Heart: Anatomy and Physiology
Thank you, everybody, for taking the time out to listen to this webinar today. Today, we are going to tackle heart failure in three different ways. First, we are going to discuss the normal physiology and pathophysiology of heart failure. Then, we are going to discuss a way to assess or look at our heart failure patients to guide our treatment, as well as, highlight the importance of goal setting in the context of lifestyle modification and self-management. Lastly, we are going to discuss self-management for heart failure, and how as occupational therapists, we can really contribute a lot to this aspect.
- Upper chamber
- Left and right
- Lower chamber
- Left and right
- Separates the left and right sides of the heart
- Participates in conductivity and ventricular contraction
We all know that the heart has four chambers, and there are left and right sides. The upper chambers are the atria, and the lower chambers are the ventricles. The septum separates the heart into a left side and a right side. And, there are valves.
- Atrioventricular Valves
- Tricuspid: R atrium and R ventricle
- Mitral: L atrium and L ventricle
- Semilunar Valves
- Pulmonary: R ventricle and pulmonary artery
- Aortic: L ventricle and aorta
The valves allow the heart to fill with blood that will be brought out to the rest of the body. Figure 1 shows a schematic of how the blood goes throughout the rest of our body.
Figure 1. Heart structures.
As you can see, our lungs and our heart are interrelated. If there is something wrong with the lungs, it can affect the heart. Consequently, if there is something wrong with the heart, it can eventually involve the lungs.
Figure 2 is a Sankey diagram of how the blood is distributed to the different parts of our body. You can see in this diagram how the body distributes blood to where it is needed the most.
Figure 2. Sankey diagram showing circulation to different parts of the body.
For example, when exercising, the circulatory system can shift blood to the skeletal muscles instead of other parts of the body. Below is another diagram to represent blood flow (Figure 3).
Figure 3. Circulation diagram.
Heart Failure: Definition and Pathophysiology
- The inability of the heart to meet the body’s metabolic needs (Cassady & Cahalin, 2011)
- The heart cannot fill chambers with enough blood
- The heart cannot pump blood to the body effectively (National Heart, Lung, and Blood Institute, n.d.)
- Not all patients with HF are congested (Yancy et al., 2013)
- Complex clinical syndrome vs a diagnosis
Heart failure is an inability of the heart to meet a body's metabolic needs. The heart cannot fill the chambers with enough blood or pump blood to the body effectively. It is also very important for us to realize that not all heart failure is congestive. There is also an issue where the heart can get so stiff that it cannot relax enough to receive the blood. Therefore, you do not have enough blood to send out to the rest of the body. We should also think about heart failure as a clinical syndrome versus a diagnosis. It is a clinical picture that lets the clinicians decide if it is heart failure or not. Figure 4 is just a depiction of what heart failure would look like after remodeling.
Figure 4. Heart failure after remodeling.
In the left picture, the left ventricle is small and really efficient in pumping out that blood. And over time, because of heart failure, it is going to adapt by making the heart muscles bigger, and therefore, inefficient in performing or meeting its function (right side pic).
- 5.7 million adults
- HF contributed in 1 in 9 deaths in 2009
- 50% of people who develop HF die within 5 years
- Mozzafarian et al., 2016
- $30.7 billion each year (health care services, medications to treat HF, missed workdays)
- Heidenreich et al., 2011
We all know that heart failure is prevalent and costs a lot as seen by the numbers above from the research.
Signs and Symptoms
- Dyspnea (exertion, paroxysmal nocturnal, orthopnea)
- Fatigue/weakness/lethargy (HF-induced skeletal muscle abnormality)
- Physical: elevated jugular venous pressure, pulmonary rales, lower extremity edema, abdominal distention)
- Right hypochondrial pain (2/2 to R-sided HF)
- Exertional chest pain
- Activity intolerance
- All HF patients report dependence on at least 1 activity
Dyspnea and fatigue are the most common sign or presentation of heart failure. There also can be fatigue, weakness, and lethargy because of a heart failure-induced skeletal muscle abnormality. You will also see your patients having exertional chest pain or activity intolerance. All heart failure patients will report at least dependence in one ADL or activity. They could also present with right hypochondrial pain, and this may be secondary to right-sided heart failure.
- Cognitive impairment: 25-80%
- Acute and fluctuating: delirium (decompensated HF)
- Chronic: subjective cognitive decline, MCI (most common), mild neurocognitive disorder, dementia (stable HF)
- Attention, executive function, psychomotor speed
- Visuospatial skills and memory may recover if HF well-controlled (Cannon et al., 2017)
- Low health literacy is associated with higher all-cause mortality and a barrier to effective disease self-management; is a modifiable risk factor for poor disease outcome
Another interesting fact is that 25 to 80% of our patients will also have cognitive impairments. There have been a lot of studies about how having heart failure can lead to cognitive impairment. It could be acute and fluctuating, such as delirium, especially if your patient is having decompensated heart failure. Or, it could be chronic. They can have a subjective cognitive decline or a mild cognitive impairment, which is the most common. They could also have a mild neurocognitive disorder or dementia. Language is also affected. And with language, you would see that over time, this would really decline. Attention, executive function, and psychomotor speed are also affected. There is also evidence that visuospatial skills and memory are able to recover if heart failure is well-controlled. Thus, it is very important to help our clients to control their heart failure as it will promote improved cognitive skills. Low heart literacy is associated with heart failure as well. And, it is associated with higher all-cause mortality. So, it is important for us to also screen and look into our patient's health literacy.
- Depression and Anxiety:
- Depressive symptoms: 21.5%
- Anxiety: 13% anxiety disorder and 30% clinically significant levels of anxiety
- Rutledge et al., depressive symptoms or depressive disorder 2x increase of death or cardiac events
- Biological and behavioral mechanisms may explain the association between depression and anxiety and poor HF outcomes
- Screen with PHQ-2 and then use PHQ-9 for the positive screen (Celano et al., 2018)
Depression and anxiety are also documented with heart failure. As many as 21.5% of patients with heart failure exhibit depressive symptoms. Thirteen percent will have anxiety disorders, and 30% will test positive for a clinically significant level of anxiety. Researchers recommend that when we see patients with heart failure to use the PHQ-2 (Patient Health Questionnaire). Then, if they screen positive using the PHQ-2, they recommend using the PHQ-9 to further explore their anxiety and depression.
- Coronary heart disease and heart attacks
- High blood pressure
- Eating foods high in fat, cholesterol, sodium
- Sedentary lifestyle
[Centers for Disease Control and Prevention (CDC), 2019]
As we talked about earlier, heart failure does not just happen by itself. It is usually triggered by heart disease, smoking, a sedentary lifestyle, obesity, heart failure, and other heart insults such as a heart attack. There are different ways that clinicians classify patients with heart failure. One of them is by using the New York Heart Association Functional Classification in Figure 5.
New York Heart Association (NYHA) Functional Classification
Figure 5. NYHA Functional Classification.
In this one, they are looking into a person's ability to tolerate physical activity, their ability to rest, and what happens to them when they are completing ordinary activities such as walking, sitting, or going to eat. They classify them according to mild, moderate, and severe.
American Heart Association (AHA) Heart Failure Stages
Figure 6. AHA Heart Failure Stages.
The American Heart Association also classifies them by different stages. Stage A would be just having risk factors for heart failure, but there is not yet any heart disease or symptoms. For example, one of the risk factors is hypertension. We all know that with chronic hypertension, there can be structural damages in the heart.
Compensated Vs. Decompensated
Heart failure could also be compensated or decompensated (Figure 7).
Figure 7. Compensated vs. decompensated.
We should note that a decompensated heart failure is a medical emergency and should be treated right away. Compensated heart failure is medically stable. This is where the heart has adapted. You will see a ventricular enlargement and activation of the sympathetic nerves in the renin-angiotensin-aldosterone system.
Left-Sided Vs. Right-Sided HF
Figure 8. Left-sided vs. right-sided.
Heart failure could also be left-sided or right-sided. With right-sided heart failure, the heart cannot pump blood to the lungs for oxygenation. For left-sided heart failure, it cannot pump blood to the rest of the body. The right side of the heart receives blood from the body. So now, the blood flows back to the venous system, and that is why you will see peripheral edema. You will also notice some orthopnea or difficulty breathing when laying down flat. With left-side heart failure, the blood flows back to the lungs. For this, you will see more pulmonary edema. And since the blood flows back and the whole system is inefficient, you will see that they will also be breathing a little bit faster.
Reduced Ejection Fraction Vs. Preserved Ejection Fraction
When classifying heart failure based on ejection fraction, the are really just looking mostly with the left ventricle because they are looking at how much blood the heart is able to pump out to the rest of the body (Figure 9).
Figure 9. Reduced EF vs. preserved EF.
So, they have what they call a reduced ejection fraction and a preserved ejection fraction. The one with reduced ejection fraction used to be called systolic heart failure, and the one with preserved ejection fraction was diastolic heart failure. With reduced ejection fraction, your left ventricle is only able to eject less than or equal to 40% of the blood that it receives. With the preserved ejection fraction, it is normal. The normal ejection fraction is between 50 to 70%. The 41 to 49% range is considered borderline reduced ejection fraction.
How do our healthcare practitioners usually manage?
Goals of Treatment
- Improve prognosis and reduce mortality
- Relieve symptoms and reduce morbidity
- Reduce the length of stay and readmission
- Prevent organ system damage
- Manage comorbidities that lead to poor prognosis
The goals of treatment are to improve prognosis and reduce mortality, as well as relieve symptoms and reduce morbidity. We also want to reduce the length of stay and readmission. We want to prevent organ system damage and manage comorbidities that lead to poor prognosis. As therapists, you can immediately see how we can contribute to helping meet all these goals.
Manage the Stages of HF
Going back to the AHA classification and the stages of heart failure, you can see that they have also recommended how to manage each stage of heart failure (Figure 10).
Figure 10. Ways to manage different stages of heart failure.
In Stage A, they recommend risk factor reduction and patient and family education. Stage A represents those patients that do not really have structural defects in their heart but have risk factors for heart failure. In this stage, you would want to educate them and their families on how to reduce their risks for developing heart failure. It is also good to note that we are really very important in this stage of the game as a lot of this education is abstract like lowering sodium, increasing physical activity, etcetera. Sometimes our patients wonder how they are going to adapt or modify their lifestyle to fit their current routine. You will also see that, in Stages B, C, D, I have added in both "risk factor reduction" and "self-management education" in italicized text. This is because these will really be helpful in all stages of heart disease. In Stage B, there will be structural defects, although not a lot of symptoms. However, you will still want them to manage their disease so they do not progress to C and D.
The following chart shows the name of medications and their actions and reasons for using them for heart failure management (Figure 11).
Figure 11. Types of medications used for HF.
When you have a heart failure client, you may note that they take a lot of medications. Medication management is a huge part of a heart failure patient's disease management. I have compiled a list of commonly prescribed medications for patients with heart failure. This list is also accessible from the American Heart Association website, heart.org. The goals of pharmacologic therapy are to improve the symptoms, slow or reverse the deterioration of myocardial function, and reduce mortality. Research has looked into why a lot of the heart failure patients do not take their medications. Many feel like the medications are not effective. Getting ourselves familiar with the medication type, routine, and their action will help us to educate our patients. For example, ACE inhibitors can have an immediate effect meaning your client would almost immediately feel like they could breathe better. But if they are prescribed beta-blockers, the results are not immediate. It actually takes effect around 30 to 60 days after they started taking it. This information is helpful to review with your patients. "You should keep taking it as the effect will be long-term versus short-term." For heart failure with preserved ejection fraction where the ventricle is stiff and unable to receive blood, there are not a lot of management options.
Management of Associated Conditions
- Lung disease
- Kidney disease
- Sleep-disordered breathing
Often, a client with HF does not have a great quality of life. Most treatments focus on managing the associated diseases hoping that they do not progress further.
Minimally Invasive Devices
One of the things for managing heart failure patients, especially with patients with reduced ejection fraction, is a minimally invasive device such as a pacemaker or an automatic implantable cardioverter defibrillator, or AICD.
Figure 12. Example of a pacemaker (An artificial pacemaker from St. Jude Medical, with electrode. Steven Fruitsmaak, 2007 https://commons.wikimedia.org/wiki/File:St_Jude_Medical_pacemaker_in_hand.jpg).
Figure 13. Example of an AICD (Automatic implantable cardioverter defibrillator. https://en.m.wikipedia.org/wiki/File:AICD.jpg).