389-P: Glycemia and Cardiac Arrhythmias in People with Type 1 Diabetes
Authors: HAGELQVIST PER G. , ANDERSEN ANDREAS , MAYTHAM KAISAR , ANDREASEN CHRISTINE R. , ENGBERG SUSANNE , LINDHARDT TOMMI B. , FORMAN JULIE , PEDERSEN-BJERGAARD ULRIK , KNOP FILIP K. , VILSBØLL TINA 
Published: June 2023

The impact of hypoglycemia, hyperglycemia and glycemic variability on cardiac arrhythmia susceptibility in people with type 1 diabetes is uncertain. We performed a 12-month prospective observational study employing continuous glucose monitoring and implantable loop recorders to investigate potential associations between glycemia and cardiac arrhythmias. Thirty adults with type 1 diabetes ([mean ± SD] age 63 ± 8 years, BMI 26 ± 5 kg/m2, HbA1c 7.3 ± 1.1% [56.9 ± 11.9 mmol/mol]) and without any history of cardiac arrhythmias were included. Daytime and nighttime incidence rate ratios (IRR) of arrhythmias were determined for hypoglycemia (interstitial glucose (IG) &lt; 3.9 mmol/L), hyperglycemia (IG &gt; 10.0 mmol/L), and glycemic variability (standard deviation and coefficient of variation). Hypoglycemia was not associated with an increased risk of cardiac arrhythmias in comparison with euglycemia (IG 3.9 - 10.0 mmol/L) and hyperglycemia. However, during daytime, a trend of increased risk of arrhythmias was observed when comparing hypoglycemia with euglycemia (IRR 1.08 [95% CI 0.99 - 1.18]). Furthermore, during daytime both the occurrence of hyperglycemia and time spent in hyperglycemia within the same hour of an arrhythmia were associated with an increased risk of arrhythmias compared to euglycemia (IRR 2.03 [95% CI 1.21 - 3.40] and IRR 1.07 [95% CI 1.02 - 1.13], respectively). Nighttime hypoglycemia and hyperglycemia were not associated with increased risk of arrhythmias. Increased glycemic variability was not associated with an increased risk of arrhythmias during daytime, whereas a reduced risk was observed during nighttime. In conclusion, daytime hypoglycemia and hyperglycemia may contribute to an increased risk of cardiac arrhythmias compared to euglycemia, in people with type 1 diabetes. No associations were found between glycemic levels and cardiac arrhythmias during nighttime, indicating diurnal differences in arrhythmogenic susceptibility.

Disclosure
P.G.Hagelqvist: None. T.Vilsbøll: Consultant; AstraZeneca, Boehringer Ingelheim Inc., Gilead Sciences, Inc., Eli Lilly and Company, Mundipharma, Merck & Co., Inc., Novo Nordisk A/S, Sanofi, Sun Pharmaceutical Industries Ltd., Bristol-Myers Squibb Company. A.Andersen: None. K.Maytham: None. C.R.Andreasen: None. S.Engberg: Employee; Novo Nordisk A/S. T.B.Lindhardt: None. J.Forman: None. U.Pedersen-bjergaard: Advisory Panel; Novo Nordisk A/S, Sanofi, Vertex Pharmaceuticals Incorporated. F.K.Knop: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Novo Nordisk, Sanofi, Consultant; AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Novo Nordisk, Sanofi, Research Support; Novo Nordisk, Zealand Pharma A/S, Speaker's Bureau; AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Novo Nordisk, Sanofi, Lundbeck.

Funding
Novo Nordisk Foundation (28300)