Increased Short-Term Beat-to-Beat QT Interval Variability in Patients with Impaired Glucose Tolerance

Abstract

Prediabetic states and diabetes are important risk factors for cardiovascular morbidity and mortality. Determination of short-term QT interval variability (STVQT) is a non-invasive method for assessment of proarrhythmic risk. The aim of the study was to evaluate the STVQT in patients with impaired glucose tolerance (IGT). 18 IGT patients [age: 63 ± 11 years, body mass index (BMI): 31 ± 6 kg/m2, fasting glucose: 6.0 ± 0.4 mmol/l, 120 min postload glucose: 9.0 ± 1.0 mmol/l, hemoglobin A1c (HbA1c): 5.9 ± 0.4%; mean ± SD] and 18 healthy controls (age: 56 ± 9 years, BMI: 27 ± 5 kg/m2, fasting glucose: 5.2 ± 0.4 mmol/l, 120 min postload glucose: 5.5 ± 1.3 mmol/l, HbA1c: 5.4 ± 0.3%) were enrolled into the study. ECGs were recorded, processed, and analyzed off-line. The RR and QT intervals were expressed as the average of 30 consecutive beats, the temporal instability of beat-to-beat repolarization was characterized by calculating STVQT as follows: STVQT = Σ|QTn + 1 − QTn| (30x√2)−1. Autonomic function was assessed by means of standard cardiovascular reflex tests. There were no differences between IGT and control groups in QT (411 ± 43 vs 402 ± 39 ms) and QTc (431 ± 25 vs 424 ± 19 ms) intervals or QT dispersion (44 ± 13 vs 42 ± 17 ms). However, STVQT was significantly higher in IGT patients (5.0 ± 0.7 vs 3.7 ± 0.7, P < 0.0001). The elevated temporal STVQT in patients with IGT may be an early indicator of increased instability of cardiac repolarization during prediabetic conditions.

The relationship between QT interval indices with cardiac autonomic neuropathy in diabetic patients: a case control study

“…The mean ± SD of QTc did not differ significantly between two groups. This finding is consistent with results of Orosz A and Stern K researches which found that the QT interval in DM and pre-DM individuals was no longer than normal individuals [23,24]. However, other researchers have found different results.…”

Transgenic Rabbit Models in Proarrhythmia Research

“…First in the chronic AV-block dog model, then in other animal experimental proarrhythmia models (Thomsen et al, 2004;Lengyel et al, 2007a;Jacobson et al, 2011) and in clinical settings (Hinterseer et al, 2008;Hinterseer et al, 2009;Hinterseer et al, 2010;Oosterhoff et al, 2010), it has been repeatedly shown that STV QT has a higher predictive value for proarrhythmia risk than the overall prolongation of repolarization (QT duration). STV QT has been used in several studies to confirm the safety of different drugs (Oros et al, 2006;Antoons et al, 2010;Varkevisser et al, 2012), to characterize pro-arrhythmic drug effects (Thomsen et al, 2004;Thomsen et al, 2006b;Kristof et al, 2012), and to assess temporal repolarization instability in patients with co-morbidities associated with repolarization disturbances (Orosz et al, 2015a;Orosz et al, 2015b;Orosz et al, 2017).…”

Circadian pattern of short-term variability of the QT-interval in primary prevention ICD patients - EU-CERT-ICD methodological pilot study

“…[ 29 ] Recently, a significant correlation was shown between elevated STV-QT and parameters of sympathetic predominance in patients with impaired glucose tolerance. [ 30 ] A study by Piccirillo et al found a positive relation between the level of anxiety and a high QTVI. [ 31 ] On the other hand, QT variability was significantly reduced after administration of metoprolol or carvedilol compared to placebo in patients with ischemic cardiomyopathy.…”