TAIPEI (AFP) - Thai golf star Thaworn Wiratchant rushed to see a doctor after suffering irregular heartbeats and trembling hands during his second round at the Yeangder Tournament Players Championship (TPC) in Taipei on Friday.

The defending champion shot a 69 to lie two shots off the lead on five-under par despite not feeling himself on the par-72 Linkou International Golf and Country Club.

"I was shaking during the round so I went to see the doctor after submitting my scorecard," the 47-year-old said in comments released by the organisers.

"The doctor said everything was okay and she explained that it might have been stress. Hopefully I feel better tomorrow," added Thaworn, a two-time winner of the event.

The Thai veteran is joint fourth, behind leaders Antonio Lascuna and Cameron Smith who are on seven-under.

The Filipino holed a crucial 10-foot birdie putt on the 18th as he bids for a first Asian Tour title, while the Australian signed for a 67 and a halfway score of 137.

"My putting was really good. I managed to save a lot for pars. It's not easy to putt here so I'm very pleased with my performance so far," Lascuna said.

Chinese Taipei's Lien Lu-sen scored a 71 to lead the local charge and sits just one shot back.

India's Anirban Lahiri fired the lowest round of the day - a six-under-par 66 - to lie tied in fourth with Thaworn and two others.

Overnight leader Elmer Salvador struggled to a 74 after his opening-round 66.