Cardiac autonomic neuropathy linked to left ventricular dysfunction in type 1 diabetic patients

Type 1 diabetes is a major cause of cardiovascular death; diabetic cardiomyopathy (DCM) is the most important cause of mortality among diabetic patients. There is an increasing body of evidence that the most important inducer of DCM is microvascular injury. The aim of this study is to establish a potential relationship between low frequency/high frequency (LF/HF) ratio and DCM and to set a possible predictive cutoff of LF:HF ratio for early detection of DCM.

75 type 1 diabetic patients together with 75 controls were assessed using tissue Doppler imaging for left ventricular (LV) and right ventricular (RV) diastolic function, and heart rate variability (HRV) indices including LF/HF ratio. Type 1 diabetic patients were also assessed for parameters of glycemic and lipid profile control.

Cases showed a statistically significant increase in LF/HF ratio compared to controls reflecting reduced HRV. Also, LV and RV diastolic function were reduced in cases compared to controls, there was a significant correlation between LV E/E' ratio (ratio of early transmitral velocity and average early mitral annular and basal septal velocities) and LF/HF ratio. LF/HF ratio was able to predict LV diastolic dysfunction as expressed by the LV E/E' ratio with a sensitivity of 96%.

HRV indices notably LF/HF ratio seem to be an early and sensitive predictor of DCM, the latter finding not only underlines the role of microvascular injury in the induction of DCM but might help also for the early detection and reversal of it.