Over-diagnosis of long-QT syndrome - a common phenomenon

Researchers have found that despite advances in knowledge and increased awareness of long-QT syndrome (LQTS), this potentially lethal but highly treatable condition is commonly over-diagnosed leading to unnecessary treatments and interventions. LQTS is often mistaken for palpitations, neurocardiogenic syncope and epilepsy, and some people may experience a lifelong asymptomatic course. However, in a small proportion of people the first indicator of LQTS is sudden death. Over the past decade, efforts have been made to increase public awareness regarding warning signs of the condition; some argue that this has led to potential over-diagnosis. The accurate importance of an accurate diagnosis is paramount since failure to diagnose LQTS putting a person at risk of sudden death, yet an incorrect diagnosis of LQTS can lead to unnecessary distress. Taggart et al. sought to examine whether or not LQTS is being over-diagnosed.They assessed the level of concordance between LQTS dismissal diagnoses from a specialty clinical with that of original referrals. Medical record data were compared for 176 consecutive patients (121 females, median age 16 years) referred with a diagnosis of LQTS. Following specialist evaluation, 27%, 32%, 41% of patients, respectively, were classified as having definite LQTS, possible LQTS, or no LQTS.Results of the analysis revealed that two of every five patients previously diagnosed and treated for LQTS were deemed not to have LQTS following specialist diagnosis, that is, diagnostic concordance was present for less than one third of patients seeking a second opinion. Indeed, the authors stated that the majority of these patients were dismissed as "otherwise healthy individuals without any significant cardiovascular disease.""Miscalculations of the QT interval (QTc), misinterpretation of the normal distribution of QTc values, and misinterpretation of symptoms appear responsible for most of the diagnostic miscues," the authors claimed....