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LETTER TO EDITOR
Year : 2021  |  Volume : 31  |  Issue : 3  |  Page : 187-188

Echocardiography-guided arrhythmic risk prediction in the long qt syndrome


1 Department of Cardiology, Institute of Postgraduate Medical Education and Research, Kolkata, West Bengal, India
2 Department of Cardiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India

Date of Submission06-Mar-2021
Date of Decision06-Mar-2021
Date of Acceptance06-Apr-2021
Date of Web Publication26-Oct-2021

Correspondence Address:
Rakesh Agarwal
Department of Cardiology, SSKM Hospital and Institute of Postgraduate Medical Education and Research, AJC Bose Road, Kolkata - 700 020, West Bengal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcecho.jcecho_20_21

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How to cite this article:
Agarwal R, Gupta A. Echocardiography-guided arrhythmic risk prediction in the long qt syndrome. J Cardiovasc Echography 2021;31:187-8

How to cite this URL:
Agarwal R, Gupta A. Echocardiography-guided arrhythmic risk prediction in the long qt syndrome. J Cardiovasc Echography [serial online] 2021 [cited 2021 Nov 29];31:187-8. Available from: https://www.jcecho.org/text.asp?2021/31/3/187/329308



A 31-year old man presented to the cardiology emergency department with palpitations. An electrocardiogram (ECG) obtained showed polymorphic ventricular tachycardia [Figure 1]a. The patient developed cardiac arrest in the ER and was resuscitated with synchronized direct current cardioversion. A baseline ECG showed prolonged QT (corrected QTc 641 msec by Bazett's formula) [Figure 1]b.
Figure 1: (a) ECG showing VT; (b) Baseline ECG showing Long QT; (c) Electromechanical Window on Echocardiography

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Echocardiography revealed no structural abnormality. However, the electromechanical window (EMW) was found to be negative with a value of − 49 ms [Figure 1]c. Coronary angiography and cardiac magnetic resonance imaging were normal. An implantable cardioverter-defibrillator was implanted and the patient was discharged for routine follow-up.

The electromechanical window refers to the difference between mechanical and electrical systole in the same heart beat. Normally, mechanical systole is longer than electrical systole, resulting in the EMW being a positive number. In patients with long QT syndrome (LQTS), the EMW is negative as the electrical systole becomes prolonged.[1]

Mechanical systole is calculated from beginning of QRS to aortic valve closure. Electrical systole is calculated as the QT interval from the ECG for the same beat. EMW has been shown to outperform QTc in predicting symptomatic patients. Furthermore, the measurement has shown good reliability among different operators. Exercise-induced greater negativity of the EMW and drug response as judged by reduced negative values (i.e., more positive values) may provide assessment of arrhythmic risk in patients with LQTS.[2],[3]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Sugrue A, van Zyl M, Enger N, Mancl K, Eidem BW, Oh JK, et al. echocardiography-guided risk stratification for Long QT syndrome. J Am Coll Cardiol 2020;76:2834-43.  Back to cited text no. 1
    
2.
Vargas HM. A new preclinical biomarker for risk of Torsades de pointes: Drug-induced reduction of the cardiac electromechanical window. Br J Pharmacol 2010;161:1441-3.  Back to cited text no. 2
    
3.
Charisopoulou D, Koulaouzidis G, Rydberg A, Michael HY. Exercise worsening of electromechanical disturbances: A predictor of arrhythmia in long QT syndrome. Clin Cardiol 2019;42:235-40.  Back to cited text no. 3
    


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