Photo: Jim Smeal/BEImages. I first noticed Sia's relatively new face-shrouding performance ritual when she was the musical guest on a recent episode of SNL. During  Elastic Heart , the singer faced off to the side, a tulle shield obscuring most of her face underneath her signature blonde wig. Sia faced the audience for  Chandelier , but she still wore the same black visor, and a mime performed next to her to draw attention away from the singer.
A cardiac arrest is different to a heart attack. In a cardiac arrest the heart actually stops beating; whereas in a heart attack the heart normally continues to beat even though the blood supply to the heart is disrupted. heart attack occurs when the blood supply to part of the heart stops and thus causes a section of the heart muscle to begin to die; whereas a cardiac arrest occurs when the heart stops beating as a whole. There are various symptoms of a heart attack.
A person having a heart attack is at high risk of experiencing a cardiac arrest. Both a heart attack and a cardiac arrest are life-threatening medical emergencies and require immediate medical help. Call 999 if you think you are having a heart attack or if you witness someone having a cardiac arrest.