The R-R Interval Variation as the Good Outcomes Predictor in Survivors after Cardiac Arrest with Targeted Temperature Management
Muengtaweepongsa S, MD1, Visuttichaikit S, MD1, Jantanukul A, MSc2
Affiliation : 1 Faculty of Medicine, Thammasat University, Pathumthani, Thailand 2 Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand
Objective : Targeted temperature management (TTM) is recommended for patients suffering a cardiac arrest after restoration of
spontaneous circulation (ROSC). Heart rate variability (HRV), which reflects autonomic function, has been proposed as an outcome
predictor but HRV measurement is not suitable for everyday practice. RR interval variation (RRIV), which can be measured easily
at the bedside using surface electrocardiography, is a parameter indicating the integrity of the autonomic nervous system. We
assessed the neurologic outcomes and predictive factors involving RRIV in cardiac arrest patients who received TTM.
Materials and Methods : We performed a retrospective, single-center, observational study to describe the neurologic outcomes of
cardiac arrest patients who received TTM measured by the cerebral performance categories (CPC) scale. Clinical data was collected
from medical records dated from January 2010 to June 2015. RRIV was calculated by difference between the maximum RR interval
and the minimum RR interval.
Results : During the study period, 46 patients were examined; 56.5% were male. The most common cause of cardiac arrest was
cardiac in origin (37%). The most common initial cardiac rhythm was asystole (52.2%). RRIV was correlated with HRV parameter
by standard analysis software in the first 11 patients. In our setting, 12 patients (26.1%) displayed favorable neurologic outcomes
(CPC1 or 2). RRIV >40 msec was associated with favorable neurologic outcomes (p = 0.046).
Conclusion : RRIV may be used as a tool for predicting neurologic outcomes. RRIV at >40 msec was associated with favorable
neurologic outcomes.
Keywords : Targeted temperature management, Cardiac arrest, Neurologic outcomes, RR interval variation
