Tall R wave in ECG represents:
Right ventricular hypertrophy due to a sustained, severe pressure load (e.g. due to right pulmonary valve stenosis or certain pulmonary artery hypertension syndromes) is characterized by a relatively tall R wave in lead V, (R >S wave), usually with right axis deviation.
Right atrial overload
Left atrial overload
Right ventricular hypertrophy
All of the above