The activation time from electrical signals to chamber conformational change has long been demonstrated to associate with LV performance and ventriculo-arterial coupling with prognostic implications in heart failure patients. P wave peak time (PWPT), an easily obtainable parameter from conventional surface electrocardiography, represents the time taken for excitation spreading from sinoatrial node to the maximal summation of positive deflection from both atria. Increased PWPT denotes prolonged intra- or inter-atrial conduction time and indicates elevated intra-atrial pressure. As shown in a recently published study, PWPT was highly correlated with LV end diastolic pressure (LVEDP) derived from direct measurement during cardiac catheterization. With its objective and easily obtainable nature, clinical application of PWPT to evaluate diastolic function can be expected, if more studies in different populations can confirm its clinical utility.