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Modified Schwartz Score for Long QT Syndrome (LQTS)*

Modified Schwartz Score for Long QT Syndrome (LQTS)*

Criteria

Points

Patient history

Syncope with stress†

2

Syncope without stress†

1

Congenital deafness

0.5‡

Family history

Family member with known LQTS¶

1

Family member with unexplained cardiac death before age 30 years ¶

0.5

Electrocardiography§

QTc ≥ 480 msec

3‡

QTc 460-479 msec

2

QTc 450-459 msec (males only)

1

QTc ≥ 480 msec during 4th minute of recovery from an exercise test

1

Torsades de pointes arrhythmia§

2

T wave alternans

1

Notched T wave in 3 leads

1

Resting heart rate < 2nd percentile for age

0.5

* SCORE: ≤ 1 low probability; 1.5–3 intermediate probability; ≥ 3.5 high probability

† Mutually exclusive (ie, if syncope occurs with stress, no points are given for syncope without stress)

‡ In the modified long QT syndrome diagnostic score:

  • A score ≥ 3.0 is diagnostic of LQTS

  • Congenital deafness is removed as a criterion

  • The score for a QTc ≥ 480 msec is 3.5

  • A pathogenic mutation is added as a criterion, earning 3.5 points

¶ Mutually exclusive

§ If torsades de pointes present, do not score syncope

Data from Schwartz PJ, Crotti L: QTc behavior during exercise and genetic testing for the long-QT syndrome. Circulation. 2011;124:2181-2184. doi: 10.1161/CIRCULATIONAHA.111.062182; Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2018;138(13):e272-e391. doi:10.1161/CIR.0000000000000549; and Zeppenfeld K, Tfelt-Hansen J, de Riva M, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. doi:10.1093/eurheartj/ehac262

* SCORE: ≤ 1 low probability; 1.5–3 intermediate probability; ≥ 3.5 high probability

† Mutually exclusive (ie, if syncope occurs with stress, no points are given for syncope without stress)

‡ In the modified long QT syndrome diagnostic score:

  • A score ≥ 3.0 is diagnostic of LQTS

  • Congenital deafness is removed as a criterion

  • The score for a QTc ≥ 480 msec is 3.5

  • A pathogenic mutation is added as a criterion, earning 3.5 points

¶ Mutually exclusive

§ If torsades de pointes present, do not score syncope

Data from Schwartz PJ, Crotti L: QTc behavior during exercise and genetic testing for the long-QT syndrome. Circulation. 2011;124:2181-2184. doi: 10.1161/CIRCULATIONAHA.111.062182; Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2018;138(13):e272-e391. doi:10.1161/CIR.0000000000000549; and Zeppenfeld K, Tfelt-Hansen J, de Riva M, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. doi:10.1093/eurheartj/ehac262

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