Background: The 12-lead surface electrocardiogram (ECG) is a useful tool to predict both atrial and ventricular arrhythmias via P-wave and QT measurements and its derivatives. Polycythemia vera (PV) is a chronic myeloproliferative disorder associated with cardiovascular events. The aim of this study was to assess ECG findings of patients with PV.

Method and materials: Sixty patients with PV (34 male, mean age 58±11 years) and 60 age and gender-matched healthy volunteers were enrolled into the study. From the 12-lead surface ECG, P-wave and both conventional QT measurements and transmyocardial repolarization parameters (T_peak-T_end interval (T_p-T_e) and derivatives) were evaluated digitally by two experienced cardiologists. In addition, a novel parameter, Pi was calculated digitally as the standard deviation of the P-wave duration across the 12 ECG leads.

Results: QT duration and corrected QT interval were significantly longer in the PV group compared to healthy controls (p<0.01 and p<0.01, respectively). The T_p-T_e was longer and the T_p-T_e/QT ratio was significantly higher in the PV group compared to the controls. P-wave analyses showed that all P-wave parameters including Pmax, Pmin, P dispersion, and Pi were significantly prolonged in PV patients compared to the controls. The increase of both T_p-T_e and P max in the PV group was independent of age, BMI, diabetes and hypertension, gender, systolic blood pressure, hemoglobin, hematocrit, left atrial dimension, left ventricular end-diastolic diameter and early deceleration time in a univariate analysis of co-variance model (F=11.097, p=0.001 and F=31.537, p=0.0001, respectively).

Conclusion: The present study demonstrated that PV may be associated with electrocardiographic abnormalities of both atrium and ventricle.