Washington University School of MedicineDigital Commons@Becker

Conference Abstracts and Posters Division of Emergency Medicine/Emergency CareResearch Section

2012

QTc prolongation is associated with hypokalemiaand hypocalcemia in emergency departmentpatientsLucy FranjicWashington University School of Medicine in St. Louis

Stacey HouseWashington University School of Medicine in St. Louis

Irena VitkovitskyWashington University School of Medicine in St. Louis

S. Eliza HalcombWashington University School of Medicine in St. Louis

Follow this and additional works at: http://digitalcommons.wustl.edu/em_conf

This Presentation Paper is brought to you for free and open access by the Division of Emergency Medicine/Emergency Care Research Section atDigital Commons@Becker. It has been accepted for inclusion in Conference Abstracts and Posters by an authorized administrator of DigitalCommons@Becker. For more information, please contact engeszer@wustl.edu.

Recommended CitationFranjic, Lucy; House, Stacey L.; Vitkovitsky, Irena; Halcomb, S. Eliza, "QTc prolongation is associated with hypokalemia andhypocalcemia in emergency department patients" (2012). Conference Abstracts and Posters. Paper 12.http://digitalcommons.wustl.edu/em_conf/12

QTc Prolongation is Associated with Hypokalemia and Hypocalcemia in Emergency Department Patients

Stacey L. House MD PhD, Lucy Franjic MD, Irena Vitkovitsky MD, S. Eliza Halcomb MD

Washington University in St. Louis

Division of Emergency Medicine

Lucy Franjic, MD

Society for Academic Emergency Medicine Great Plains Regional Research Forum St. Louis, MO. September 2012 © Stacey House, 2012

Congenital Six types (LQT1-LQT6) Mutations in genes encoding potassium and

sodium transmembrane channel proteins

Acquired Hypokalemia, hypocalcemia, hypomagnesemia, HIV,

myocardial ischemia, numerous medications and drugs (i.e. cocaine)

QTc Prolongation

Increased risk of cardiac arrhythmias Torsades de pointes Ventricular fibrillation Sudden cardiac death

QTc Prolongation

Multiple case reports and small studies in select populations have shown a correlation between electrolyte abnormalities and prolonged QTc interval

Recently Golsari et al evaluated 258 medicine

admit patients and did not find any association between electrolyte abnormalities and QTc interval

Electrolyte Abnormalities and QTc Interval

Retrospective chart review of all ED patients who received an ECG for any reason during the 5 month period of June 2009 – October 2009 at a large volume, tertiary care center.

Inclusion Criteria: Patients with a computer generated QTc ≥ 460 ms.

Exclusion Criteria: Bradycardia (HR < 60 bpm) Tachycardia (HR > 100 bpm) QRS > 120 ms Non-sinus or paced rhythm Patients who left without being seen or against medical advice ED electronic medical records were reviewed for patient demographics, presenting symptoms, comorditities, electrolyte concentrations, medication administration, and disposition. Statistical Analysis - Data is expressed as proportion with 95% confidence intervals. Data was compared among groups using a Chi-squared test.

Methods

2402 pts (20%) QTc ≥ 460 ms

11,359 Patients

8957 pts (80%) Normal QTc

1084 pts (45%) Eligible

1318 pts (55%) Excluded

615 pts (57%) QTc 460-479 ms

274 pts (25%) QTc 480-499 ms

195 pts (18%) QTc 500+ ms

5.4% % of all pts 2.4% 1.7%

Excluded Patients QRS > 120 ms 559 pts Tachycardia 581 pts Bradycardia 151 pts Non-sinus rhythm 239 pts Paced rhythm 182 pts LWBS or AMA 27 pts

RESULTS

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

Chest Pain SOB Lightheaded/dizzy Syncope Ingestion Palpitations Fatigue/weakness Seizure

Prop

ortio

n Pr

esen

t Presenting Symptoms

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Chest Pain SOB Lightheaded/dizzy Syncope Ingestion Palpitations Fatigue/weakness Seizure

Prop

ortio

n Pr

esen

t

460-479 ms480-499 ms500+ ms

Presenting Symptoms

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Htn DM CHF CAD/MI Pacemaker/AICD Arrhythmia Psych Drug Abuse HIV

Prop

ortio

n Pr

esen

t

Past Medical History

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Htn DM CHF CAD/MI Pacemaker/AICD Arrhythmia Psych Drug Abuse HIV

Prop

ortio

n Pr

esen

t

460-479 ms

480-499 ms

500+ ms

Past Medical History

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

[K] obtained [Mg] obtained [Ca] obtained

Prop

ortio

n Pr

esen

t

460-479 ms

480-499 ms

500+ ms

Electrolytes Obtained

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Abnormal [K] Hypokalemia Hyperkalemia

Prop

ortio

n Pr

esen

t

460-479 ms

480-499 ms

500+ ms

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

Abnormal [Ca] Hypocalemia Hypercalcemia

Prop

ortio

n Pr

esen

t

460-479 ms

480-499 ms

500+ ms

Electrolyte Abnormalities and association with QTc interval

* *

*

* p<0.01

Electrolyte Repletion

Potassium was repleted in 66 ± 10% of patients with hypokalemia

Calcium was repleted in 13 ± 5% of patients with hypocalcemia

Magnesium supplementation occurred in only to 2 ± 1% of pts

Only 1 ± 0.6% of pts with QTc > 500 ms had magnesium supplementation

CONCLUSIONS QTc prolongation is associated with hypokalemia

and hypocalcemia in ED patients The decision to replete electrolytes in the ED does

not appear to be related to QTc interval ED patients with prolonged QTc infrequently have

Mg determined and rarely receive prophylactic treatment

Further studies necessary to determine effect of electrolyte repletion and magnesium prophylaxisis in prevention of cardiac dysrhythmias in ED patients

El-Sherif, N. "Electrolyte Disorders and Arrhythmogenesis." Journal of Cardiology. 18 (2011): 233-45.

Golzari, H. “Prolonged QTc intervals on admission electrocardiograms: prevalence and correspondence with admission electrolyte abnormalities.” Connecticut Medicine. 7 (2007): 389-97.

Schulman M. “Hypokalemia and cardiovascular disease.” American Journal of Cardiology. 65 (1990): 4E-9E.

Seftchick, Michael. “The prevalence and factors associated with QTc prolongation among emergency department patients.” Annals of Emergency Medicine. 54 (2009). 763-768.

Taylor, D. “Cocaine induced prolongation of the QT interval.” Emergency Medicine Journal. 21 (2004): 252-253.

Thomspon, RG. “Hypokalemia after resuscitation out-of-hospital ventricular fibrillation.” JAMA. 248 (1982): 2860-2863.

BIBLIOGRAPHY