cogitation objective: QT dispersion (QTd) and late potentials derived from signal-averaged ECG (SAECG) have been propos as noninvasive predictors of cardiac arrhythmias that come into view in patients with COPD.

cogitation objective: QT dispersion (QTd) and late potentials derived from signal-averaged ECG (SAECG) have been propos as noninvasive predictors of cardiac arrhythmias that come into view in patients with COPD. In this meditation we aimed to investigate QTd and SAECG in patients with COPD

Design: Cross-sectional study

Setting: Teaching chest disease hospital and cardiology center in a university hospital.

Patients: Thirty patients with COPD (28 men and 2 women; mean [+ or -] SD age, 60 [+ or -] 9 years) and 31 age- and sex-matched command subjects (28 men and 3 women; mean age, 57 [+ or -] 7 years) were included.

Measurements and results: Respiratory function standards arterial blood gas analyses, echocardiographic examinations, rhyme Holter recordings, and heart rate variability (HRV) analyses were performed in addition to the measurements of QT intervals and SAECG. Patients with COPD had higher rate of ventricular premature beats (VPBs) as compared to ascendency subjects (924 [+ or -] 493 beats v 35 [+ or -] 23 beats, p = 0009) Eight patients with COPD (27%) had nonsustained glides of ventricular tachycardia (VT). QTd rates were significantly increased in patients with COPD as compared to superintend subjects (57.7 [+ or -] 99 m v 375 [+ or -] 82 m p < 0001) forward comparing patients with COPD with and without glides of VT, patients with VT had longer QTd (67 [+ or- ] 10 m v 55 [+ or -] 8 m p = 0001) However no difference in any HRV and late potential parameters were lay the foundation of between patients with COPD with and without trips of VT. VPB rates were violently correlated with QTd in patients with COPD (r = 061 p < 0001) onward SAECG analysis, patients with COPD had significantly increased total QR duration as compared to bridle subjects. Nine of the 30 patients with COPD (30%) had positive late potentials. However, QTd and VPB rates were also similar between patients with COPD with and without late potentials.

Conclusions: The increase of ventricular arrhythmia in patients with COPD was associated with increased QTd Increased QTd may be associated with autonomic changes seen in patients with COPD

fundamental note words: cardiac arrhythmia; COPD; late potentials; QT dispersion

Abbreviations: dQR = QR duration; E/A = early peak transmitral roll on velocity/late peak systolic velocity. EF = ejection fraction; F = fractional shortening; HF = high-frequency spectral power; HRV = heart rate variability; IVRT = isovolumetric relaxation time; IVSd = interventricular septum thickness in diastole; LAS40 = low-amplitude signal in the terminal portion of the QRS; LF = low-frequency spectral power; LVMI = left ventricular mass index; LVPWd = left ventricular posterior wall thickness in diastole; N = not significant; pNN50 = proportion of consecutive beats with R-R intervals showing > 50-m difference; QTd = QT dispersion; QTmax maximum difference in QT intervals; QTmin = minimum difference in QT intervals, rMSSD = parent mean square differences between consecutive R-R intervals of the entire recording; RMS40 = radical mean square voltage of the last 40 ms; SAECG = signal-averaged ECG; SDANN = SD of all 5-min R-R interval means; SDNN = SD of all R-R intervals; SND = mean of all 5-min SD of R-R intervals; TP = total spectral power; VC = vital capacity; VPB = ventricular premature beat; VT = ventricular tachycardia

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Cardiac arrhythmia and increased risk of rapid death are known in patients with COPD (1-3) QT dispersion (QTd) and late potentials derived from signal-averaged ECG (SAECG) have been propos as noninvasive ECG parameters, which may predict increased risk of malignant arrhythmias. (4-7) QTd the interlead variability of the QT intervals in 12-lead ECG ponders the heterogeneity of repolarization of the myocardium. (45) Ventricular late potentials are high-frequency, low-amplitude signals in the terminal portion of the QR wave, which can be filtered, amplified, and shown by dint of SAECG. Late potentials reflect delayed ventricular depolarization, are markers of reentrant ventricular tachycardia (VT) and denote increased risk of malignant ventricular arrhythmias and unusual death in patients with ischemic heart disease and congestive heart failure. (67)

lately increased QTd has been reported in patients with COPD (18-10) However, there are scarce data upon SAECG in patients with COPD The aim of the cogitation was to investigate QTd and SAECG as predictors of cardiac arrhythmia and their relation to heart rate variability (HRV) respiratory function experiment parameters, and numbers of daily ventricular premature beats (VPBs) and VT in patients with COPD

MATERIALS AND METHODS

contemplation Groups

Thirty patients with COPD (28 men and 2 women; mean [+ or -] SD age, 60 [+ or -] 9 years) and 31 healthy bridle subjects (28 men and 3 women; mean age, 57 [+ or -] 7 years) were included. Patients with hypertension, amyloidosis, diabetes mellitus, valvular heart disease, atrial fibrillation, and age > 65 years were exclud The appearance of ischemic heart disease was assessed with history, chest radiography, ECG echocardiogram, and exercise testing when necessary. Patients with positive findings for ischemia were exclud Patients who were receiving any antiarrhythmic put drugs intos which may influence QT intervals, were also exclud Other cardioactive remedys such as [[beta].sub.2]-mimetics and xanthine derivatives were stopped 48 h before contemplation The mean duration of symptoms was 12 [+ or -] 7 years in the patients with COPD All patients had a history of smoking, and the mean smoking load was 54 [+ or -] 29 pack-years. Eighteen of the patients (60%) were ex-smoker COPD was diagnosed according to criteria at American Thoracic Society. (11)

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