What does this research mean for the field?

Mechano-electrical feedback induces the most pronounced pro-arrhythmic effects in Long QT Syndrome Type 2, characterized by increased action potential duration and QTc changes compared to Short QT Syndrome Type 1 and wild-type models. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This research focuses on understanding the role of mechano-electrical feedback (MEF) in arrhythmias associated with long QT syndrome type 2 and short QT syndrome type 1.

January 23, 2026Open Access

Mechano-Electrical Feedback in Transgenic Rabbit Models of Long QT Syndrome Type 2 and Short QT Syndrome Type 1.

Key Result

Mechano-electrical feedback induced the most pronounced pro-arrhythmic effects in LQT2, with increased APD and QTc changes compared to SQT1 and wild-type models.

Key Points

This research focuses on understanding the role of mechano-electrical feedback (MEF) in arrhythmias associated with long QT syndrome type 2 and short QT syndrome type 1.
Utilized patch-clamp and fluorescence imaging techniques.
Analyzed action potential duration (APD), Ca²⁺ transients, and contractility in ventricular cardiomyocytes from different rabbit models.
Conducted ex vivo Langendorff experiments to observe pressure impacts on cardiac function.
Developed in silico models to simulate arrhythmia potential with SAC involvement.
LQT2 showed prolonged action potential duration and Ca²⁺ transients compared to wild-type and SQT1.
MEF effects on QTc changes were most significant in LQT2, especially under varying preload conditions.
SAC-blocker GSMTx4 reduced the prolonged APD effects seen in cardiac tissue exposed to increased pressure.
In silico models suggested heightened arrhythmia vulnerability in SQT1 and LQT2 due to MEF.

Structured PICO

Does mechano-electrical feedback induce pro-arrhythmic electrical changes in transgenic rabbit models of SQT1 and LQT2 compared to wild-type?

Population

Transgenic rabbit models of Long QT Syndrome Type 2 (LQT2) and Short QT Syndrome Type 1 (SQT1), wild-type (WT) rabbits, and in silico models of human ventricular cardiomyocytes.

Intervention

Mechanical stretch/mechano-electrical feedback (MEF) via preload/afterload changes and increased right ventricular pressure; application of stretch-activated channel (SAC) blocker GSMTx4.

Comparator

Wild-type (WT) rabbits; baseline conditions without mechanical stretch; conditions without SAC-blocker.

Outcome

Action potential duration (APD), Ca²⁺ transients, contractility, QTc changes, and vulnerability to stretch/MEF-induced arrhythmias.surrogate

Mechano-electrical feedback induces pronounced pro-arrhythmic electrical changes in LQT2 and SQT1 models, partly mediated by stretch-activated channels, highlighting its role in vulnerable electrophysiological substrates.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Aims Electro-mechanical coupling and mechano-electrical feedback (MEF) are crucial for cardiac function, but their pro-arrhythmic roles in short and long QT syndromes (SQT1, LQT2) are not fully understood. We aimed to evaluate MEF-induced electrical changes, their arrhythmic impact, and the involvement of stretch-activated channels (SACs) in transgenic rabbit models of SQT1 and LQT2.Methods And Results Patch-clamp and fluorescence imaging were used to analyze action potential duration (APD), Ca²⁺ transients, and contractility in ventricular cardiomyocytes (VCMs) from LQT2, SQT1, and wild-type (WT) rabbits. LQT2 cells showed prolonged APD and Ca²⁺ transients, increased early afterdepolarizations, Ca²⁺ oscillations, and impaired mechanics compared to WT and SQT1. The cellular electromechanical window (Ca²⁺-transient duration minus APD) was more negative in LQT2 and more positive in SQT1 than in WT. QTc prolonged with preload/afterload increase and decreased with preload reduction across all genotypes, but MEF-induced QTc changes and dispersion were most pronounced in LQT2. Ex vivo Langendorff experiments showed that increased RV pressure prolonged APD and QTc in WT hearts. This was attenuated by SAC-blocker GSMTx4, suggesting a role for SACs in MEF. In silico models of human VCMs including SACs confirmed higher vulnerability to stretch/MEF-induced arrhythmias, including re-entry, in SQT1 and LQT2.Conclusion MEF-induced electrical changes, partly mediated by SACs, occur in WT, SQT1, and LQT2, but MEF-effects are strongest in LQT2. MEF induces pro-arrhythmic effects in silico more prominently in LQT2 and SQT1 than in WT, highlighting the potential pro-arrhythmic role of MEF in a vulnerable electrophysiological substrate.