F004: Comparative analysis of QT dispersion in hypertensive cardiomyopathy. 12 leads or precordials?

QT dispersion (QTd) in 12 lead electrocardiogram try to represents this dispersion of refractoriness and has been identified as a predictor of risk in patients with chronic ischemic heart disease. Most of the published data about QTd has considered the 12 lead electrocardiogram and calculated it as...

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Veröffentlicht in:American journal of hypertension 2000-04, Vol.13 (S2), p.99A-99A
Hauptverfasser: Palma-Gámiz, José Luis, Barbero, Elena, Hernández-Madrid, A., González-Rebollo, V.Barrios, Gonzalo, Peña, Rey, del, Villar, Margarita, Moro, Concepción
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Sprache:eng
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Zusammenfassung:QT dispersion (QTd) in 12 lead electrocardiogram try to represents this dispersion of refractoriness and has been identified as a predictor of risk in patients with chronic ischemic heart disease. Most of the published data about QTd has considered the 12 lead electrocardiogram and calculated it as the difference between the maximum and minimum QT intervals. However, precordial leads could be a better marker of global dispersion because these leads pick up local electrical activity of the heart. We analyzed the electrocardiogram of 42 patients with hypertensive cardiomyopathy (mean age 58±12 years old, 24 female). These patients had both electrocardiographic and echocardiographic diagnosis of left ventricular hypertrophy. The QTd was measured considering: 12 lead ECG (method A), the limb leads (method B) only and the precordials leads only (method C). The QTd measured only with the precordial leads was significantly lower than when measured with the 12 lead ECG. With the standard criteria QTd≥70 msec the method A diagnose 5/42 (11%) patients as positive, and only 1 with B. QTd≥60 and B identified correctly all the five patients. The concordance, evaluated by the kappa statistics was 0.72. Some experimental data has appointed that the use of the bipolar and unipolar limbs leads may be inappropriate to evaluate QTd. The use of only the precordial leads V1–V6 may be more accurate to evaluate the regional cardiac repolarization. We recommend a cut-off of QTd of 60 msec when using only precordial leads. (See Table) 12 LEADS LIMBS PRECORDIALS QTd>50 15 11 10 QTd>60 14 9 9 QTd>70 5 3 1 Mean±sd 50±19* 38±21 40±18 P (t Student) *0.000013
ISSN:0895-7061
1941-7225
1879-1905
DOI:10.1016/S0895-7061(00)00503-3