TY - JOUR
T1 - Unstable QT interval dynamics precedes ventricular tachycardia onset in patients with acute myocardial infarction
T2 - A novel approach to detect instability in QT interval dynamics from clinical ECG
AU - Chen, Xiaozhong
AU - Hu, Yuxuan
AU - Fetics, Barry J.
AU - Berger, Ronald D.
AU - Trayanova, Natalia A.
PY - 2011/12
Y1 - 2011/12
N2 - Background-Instability in ventricular repolarization in the presence of premature activations (PA) plays an important role in arrhythmogenesis. However, such instability cannot be detected clinically. This study developed a methodology for detecting QT interval (QTI) dynamics instability from the ECG and explored the contribution of PA and QTI instability to ventricular tachycardia (VT) onset. Methods and Results-To examine the contribution of PAs and QTI instability to VT onset, ECGs of 24 patients with acute myocardial infarction, 12 of whom had sustained VT (VT) and 12 nonsustained VT (NSVT), were used. From each patient ECG, 2 10-minute-long ECG recordings were extracted, 1 right before VT onset (onset epoch) and 1 at least 1 hour before it (control epoch). To ascertain how PA affects QTI dynamics stability, pseudo-ECGs were calculated from an MRI-based human ventricular model. Clinical and pseudo-ECGs were subdivided into 1-minute recordings (minECGs). QTI dynamics stability of each minECG was assessed with a novel approach. Frequency of PAs (f PA) and the number of minECGs with unstable QTI dynamics (N us) were determined for each patient. In the VT group, f PA and N us of the onset epoch were larger than in control. Positive regression relationships between f PA and N us were identified in both groups. The simulations showed that both f PA and the PA degree of prematurity contribute to QTI dynamics instability. Conclusions-Increased PA frequency and QTI dynamics instability precede VT onset in patients with acute myocardial infarction, as determined by novel methodology for detecting instability in QTI dynamics from clinical ECGs.
AB - Background-Instability in ventricular repolarization in the presence of premature activations (PA) plays an important role in arrhythmogenesis. However, such instability cannot be detected clinically. This study developed a methodology for detecting QT interval (QTI) dynamics instability from the ECG and explored the contribution of PA and QTI instability to ventricular tachycardia (VT) onset. Methods and Results-To examine the contribution of PAs and QTI instability to VT onset, ECGs of 24 patients with acute myocardial infarction, 12 of whom had sustained VT (VT) and 12 nonsustained VT (NSVT), were used. From each patient ECG, 2 10-minute-long ECG recordings were extracted, 1 right before VT onset (onset epoch) and 1 at least 1 hour before it (control epoch). To ascertain how PA affects QTI dynamics stability, pseudo-ECGs were calculated from an MRI-based human ventricular model. Clinical and pseudo-ECGs were subdivided into 1-minute recordings (minECGs). QTI dynamics stability of each minECG was assessed with a novel approach. Frequency of PAs (f PA) and the number of minECGs with unstable QTI dynamics (N us) were determined for each patient. In the VT group, f PA and N us of the onset epoch were larger than in control. Positive regression relationships between f PA and N us were identified in both groups. The simulations showed that both f PA and the PA degree of prematurity contribute to QTI dynamics instability. Conclusions-Increased PA frequency and QTI dynamics instability precede VT onset in patients with acute myocardial infarction, as determined by novel methodology for detecting instability in QTI dynamics from clinical ECGs.
KW - Acute myocardial infarction
KW - Premature activation
KW - QT interval
KW - Repolarization instability
KW - Ventricular tachycardia
UR - http://www.scopus.com/inward/record.url?scp=84863373117&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84863373117&partnerID=8YFLogxK
U2 - 10.1161/CIRCEP.110.961763
DO - 10.1161/CIRCEP.110.961763
M3 - Article
C2 - 21841208
AN - SCOPUS:84863373117
SN - 1941-3149
VL - 4
SP - 858
EP - 866
JO - Circulation: Arrhythmia and Electrophysiology
JF - Circulation: Arrhythmia and Electrophysiology
IS - 6
ER -