Heart Rate Fragmentation and its Relationship with Cardiovascular Control in type 2 Diabetes with Cardiovascular Autonomic Neuropathy

Cardiovascular autonomic neuropathy (CAN) alters cardiovascular autonomic control in type 2 diabetes (T2DM). We evaluated the heart rate fragmentation (HRF) in T2DM with and without CAN and relate it to heart period (HP) and systolic arterial pressure (SAP). HP and SAP series were collected in T2DM with CAN (n = 28) and without CAN ($n=36$) at supine and during active standing for 15 min. The number of words with $\boldsymbol{n}$ inflection points ($\mathbf{W n}$), the percentage of inflection points (PIP), and the coherence ($\mathrm{K}^{2}{ }_{\text {HP-SAP }}$) at low frequency (LF) and high frequency (HF) were quantified. T2DM with CAN showed higher W<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> in supine with an increase during STAND. At REST, PIP, W<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</inf> and W<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> were linearly correlated with $\mathrm{K}^{2}{ }_{\text {HP-SAP }}$ at HF. During STAND, PIP was linearly correlated with $\mathrm{K}^{2}{ }_{\mathrm{HP}-\mathrm{SAP}}$ at LF. CAN increases HRF and a higher HRF was associated with a lower $\mathrm{K}^{2}{ }_{\text {HP-sap }}$ indicating a less efficient baroreflex especially during STAND.