[Significance of QT interval as a premonitory sign of severe ventricular arrhythmia in the early phase of myocardial infarct].
In order to evaluate the relationship between the length of the corrected QT interval (QTc), calculated according to Bazett's formula, and the incidence of ventricular fibrillation (V.F.) in the early phase of acute myocardial infarction (A.M.I.), the QTc interval was measured in 494 patients (mean age 66.42 +/- 11 years; 357 males and 137 females) assisted by the Mobile Coronary Care Unit of Florence. A.M.I. was anterior in 269 patients, inferior in 177 and non-Q in 34. The QTc interval measured on E.C.G. was recorded within the first hour after the onset of pain in 203 patients and between the first and sixth hour in 291 patients. The QTc interval was also measured in a control group consisting of 96 non A.M.I. patients with no history of coronary artery disease. 43 patients with A.M.I. (8.6%) developed V.F. in the first 24 hours. It was observed that: 1) The QTc interval of patients with A.M.I. was longer than that in patients without A.M.I. (432 +/- 34.18 msec. versus 425.37 +/- 25, p less than 0.02). 2) The QTc interval of patients with A.M.I. who developed V.F. was the same as that of patients with A.M.I. but without V.F., (432.6 +/- 34.18 msec. versus 438.11 +/- 34.13, N.S.). 3) 60.46% of patients with V.F. had a value of QTc less than 440 msec.; the incidence of QTc greater than 440 msec. showed no difference in the groups with or without V.F. (41.86% versus 41.11%). 4) The QTc interval length was greater in anterior than in inferior A.M.I. (435.12 +/- 30.81 msec. versus 429.05 +/- 34.5, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
Giglioli
C
C
Istituto di Clinica Medica I, Università degli Studi di Firenze.
Margheri
M
M
Bartoletti
A
A
Conti
A
A
De Simone
L
L
Fradella
G
G
Mangialavori
G
G
Masini
M
M
Gabbrielli
A
A
Pini
C
C
D000368:Aged; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009203:Myocardial Infarction / Q000150:complications* / Q000503:physiopathology; D011379:Prognosis; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology
Valore dell'intervallo QT come segno premonitore di gravi aritmie ventricolari nella fase precoce dell'infarto miocardico.