Nocturnal ventricular arrhythmias are associated with severity of cardiovascular autonomic neuropathy in type 2 diabetes.

BACKGROUND: Cardiovascular autonomic neuropathy (CAN) is a risk factor for arrhythmias and adverse cardiovascular events, but the relation between the severity of CAN progression and nocturnal arrhythmias needs to be furthermore clarified. The following study aims to evaluate the association between nocturnal arrhythmias and severity of CAN in patients with type 2 diabetes.

METHODS: 219 type 2 diabetes patients were recruited from January 2017 to May 2018. Subjects were classified into no CAN (NCAN), early CAN (ECAN), definite CAN (DCAN) or advanced CAN (ACAN) according to cardiovascular autonomic reflex tests (CARTs). Heartbeats were recorded by the 24-hour Holter ECG, and the data during daytime (07:00-23:00) and nighttime (23:00-07:00) were analyzed separately.

RESULTS: After adjusting for age, the incidence of ventricular arrhythmias increased with CAN progression at nighttime (18.6%in NCAN, 29.9%in ECAN, 36.2%in DCAN, 60.0%in ACAN, P for a trend=0.034). Patients with nocturnal ventricular arrhythmias had higher CARTs scores (2.0&pm;1.0vs.1.5&pm;0.9, P<0.001), smaller heart rate variability during deep breathing (9.5&pm;5.7vs11.6&pm;6.6, P=0.021), valsalva ratio (1.2&pm;0.1vs. 1.2&pm;0.2, P = 0.006) and postural BP change (-8.8&pm;15.5mmHg vs. -4.1&pm;11.2mmHg. P = 0.023) when compared with those without nocturnal ventricular arrhythmias. Multivariate regression analysis revealed that CAN stage (OR=1.765, 95%CI: 1.184-2.632, P=0.005) was independently associated with nocturnal ventricular arrhythmias.

CONCLUSIONS: CAN stage was independently associated with the presence of nocturnal ventricular arrhythmias in type 2 diabetes. Early detection, diagnosis and treatment of CAN may help predict and prevent adverse cardiovascular events and cardiovascular mortality in diabetes.