Download Characterization of short QTc interval in Emergency Department

Washington University School of Medicine
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Conference Abstracts and Posters
Division of Emergency Medicine/Emergency Care
Research Section
2012
Characterization of short QTc interval in
Emergency Department patients
Peta-Gay Nolan
Washington University School of Medicine in St. Louis
Stacey House
Washington University School of Medicine in St. Louis
S. Eliza Halcomb
Washington University School of Medicine in St. Louis
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Recommended Citation
Nolan, Peta-Gay; House, Stacey; Halcomb, S. Eliza, "Characterization of short QTc interval in Emergency Department patients"
(2012). Conference Abstracts and Posters. Paper 15. http://digitalcommons.wustl.edu/em_conf/15
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CHARACTERIZATION OF SHORT
QTC INTERVAL IN EMERGENCY
DEPARTMENT PATIENTS
Peta-Gay Nolan MD
Stacey House MD, PhD
S. Eliza Halcomb MD
Washington University in St. Louis School of Medicine
Society for Academic Emergency Medicine
Great Plains Regional Research Forum
St. Louis, MO. September 2012
© Stacey House, 2012
Contributors to Short QTc Interval
 Congenital
 Short
QTc Syndrome, <300ms
 channelopathy with gain of function genetic mutations
 Prescriptions
 Thiazides
 Lithium
 Digoxin
 Lab
abnormalities
 Hypercalcaemia
 Hypokalemia
Complications of Short QTc Interval
Early
repolarization
Atrial fibrillation
Atrial flutter
Ventricular fibrillation
Sudden death
Inducible ventricular fibrillation
Treatment of Short QTc Syndrome
Implantable
cardioverter/defibrillator
Hydroquindine (prolongs QT)
Objective

The study objective was to characterize the ED
population with Short QTc Interval.
 Electrolyte abnormalities
 Temperature
 Chief complaints
 Presenting symptoms
 Medications
Method
Retrospective review of all ED patients who received an
EKG from December 1, 2008 to November 30, 2009
 Inclusion Criteria

 QTC

≤ 390 ms
Exclusion Criteria
 Bradycardia
(HR < 60 bpm)
 Tachycardia (HR >100 bpm)
 QRS >120 ms
 Non-sinus rhythm
 Left without being seen
Patient Enrollment
Excluded Patients
Bradycardia
Tachycardia
Non-sinus rhythm
Paced rhythm
QRS > 120 ms
LWBS or AMA
27,119 Patients
26,579 pts (98%)
QTc > 390 ms
540 pts (2%)
QTc ≤ 390 ms
265 pts (49%)
Excluded
275 pts (51%)
Eligible
211 pts (77%)
QTc 380-390 ms
% of all pts
184 pts
28 pts
62 pts
24 pts
8 pts
13 pts
0.8%
48 pts (17%)
QTc 370-379 ms
0.2%
16 pts (6%)
QTc ≤ 369 ms
0.1%
Results


These pts were 40±19 years old
Male - 73%, 95%CI 68-78%.
Comorbidities
0.35
0.3
Proportion Present
0.25
0.2
0.15
0.1
0.05
0
Htn
DM
CHF
CAD/MI
Pacemaker/AICD
Arrhythmia
Psych
Drug Abuse
HIV
Presenting Symptoms
0.7
0.6
Proportion Present
0.5
0.4
0.3
0.2
0.1
0
Chest Pain
SOB
Lightheaded/dizzy
Syncope
Ingestion
Palpitations
Fatigue/weakness
Seizure
Results



15% (95%CI 10-20%) had abnormal serum
potassium.
13% (95%CI 9-18%) had abnormal serum calcium.
2% (95%CI 0.5-3.9%) were hyperthermic.
Results



Only 3% (95%CI 1-5%) were on home medications
which shortened QTc interval including <1% on
Digoxin, the most commonly described cause of
medication-induced short QTc.
67% (95%CI 62-73%) were discharged from the
ED.
There were no significant differences among the
different length QTc groups with regards to
comorbidities, symptoms, electrolyte abnormalities,
QTc shortening medications, or disposition.
Discussion




Shortened QTc interval occurs in 2% of ED patients
<0.1% have QTc<369 ms
Very small portion with short QTc interval also have
hypercalcaemia, hyperthermia, and/or Digoxin
therapy.
As the majority of these patients are discharged to
home, further studies are needed to determine the
rates of cardiac events in patients with shortened
QTc interval.
References






Panicker et al, 2012. Early repolarization and short qt interval in healthy subjects.
Heart rhythm, vol 9, no 8. 1265-1271.
Koboza et al. Identifying risk of cardiac events in short QT syndrome. Heart Rhythm,
vol 9, No1 , January 2012 . Pages 76-77
Couderc et al. Short and long Qt syndrome: does QT length really matter? Journal
of Electrocardiology43 (2010)396-399
Viskin, S. 2009. The Qt interval: Too long, too short or just right. Heart Rhythm, vol 6,
no 5, May 2009
Miyamoto , A. et al. Clinical and electrocardiographic characteristics of patients
with short Qt interval in a large hospital-base population. Heart rhythm, vol9, No1,
January 2012. pages 66-74
Bjerregaard, P. short QT interval in clincal practice. Journal of electrocardiology 43
(2010) 390-395