Sudden death in noncoronary heart disease is associated with delayed paced ventricular activation.
BACKGROUND
Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogram duration starts to increase (S1S2delay) are seen both in hypertrophic cardiomyopathy (HCM) in those at risk of VF and in patients with idiopathic VF (IVF).


RESULTS
DeltaED and S1S2delay have been measured using paced electrogram fractionation analysis in 266 patients with noncoronary heart disease. Of these, one group of 61 patients had a history of VF and included 21 HCM, 17 IVF, 13 long-QT syndrome (LQTS), 5 dilated cardiomyopathy (DCM), and 5 others. These were compared with 205 patients with similar diseases with no VF history (non-VF group) and a control group (n=12) without heart disease. Results from HCM VF patients (DeltaED, 19+/-3.3 ms; S1S2delay, 350+/-9.7 ms) differed sharply from observations in HCM non-VF patients (DeltaED, 7.3+/-1.35 ms; S1S2delay, 312+/-6.7 ms; P<0.001). DCM VF patients had longer delays (DeltaED, 14.3+/-5.9; S1S2delay, 344+/-11.2) than DCM non-VF patients (DeltaED, 5.8+/-1.87 ms; S1S2delay, 311+/-5.7 ms; P<0.001), with major differences also seen comparing LQTS VF (DeltaED, 12.4+/-5.3 ms; S1S2delay, 343+/-13.8 ms) and LQTS non-VF patients (DeltaED, 11.0+/-2.7 ms; S1S2delay, 320+/-5.4 ms; P<0.001). IVF patients had both severely abnormal and normal areas of myocardium.


CONCLUSIONS
Slowed or delayed myocardial activation is a common feature in patients with noncoronary heart disease with a history of VF, and its assessment may allow the prospective prediction of VF risk in these patients.
Department of Cardiology, Papworth Hospital, University of Cambridge, Cambridge CB3 8RE, UK. rcs23@eng.cam.ac.uk
Richard C
RC
Saumarez
Lidia
L
Chojnowska
Richard
R
Derksen
Mariusz
M
Pytkowski
Maciej
M
Sterlinski
Christopher L-H
CL
Huang
Nicolas
N
Sadoul
Richard N W
RN
Hauer
Witold
W
Ruzyłło
Andrew A
AA
Grace
D002304:Cardiac Pacing, Artificial; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D003937:Diagnosis, Differential; D016002:Discriminant Analysis; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D006329:Heart Conduction System / Q000503:physiopathology; D006331:Heart Diseases / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008133:Long QT Syndrome / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D018754:Ventricular Dysfunction / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology