QT Adaptation and Intrinsic QT Variability in Congenital Long QT Syndrome

Srikanth Seethala; Prabhpreet Singh; Vladimir Shusterman; Margareth Ribe; Kristina H Haugaa; Jan Němec

doi:10.1161/JAHA.115.002395

Back

QT Adaptation and Intrinsic QT Variability in Congenital Long QT Syndrome

Journal article

Open access

QT Adaptation and Intrinsic QT Variability in Congenital Long QT Syndrome

Srikanth Seethala, Prabhpreet Singh, Vladimir Shusterman, Margareth Ribe, Kristina H Haugaa and Jan Němec

Journal of the American Heart Association, Vol.4(12), e002395

12/16/2015

DOI: 10.1161/JAHA.115.002395

PMCID: PMC4845278

PMID: 26675252

Files and links (1)

url

https://doi.org/10.1161/JAHA.115.002395View

Published (Version of record) Open Access

Abstract

Increased variability of QT interval (QTV) has been linked to arrhythmias in animal experiments and multiple clinical situations. Congenital long QT syndrome (LQTS), a pure repolarization disease, may provide important information on the relationship between delayed repolarization and QTV. Twenty-four-hour Holter monitor tracings from 78 genotyped congenital LQTS patients (52 females; 51 LQT1, 23 LQT2, 2 LQT5, 2 JLN, 27 symptomatic; age, 35.2±12.3 years) were evaluated with computer-assisted annotation of RR and QT intervals. Several models of RR-QT relationship were tested in all patients. A model assuming exponential decrease of past RR interval contributions to QT duration with 60-second time constant provided the best data fit. This model was used to calculate QTc and residual "intrinsic" QTV, which cannot be explained by heart rate change. The intrinsic QTV was higher in patients with long QTc (r=0.68; P<10(-4)), and in LQT2 than in LQT1/5 patients (5.65±1.28 vs 4.46±0.82; P<0.0002). Both QTc and intrinsic QTV were similar in symptomatic and asymptomatic patients (467±52 vs 459±53 ms and 5.10±1.19 vs 4.74±1.09, respectively). In LQTS patients, QT interval adaptation to heart rate changes occurs with time constant ≈60 seconds, similar to results reported in control subjects. Intrinsic QTV correlates with the degree of repolarization delay and might reflect action potential instability observed in animal models of LQTS.

Humans

Middle Aged

Adaptation, Physiological - physiology

Male

Long QT Syndrome - physiopathology

Young Adult

Long QT Syndrome - congenital

Adolescent

Electrocardiography

Heart Rate - physiology

Long QT Syndrome - genetics

Adult

Female

Electrocardiography, Ambulatory

Details

Title: Subtitle: QT Adaptation and Intrinsic QT Variability in Congenital Long QT Syndrome
Creators: Srikanth Seethala - Scripps Clinic, San Diego, CA (S.S.) University of Tennessee, College of Medicine, Chattanooga, TN
Prabhpreet Singh - University of Pittsburgh, PA (P.S., J.)
Vladimir Shusterman - University of Iowa, Iowa City, IA (V.S.)
Margareth Ribe - Department of Cardiology, Center for Cardiological Innovation and Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway (M.R., K.H.H.)
Kristina H Haugaa - Department of Cardiology, Center for Cardiological Innovation and Institute for Surgical Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway (M.R., K.H.H.) University of Oslo, Norway (K.H.H.)
Jan Němec - University of Pittsburgh, PA (P.S., J.)
Resource Type: Journal article
Publication Details: Journal of the American Heart Association, Vol.4(12), e002395
DOI: 10.1161/JAHA.115.002395
PMID: 26675252
PMCID: PMC4845278
NLM abbreviation: J Am Heart Assoc
ISSN: 2047-9980
eISSN: 2047-9980
Language: English
Date published: 12/16/2015
Academic Unit: Cardiovascular Medicine; Internal Medicine
Record Identifier: 9984094358902771

Metrics

35 Record Views

8 Times Cited - Web of Science