Role of signal-averaged electrocardiography and ventricular late potentials in patients with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for cardiac arrhythmias. Ventricular late potentials (VLP) on signal-averaged electrocardiography (SAECG) are associated with an increased risk for malignant ventricular arrhythmias. Our aim is to investigate the modifications of SAECG parameters and the presence of VLP as possible indicators of proarrhythmic substrate in patients with COPD. We prospectively enrolled 41 consecutive patients in the COPD group and 63 patients without any history of pulmonary disease, matched for age and hypertension history, in the control group. Pulmonary function tests, arterial blood gases, echocardiography, 24-hour Holter monitoring and SAECG were performed. We measured total filtered QRS duration (QRSf), duration of high frequency, low-amplitude signals < 40 V (HFLA40), and root mean square voltage in the last 40 ms (RMS40). VLP were considered if at least two of these parameters were abnormal. Results. We did not register any significant differences in QRSf, HFLA40 or RMS40 between the two groups. In the COPD group there was a non-significant higher percentage of patients with VLP in comparison with the control group. In the COPD patients we registered a significantly higher number of isolated premature ventricular beats and of combined complex ventricular arrhythmias, consisting of polymorphic PVC, couplets, triplets or nonsustained ventricular tachycardias. None of these arrhythmic parameters correlated with SAECG variables or with the presence of VLP. Conclusion. In COPD patients parameters measured on signal-averaged electrocardiography and ventricular late potentials analysis have little value in risk stratification for ventricular arrhythmias.

P Wave Signal-Averaged Electrocardiography in Patients with Chronic Obstructive Pulmonary Disease.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is associated with higher incidence of supraventricular arrhythmias. Atrial late potentials (ALP) detected by P-wave signal-averaged electrocardiography (SAECG) could be useful in detecting the patients at risk for supraventricular arrhythmias. Our objective was to assess the role of P-wave SAECG and ALP detection for arrhythmic risk evaluation of the patients with exacerbated COPD. METHODS: We prospectively included 45 patients with exacerbation of COPD and 58 age- matched patients with no history of pulmonary disease in a control group. We performed pulmonary function tests, arterial blood gases, echocardiography, 24-hour Holter monitoring and P-wave SAECG. We measured filtered P-wave duration (FPD), the root mean square (RMS) voltages in the last 40, 30 and 20 ms of the filtered P-wave (RMS 40, RMS 30 and RMS 20), the root mean square voltage of the filtered P-wave potentials (RMS-p), and the integral of the potentials during the filtered P-wave (Integral-p). ALP was defined as FPD > 132 ms and RMS 20 < 2.3 µV. RESULTS: Isolated atrial premature beats (APB) and supraventricular tachycardias (SVT) were more frequent in the COPD group. There were no significant differences between groups regarding the P wave SAECG parameters. In the COPD group none of the supraventricular arrhythmias was correlated with ALP or any P-wave SAECG parameters. CONCLUSIONS: The patients with acute exacerbation of COPD but no apparent cardiac disease have a higher incidence of supraventricular arrhythmias. P-wave SAECG analysis and ALP detection have little value in the arrhythmic risk evaluation of these patients.

Syncope in elderly patients--is there a place for endomyocardial biopsy?

Syncope in the aging population has two characteristics--it always has a multifactorial origin and age by itself is a predictor of a worse outcome even in syncope with an apparent benign mechanism. Therefore, it is worthwhile investigating extensively the cardiac substrate in selected cases when the initial evaluation demonstrates its presence. In the cases where the usual workup fails to unveil the cause for the decompensating heart substrate, morphological examination with endomyocardial biopsy should be taken into account, after matching every particular case with one of the clinical scenarios listed in the Scientific Statement on the role of endomyocardial biopsy in the management of cardiovascular disease.

A debate on the certainty of etiology in a case of syncope.

We present the case of a 47-year-old woman with reccurent syncope. The investigations for establishing the etiology of syncope were extended over 4 years and multiple possible mecahisms for the syncope were identified. Even if the guidelines mention a good diagnostic yield for history and initial evaluation, for some selected cases the initial diagnostic supposition should be revised.