodes of inducible uniform sustained VT with coincident atrial pacing to look for continuous diastolic electrical activity. Simultaneous AV pacing in seven patients served as controls. The number of QRS complexes averaged (187 +/- 47 vs 183 +/- 63), the noise level (1.26 +/- 0.88 vs 1.39 +/- 0.47) and cycle length (385 +/- 52 vs 404 +/- 40) did not differ between VT and paced recordings. In each lead the difference in onset between the unfiltered surface recording and the filtered data (40 Hz bidirectional) was significantly greater in VT than the paced recordings (25 +/- 16 vs 11 +/- 8 msec, P = 0.0012). These late diastolic (pre-QRS) potentials were greater than 15 msec duration in 65% of the leads in VT versus 20% of paced recording (P = 0.021). The maximum value was greater than 20 msec in six VT (75%) versus one (14%) paced recording (P = 0.019). The earliest filtered onset in any lead preceeded the earliest surface activity by greater than 12 msec, in 6 VT versus one paced recording (P = 0.019). Early diastolic (post-QRS) potentials were also longer in VT than pacing (49 +/- 40 versus 5 +/- 20, P = 0.001) and exceeded 38 msec in seven of the VTs but none of the paced recordings (P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: University of Texas Southwestern Medical Center, Division of Cardiology, Dallas.
authors.forename: M S
authors.initials: MS
authors.lastname: Kremers
authors.forename: H
authors.initials: H
authors.lastname: Hsia
authors.forename: P
authors.initials: P
authors.lastname: Wells
authors.forename: W
authors.initials: W
authors.lastname: Black
authors.forename: M
authors.initials: M
authors.lastname: Solo
authors.forename: D
authors.initials: D
authors.lastname: Albert
mesh_terms: D001283:Atrioventricular Node / Q000503:physiopathology; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D003971:Diastole / Q000502:physiology*; D004562:Electrocardiography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D013610:Tachycardia / Q000503:physiopathology*; D013997:Time Factors; D016276:Ventricular Function / Q000502:physiology*