Skip to main content

QTc prolongation in children following congenital cardiac disease surgery

  • Rajesh Punn (a1), John J. Lamberti (a2), Raymond R. Balise (a3) and Stephen P. Seslar (a4)

QTc prolongation has been reported in adults following cardiopulmonary bypass; however, this phenomenon has not been studied in children with congenital cardiac disease. This study's aim was to formally assess QTc in children undergoing cardiac surgery.


Pre-operative and post-operative electrocardiograms during hospital stays were prospectively analysed on 107 consecutive patients under 18 years of age undergoing cardiac surgery. QTc was measured manually in leads II, V4, and V5. Measurements of 440 and 480 milliseconds were used to categorise patients. Peri-procedural data included bypass and cross-clamp time, medications, and electrolyte measurements. Outcome data included arrhythmias, length of mechanical ventilation, and hospital stay. Patients with post-operative new bundle branch block or ventricularly paced rhythm were excluded.


In all, 59 children were included, out of which 26 had new QTc over 440 milliseconds and 6 of 59 had new QTc over 480 milliseconds post-operatively. The mean increase in post-operative QTc was 25 milliseconds, p=0.0001. QTc over 480 was associated with longer cross-clamp time, p=0.003. Other risk factors were not associated with post-operative QTc prolongation. This phenomenon was transient with normalisation occurring in 67% of patients over 60 hours on average. One patient with post-operative QTc over 440 milliseconds developed ventricular tachycardia. There was no correlation between prolonged QTc and duration of mechanical ventilation, or hospital stay.


A significant number of children undergoing cardiac surgery showed transient QTc prolongation. The precise aetiology of QT prolongation was not discerned, though new QTc over 480 milliseconds was associated with longer cross-clamp time. In this cohort, transient QTc prolongation was not associated with adverse sequela.

Corresponding author
Correspondence to: R. Punn, MD, Clinical Assistant Professor, Division of Pediatric Cardiology, Lucile Packard Children's Hospital, Stanford University, 750 Welch Road, Suite number 305, Palo Alto, California 94304, United States of America. Tel: (650) 723 7913; Fax: (650) 725 8343; E-mail:
Hide All
1.Garson A Jr, Dick M 2nd, Fournier A, et al. The long QT syndrome in children. An international study of 287 patients. Circulation 1993; 87: 18661872.
2.Krasner BS, Girdwood R, Smith H. The effect of slow releasing oral magnesium chloride on the QTc interval of the electrocardiogram during open heart surgery. Can Anaesth Soc J 1981; 28: 329333.
3.Bazette H. An analysis of the time-relation of electrocardiograms. Heart 1920; 7: 353367.
4.Postema PG, De Jong JS, Van der Bilt IA, Wilde AA. Accurate electrocardiographic assessment of the QT interval: teach the tangent. Heart Rhythm 2008; 5: 10151018.
5.Berul CI, Sweeten TL, Dubin AM, Shah MJ, Vetter VL. Use of the rate-corrected JT interval for prediction of repolarization abnormalities in children. Am J Cardiol 1994; 74: 12541257.
6.Rautaharju PM, Zhang ZM, Prineas R, Heiss G. Assessment of prolonged QT and JT intervals in ventricular conduction defects. Am J Cardiol 2004; 93: 10171021.
7.Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation 1993; 88: 782784.
8.Priori SG, Schwartz PJ, Napolitano C, et al. Risk stratification in the long-QT syndrome. N Engl J Med 2003; 348: 18661874.
9.Kenigsberg DN, Khanal S, Kowalski M, Krishnan SC. Prolongation of the QTc interval is seen uniformly during early transmural ischemia. J Am Coll Cardiol 2007; 49: 12991305.
10.Kawabata M, Hirao K, Takeshi S, et al. Torsades de pointes related to transient marked QT prolongation following successful emergent percutaneous coronary intervention for acute coronary syndrome. J Electrocardiol 2008; 41: 117122.
11.Bijl M, Verheugt FW. Extreme QT prolongation solely due to reversible myocardial ischemia in single-vessel coronary disease. Am Heart J 1992; 123: 524526.
12.Rebeiz AG, Al-Khatib SM. A case of severe ischemia-induced QT prolongation. Clin Cardiol 2001; 24: 750.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Cardiology in the Young
  • ISSN: 1047-9511
  • EISSN: 1467-1107
  • URL: /core/journals/cardiology-in-the-young
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 1
Total number of PDF views: 12 *
Loading metrics...

Abstract views

Total abstract views: 88 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 19th November 2017. This data will be updated every 24 hours.