Complexity of the dynamic QT variability and RR variability in patients with acute anterior wall myocardial infarction: a novel technique using a non-linear method.
QT and RR intervals' fluctuations are implicated in the development of malignant arrhythmias. Recent research has quantified repolarization lability using stochastic and linear methods. However, QT-RR intervals are nonlinearly coupled. To this end, QT and RR intervals were extracted from twenty four patients with acute myocardial infarction (AMI) and 13 controls, and a measure of local dimensional complexity (pointwise correlation dimension, PD2) was calculated. PD2 of QT intervals was significantly higher for the patients than for controls (4.83 +/- 0.81 versus 3.40 +/- 0.76, P =.0001), and vice versa for RR intervals (2.51 +/- 0.62 versus 2.91 +/- 0.42, P =.028). The RR and QT measures of complexity were highly correlated only among controls (r = 0.769, P =.0021). Our results support the presence of autonomic abnormalities during infarction and might complement existing tools for assessment of increased risk for sudden death after AMI.
Nahshoni
Eitan
E
The Gehah Mental Heallth Center, Geha Research Unit, Petah Tikva, Israel. ENahshoni@clalit.org.il
Strasberg
Boris
B
Adler
Edgar
E
Imbar
Shula
S
Sulkes
Jacqueline
J
Weizman
Abraham
A
D000465:Algorithms; D001341:Autonomic Nervous System / Q000503:physiopathology; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*