Abstract
Abstract
Objective
. The link between ultrafast heart period (HP) dynamics and baroreflex is poorly analyzed, especially in pathologies altering autonomic regulation. This study assesses this link via heart rate fragmentation (HRF) analysis in type 2 diabetes mellitus (T2DM) with or without cardiac autonomic neuropathy (CAN).
Approach
. Sixty-four individuals with T2DM, divided into those with CAN (DM
CAN
, n=28, 55-62 yrs, 17 males) and without CAN (DM
noCAN
, n=36, 49-61 yrs, 19 males), were evaluated at supine resting (REST) and during active standing (STAND). HRF was calculated using sequences of four consecutive HPs categorized as words with zero (W
0
), one (W
1
), two (W
2
), three (W
3
) and total (PIP) inflection points. Baroreflex control was assessed from HP and systolic arterial pressure (SAP) variabilities cross-spectral analyses in low frequency (LF) and high frequency (HF) bands and via sequence method (SEQ). Also squared coherence between HP and SAP in LF and HF bands, namely K
2
HP-SAP
(LF) and K
2
HP-SAP
(HF), and percentage of baroreflex sequences (%
SEQ
) were assessed.
Main results
. W
3
was higher in DM
CAN
at REST compared to DM
noCAN
and W
3
increased in STAND for both groups. At REST %
SEQ
and K
2
HP-SAP
(HF) were positively associated with W
0
and W
1
, while they were negatively associated with W
3
and PIP. During STAND K
2
HP-SAP
(LF), %
SEQ
and α
SEQ
were negatively correlated with PIP and W
3
.
Significance
. Greater presence of inflection points in 4-beat words was associated with a less effective baroreflex, thus suggesting that an impaired baroreflex augmented the likelihood of fast HP changes in DM
CAN
.