Impaired Ventricular Repolarization Dynamics in Patients with Early Repolarization Syndrome

Abstract

ERS patients had a continuously depressed diurnal and nocturnal adaptation of the QT interval to the heart rate. Such abnormal repolarization dynamics might provide a substrate for reentry and be an important element for developing ventricular fibrillation in the ERS cohort.

Late Gadolinium Enhancement on Cardiac MRI Correlates with QT Dynamicity Represented by QT/RR Relationship in Patients with Ventricular Arrhythmias

“…15 Indeed, β-blockers decrease the QT/RR slope in daytime, and not at nighttime, whereas sympatho-excitation increases the QT/RR slope. 14,25 In our study, in the LGE(+) patients, the QTe day/night and QTa day/night ratios were significantly greater than those in the LGE(−) patients. On the other hand, low QTe day/night and QTa day/night ratios were observed in the LGE(−) patients.…”

“…Indeed, it has been shown that the QT/RR slope is significantly increased in patients with organic heart disease [6][7][8][9][10] whereas it is remarkably decreased in patients with idiopathic ventricular fibrillartion. [11][12][13][14] Thus, both CMR imaging and QT dynamicity are expected to be powerful tools for risk stratification of SCD.…”

Repolarization Characteristics in Early Repolarization and Brugada Syndromes: Insight into an Overlapping Mechanism of Lethal Arrhythmias

“…showed that the QT/heart rate relationship was reduced in BrS patients with L‐type Ca channel mutations compared to the controls. Recently, we have found that compared to a control group, ERS patients have impaired QT‐rate dependence suggesting that such a repolarization heterogeneity may provide a baseline substrate for reentry in ERS patients …”

“…The QT intervals were automatically measured using the CM5 lead, and a visual review was always performed to confirm the correct measurement of the QT intervals. We described the method previously; briefly, after conversion of the 24‐hour recordings into 2,880 templates sampled at 30‐second intervals, the intervals with ≤80% eligible QRS complexes were considered as ectopy or noise and therefore eliminated. The average QT intervals were then measured automatically at the apex (QTa) of the T wave, where the peak of the parabola was fitted to the highest amplitude change after the QRS and, at the end of the T wave (QTe), defined as the intersection of the tangent to the downslope of the T‐wave and the isoelectric line.…”

“…Apart from the J‐wave characteristics, it was reported that, among patients with idiopathic ventricular fibrillation (VF), ER syndrome (ERS) patients have a shorter corrected QT (QTc) interval than non‐ER patients . Recently, we have found that although the QT and QTc intervals do not differ between uneventful ER pattern (ERP) subjects and ERS patients with a history of VF, the latter have a depressed adaptation of the QT interval to the heart rate, which may act as an abnormal substrate …”