Effect of blood gas derangement on QTc dispersion in severe chronic obstructive pulmonary disease: evidence of an electropathy?
ABSTRACT Cardiac arrhythmias are common in patients with respiratory failure from chronic obstructive pulmonary disease (COPD). Several factors may be potentially arrhythmogenic in these patients, including hypoxemia and hypercapnia, acid-base disturbances, cor pulmonale and the use of digitalis, methylxanthines, and sympathomimetic drugs. The aim of this study was to examine the effect of hypoxemia and hypercapnia on QTc dispersion (QTcD) in COPD patients, and to evaluate the effect of a partial correction of one of these pro-arrhythmic factors, the hypoxemia, on Qtc dispersion, as QTcD has been proposed as a marker of heterogeneous repolarization and, hence of ventricular electrical instability. We showed that in 15 hypoxemic/hypercapnic COPD patients, compared to 20 controls, the QTcD was significantly higher (49.7 +/- 10.6 vs. 22.9 +/- 9.8 ms; P = 0.0001); furthermore, after only 24 h of oxygen therapy, and hence after a partial correction of hypoxemia, there was a significant reduction in QTcD in COPD patients (49.7 +/- 10.6 vs. 36.3 +/- 10.1 ms; P = 0.018). The data of the present study suggest that the increase in QTcD may be an early marker of a blood gas mediated electropathy in COPD patients.
- [show abstract] [hide abstract]
ABSTRACT: OBJECTIVE: The aim of this research was to investigate relationships between cognitive function and non-invasive, repeatable cardiac parameters in elderly subjects suffering from mild cognitive impairment (MCI) or Alzheimer's disease (AD). METHODS: Two hundred and twenty-four community-living elderly subjects, 31 AD patients, 77 MCI patients, and 116 cognitively normal subjects (CNS), were evaluated for cognitive abilities (Mini Mental State Examination score (MMSE)) and for electrocardiographic [corrected heart rate QT interval dispersion (QTcD)] and echocardiographic [Left ventricular ejection fraction (LVEF)] parameters. RESULTS: Mean values of LVEF were not significantly different between the three groups; QTcD mean values were significantly lower in CNS group than in subjects with MCI and AD. The Pearson Product Moment Correlation test, carried out in the three study groups, showed a significant inverse correlation between QTcD and MMSE score (r = -0.357; p < 0.01) in the group of MCI patients, only. In multivariable-adjusted linear regression tests, QTcD (p = 0.030) and education (p = 0.021) are associated with MMSE score in MCI group. Only the parameter of education appears to predict MMSE in CNS group; none of these parameters appear to predict MMSE in the group of patients with AD. CONCLUSION: The association between QTcD and MMSE requires cautious interpretation and further extensive investigation. However, if confirmed by longitudinal studies, the finding could play a role in the management of the subjects with MCI. Copyright © 2012 John Wiley & Sons, Ltd.International Journal of Geriatric Psychiatry 09/2012; · 2.98 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Previous large epidemiological studies reporting on the association between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases mainly focussed on prevalent diseases rather than on the incidence of newly diagnosed cardiovascular outcomes. We used the UK-based General Practice Research Database (GPRD) to assess the prevalence and incidence of cardiovascular diseases in COPD patients aged 40-79 between 1995 and 2005, and we randomly matched COPD-free comparison patients to COPD patients. In nested-case control analyses, we compared the risks of developing an incident diagnosis of cardiac arrhythmias, venous thromboembolism, myocardial infarction, or stroke between patients with and without COPD, stratifying the analyses by COPD-severity, using COPD-treatment as proxy for disease severity. We identified 35,772 patients with COPD and the same number of COPD-free patients. Most cardiovascular diseases were more prevalent among COPD patients than among the comparison group of COPD-free patients. The relative risk estimates of developing an incident diagnosis of cardiac arrhythmia (OR 1.19, 95% CI 0.98-1.43), deep vein thrombosis (OR 1.35, 95% CI 0.97-1.89), pulmonary embolism (OR 2.51, 95% CI 1.62-3.87), myocardial infarction (OR 1.40, 95% CI 1.13-1.73), or stroke (OR 1.13, 95% CI 0.92-1.38), tended to be increased for patients with COPD as compared to COPD-free controls. The findings of this large observational study provide further evidence that patients with COPD are at increased risk for most cardiovascular diseases.European Journal of Epidemiology 02/2010; 25(4):253-60. · 5.12 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The electrical activity of atria can be demonstrated by P waves on surface electrocardiogram (ECG). Atrial electromechanical delay (AEMD) measured with tissue Doppler imaging (TDI) echocardiography can be a useful non-invasive method for evaluating atrial conduction features. We investigated whether AEMD is prolonged in patients with chronic obstructive pulmonary disease (COPD). Study consisted of 41 (15 female, 26 male, mean age 62 + 12 years) patients with COPD and 41 healthy subjects. Pulmonary function tests,12 lead surface ECG and echocardiographic examination were performed and recorded. P wave changes on surface ECG, minimum (P (min)) and maximum (P (max)) duration of P wave and its difference as P wave dispersion (P (wd)) were measured and recorded. Atrial electromechanic delay (AEMD) was calculated from colored-TDI recordings. Pulmonary functions were significantly lower in COPD group than the control group as expected. Right atrial areas and pulmonary arterial systolic pressures (PAP) were significantly higher in COPD group than the controls (right atrial area: 11.9 ± 3.4 cm(2) and 8.2 ± 2.2 cm(2), p < 0.0001 and PAP: 38.4 ± 12.2 and 19.0 ± 3.2 mmHg p < 0.0001, respectively). P wave intervals on surface ECG were significantly increased in COPD patients than the control group (P (max): 105 ± 11 and 90 ± 12 ms, p < 0.0001; P (min): 60 ± 12 and 51 ± 10 ms, p = 0.003 and P (wd): 39 ± 10 and 31 ± 7 ms, p < 0.0001). According to the AEMD measurements from different sites by TDI, there was a significant delay between the onset of the P wave on surface ECG and the onset of the late diastolic wave in patients with COPD when compared with controls measured from tricuspid lateral septal annulus (TAEMD) (COPD: 41.3 ± 9.8 ms, control: 36 ± 4.5 ms; p = 0.005). There was a positive correlation between TAEMD and right atrial area (r = 0.63, p < 0.0001) and also between TAEMD and PASP (r = 0.43, p < 0.0005) and a negative correlation between TAEMD and forced expiratory volume (FEV1) (r = -0.44, p = 0.04). Right atrial electromechanical delay is significantly prolonged in patients with COPD. The right atrial area, PAP and FEV1 levels are important factors of this prolonged delay. Also the duration of atrial depolarization is significantly prolonged and propagation of depolarization is inhomogeneous in patients with COPD. These may be the underlying mechanisms to explain the atrial premature beats, multifocal atrial tachycardia, atrial flutter and fibrillation often seen in patients with COPD secondary to these changes.Clinical Research in Cardiology 03/2012; 101(8):599-606. · 3.67 Impact Factor