Woman blamed dizzy spells on poor fitness - but they were actually caused by something far more serious

Woman blamed dizzy spells on poor fitness - but they were actually caused by something far more serious Denisa Fraser, 33, put down her dizzy spells to being stressed or unfit, but she also suffered heart palpitations at work that led to her to take up a health assessment A woman who suffered with dizzy spells, putting it down to poor fitness, discovered she had been living with two rare heart conditions. Denisa Fraser, 33, spent years dismissing dizzy spells and faintness as being too unfit or stressed. But following a free workplace health assessment at the Clevedon Clinic London Hospital in March 2026, she was diagnosed with Wolff-Parkinson-White syndrome - a rare heart rhythm disorder. Denisa, from Horsham, West Sussex, was found to have a large coronary sinus diverticulum - a rare pouch in a vein of her heart that made it much harder for doctors to treat the condition. After two operations to map and treat the abnormal electrical pathways in her heart, including an eight-hour procedure, she returned to exercise symptom-free. Denisa, originally from Czechia, said: "I genuinely thought everyone felt like that. I thought it was just going to be an MOT because I considered myself healthy. "I do yoga, I went to spin classes and I'd started running, so I didn't think anything bad or sinister would happen. When I ran though I struggled. I'd feel faint and my heart would race. I just thought I wasn't fit enough or that I needed to train harder. "I'd have times where my heart would suddenly go crazy, into the hundreds, and stay there. At work I thought it was just because I was angry or stressed. I genuinely thought it was normal." Every time Denisa ran, she became dizzy, felt faint, and experienced episodes where her heart would suddenly race. She also suffered heart palpitations at work but assumed they were caused by stress, believing the symptoms were simply something that everyone experienced. Thinking she just needed to improve her fitness, Denisa pushed herself harder by running more often and even taking cold plunges to lower her heart rate. She expected a free workplace health assessment to be little more than an "MOT". Instead, routine heart tests prompted doctors to investigate further after questioning her about her symptoms. She genuinely believed nothing was wrong with her and was confused by the doctor's concern. She said: "The doctor started asking me weird questions. I was oblivious. I even rang my mum afterwards and said, 'This guy's having me on. There's nothing wrong with me.'" During a procedure that was expected to last around 30 minutes, doctors triggered one of Denisa's abnormal heart rhythms within minutes, sending her heart rate soaring to 260 beats per minute. Specialists discovered a far more complex problem than expected and kept her under general anaesthetic for more than three hours while carrying out further investigations. Doctors diagnosed Denisa with Wolff-Parkinson-White syndrome. During the procedure, they also discovered a rare pouch in one of her heart's veins that meant they could not safely complete the procedure at that time. Three weeks later, on May 22, she underwent a second operation lasting eight hours to map and treat the abnormal heart rhythm carefully. Although the first few days of recovery were difficult, she soon noticed dramatic improvements. Not only could she exercise without her heart racing uncontrollably, but she also found she was breathing more easily and felt noticeably calmer throughout the day. Denisa, a procurement manager, said: "The recovery after the second surgery was quite rough because it was such a long operation, but after the first week things improved really quickly. "The biggest difference is that everything feels calmer. I breathe better, my heart rate is lower and even at work my body's physiology is calmer. I didn't realise how much I'd been living with until afterwards." Looking back, Denisa believes she had accepted symptoms that were never normal simply because she had lived with them for so long. She is now urging others not to ignore persistent symptoms or assume they are part of everyday life. She added: "I didn't realise how much I'd been living with until afterwards. If you're offered a health check, just do it. Don't assume you're not in the risky category because you're young or active. "I think a lot of women put symptoms down to stress, hormones or their period and just carry on. I was putting so many symptoms down to not being fit enough when actually there was something wrong. "I wasn't hiding symptoms from anyone. I genuinely thought this was just how everybody felt because I'd been born that way."