P Wave Analysis in Patients with Sarcoidosis

Introduction: Atrial arrhythmias in patients with sarcoidosis (Sar) are not unusual and can occur due to either atrial myocardial fibrosis and/or due to autonomic nervous system imbalance. Electrocardiographic markers (ECG), like maximum and minimum P wave duration and P wave dispersion {Pdis = Pmax − Pmin} reflect atrial depolarization inhomogeneity and can indicate patients prone to develop atrial arrhythmias while standard deviation of RR interval (SDNN) is an index of heart rate variability, reflecting autonomic nervous system (ANS) activity. Methods: 90 patients with sarcoidosis (41 males/49 females) enrolled in this multicenter prospective study underwent digital electrocardiography, echocardiography and pulmonary function tests (PFTs). Diastolic and systolic indices of right and left ventricle were measured echocardiographically including Doppler parameters while Pmax, Pmin, Pdis and SDNN were measured in a 5minute duration digital electrocardiogram. All consecutive patients were compared to 65 healthy volunteers (30 males/35 females). Results: Although heart rate and the echocardiographic indices were similar among the two groups, the electrocardiographic indices were significantly prolonged in the patient group compared to controls. Maximum P wave duration was correlated with SDNN (p < 0.05, r = −0.272) and the age of the patients (p < 0.05, r = 0.219) while Pdis was correlated with SDNN (p < 0.001, r = 0.350) and the heart rate (p < 0.005, r = 0.323). Multivariate analysis showed that Pmax and Pdis were independently correlated with SDNN. Conclusion: P wave dispersion is significantly increased in patients with systemic sarcoidosis compared to healthy persons while maximum P wave duration and P wave dispersion are negatively correlated with the standard deviation of RR, an index of heart rate variability implying imbalance of ANS function. Further studies are needed for the clarification of the significance of this correlation.