Abstract 12224: Electrocardiographic Beat-to-Beat QT Interval is affected by Phases of Respiration: The Atherosclerosis Risk in Communities Study
Introduction: Respiration causes changes in heart rate and autonomic tone. The effect of electrocardiographic (ECG) RR interval (RRI) on QT interval (QTI) is well described, but correction of QTI for RRI has limitations.
Hypothesis: We hypothesized that respiration affects QTI independently from its effect on RRI, and that this effect is different in sudden cardiac death (SCD) victims vs. those without SCD.
Methods: We prospectively analyzed 10 second 12-lead ECGs containing only sinus beats in 14908 participants including those who succumbed to SCD during median 14 years of follow-up (n=272; age:56±6y; 39% female; 55% white) in The Atherosclerosis Risk in Communities (ARIC) study. Respiration effect was derived from magnitude changes in QRS loops on vectorcardiograms derived from 12 lead ECGs. Panel time-series regression models were used. Time series of RRI and change in respiratory phase (RPH), magnitude and RR angle served as patient-specific random effect predictors. Age, sex and race were entered as fixed effect predictors. QTI time series served as an outcome.
Results: In healthy ARIC participants with no history of coronary heart disease (CHD), heart failure, stroke, hypertension, diabetes, smoking, or bundle branch block (n=10,553; age:53±6y; 71% female; 81% white), the relationship between QTI and RPH (adjusted for RRI and demographics) was direct: 1 radian RPH increase was associated with a 5.2 ms increase in QTI (95%CI 0.78 - 9.63; P=0.021). QTI and RPH showed inverse relationships in SCD victims: 1 radian decrease in RPH was associated with a 99.9 ms increase in QTI (95%CI 26.7 - 173.2 ms; P=0.008) in CHD SCDs (n=28; age:57±6y; 34% female; 66% white) as compared to no effect in non-CHD SCDs (n=146; age:54±7y; 34% female; 100% white): +16.1 (95%CI -17.3 to 49.5 ms; P=0.344) QTI.
Conclusion: Respiration affects QTI independently from its effect on RRI, and differently in SCD victims compared to healthy individuals. Correction of QTI should include both RRI and RPH.
- Sudden cardiac death
- Coronary heart disease
- Heart rate/Heart rate variability
- QT interval
Author Disclosures: M.M. Kabir: None. G. Sedaghat: None. J. Thomas: None. J.W. Waks: None. C.M. Sitlani: None. M.L. Biggs: None. N. Sotoodehnia: None. D.S. Siscovick: None. W.S. Post: None. C.A. Henrikson: None. S.D. Solomon: None. E.Z. Soliman: None. A.E. Buxton: None. M.E. Josephson: None. L.G. Tereshchenko: None.
- © 2016 by American Heart Association, Inc.