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Abnormal QT-Response to the Sudden Tachycardia Provoked by Standing in Individuals With Drug-induced Long QT Syndrome

NCT02581241 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 5

Last updated 2018-02-15

No results posted yet for this study

Summary

The drug-induced long QT syndrome (diLQTS) describes a clinical entity in which administration of a drug produces marked prolongation of the QT interval of the electrocardiogram, associated with the development of a polymorphic ventricular tachycardia, termed torsades de pointes (TdP). The heart rate is an important variable affecting the QT interval. The QT interval normally shortens as the heart rate accelerates; however, the adaptation of the QT interval to sudden heart rate acceleration is not instantaneous. Interestingly, Holter studies show that the speed of response of the QT interval to sudden changes in heart rate (that is, the time it takes the QT interval of a given person to reach a new steady-state QT/RR relation) in healthy persons is highly individual and independent of the basic QTc. The investigators and others recently proposed the "quick standing" test as a simple bedside test that facilitates the diagnosis of congenital LQTS. The test takes advantage of the fact that as one stands up, the heart rate acceleration is abrupt while the associated QT-interval shortening is gradual. As the R-R interval shortens faster than the QT interval, the QT appears to "stretch" toward the next P wave and the corrected QT interval (QTc) for heart rate actually increases momentarily. The phenomenon of "QT stretching" is universal but is exaggerated in patients with LQTS, allowing for a simple but accurate diagnostic test. There is no data on the effects of quick standing on drug-associated form of the long QT syndrome. The investigators therefore propose the present study to better understand who these patients with drug-associated form of the long QT syndrome are and what the significance of their abnormal QT-response is.

Conditions

  • Long QT Syndrome

Interventions

DEVICE

tilt table

Participating individuals will be instructed to rest supine for 10 minutes while repeat electrocardiograms are recorded. They will then be instructed to stand up quickly and remain standing still for 10 minutes. Individuals with inability to stand up quickly will be tested with tilt table test used in our hospital

Sponsors & Collaborators

  • Tel-Aviv Sourasky Medical Center

    lead OTHER_GOV

Principal Investigators

  • Udi Chorin, MD · Tel Aviv MC

Study Design

Allocation
NON_RANDOMIZED
Purpose
DIAGNOSTIC
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
99 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2016-01-01
Primary Completion
2017-08-17
Completion
2017-08-23

Countries

  • Israel

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT02581241 on ClinicalTrials.gov