The Ins and Outs of Heart Failure
By Arvind Sommi
Heart failure is one of the most common complications experienced by people with diabetes. We spoke with Dr. Lee Goldberg, a leading cardiologist, to help us understand the different types of heart failure.
Heart failure is a dangerous complication, and all people with diabetes should be aware of their risk. However, it can be tricky to decipher all of the complex terminology associated with heart disease and heart failure in particular. What is congestive heart failure? What do the acronyms HFpEF and HFrEF mean? What are MACE outcomes?
We spoke with Dr. Lee Goldberg, a leading professor and cardiologist at the University of Pennsylvania, to better understand these terms, the different types of heart failure, and what is really going on in your body when this complication occurs.
What is heart failure?
Each day, your heart beats approximately 100,000 times and pumps roughly 2,000 gallons of blood. The left side of your heart is primarily responsible for delivering blood with oxygen to the rest of your body (except for your lungs). After this blood delivers oxygen to all your organs and limbs, it travels back to the right side of your heart. The right side of your heart then pumps this deoxygenated blood to the lungs to become oxygenated again. This oxygenated blood travels to the left of the heart and the cycle repeats.
In general, heart failure is a condition in which the heart is unable to provide adequate blood flow to the organs, or it can only provide adequate blood flow at very high pressures inside of the heart.
When your heart is unable to pump enough blood to the rest of your body, some blood may get backed up in your lungs and lower body. As the blood gets backed up, it can lead to fluid buildup in the ankles and feet, arms, lungs, and other organs which is why many refer to heart failure as congestive heart failure (CHF).
To learn more about heart failure, you can check out the Know Diabetes By Heart (KDBH) initiative’s article, “What is Heart Failure?”
What are the different types of heart failure?
People with diabetes are two to four times more likely to develop heart failure than someone without diabetes.
Dr. Goldberg described the different types of heart failure and how they relate to each other. The two main types of heart failure, heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). These are “the two main flavors of heart failure – either a weak left-sided pumping function or a normal, but very stiff, lop-sided pumping function,” said Goldberg.
HFrEF: Normally, around 55% to 60% of blood is pumped out of your heart with each heartbeat. This percentage is called the “ejection fraction.” HFrEF is a condition where that percentage is less than 35% or 40% – often a result of having a weakened heart muscle.
HFpEF: For HFpEF, while the ejection fraction might remain in what is considered the normal range (above 50%), the pressure inside the heart is extremely high due to the stiffness of the heart muscle. “The heart becomes very stiff, so it has difficulty relaxing to allow the blood in, and therefore the pressures are very, very high in order to fill the heart,” Dr. Goldberg said.
HFrEF and HFpEF are the most common terms that you will hear to describe heart failure. However, at times, you may encounter the older, less common terms, “left-sided heart failure” and “right-sided heart failure.” When these terms are used, they are often in reference to the resulting symptoms.
Left-sided heart failure: Previously, healthcare professionals would categorize certain types of heart failure as “left-sided” if the symptoms resulted from dysfunction of the heart’s left side. The blood can back up in the lungs, causing breathlessness notably while lying flat. Other symptoms include shortness of breath on exertion, fatigue, and a rapid or irregular heart beat.
Right-sided heart failure: With right-sided heart failure, “the right side is either really weak or the pressures are so high from the left side, that the blood is actually backed up across the lungs and into the right side of the heart,” said Goldberg. Since the right side is responsible for receiving blood from the rest of the body and sending it across the lungs, “right-sided heart failure symptoms include things like swelling in the ankles, bloating in the abdomen, decreased appetite, and oftentimes shortness of breath.”
Many people with left-sided heart failure (HFrEF or HFpEF) ultimately end up with dysfunction of both sides of the heart. “The longer that you have left-sided heart failure, the more likely it is that you then ultimately develop right-sided heart failure because the right side is working so hard to overcome the weakness on the left that eventually the right side gets into trouble as well,” he said.
Our understanding of heart failure
Dr. Goldberg emphasized two pieces of information that he believes are absolutely critical.
First, heart failure is preventable. Managing hypertension (high blood pressure) can significantly reduce your risk for heart failure. Those with high blood pressure may not have heart failure yet, but they are at higher risk to develop heart disease or heart failure down the road.
“People might know that there are lifestyle changes that might reduce their risk of diabetes, but I'm not sure that people really get the idea that [addressing] those same risk factors can prevent heart failure,” said Goldberg.
Additionally, Goldberg stressed that once your heart stops working properly, you have to manage it for life. He recommends his patients with cardiac dysfunction to continue taking their prescribed medications for treating heart failure, such as ACE-inhibitors, ARBs, Beta blockers, indefinitely (all of these drugs are used primarily for reducing blood pressure to make it easier to pump blood – learn more about these medications here). As is the case with high cholesterol or high blood pressure, it could be that when “your numbers are good today, it's because of the medicine, not because you've been cured.” He cited results from the landmark study TRED-HF that provided data supporting the continued use of medication even if your heart function improves.
Prevention of heart failure and management are both entirely possible. Prevention, and management, include avoiding or quitting smoking, reducing your alcohol intake, decreasing your A1C and increasing your Time in Range, lowering blood pressure and cholesterol, being mindful of what you eat and losing weight for those with excess weight or obesity, and engaging in regular physical activity.
There are also medications that your healthcare team may prescribe to help you manage heart failure, including SGLT-2 inhibitors. You can learn about more medication options to treat heart failure in our article, “Heart Failure – The Overlooked Diabetes Complication, Part 2: Prevention and Management,” or check out KDBH’s article, “Diabetes and Heart Failure a Troubling Pair: Treatments Can Help”
What information should you look for in heart failure clinical trials?
Recently, medications that address heart failure have been a particular interest in clinical trials. Just this year, Jardiance and Farxiga, popular SGLT-2 inhibitors, were found to be able to reduce the risk for hospitalization and death from heart failure in people with type 2 diabetes and HFpEF or HFrEF.
Unfortunately, the results from clinical trials can sometimes be hard to make sense of. When trying to understand what researchers are talking about, here are a few things to keep an eye out for:
Major adverse cardiovascular events (MACE): MACE is a commonly reported measure in many cardiovascular trials. Each trial may define what events fall under the definition of MACE differently, but it often includes things like stroke, heart attack, and cardiovascular death. Heart attacks damage and weaken the heart, potentially leading to heart failure.
Quality of life (QoL): One of the most important, and sometimes underappreciated, outcomes of a clinical trial is improvement in QoL. Were participants able to spend more time engaging with activities that brought them joy? Although this measure can be somewhat subjective, it is usually measured with validated tests. When a drug or treatment is shown to improve a person’s QoL, it is considered a very positive result.
Survival rate/mortality: This is a more straightforward measurement that measures if participants on a certain treatment lived longer than those without the treatment. If this is shown, it is referred to as an “improvement in mortality.”
Hospital admission rate: Another important measure of success to consider is the hospital admission rate. This describes whether clinical trial participants were less likely to be hospitalized for a specific heart failure condition as a result of the treatment. Additionally, researchers might measure the number of days participants spent inside versus outside of the hospital.
To learn more about diabetes and heart failure, check out our other articles:
Heart Failure – The Overlooked Diabetes Complication, Part 1: What and Why?
Heart Failure – The Overlooked Diabetes Complication, Part 2: Prevention and Management
Preventive Cardiology: Rethinking Diabetes Care to Improve Heart Health
This article is part of a series to help people with diabetes learn how to support heart health, made possible in part by the American Heart Association and American Diabetes Association’s Know Diabetes by Heart initiative.