UTICA — Researchers led by the Masonic Medical Research Laboratory have discovered two genetic mutations that can cause sudden cardiac arrest.

The discovery means that doctors can identify a new group of patients who are at risk of suddenly dying and advise them on precautions.

The only problem is that people who are young and healthy could easily die before they get an electrocardiogram, which can point to the likely presence of these mutations, said Dr. Charles Antzelevitch, Masonic's executive director and director of research. Genetic testing confirms the mutations' existence.

"Many of these things can be spotted early and prevented, but unfortunately many of us don't get an ECG until we get to be 40 years old," he said.

Antzelevitch believes that, at the very least, all student athletes should receive ECGs to test for abnormal electrical activity in the heart, he said. In Japan, all school children receive routine ECGs, he said.

Antzelevitch presented an abstract of the two years' of research on Nov. 13, at the American Heart Association's annual meeting in Chicago during a session highlighting important, late-breaking discoveries. Masonic's Dr. Guido Pollevick, acting head of the molecular genetics program, presented a poster on the research at the meeting on Nov. 14.

Sudden cardiac arrest refers to an abrupt stopping of the effective beating of the heart, sometimes in people who have not been diagnosed with heart disease and may not have shown any symptoms. It leads to death unless the patient is treated with an electric shock, called defibrillation, within minutes of the arrest.

Although the heart is a mechanical organ, it is run by electricity, which causes and regulates each heartbeat.

Most sudden cardiac arrests happen when the electrical impulses in the heart become too fast (ventricular tachycardia), too chaotic (ventricular fibrillation) or both.

To produce that electricity, protein pathways in the heart, known as ion channels, transmit electric charges, i.e. ions, according to the heart's needs at the moment. Each ion channel transmits only one kind of ion.

The newly discovered mutations affect the calcium channels, which carry calcium ions across the membrane of heart cells.

The mutations make up what scientists call "a new clinical entity" that combines two previously described sudden death syndromes, known as Brugada and Short QT syndromes, Antzelevitch said.

Masonic scientists also first discovered the genes responsible for both these syndromes, which encode sodium and potassium channels in the heart.

There are many known causes of sudden cardiac arrest, including most forms of heart disease and Antzelevitch thinks researchers will in time discover more mutations affecting the ion channels and leading to sudden cardiac arrest, he said.

"We're at the tip of the iceberg," he said.