Lifestyle modifications, started early enough, may reduce the risk of an irregular heartbeat that is often treated with a pacemaker.
Controlling your blood pressure and blood glucose has long been known to reduce the risk of serious health problems such as heart attack and stroke.
Now a new study suggests that keeping these under control may also prevent a common heart arrhythmia, one that’s often treated with a pacemaker.
The study, published on May 24 in
Researchers found that higher blood pressure and higher fasting glucose were both linked to a type of arrhythmia, or irregular heartbeat, known as AV block.
Atrioventricular (AV) block is a condition in which the conduction of electrical signals from the top to bottom chambers of the heart — the atria and ventricles — is partially or completely blocked.
This can cause symptoms such as dizziness, fainting, fatigue, chest pain, and shortness of breath.
Experts point out, though, that the study doesn’t mean that people who already have AV block can treat their condition with diet or exercise.
“AV block isn’t a chronic condition that we manage with lifestyle changes,” said Dr. Eli Gelfand, section chief of general cardiology at Beth Israel Deaconess Medical Center in Boston, who wasn’t involved in the study.
Depending on the severity of the AV block, people may still need treatment. This sometimes means having a pacemaker implanted to help their heartbeat at a regular rhythm.
However, high blood pressure and elevated blood glucose are known risk factors for other cardiovascular problems, such as heart attack, coronary artery disease, stroke, and a common type of arrhythmia known as atrial fibrillation.
Cardiologists and other doctors already routinely talk to patients about managing these and other risk factors for heart and circulation problems. This research adds another, AV block, to that list.
“This study provides an additional impetus to counsel and treat patients aggressively in order to reduce their risks of developing this conduction system disease,” said Gelfand.
The new study was based on data from more than 6,000 Finnish patients who were followed for up to 32 years.
Researchers found that several factors were linked to a higher risk of developing AV block, including older age, being male, higher systolic blood pressure, higher fasting glucose, history of heart attack, and history of congestive heart failure.
Only blood pressure and glucose level can be directly modified with lifestyle modifications — although managing these would also reduce the risk of heart attack and heart failure.
Researchers estimated that 47 percent of cases of AV block were due to people having higher systolic blood pressure. An estimated 11 percent were due to elevated glucose level.
Dr. Michael Chan, an interventional cardiologist with St. Joseph Hospital in Orange, California, cautioned that this is an observational study. So the authors can’t show that higher blood pressure or glucose level causes AV block — only that there’s a link between them.
Also, “Only a very small number of patients were diagnosed with AV block during the follow-up period,” said Chan, who wasn’t involved in the study.
Dr. Raul Weiss, a cardiologist and professor of clinical medicine at The Ohio State University Medical Center in Columbus, said as an observational study, the results should be viewed with caution.
But it’s an important starting point for additional research, including on the link between glucose level and heart problems.
“I happen to be one of the doctors who thinks that blood glucose has a lot to do with arrhythmias and heart block,” said Weiss, who wasn’t involved in the study. “This is probably one of the first studies to demonstrate that.”
About 3 million people worldwide have pacemakers, with 600,000 implanted each year. The majority of people need one because of some kind of arrhythmia, including AV block.
Most often, AV block is caused by damage to heart tissue, such as from a heart attack or heart disease.
Gelfand said this damage causes normal cardiac tissue to be replaced with connective tissue — what’s known as fibrosis. This interferes with the flow of electrical signals from the top to bottom chambers of the heart.
Chan said not all types of AV block require treatment. But in more severe cases, “Pacemaker implantation would be considered the treatment of choice if there are no reversible causes.”
Although pacemakers are a common treatment and implanting them is a low-risk procedure, they can result in complications.
“A pacemaker is very good to have when you need one,” said Weiss. But he pointed out that pacemakers also carry risks, including infection at the implantation site and damage to nearby blood vessels.
Being able to reduce the number of people who need a pacemaker through lifestyle modifications could have “a big impact on healthcare costs and the patients themselves,” said Weiss.
In order to reduce the risk of AV block, people would need to start eating healthier, exercising regularly, not smoking, and making other changes before the heart tissue is damaged.
However, convincing people to make these changes early enough can be difficult for doctors to do, especially when it comes to managing blood pressure or glucose level — both “silent killers.”
“It is sometimes difficult for patients to aggressively modify their lifestyle or even start medications for conditions that are essentially asymptomatic in the beginning,” said Gelfand.
But this study adds another angle to these conversations.
“People with high blood pressure and high serum glucose are also at risk for this conduction system disease that may require a pacemaker,” said Gelfand.