Cardiac conduction disorders [51 genes]

Cardiac conduction disorders constitute a heterogeneous group of entities characterized by an alteration in the electrical impulse propagation at different levels: the sinus node, the atrioventricular (AV), and the His-Purkinje system. In the surface ECG, sinus bradycardia, prolonged duration of the PR wave and interval that can lead to atrioventricular block, and different degrees of bundle branch block can be observed.

In addition, there is a large number of genes that have been associated with the development of cardiomyopathies whose first clinical manifestation may be the presence of cardiac conduction disorders, such as atrioventricular blocks. The same thing happens in some channelopathies. Many of these pathologies can be underdiagnosed because, in their early stages, the clinical expression can be very mild.

The prevalence of this group of disorders has not been established.

The genetic study in cardiac conduction disorders allows:

• A diagnostic confirmation, which often represents important support in the differential diagnosis.
• A most precise study of the patient’s relatives so that carriers have access to an early / preclinical diagnosis and non-carriers can be safely discharged from cardiology consultations. It has been shown in this disease that this is a cost-effective strategy.
• A clinical approach in the prognosis of each patient, depending on the type of genetic variant identified. Our scientific group has been a pioneer in this type of genotype-phenotype correlation analysis.

This panel, according to current clinical guidelines, is recommended as part of the diagnostic evaluation in:

• Patients with isolated cardiac conduction disorder (especially when a positive family history is documented).
• Patients with cardiac conduction disorder, and concomitant structural heart disorder or extracardiac disorder.
• When there is a young age of diagnosis or suspicion of laminopathy.

The probability of finding a pathogenic mutation when a patient presents cardiac conduction disorders has not been clearly established. However, the probability could be higher in cases where there is a family history of these disorders, and when it occurs in young subjects without a clear cause.