Washington University School of Medicine Digital Commons@Becker Division of Emergency Medicine/Emergency Care Conference Abstracts and Posters Research Section

2012 QTc prolongation is associated with hypokalemia and hypocalcemia in emergency department patients Lucy Franjic Washington University School of Medicine in St. Louis

Stacey House Washington University School of Medicine in St. Louis

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

This Presentation Paper is brought to you for free and open access by the Division of Emergency Medicine/Emergency Care Research Section at Digital Commons@Becker. It has been accepted for inclusion in Conference Abstracts and Posters by an authorized administrator of Digital Commons@Becker. For more information, please contact [email protected]. QTc Prolongation is Associated with Hypokalemia and Hypocalcemia in Emergency Department Patients

Lucy Franjic, MD

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

Washington University in St. Louis Division of Emergency Medicine

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

 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

Electrolyte Abnormalities and QTc Interval

 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 Methods

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. RESULTS

Excluded Patients 11,359 Patients QRS > 120 ms 559 pts Tachycardia 581 pts Bradycardia 151 pts 8957 pts (80%) 2402 pts (20%) Non-sinus rhythm 239 pts Normal QTc QTc ≥ 460 ms Paced rhythm 182 pts LWBS or AMA 27 pts

1318 pts (55%) 1084 pts (45%) Excluded Eligible

615 pts (57%) 274 pts (25%) 195 pts (18%) QTc 460-479 ms QTc 480-499 ms QTc 500+ ms % of all pts 5.4% 2.4% 1.7% Presenting Symptoms

0.45

0.4

0.35

0.3

0.25

0.2 Proportion Present Proportion

0.15

0.1

0.05

0 Chest Pain SOB Lightheaded/dizzy Syncope Ingestion Palpitations Fatigue/weakness Seizure Presenting Symptoms 0.5

0.45 460-479 ms 480-499 ms 0.4 500+ ms

0.35

0.3

0.25

Proportion Present Proportion 0.2

0.15

0.1

0.05

0 Chest Pain SOB Lightheaded/dizzy Syncope Ingestion Palpitations Fatigue/weakness Seizure Past Medical History

0.9

0.8

0.7

0.6

0.5

0.4 Proportion Present Proportion

0.3

0.2

0.1

0 Htn DM CHF CAD/MI Pacemaker/AICD Arrhythmia Psych Drug Abuse HIV Past Medical History 0.9

0.8 460-479 ms 480-499 ms

0.7 500+ ms

0.6

0.5 Proportion Present Proportion

0.4

0.3

0.2

0.1

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

1

0.9 460-479 ms

0.8 480-499 ms

0.7 500+ ms

0.6

0.5

0.4 Proportion Present Proportion

0.3

0.2

0.1

0 [K] obtained [Mg] obtained [Ca] obtained Electrolyte Abnormalities and association with QTc interval

0.35 460-479 ms 0.45 460-479 ms 0.3 480-499 ms 0.4 480-499 ms 500+ ms * 500+ ms 0.25 0.35 * *

0.3 0.2 0.25

0.15 0.2 Proportion Present Proportion Proportion Present Proportion 0.1 0.15

0.1 0.05 0.05

0 0 Abnormal [K] Hypokalemia Hyperkalemia Abnormal [Ca] Hypocalemia Hypercalcemia

* 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

BIBLIOGRAPHY

 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.