Katie has been resting since the shock medical scare and posted a photo from her home as she relaxed to update her Instagram followers on her condition.
In the photo Katie, 35, is seen wearing a Holter Monitor – a wearable device that monitors your heart rate and rhythm.
She wrote: “Currently wearing the Holter Monitor as part of my ongoing cardiac testing. I will be wearing this device for 48 hours as it records my heart activity. Other testing follows this week, but emotionally I am taking them just one test at a time.”
The singer then admitted that while she wants to remain private about her personal life, she had been so overwhelmed by the support and offers of help from her fans that she wanted to keep them in the loop.
She posted: “Please do know that albeit this is a personal medical issue, I have listened and onboarded so compassionately to your questions and concerns relating to potential causes etc.
“I want you to know that I absolutely intend to share my findings with you and hope to either give you clarity or peace of mind, to those that are seeking it.
“Until then, we must try to onboard an objective mindset and focus on staying healthy, safe and warm.
“I appreciate you all so greatly, and thank you for kindly embracing this discovery process with me.”
Katie gained fame when she took part in the seventh series of the X Factor in 2010.
She used her social media platforms to thank NHS staff for caring for her when she fell ill earlier this year.
“I was initially told there was a wait by the ambulance call centre, but an ambulance was at my door within minutes. The entire team at Watford were / are beyond impeccable, and I am so grateful for your continued help!!’
At the time Katie’s rep released a statement confirming her condition. It read: “Wednesday morning an ambulance was called to Katie Waissel’s North London home, as she had experienced both signs and symptoms of a heart attack.
“Paramedics arrived on scene and took Katie immediately to hospital where she was placed on a ward for observations and tests as her ECG were showing signs of abnormalities.
“The doctors, nurses and entire team at NHS Watford General Hospital, including the ambulance service were fantastic. We appreciate the tremendous amount of pressure they are still under, yet their efficiency and thoroughness in taking care of Katie was incredible and never wavered. Katie is now home resting up and under the care of the cardiac team.”