Clinical trial NCT03291145: Exploring Mechanisms and Morphology of QT Interval Prolongation
Official title: Exploring Mechanisms and Morphology of QT Interval Prolongation - An Inheritable as Well as an Inducible Phenomenon
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Long Qt Syndrome 1-2
Sudden Cardiac Death
Keywords: Long QT Syndrome
Lead sponsor: Herlev and Gentofte Hospital
Sponsor class: OTHER
First posted: 2017-09-25
Enrollment: 28
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The projects will try and optimise the risk stratification for patients with Long QT syndrome by investigating how the exposure of physical and acoustic stress will affect the QT-dynamics and if beta blockers protect against arrhythmias by suppressing this dynamic QT-prolongation. Furthermore, the project will investigate the effects of Spironolactone on the QT-dynamics tested by "Brisk Standing".

First, patients are tested with known arrhythmic triggers and they are then administered thier normal dose of beta blockers. Hereafter, "Brisk Standing" test is performed and the patients are on Spironolactone for seven days. After seven days treatment the "Brisk Standing" is repeated.

Detailed description: The aim of the projects is to try and optimise the risk stratification for patients with Long QT syndrome by investigating how the exposure of physical and acoustic stress will affect the QT-dynamics and if beta blockers protect against arrhythmias by suppressing this dynamic QT-prolongation. Furthermore, the project will investigate the effects of Spironolactone on the QT-dynamics tested by "Brisk Standing".

First, patients are tested with known arrhythmic triggers and they are then administered thier normal dose of beta blockers. Hereafter, "Brisk Standing" test is performed and the patients are on Spironolactone for seven days. After seven days treatment the "Brisk Standing" is repeated.

Eligibility criteria: Inclusion Criteria:

* Verified Long QT syndrome mutation, subtype 1 or 2.
* over 18 years of age

Exclusion Criteria:

* Atrioventricular block,
* Left bundle branch block,
* Left ventricular hypertrophy,
* Pace rhythm,
* ST-deviations \>1 mm),
* Left ventricular ejection fraction \<50 % and significant valvulopathy,
* Unstable psychiatric disease
* Unstable cardiovascular disease.

Primary outcomes:
measure: QTc
timeFrame: 7 days
Secondary outcomes:
Other outcomes:
Locations:
city: Herlev
country: Denmark
facility: Herlev-Gentofte Hospital
state: Copenhagen
Study officials:
References:
citation: Marstrand P, Almatlouh K, Kanters JK, Graff C, Christensen AH, Bundgaard H, Theilade J. Effect of moderate potassium-elevating treatment in long QT syndrome: the TriQarr Potassium Study. Open Heart. 2021 Sep;8(2):e001670. doi: 10.1136/openhrt-2021-001670.
citation: Marstrand P, Almatlouh K, Kanters JK, Graff C, Christensen AH, Bundgaard H, Theilade J. Long QT syndrome type 1 and 2 patients respond differently to arrhythmic triggers: The TriQarr in vivo study. Heart Rhythm. 2021 Feb;18(2):241-249. doi: 10.1016/j.hrthm.2020.08.017. Epub 2020 Aug 31.