Honolulu Emergency Medical Services received 29 calls in the hour following Saturday’s false missile alarm.

That’s substantially up from the average of between eight to 15 calls an hour, said spokeswoman Shayne Enright. Four calls were related to the panic and chaos that ensued following the nuclear bomb alert, she said.

The Honolulu Star-Advertiser earlier reported that Sean Shields, 51, suffered a massive heart attack minutes after saying his last goodbyes over the phone to his 10-year-old daughter and grown son while at Sandy Beach on East Oahu following the false missile alert. He was transported to Straub Medical Center at 9:31 a.m. in critical condition, EMS records show.

Shields started violently throwing up and then drove himself, along with his girlfriend Brenda Reichel, who is disabled, to the Straub Hawaii Kai Family Health Center where she said he collapsed in the waiting room. Paramedics were able to perform CPR and transport him to Straub, where he had emergency surgery and four stents inserted into his heart, Reichel said. He was discharged Tuesday.

The other missile-alert-related injuries included an 89-year-old Waimanalo care home patient who fell and was transported in stable condition at 8:39 a.m.; a 37-year-old woman at 7-Eleven on Kaahumanu Street who got into a motor vehicle collision at 8:42 a.m., but refused transport; and a 38-year-old woman in Kailua, who was treated for anxiety and transported in stable condition at 9:13 a.m., according to EMS.

“We had two crews on calls with patients who stayed with the patients until the all-clear was given,” Enright said.

Honolulu Mayor Kirk Caldwell previously said there were no apparent injuries or accidents related to the false alarm, except for a driver who damaged a golf cart following the alert. However, the Honolulu Police Department’s 911 dispatch system was overwhelmed with more than 5,000 telephone calls, Caldwell said at a press conference Saturday. The state took 38 minutes to issue a correction via cellphone for the mistaken 8:07 a.m. notice that a missile attack was coming. Roughly 2,500 911 callers could not get through to emergency lines, according to HPD.

EMS said it is investigating why some calls did not get through and were instead rerouted to a 911 service on the mainland.

>> For the Honolulu Star-Advertiser’s full coverage of Hawaii’s missile alert scare, go to 808ne.ws/Hawaiimissilescare.