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

NCT02581241 | Completed

• 1 other identifier: TASMC-15-EC-0379-15-CTIL
• Study Type: interventional
• Target: 5
• Locations: 1 country
• Sites: 1

Brief 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

Keywords

QT interval prolongation

Outcome Measures

Primary Outcomes (1)

• ECG measurements of QT before and during stand up test

  ECG measurements of QT and RR before and during stand up test. measured in msec units

  12 months

Study Arms (2)

drug-induced long QT syndrome

EXPERIMENTAL

20 adults aged above 18 years which were hospitalized in Tel Aviv medical center between January 2013 and June 2015 due to drug-induced long QT syndrome and the associated torsades de pointes, have no exclusion criteria and provide informed consent to participate in the study. Interventions. 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

Device: tilt table

control

ACTIVE COMPARATOR

20 adults aged above 18 years which were hospitalized in Tel Aviv medical center between January 2013 and June 2015 and were treated with specific drugs (antibiotics) that potentially prolong the QT interval but they do not have drug-induced long QT syndrome, have no exclusion criteria and provide informed consent to participate in the study. Interventions. 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

Device: tilt table

Interventions

tilt table DEVICE

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

control; drug-induced long QT syndrome

Eligibility Criteria

• Age: 18 Years - 99 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• age above 18 years
• were hospitalized in Tel Aviv medical center between January 2013 and June 2015 due to drug-induced long QT syndrome and the associated torsades de
• were treated with specific drugs (antibiotics) that potentially prolong the QT interval (only for control group)

You may not qualify if:

• Subjects with an inability to communicate well with the investigators (i.e., language problem, poor mental development or impaired cerebral function).
• Subjects with any acute medical situation (e.g. acute infection) within 48 hours of study start, which is considered of significance by Investigator.
• Subjects who are non-cooperative or unwilling to sign consent form.

Sponsors & Collaborators

• Tel-Aviv Sourasky Medical Center: lead

Study Sites (1)

Sourasky medical center (Ichilov)

Tel Aviv, Israel

Location

MeSH Terms

Conditions

Long QT Syndrome

Interventions

Tilt-Table Test

Condition Hierarchy (Ancestors)

Arrhythmias, Cardiac; Heart Diseases; Cardiovascular Diseases; Cardiac Conduction System Disease; Heart Defects, Congenital; Cardiovascular Abnormalities; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diagnostic Techniques, Cardiovascular; Diagnostic Techniques and Procedures; Diagnosis

Study Officials

• Udi Chorin, MD

  Tel Aviv MC

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 8, 2015
• First Posted: October 20, 2015
• Study Start: January 1, 2016
• Primary Completion: August 17, 2017
• Study Completion: August 23, 2017
• Last Updated: February 15, 2018

Record last verified: 2018-02

Data Sharing

• IPD Sharing: Will not share

Locations

IL (1)