RESUMEN
AIMS: To investigate changes in cardiac repolarisation during exercise-related hypoglycaemia compared to hypoglycaemia induced at rest in people with type 1 diabetes. MATERIAL AND METHODS: In a randomised crossover study, 15 men with type 1 diabetes underwent two separate hyperinsulinaemic euglycaemic-hypoglycaemic clamp experiments during Holter-ECG monitoring. One experiment included a bout of moderate-intensity cycling exercise (60 min) along with declining plasma glucose (PG; Clamp-exercise). In the other experiment, hypoglycaemia was induced with the participants at rest (Clamp-rest). We studied QTc interval, T-peak to T-end (Tpe) interval and hormonal responses during three steady-state phases: (i) baseline (PG 4.0-8.0 mmol/L); (ii) hypoglycaemic phase (PG <3.0 mmol/L); and (iii) recovery phase (PG 4.0-8.0 mmol/L). RESULTS: Both QTc interval and Tpe interval increased significantly from baseline during the hypoglycaemic phase but with no significant difference between test days. These changes were accompanied by an increase in plasma adrenaline and a decrease in plasma potassium on both days. During the recovery phase, ΔQTc interval was longer during Clamp-rest compared to Clamp-exercise, whereas ΔTpe interval remained similar on the two test days. CONCLUSIONS: We found that both exercise-related hypoglycaemia and hypoglycaemia induced at rest can cause QTc-interval prolongation and Tpe-interval prolongation in people with type 1 diabetes. Thus, both scenarios may increase susceptibility to ventricular arrhythmias.
Asunto(s)
Diabetes Mellitus Tipo 1 , Hipoglucemia , Masculino , Humanos , Hipoglucemia/inducido químicamente , Arritmias Cardíacas , Hipoglucemiantes/efectos adversos , Epinefrina , GlucemiaRESUMEN
AIM: To investigate changes in cardiac repolarization abnormalities (heart rate-corrected QT [QTc ] [primary endpoint], T-wave abnormalities) and heart-rate variability measures in people with type 1 diabetes during insulin-induced hypoglycaemia followed by recovery hyperglycaemia versus euglycaemia. METHODS: In a randomized crossover study, 24 individuals with type 1 diabetes underwent two experimental clamps with three steady-state phases during electrocardiographic monitoring: (1) a 45-minute euglycaemic phase (5-8 mmol/L), (2) a 60-minute insulin-induced hypoglycaemic phase (2.5 mmol/L), and (3) 60-minute recovery in either hyperglycaemia (20 mmol/L) or euglycaemia (5-8 mmol/L). RESULTS: All measured markers of arrhythmic risk indicated increased risk during hypoglycaemia. These findings were accompanied by a decrease in vagal tone during both hyperglycaemia and euglycaemia clamps. Compared with baseline, the QTc interval increased during hypoglycaemia, and 63% of the participants exhibited a peak QTc of more than 500 ms. The prolonged QTc interval was sustained during both recovery phases with no difference between recovery hyperglycaemia versus euglycaemia. During recovery, no change from baseline was observed in heart-rate variability measures. CONCLUSIONS: In people with type 1 diabetes, insulin-induced hypoglycaemia prolongs cardiac repolarization, which is sustained during a 60-minute recovery period independently of recovery to hyperglycaemia or euglycaemia. Thus, vulnerability to serious cardiac arrhythmias and sudden cardiac death may extend beyond a hypoglycaemic event, regardless of hyperglycaemic or euglycaemic recovery.
Asunto(s)
Diabetes Mellitus Tipo 1 , Hiperglucemia , Hipoglucemia , Síndrome de QT Prolongado , Humanos , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hiperglucemia/inducido químicamente , Frecuencia Cardíaca , Estudios Cruzados , Hipoglucemia/inducido químicamente , Hipoglucemia/prevención & control , Hipoglucemia/complicaciones , Arritmias Cardíacas/inducido químicamente , Hipoglucemiantes/efectos adversos , Insulina Regular Humana/efectos adversos , Síndrome de QT Prolongado/inducido químicamente , Síndrome de QT Prolongado/complicacionesRESUMEN
AIM: To investigate the impact of hypoglycaemia, hyperglycaemia and glycaemic variability on arrhythmia susceptibility in people with type 1 diabetes. MATERIALS AND METHODS: Thirty adults with type 1 diabetes were included in a 12-month observational exploratory study. Daytime and night-time incident rate ratios (IRRs) of arrhythmias were determined for hypoglycaemia (interstitial glucose [IG] <3.9 mmol/L), hyperglycaemia (IG >10.0 mmol/L) and glycaemic variability (standard deviation and coefficient of variation). RESULTS: Hypoglycaemia was not associated with an increased risk of arrhythmias compared with euglycaemia and hyperglycaemia combined (IG ≥ 3.9 mmol/L). However, during daytime, a trend of increased risk of arrhythmias was observed when comparing time spent in hypoglycaemia with euglycaemia (IRR 1.08 [95% CI: 0.99-1.18] per 5 minutes). Furthermore, during daytime, both the occurrence and time spent in hyperglycaemia were associated with an increased risk of arrhythmias compared with euglycaemia (IRR 2.03 [95% CI: 1.21-3.40] and IRR 1.07 [95% CI: 1.02-1.13] per 5 minutes, respectively). Night-time hypoglycaemia and hyperglycaemia were not associated with the risk of arrhythmias. Increased glycaemic variability was not associated with an increased risk of arrhythmias during daytime, whereas a reduced risk was observed during night-time. CONCLUSIONS: Acute hypoglycaemia and hyperglycaemia during daytime may increase the risk of arrhythmias in individuals with type 1 diabetes. However, no such associations were found during night-time, indicating diurnal differences in arrhythmia susceptibility.
Asunto(s)
Diabetes Mellitus Tipo 1 , Hiperglucemia , Hipoglucemia , Adulto , Humanos , Diabetes Mellitus Tipo 1/complicaciones , Hipoglucemia/inducido químicamente , Hipoglucemia/complicaciones , Hipoglucemia/epidemiología , Glucemia , Hiperglucemia/complicaciones , Hiperglucemia/epidemiología , Arritmias Cardíacas/epidemiología , Arritmias Cardíacas/etiología , GlucosaRESUMEN
Background: Hypoglycemia is common in individuals with type 1 diabetes, especially during exercise. We investigated the accuracy of two different continuous glucose monitoring systems during exercise-related hypoglycemia in an experimental setting. Materials and methods: Fifteen individuals with type 1 diabetes participated in two separate euglycemic-hypoglycemic clamp days (Clamp-exercise and Clamp-rest) including five phases: 1) baseline euglycemia, 2) plasma glucose (PG) decline ± exercise, 3) 15-minute hypoglycemia ± exercise, 4) 45-minute hypoglycemia, and 5) recovery euglycemia. Interstitial PG levels were measured every five minutes, using Dexcom G6 (DG6) and FreeStyle Libre 1 (FSL1). Yellow Springs Instruments 2900 was used as PG reference method, enabling mean absolute relative difference (MARD) assessment for each phase and Clarke error grid analysis for each day. Results: Exercise had a negative effect on FSL1 accuracy in phase 2 and 3 compared to rest (ΔMARD = +5.3 percentage points [(95% CI): 1.6, 9.1] and +13.5 percentage points [6.4, 20.5], respectively). In contrast, exercise had a positive effect on DG6 accuracy during phase 2 and 4 compared to rest (ΔMARD = -6.2 percentage points [-11.2, -1.2] and -8.4 percentage points [-12.4, -4.3], respectively). Clarke error grid analysis showed a decrease in clinically acceptable treatment decisions during Clamp-exercise for FSL1 while a contrary increase was observed for DG6. Conclusion: Physical exercise had clinically relevant impact on the accuracy of the investigated continuous glucose monitoring systems and their ability to accurately detect hypoglycemia.
Asunto(s)
Monitoreo Continuo de Glucosa , Diabetes Mellitus Tipo 1 , Ejercicio Físico , Técnica de Clampeo de la Glucosa , Hipoglucemia , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Glucemia/análisis , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/complicaciones , Hipoglucemia/sangre , Hipoglucemia/diagnóstico , Hipoglucemia/etiologíaRESUMEN
CONTEXT: People with type 1 diabetes (T1D) are at increased risk of thrombosis, however, the underlying mechanisms remain unclear. Hypoglycemia induced at rest can induce coagulation activation, but little is known about the hemostatic effects of exercise-related hypoglycemia in people with T1D. OBJECTIVE: We compared hemostatic profiles of individuals with T1D with healthy controls and explored hemostatic effects of hypoglycemia, induced with or without exercise, in participants with T1D. METHODS: Thrombelastography (TEG) was used for a baseline hemostatic comparison between fifteen men with T1D and matched healthy controls. In addition, the participants with T1D underwent two euglycemic-hypoglycemic clamp days in a randomized, crossover fashion. Hypoglycemia was induced with the participants at rest (Hypo-rest) or during exercise (Hypo-exercise). TEG provides data on the rate of coagulation activation (R-time), the rate of clot formation (K-time, α-Angle), the maximum clot amplitude (MA), the functional fibrinogen contribution to the clot strength (MA-FF) and the fibrinolysis (LY-30). RESULTS: The T1D group exhibited shorter R-time and K-time and a greater α-Angle compared to the controls. During the clamp experiments, Hypo-exercise induced an increased clot strength (MA) with a mean difference from baseline of 2.77 mm [95% confidence interval 2.04; 3.51] accompanied with a decreased fibrinolysis (LY-30) of -0.45 percentage points [-0.60; -0.29]. Hypo-rest resulted in increased functional fibrinogen (MA-FF) of 0.74 mm [0.13; 1.36] along with an increased fibrinolysis (LY-30) of 0.54 percentage points [0.11; 0.98]. CONCLUSION: Individuals with T1D exhibit a hypercoagulable hemostatic profile compared to healthy controls and exercise-related hypoglycemia may increase the susceptibility to thrombosis via both procoagulant and antifibrinolytic effects.