A famous athlete collapses and dies during the game. A neighbor is found dead at home but never had any symptoms. In a moment, a person we knew or loved is gone. It’s known as sudden cardiac death, and it’s frightening. Why does it happen?
Surprisingly, a blocked artery or a heart attack often is not the cause of sudden cardiac death, as most people believe. The problem is usually with the electrical impulses of the heart, and UCLA researchers are studying why it happens and how to prevent it.
Electrical impulses in a normal heart keep the heart beating. When these impulses are interrupted, the heart can beat too fast, too slow or with an irregular pattern – all forms of arrhythmia. Arrhythmia contributes to approximately 200,000-300,000 sudden deaths per year – a higher incidence than stroke, lung cancer or breast cancer.
Cardiologists can help people live with some forms of arrhythmia, but the abrupt and deadly arrhythmias keep researchers and physicians awake at night.
That’s why a team of researchers based at the UCLA Cardiac Arrhythmia Center is focused on:
“If we can correct the issues that cause arrhythmias and find new, less invasive ways to treat them, we will go a long way toward reducing the incidence of sudden cardiac death,” says Dr. Kalyanam Shivkumar, director of the UCLA Cardiac Arrhythmia Center as well as chief of the UCLA Interventional Cardiology Program and the Adult Cardiac Catheterization Laboratory.
Scars on the heart may be caused by a past heart attack or simply by aging. Understanding the functional impact of these factors has revolutionized research in arrhythmias.
The cardiology community previously believed that scars on the heart did not disrupt the electrical flow. They believed electrical impulses would learn to bypass the dead tissue and continue with their normal conduction. Within the past several years, however, research by UCLA and other investigators has found that scars do in fact cause problems for the heart:
Learn more about scarless healing after heart attack.
Arrhythmia treatments usually consist of pharmacological approaches and implantable devices.
Today’s common treatments have several drawbacks:
Because of these disadvantages, UCLA investigators are looking for an effective, one-time, single-cost cure.
Driven by the needs of patients with complex arrhythmias who come to UCLA from all over the world, we are developing new techniques to treat and cure arrhythmias. These include:
UCLA scientists are also assessing the potential of novel energy sources to non-invasively homogenize scars. One option is the kind of radiation beams used to pinpoint cancer without affecting surrounding tissue.
Some heart rhythm disorders are inherited. In these cases, the heart structure is normal, but a genetic mutation causes dangerous arrhythmias. To help patients with such inherited arrhythmias, UCLA has a dedicated program for at-risk patients and families.
The most common form of an inherited arrhythmia is Long QT Syndrome.
Patients with Long QT Syndrome and other inherited heart rhythm disorders have specific medical needs. They may benefit from:
UCLA’s Inherited Cardiac Arrhythmia Program, led by Dr. Bradfield, provides comprehensive care and serves as a vital referral center for patients and families with these complex disorders in California and nationally.
The nervous system influences all aspects of heart function. As Dr. Jeffrey Ardell describes it: “Our minds and our hearts are intimately connected in ways that we are only now discovering.”
UCLA researchers have discovered that the nervous system also can play a powerful role in the development of arrhythmias – and their treatment. In fact, UCLA is one of the nation’s preeminent centers for neurocardiology research.
Investigators at the UCLA Neurocardiology Research Center of Excellence, directed by Dr. Ardell, have shown that when the heart is injured, the characteristics of neurons that control the heart also change.
A cover story in the January 2016 issue of the Journal of Physiology detailed how a heart attack alters both the size and the function of neurons that control the heart:
Drs. Ajijola and Ardell and their teams created a map of both heart and nerve function to demonstrate that this happens – the first study of its kind.
Dr. Marmar Vaseghi, a cardiac electrophysiologist and director of the Clinical and Translational Research Center, has partnered with UCLA surgeons and UCLA anesthesiologists to develop, research and offer a procedure called cardiac sympathectomy.
Ablation on the surface of the heart has limitations in reaching substrates from scars that may lie within the heart muscle. In these cases, neuromodulation interventions represent a new avenue of therapies for treatment of ventricular arrhythmias.
Ongoing neurocardiology research aims at developing other methods of stimulating or blocking nerves that affect the heart. UCLA teams are investigating neurotransmitter replacement drug therapy, nerve stimulation and other techniques.
A team of investigators in the Cardiovascular Research Laboratory are combining mathematical biology and computer simulation (Drs. Zhilin Qu and Alan Garfinkel) with experimental arrhythmia biology (Drs. James Weiss, Riccardo Olcese, Thao Nguyen and Hryar Karagueuzian) to unravel the mechanisms underlying the electrical instability in the heart that causes sudden cardiac death from ventricular fibrillation and complications such as strokes from atrial fibrillation. They are exploring novel ways to modify the electrical properties of the heart using drugs and gene therapy approaches to prevent the life-threatening complications of these arrhythmias.