Patients with Long-QT Syndrome are at Greater Risk of Comorbidities


Long QT syndrome (LQTS) is a congenital disorder that manifests as a prolonged QT interval on patient electrocardiograms. Those who are affected by LQTS are more likely to experience ventricular tachyarrhythmias, potentially leading to cardiac arrest or sudden death. A recent matched cohort study from Denmark suggests that those with long QT syndrome may have other health concerns as well; the study suggests that they are also more likely than the general population to suffer from comorbid conditions such as diabetes, neurological problems, or psychiatric disorders.

Examining Comorbidity

The Danish study examined 463 patients who had received a new diagnosis of congenital long QT syndrome that were listed in national registries. These patients were then age-matched and sex-matched to 2315 individuals without LQTS who were listed in the Danish National Population Register. Those with long QT syndrome experienced higher mortality rates over an average follow-up of 4.3 years than those in the control group (4.2 percent vs. 3.6 percent) and were also found to have higher rates of diabetes, atrial fibrillation (AF), myocardial infarction (MI), and other health issues.


Approximately 3.7 percent of individuals with LQTS in the study suffered from diabetes, which was over twice the rate in the control group (1.8 percent). Fortunately, members of the study did appear to be taking the condition seriously as pharmacy records also showed that the group had a higher rate of prescriptions for antidiabetic drugs than the control group. This is good news, given how damaging uncontrolled diabetes can be to some of the same organs that are affected by long QT syndrome.

Neurological and Psychiatric Issues

Of the neurological conditions identified in the Danish study, the most prevalent is epilepsy. This can be dangerous in its own right, given the possibility of severe seizures that can accompany the condition. Several psychiatric conditions were identified in the study, though unlike with the neurological issues there was no single condition that seemed predominant. Instead, the study suggests that those with LQTS are more prone than the non-LQTS population to psychological conditions in general.

New Heart Concerns

It was already known that long QT syndrome had an association with AF and a few other heart conditions. What was not known was that individuals with LQTS were more likely to suffer from myocardial infarction as well. The study did not suggest a reason for this link, though there is speculation that the increased prevalence of diabetes in those who suffer from long QT syndrome may play a part in this connection. MI is known to be a common cause of mortality in those who suffer from diabetes, showing significantly larger risk of myocardial infarction than those without diabetes regardless of whether the other individual has suffered an MI or not.

Treatment Options

Because LQTS affects multiple organs in the body, it was already known to be a complex condition. With the results of this study suggesting greater risks of comorbidity, however, medical professionals who are treating those with long QT syndrome need to be aware of the risks associated with these comorbid conditions. Screenings and observations for signs of diabetes, epilepsy, psychiatric disorders, and other potential comorbidities should be employed, in order to identify problems and start treatment earlier. They should also take the time to explain the risks to their patents so they will be able to report new symptoms sooner, should they arise.

By Jack Gerard from In The Cloud Copy

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