Heart dysfunction and heart rate variability prognoses in sepsis

Objective

Sepsis is a leading cause of mortality in intensive care units (ICUs). Septic patients have better prognoses when multiple organ dysfunction syndrome is not present. Regarding the heart, the variability of the R-R interval (HRV) also depends on the coupling between the heart and other organs; sepsis may be a readily available tool for evaluation of nonlinear dynamic relationships among organ and multiple organ dysfunction syndrome development. We conducted a prospective study to analyze HRV, hemodynamic, ecocardigraphic, and serum cardiac markers (troponin and creatin phosphate kinase), and to evaluate its possible relation with outcome.

Design

A prospective observational analysis of serum of patients meeting the criteria for septic shock.

Setting

A 28-bed medical–surgical ICU in a university hospital.

Patients

Twenty-five patients were analyzed in the study.

Materials and methods

We selected all consecutive patients who met the criteria for septic shock in our ICU and we collected blood samples for analysis on days 1, 3, 6, 9, 12 or until death. We analyzed creatin phosphate kinase total (CPK) and MB (CK-MB), and also analyzed troponin. We analyzed hemodynamic parameters by pulmonary catheter, cardiac ultrasonography and Holter recording for 24 hours on the time points days 1, 3, 6, 9, and 12.

Statistical analysis

All results are presented as the mean and standard deviation. For analysis we divided patients into survivors and nonsurvivors up to hospital release. We performed an ANOVA for repeated measurements in continuous variables, and correlation coefficients were determined according to multiple-level regession analysis. P < 0.05 was considered significant.

Results

Our mortality was 60%. We had 15 patients in the nonsurvivor group and 10 patients as survivors. The two groups had similar APACHE II scores (nonsurvivors 26; survivors 24 ± 5; NS). CPK, CK-MB, ecocardiography analysis, cardiac output, and vascular resistance did not show any significant difference at any moment during the study period. However, troponin showed a significant difference from the first day of study, followed by the stroke work analysis as a significant difference between survivors and nonsurvivors. The difference in stroke work data become higher from day 3 onwards. The HRV showed a significant difference in maximal and minimal low frequency (LF) and in maximal high frequency. There was correlation as an independent variable only for maximal LF as a predictor of patient outcome.

Conclusions

In our study, HRV showed the capability to prognose patient outcome. Heart dysfunction was detected only by serum troponin levels and the hemodynamic data: stroke work.