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. 2025 Apr 8;14(8):2540.
doi: 10.3390/jcm14082540.

Clinical, Electrical, and Mechanical Parameters in Potassium Channel-Mediated Congenital Long QT Syndrome

Neringa Bileišienė  1   2 , Violeta Mikštienė  2   3 , Eglė Preikšaitienė  2   3 , Ieva Kažukauskienė  4 , Gabrielė Tarutytė  2   5 , Diana Zakarkaitė  1   2 , Rita Kramena  2 , Germanas Marinskis  1   2 , Audrius Aidietis  1   2 , Jūratė Barysienė  1   2
Affiliations

Clinical, Electrical, and Mechanical Parameters in Potassium Channel-Mediated Congenital Long QT Syndrome

Neringa Bileišienė et al. J Clin Med. .

Abstract

Background: Congenital long QT syndrome (LQTS) is a rare cardiac disorder caused by repolarization abnormalities in the myocardium that predisposes to ventricular arrhythmias and sudden cardiac death. Potassium channel-mediated LQT1 and LQT2 are the most common types of channelopathy. Recently, LQTS has been acknowledged as an electromechanical disease. Methods: A total of 87 genotyped LQT1/LQT2 patients underwent cardiac evaluation. A comparison between LQT1 and LQT2 electrical and mechanical parameters was performed. Results: LQT2 patients had worse electrical parameters at rest: a longer QTc interval (p = 0.007), a longer Tpe in lead V2 (p = 0.028) and in lead V5 (p < 0.001), and a higher Tpe/QT ratio in lead V2 (p = 0.011) and in lead V5 (p = 0.005). Tpe and Tpe/QT remained significantly higher in the LQT2 group after brisk standing. Tpe was longer in LQT2 patients compared with LQT1 patients during peak exercise (p = 0.007) and almost all recovery periods in lead V2 during EST. The mid-cavity myocardium mean radial contraction duration (CD) was longer in LQT2 patients (p = 0.02). LQT2 patients had a longer mean radial CD in mid-septal (p = 0.015), mid-inferior (p = 0.034), and mid-posterior (p = 0.044) segments. Conclusions: Potassium channel-mediated LQTS has different effects on cardiac electromechanics with a more pronounced impact on LQT2 patients. Tpe was more prominent in the LQT2 cohort, not only at rest and brisk standing but also during EST exercise and at recovery phases. The altered mean radial CD in the mid-cavity myocardium was also specific for LQT2 patients.

Keywords: LQT1; LQT2; echocardiography; electrocardiogram; electromechanical; long QT syndrome.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
ROC curves for (a) Tpe in ms and (b) Tpe/QT values in precordial V2 and V5 leads.
Figure 2
Figure 2
Mean QT intervals using the Bazett formula (ms) [top] and mean heart rate (bpm) [under] plotted against time during EST. Values marked in red differed significantly (p ≤ 0.05).
Figure 3
Figure 3
ROC curve for QTcB (ms) during 3rd minute of recovery during EST.
Figure 4
Figure 4
Mean Tpe plotted against time during EST. Values marked in red differed significantly (p ≤ 0.05).
Figure 5
Figure 5
Box plots showing difference in electromechanical window between patients in LQT1 and LQT2.
See this image and copyright information in PMC

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