LAHORE - Doctors are concerned about the health of jailed former Pakistani Prime Minister Nawaz Sharif and have requested prison authorities in Rawalpindi to transfer him to a hospital, a government official said on Sunday.Sharif and his daughter Maryam were arrested on July 13, minutes after they returned to Pakistan seeking to revitalise their flagging party ahead of a July 25 national election. They were moved to Adiala jail in the garrison town of Rawalpindi and face lengthy sentences."Doctors at Adiala jail have observed changes in the ECG of Nawaz Sharif," Punjab Chief Minister Hasan Askari Rizvi told Reuters. An ECG, or electrocardiogram, is a test that checks the heart's electrical activity."We cannot take any risk about Sharif's health and have directed the jail authorities to shift him to either Rawalpindi Institute of Cardiology or PIMS (Pakistan Institute of Medical Sciences) immediately."Sharif, who returned from Britain, was handed a 10-year jail term on July 6 by an anti-corruption court in Pakistan, while his daughter and political heir was sentenced to seven years in prison over the purchase of luxury flats in London in the 1990s.