Inaccurate electrocardiographic interpretation of long QT: the majority of physicians cannot recognize a long QT when they see one.
BACKGROUND
Physicians in all fields of medicine may encounter patients with long QT syndrome (LQTS). It is important to define the percentage of physicians capable of distinguishing QT intervals that are long from those that are normal because LQTS can be lethal when left untreated.


OBJECTIVE
The purpose of this study was to define the percentage of physicians in the different disciplines of medicine who can recognize a long QT when they see one.


METHODS
We presented the ECGs of two patients with LQTS and two healthy females to 902 physicians (25 world-renowned QT experts, 106 arrhythmia specialists, 329 cardiologists, and 442 noncardiologists) from 12 countries. They were asked to measure the QT, calculate the QTc (the QT interval corrected for the heart rate), and determine whether the QT is normal or prolonged.


RESULTS
For patients with LQTS, >80% of arrhythmia experts but <50% of cardiologists and <40% of noncardiologists calculated the QTc correctly. Underestimation of the QTc of patients with LQTS and overestimation of the QTc of healthy patients were common. Interobserver agreement was excellent among QT experts, moderate among arrhythmia experts, and low among cardiologists and noncardiologists (kappa coefficient = 0.82, 0.44, and < 0.3, respectively). Correct classification of all QT intervals as either "long" or "normal" was achieved by 96% of QT experts and 62% of arrhythmia experts, but by only <25% of cardiologists and noncardiologists.


CONCLUSIONS
Most physicians, including many cardiologists, cannot accurately calculate a QTc and cannot correctly identify a long QT.
Viskin
Sami
S
Department of Cardiology, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel. saviskin@tasmc.health.gov.il
Rosovski
Uri
U
Sands
Andrew J
AJ
Chen
Edmond
E
Kistler
Peter M
PM
Kalman
Jonathan M
JM
Rodriguez Chavez
Laura
L
Iturralde Torres
Pedro
P
Cruz F
Fernando E S
FE
Centurión
Osmar A
OA
Fujiki
Akira
A
Maury
Philippe
P
Chen
Xiaomin
X
Krahn
Andrew D
AD
Roithinger
Franz
F
Zhang
Li
L
Vincent
G Michael
GM
Zeltser
David
D
D002309:Cardiology / Q000592:standards; D002983:Clinical Competence; D003951:Diagnostic Errors; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data