Synchronous heart rate reduction with suppression-burst pattern in KCNT1-related developmental and epileptic encephalopathies.

Suppression-burst (SB) is an electroencephalographic pattern observed in neonatal- and infantile-onset developmental and epileptic encephalopathies (DEEs), which are associated with high mortality in early life. However, the relation of SB electroencephalogram (SB-EEG) with autonomic function requires clarification. We investigated the relationship between heart rate (HR) and phasic transition during SB-EEG in DEEs to explore the mechanism of early death. Seven patients (two with KCNT1-DEE) with neonatal- and infantile-onset DEE who presented with SB-EEG were retrospectively identified. Five-minute SB-EEGs were analyzed with simultaneous recording of electrocardiograms. Mean HR, suppression duration, and burst period were calculated by measuring RR intervals. Two patients with KCNT1-DEE exhibited synchronous HR fluctuations, with an HR decrease during suppression and an increase during burst. The HR decrease was larger (-6.1% and -7.7%) and the median duration of suppression was longer (4.0 and 8.2 s) in patients with KCNT1-DEE than the other five (range: -2.9% to 0.9% and 0.7-1.7s, respectively). A strong negative correlation was confirmed between suppression duration and HR reduction rates in one patient with KCNT1-DEE. SB phases may influence HR regulation in patients with KCTN1-DEE.

Cardiovascular Outcomes in Sleep-Disordered Breathing: Are We Under-estimating?

Obstructive sleep apnea is a growing health concern, affecting nearly one billion people worldwide; increasingly recognized as an independent cardiovascular risk factor associated with incident obesity, insulin resistance, hypertension, arrhythmias, stroke, coronary artery disease, and heart failure. The prevalence of obstructive sleep apnea could be underestimated in the previous studies, leading to only modest predictions of cardiovascular outcomes. Using more physiologic data will increase sensitivity for the diagnosis of obstructive sleep apnea. Individuals at high risk of obstructive sleep apnea should be identified so that treatment efforts can be focused on them. This review will assess the evidence for the relationship between obstructive sleep apnea and cardiovascular consequences in the past, present, and future. We will also explore the role of adding physiological data obtained from sleep studies and its ability to enhance the cardiovascular outcome's predictability. Finally, we will discuss future directions and gaps that need further research.

Laughter as a social rejection cue: Influence of prior explicit experience of social rejection on cardiac signs of "freezing".

The study aimed at investigating the immediate cardiac effect of the sudden perception of other people's laughter after experimentally manipulating healthy participants' proneness to experience laughter as a cue of social threat. We expected that participants would show cardiac signs of freezing (i.e., sustained heart rate deceleration immediately after perception of the laughter) after prior social rejection but not or less so after prior acceptance, due to an increased bias to perceive the ambiguous social signal as a cue of social threat and rejection after rejection had been primed. Contrary to expectations, the perception of other people's laughter elicited a decelerative (freezing) response regardless of whether it was preceded by the experience of social rejection or acceptance. The response was prolonged in participants who had been accepted beforehand compared to those who had been rejected. The findings indicate that, given a relevant social context, other people's laughter can be a powerful cue of social threat and rejection also in healthy individuals. Prolonged heart rate deceleration after an ambiguous social signal may facilitate the processing of significant social information in the socially threatening situation. The study adds to the literature rendering the course of the immediate transient heart rate response a useful tool in social rejection research. Additionally, the findings suggested that in some cases the further progress of transient heart rate changes in more extended time-windows (about 30 s) may provide additional relevant information about the processing of social cues.

Ictal heart rate changes and the effects of vagus nerve stimulation for patients with refractory epilepsy.

Vagus nerve stimulation (VNS) shows long-term efficiency worldwide in most pharmacoresistant patients with epilepsy; however, there are still a small number of patients who are non-responders to VNS therapy. It has been shown that VNS treatment outcomes for drug-resistant epilepsy may be predicted by preoperative heart-rate variability measurements and that patients with epilepsy with ictal tachycardia (IT) during seizures have good responses to VNS. However, few studies have reported the efficacy of VNS in patients with epilepsy with ictal bradycardia (IB) or normal heart rate (HR), and none have explored the possible mechanisms of VNS efficacy based on different HR types. HR during seizures varies, and we presume that different HRs during seizures may impact the effects of VNS. It has been shown that blood pressure in the human body needs to be maintained through the arterial baroreflex (ABR). VNS efficacy in patients with epilepsy with IT, IB, and normal HR during seizures may be related to ABR. Mechanical signals generated by VNS are similar to the autonomic nerve pathways and, thus, we propose the hypothesis that different HRs during seizures can predict VNS efficacy in patients. If VNS is highly efficient in patients with IT during seizures, VNS in patients with a normal HR during seizures may be less efficient, and may even be inefficient in patients with IB during seizures.

Diabetic retinopathy is associated with early autonomic dysfunction assessed by exercise-related heart rate changes

Diabetic retinopathy has been associated with cardiac autonomic dysfunction in both type 1 and type 2 diabetes mellitus (DM) patients. Heart rate (HR) changes during exercise testing indicate early alterations in autonomous tonus. The aim of the present study was to investigate the association of diabetic retinopathy with exercise-related HR changes. A cross-sectional study was performed on 72 type 2 and 40 type 1 DM patients. Autonomic dysfunction was assessed by exercise-related HR changes (Bruce protocol). The maximum HR increase, defined as the difference between the peak exercise rate and the resting rate at baseline, and HR recovery, defined as the reduction in HR from the peak exercise to the HR at 1, 2, and 4 min after the cessation of the exercise, were determined. In type 2 DM patients, lower maximum HR increase (OR = 1.62, 95 percentCI = 1.03-2.54; P = 0.036), lower HR recovery at 2 (OR = 2.04, 95 percentCI = 1.16-3.57; P = 0.012) and 4 min (OR = 2.67, 95 percentCI = 1.37-5.20; P = 0.004) were associated with diabetic retinopathy, adjusted for confounding factors. In type 1 DM, the absence of an increase in HR at intervals of 10 bpm each during exercise added 100 percent to the odds for diabetic retinopathy (OR = 2.01, 95 percentCI = 1.1-3.69; P = 0.02) when adjusted for DM duration, A1c test and diastolic blood pressure. In conclusion, early autonomic dysfunction was associated with diabetic retinopathy. The recognition of HR changes during exercise can be used to identify a high-risk group for diabetic retinopathy.

The difference of heart rate recovery in ischemic heart disease comparing to normal / 대한내과학회지

BACKGROUND: The goal of this study is to evaluate the differences of the rate and the ratio of heart rate changes, which is well known to reflect the vagal reactivation, after peak exercise between ischemic heart disease and normal during treadmill exercise test. Additionally R-wave amplitude changes are evaluated to have the discriminal power between ischemic heart disease and normal. METHODS: We have studied 253 human (196 control, 57 patients) who took the symptom-limited exercise test using Marquette case 8000 model. The 57 patients who showed the positive result by exercise test have confirmed by coronary angiography. The rate of heart rate changes was defined as the absolute difference of the heart rate subtracted by the just-previous stage heart rate. The ratio of heart rate changes was defined as the percentile of the rate of heart rate changes comparing to the just-previous stage heart rate. The changes of R-wave amplitude at lead V5 and aVF were obtained by the subtraction of R-wave amplitude at the peak exercise stage from that at the standing rest stage respectively. Additively heart rate recovery was defined as the rate of heart rate change which was obtained at 1 minute later after peak exercise. RESULTS: In patients and control, the resting heart rate were 70 +/- 13 bpm and 69 +/- 11 bpm (p>0.05), and the peak heart rate were 136 +/- 22 bpm and 155 +/- 18 bpm respectively (p<0.001). The rate of heart rate changes in patients group were significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p<0.001, p=0.008, p=0.002). The ratio of heart rate changes in patients group were also significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p=0.017, p=0.027, p=0.002). With comparing both groups, the incidences of ventricular ectopy were not different during exercise and recovery stages, and the difference in the changes of R-wave amplitude at lead V5 and aVF were not observed respectively. CONCLUSION: The rate and ratio of heart rate changes are significantly lower in iscemic heart disease than in normal, and these are resulted from the depression of vagal reactivation. These findings are supplemental to make a diagnosis and a arrhythmic risk stratification of ischemic heart disease.