Voir la suite de cet article sur Cursus ECG
Patient
Young woman 21 years of age, hospitalized after the occurrence of a syncope at the swimming pool rescued by the lifeguard);
Trace
Sinus rhythm with normal PR-interval and normal QRS duration; QT-interval extremely prolonged (absolute value > 650 ms, QTc > 650 ms) with a broad and tall T-wave; genetic analysis confirmed a mutation compatible with a congenital long QT syndrome type 1;
Patient
78-year-old man with multiple risk factors hospitalized for intermittent chest pain;
Trace
Sinus rhythm with narrow QRS; negative, deep and symmetrical T-waves in the inferior leads and from V2 to V6; prolonged QT-interval (QT and QTc > 500 ms); coronary angiography revealed three-vessel disease with severe stenosis of the LAD and right coronary artery;
Exergue
A prolongation of the QT-interval exposes the patient to risk of torsades de pointes and sudden death. Its diagnosis has therefore a significant prognostic importance but is hampered by the difficulty in performing an accurate measurement (high inter-physician variability in the measurement of a same tracing).
As explained previously, a corrected QT-interval is considered long when it exceeds 450 ms in men or 470 ms in women. Values between 430 and 450 ms in men and between 450 and 470 ms in women are considered limit values.