This algorithm was designed to help stave off sudden cardiac death
■ Doctors at the University of Miami Health System have developed an algorithm to identify adults at high risk for sudden cardiac death. There are about 300,000 sudden cardiac deaths per year.
Prediction is very difficult, especially if it’s about the future, Danish physicist Neil Bohr once said. And no health forecast has confounded doctors like sudden cardiac death.
Death may be the first symptom for those who experience sudden cardiac death in the United States; as many as 50 percent of victims have no symptoms of underlying cardiovascular disease.
“It’s probably in the order of 300,000 sudden cardiac deaths per year,” said Dr. Jeffrey Goldberger, a cardiac electrophysiologist at UHealth, the University of Miami Health System. “You are talking to somebody in the morning, and later that day you hear they dropped dead.”
Despite public health efforts aimed at curbing sudden cardiac death, like cardiopulmonary resuscitation training and the placement of automated external defibrillators, or AEDs, in public spaces, the survival rate remains very low.
ALGORITHM TO HELP PREDICT SUDDEN CARDIAC ARREST
Goldberger and his colleague, Dr. Leonardo Tamariz, also a cardiac electrophysiologist at UHealth, have developed a predictive algorithm to identify adults at high risk for sudden cardiac death before trouble strikes.
“One of the best treatments for sudden cardiac death is prevention,” Goldberger said.
Golberger and Tamariz have developed an algorithm using data sets from the Framingham risk score, which was designed to estimate the risk of developing coronary heart disease in 10 years. It also uses data from the Atherosclerosis Risk in Communities Study, a longterm study that investigates the causes of atherosclerosis, the thickening of the arteries, and any variations by race, gender, location and date.
While an electrocardiogram, or ECG, can detect heart problems, many have never had one, Goldberger said. So, he described UHealth’s algorithmic formula, which includes “basic things” often found in one’s health record:
• age
• gender
• cholesterol levels
• lipid lowering and blood pressure medication
• smoking
• diabetes
• body mass index
The algorithm produces a risk score that identifies those in need for additional screenings and targeted therapies.
For example: Upon examination of high-risk, asymptomatic individuals using cardiac stress tests and magnetic resonance imaging, Goldberger discovered that two-thirds of these patients had either myocardial fibrosis, which involves scarring in the cardiac muscle and is often found in autopsies among young people who’ve died from sudden cardiac death , or another predisposition for sudden death.
CAUSES OF SUDDEN CARDIAC DEATH
There are many causes of sudden cardiac death, Goldberger said. One of the main causes is arrhythmic sudden death due to a heart rhythm disorder like ventricular tachycardia, which occurs when the lower chamber of the heart beats too fast and deprives the body of oxygenated blood.
Goldberger described another heart rhythm disorder called an asystole, which is the absence of ventricular contractions due to a lethal heart arrhythmia that is often irreversible.
Only about 20 percent of sudden cardiac death might be related to a heart attack, said Goldberger, who emphasized that a heart attack is a potential cause of sudden cardiac death. Heart attacks and arrhythmic sudden death are not the same thing.
“The definition for that [heart attack] is when one of the arteries gets completely blocked and there is no blood flow for a prolonged period of time to an area of the heart, that muscle tissue dies,” Goldberger said.
Heart disease is the leading cause of death for people of most racial and ethnic groups in the United States, including Blacks and Hispanics, who are at higher risk for high blood pressure and diabetes, respectively, two conditions that lead to heart disease, according to the Centers for Disease Control and Prevention.
High blood pressure, high blood cholesterol, and smoking are key risk factors for heart disease, the CDC says. Several other medical conditions and lifestyle choices can also put people at a higher risk for heart disease, including:
• Diabetes
• Overweight and obesity
• Unhealthy diet
• Physical inactivity
• Excessive alcohol use
“The screening process includes identifying and treating the coronary disease risk factors which include diabetes, hypertension, elevated cholesterol, smokers,” said Dr. Alexandre Ferreira, chief of cardiology at Jackson Health System’s Jackson Heart Institute.
While Jackson does not tout a specific algorithm, Ferreira said that his team uses a systematic evaluation to determine a patient’s probability of experiencing sudden cardiac death.
In Miami-Dade County, 30,000 adults are at risk for sudden cardiac death, and the probability of someone surviving sudden cardiac death is reduced in people of different social groups.
“There have been studies done in terms of the relationship between the risk of sudden death and socio-economics,” Ferreira said.
“The Latino population have a higher incidence of diabetes, for example, and there are higher incidences of elevated blood pressure in African Americans.”
Since the pandemic, Ferreira said cases of sudden cardiac death have “significantly increased” across Jackson’s four hospitals.
“Patients delayed care and we saw an increase in mortality,” Ferreira said. “There was this fear to come to the emergency room and getting exposed to the COVID infection. So, a lot of patients developed symptoms of a heart attack.”
QUICK RESPONSE CRITICAL
With every minute that passes, the chances of surviving sudden cardiac arrest drop rapidly, according to Ferreira.
“Time is muscle,” Ferreira said. “If you have a heart attack and you come to the hospital within the first six minutes, the probability of your survival increases.”
The odds of survival decrease after that, Ferreira said, and only “10 to 12 percent survive a hospital discharge.”
FIRST SIGNS OF CARDIAC ARREST
The first signs of a sudden cardiac arrest include chest pain, shortness of breath and nausea, Ferreira said, and often occur in front of a co-worker or a family member.
And just like books, one cannot judge a heart by outward appearances.
“There are those you think are going to be really high risk who end up doing quite fine, and those who are perceivably at very low risk who have had multiple screenings — for instance, professional athletes — who have really bad things happen,” said Dr. Eli Friedman, a medical and sports cardiologist at Miami Cardiac & Vascular Institute, a division of Baptist Health South Florida.
Friedman is the team cardiologist for Inter Miami CF of Major League Soccer, as well as for numerous local colleges and universities.
“Each year, it is estimated that 1 in 50,000 to 1 in 80,000 athletes will suffer sudden cardiac arrest during or soon after athletic activity,” Friedman wrote last September in the journal American College of Cardiology. “It is also well established that certain populations are at higher risk of these events than others.”
For instance, Black males who play basketball or football are at higher risk of sudden cardiac arrest than others, according to Friedman, who recommends an “emergency action plan” for every organization, school or institution that sponsors athletic activity.
Sudden cardiac arrest is the leading cause of death in student-athletes. It strikes quickly and often without warning. Approximately 95 percent of those who die of sudden cardiac arrest lose their lives because essential medical intervention, such as CPR or an automated external defibrillator was not used quickly enough.
“Anyone who is down on the ground, who is unresponsive, should be presumed to be in cardiac arrest until proven otherwise,” Friedman said. “Seizures are cardiac arrests until proven otherwise, as well, or unless the individual has a known history of seizure disorders.’
As a preventative measure, Friedman recommends annual heart screenings and blood work, and knowing your numbers: cholesterol, blood sugars, BMI and blood pressure.
He also advises monitoring risk factors such as known significant blockage in the arteries, significant leakage or narrowing of the heart valves, arrythmias known to originate from the bottom chambers of the heart and genetically inherited conditions.
“We all have to advocate for further research and development in this area because we may be the next one to have sudden cardiac death,” UHealth’s Goldberger said.