Researchers Discover Simple Test for Rare Fatal Genetic Heart Disease

A team of researchers from McMaster University has revealed a new, simple clinical test to detect Calcium Release Deficiency Syndrome (CRDS), a life-threatening genetic arrhythmia that causes dangerously fast heartbeats and can lead to severe complications such as sudden cardiac arrest and death.

The findings were published in the journal JAMA.

While 3,50,000 to 4,50,000 cardiac arrests occur annually around the globe, many of these cases remain unexplained. One of the potential underlying causes is Calcium Release Deficiency Syndrome (CRDS), a rare genetic heart condition that standard clinical tests often fail to detect.

CRDS affects the heart's ability to manage calcium release, which is crucial for proper cardiac function. Due to its rarity and the subtlety of its symptoms, CRDS frequently goes undiagnosed, leading to sudden cardiac arrests that are labelled as unexplained.

The case-controlled study, co-led by Jason Roberts and Wayne Chen involved 68 study participants from 10 centres in seven countries. The participants were from four categories of heart conditions, including Calcium Release Deficiency Syndrome (CRDS) patients and unexplained cardiac arrest (UCA) survivors.

The researchers revealed that the new diagnostic method, performed using an electrocardiogram, monitors for changes in ECG after a brief period of a fast heartbeat and a pause, which can occur naturally or be induced by artificially pacing the heart.

"CRDS has been linked to many tragic incidents and heartbreaking stories affecting families. There have been numerous cases where patients experienced fainting episodes, but their tests showed no issues, which led doctors to believe the fainting was not due to a dangerous heart condition. A portion of these individuals, often young and otherwise healthy, subsequently suffered sudden cardiac arrests, and some did not survive. This novel and simple diagnostic method, which can be performed using an electrocardiogram in a broad range of clinical settings, is hopefully an important step towards improving our evaluation of initially unexplained cardiac arrest (UCA),” said the authors.

The team anticipates that this simple pacing test will be incorporated into the routine diagnostic tests for initially unexplained cardiac arrest, providing hope for better outcomes and prevention of future tragedies.

Reference: Ni M, Dadon Z, Ormerod JOM, et al. A Clinical Diagnostic Test for Calcium Release Deficiency Syndrome. JAMA. Published online June 20, 2024. doi:10.1001/jama.2024.8599