Heart Failure Series: Part 2- Chronic Heart Failure (FL INITIAL Autonomous Practice- Differential Diagnosis)

The previous course, Heart Failure Series: Part 1- Definitions and Classifications, covered the new universal definition of Heart Failure, the risk factors for Heart Failure, a review of ejection fraction and how it is used in the staging of Heart Failure, the new staging classifications for levels of Heart Failure, and the symptoms of Heart Failure. This course, the second course in this series, will cover an in-depth explanation of left-sided Heart Failure, right-sided Heart Failure, and Biventricular Heart Failure.

Because Heart Failure is not one disease but a clinical syndrome, as first introduced in the first Heart Failure course in this series, symptoms will vary for everyone according to what their heart is responding to. For this, we will need to take sides, but first an anatomy refresher.

The chambers in each of our hearts constrict and push blood through to different areas of our bodies (Centers for Disease Control and Prevention [CDC], 2022):

• Unoxygenated blood flows from your body’s veins into your right atrium and then your right ventricle.
• Unoxygenated blood flows from your right ventricle to your lungs.
• Oxygenated blood flows from your lungs to your left atrium and then your left ventricle.
• Oxygenated blood flows from your left ventricle to your body’s arteries and circulates throughout your body.

Image 1: Circulation of Blood

Now that we have reviewed the circulation of blood through the heart, let’s review a few different types of chronic Heart Failure.

Left-sided Heart Failure is the most usual form of Heart Failure (HF). Though causes vary, it is typically associated with the presence of coronary artery disease (CAD) (Newman, 2021).

In left-sided failure, the heart handles pumping blood to the rest of the body. If it does not do so because the heart muscle is too weak to pump effectively, this is systolic failure, or HFrEF (Newman, 2021). Alternatively, if the heart muscle is too stiff to pump effectively, it is known as HFpEF, or diastolic Heart Failure.

If the left ventricle loses its ability to contract forcefully (systolic failure), it cannot exert enough force to pump the volume of blood needed through the circulatory system. If the left ventricle loses its ability to relax (diastolic failure) because the ventricular muscle has become stiff, it cannot properly fill with blood during the resting period between each beat (Newman, 2021; Judeo Christian, n.d.). This inability is an important distinction because the treatments for each type of failure, left or right, differ.

In left ventricular failure, the cardiac output decreases, and pulmonary venous pressures increase. The elevation of pulmonary capillary pressures can rise to levels that exceed the functional pressure of the plasma proteins that form the barrier between vascular fluids and atmospheric gases, about 24 mm Hg, leading to increased fluid in the lungs, reduced pulmonary compliance, and a rise in the oxygen cost of the work of breathing (Newman, 2021; Yetman, 2021; Judeo Christian, n.d.). This high vascular pressure, known as pulmonary venous hypertension, and the pulmonary edema resulting from left ventricular failure, alter the function of the lungs and those tricky ventilation-perfusion relationships significantly. Air hunger, therefore, correlates with elevated pulmonary venous pressure as well as the resultant increased work of breathing.

Because of what is happening physiologically in the heart, the symptoms of left-sided Heart Failure include (Todd, 2021; Newman, 2021; Heart Failure Society of America [HFSA], 2022; Yetman, 2021):

• Fatigue, even at rest
• Coughing, especially during physical activity
• Shortness of breath, particularly evident during activity
• Trouble breathing

One of the fascinating things about left-sided Heart Failure is that due to the vascular layout of the pulmonary system, pleural effusions will characteristically accumulate in the right hemithorax, though they later manifest bilaterally. The body's lymphatic drainage becomes enhanced to deal with this fluid crisis, yet it cannot overcome the increase in fluid in the lungs. Unoxygenated pulmonary arterial blood ends up shunted past nonaerated alveoli, decreasing mixed pulmonary capillary partial pressure of oxygen (PO₂). These changes often progress to the point where an arterial blood gas (ABG) analysis reveals an increased pH and a reduced PaO₂ (pulmonary oxygen concentration). Or, in other words, respiratory alkalosis. A PaCO₂ (pulmonary carbon dioxide concentration) above normal signifies alveolar hypoventilation due to respiratory muscle failure and may require urgent ventilatory support.

Right-sided Heart Failure is less common than left-sided Heart Failure, yet just as lethal. Right-Sided Heart Failure puts the "congestive" back into the universal description, as described in the first Heart Failure series course, even if only as a subcategory.

Remember that the right side of the heart pumps blood to the lungs, collecting oxygen. Right-sided Heart Failure (RSHF) normally follows the development of left-sided Heart Failure (LSHF); this is why cardiologists search for LSHF first. However, it can sometimes occur on its own due to specific conditions, such as lung disease or pulmonary hypertension (Yetman, 2021; Judeo Christian, n.d.).

The right atrium receives venous (unoxygenated) blood from the systemic circulation - from the arms, head, abdomen, and legs. It receives blood that returns to the heart through the superior vena cava (draining blood from the head and upper extremities), inferior vena cava (draining blood from the abdominal viscera and the lower extremities), the coronary sinus (draining blood from the circulation of the heart muscle itself) and the many tiny Thebesian veins (draining small amounts of blood directly from the atrial vessel walls). The blood is propelled through the tricuspid valve during the right atrial systole. Then it enters the right ventricle, ejected through the pulmonic valve into the left and right pulmonary arteries. After which, it is pushed into the lungs, where the blood is replenished with oxygen (Yetman, 2021; Judeo Christian, n.d.).

Right-sided ventricular failure usually, but not always, is secondary to left-sided Heart Failure (Yetman, 2021; Judeo Christian, n.d.). The reason both the left and right ventricles tend to be affected in a domino fashion is that when the left ventricle fails, increased fluid pressure is, in effect, transferred backwards through the lungs, damaging the heart's right side. When the right side loses pumping power, blood backs up in the body's veins. This failure usually causes unsightly and medically hazardous swelling in the legs and ankles.

Right-sided ventricular failure is strongly associated with the development of systemic venous congestive symptoms. The sluggish venous congestion, in turn, leads to moderate hepatic dysfunction that is common in CHF secondary to right-sided Heart Failure.

The symptoms of right-sided Heart Failure include (Todd, 2021; Newman, 2021; HFSA, 2022):

• Fatigue
• Weight gain
• Fluid buildup/swelling in the legs and around external genitals
• Fluid buildup/swelling in the organs of the abdomen
• Abdominal fullness and discomfort
• Fluid collecting around the lungs

Be aware that these same symptoms can come from other disease processes that mimic right-sided Heart Failure. Examples include generalized volume overload, the increased systemic venous pressure in polycythemia, over-perfusion of blood products, acute renal failure with overhydration, or obstruction of either vena cava. If these conditions occur, they may readily simulate right-sided Heart Failure.

The presence of peripheral edema is not a reliable sign of HF. Another easily visible clue is the presence of observable jugular venous distention with a hepatojugular reflex. The hepatojugular reflex is an elevation of venous pressure visible in the jugular veins of the neck demonstrated when there is either active or impending right-sided Heart Failure by applying firm pressure with the flat hand over the person's liver or upper abdomen (Vaidya & Bhatti, 2021).

The most common scenario in Stage D settings, as listed in the first course in this Heart Failure series, is affected by both sides of the heart. Typically risk factors are present (Stage A), cardiovascular structural changes begin to occur (Stage B), visible symptoms of left-sided (most common) Heart Failure manifest (Stage C), damage spreads to encompass all the heart and the major organ systems (Stage D).

Biventricular Heart Failure is a chronic disease process. Lifestyle choices and the effects of other predisposing disease processes set up conditions that gradually worsen with intervals of acute crisis. By the time a person receives a traditional diagnosis of Heart Failure, the chances are good that the heart has been losing pumping capacity for some time.

At first, the heart tries to make up for the loss of effective pumping capacity by (Yetman, 2021):

1. Enlarging: When a heart chamber enlarges, it is trying to stretch further to contract more forcefully and move more blood volume.
2. Increasing in muscle mass: The further development in muscle mass occurs because the contracting cells of the heart get bigger, allowing the heart to pump stronger, at least initially. Stiffness and rigidity will inevitably set in.
3. Pumping faster: This helps to increase the heart's overall cardiac output.

The heart is not in this alone. The rest of the body also tries to compensate for the loss of cardiac output via these methods (Todd, 2021; Newman, 2021):

• Systemic blood vessels narrow, also known as vasoconstriction, to elevate blood pressure, thus attempting to structurally adjust and make up for the heart's centralized loss of power.
• The body diverts blood away from less critical tissues and organs to support flow to the most vital organs: the heart, lungs, and brain.

These temporary measures achieve little more than to mask symptoms of Heart Failure. They do not solve the problem. Many clients are unaware of their condition until years after their heart becomes as effective as squeezing a soggy sponge. Inevitably, the efforts to compensate made by the heart and body will not keep up with their demands. The person experiences fatigue, breathing problems, or other vague symptoms that prompt a doctor or emergency room trip.

The symptoms of Biventricular Heart Failure include (Todd, 2021; Newman, 2021):

• Fatigue
• Weight gain
• Trouble breathing
• Breathlessness at night
• Fluid buildup/swelling in the legs and around
• Fluid buildup/swelling in the organs of the abdomen
• Abdominal fullness and discomfort
• Fluid collecting around the lungs
• Coughing

Now that we have reviewed the differences between left-sided, right-sided, and Biventricular Heart Failure, let’s review a case study to apply this knowledge.

This course covered a review of the circulation of blood through the heart, an in-depth description of left-side Heart Failure versus right-sided Heart Failure, as well as an examination of Biventricular Heart Failure. For more information regarding more acute Heart Failure presentation, sudden cardiac death, and the treatment of Heart Failure, please continue forth within the Heart Failure series to Heart Failure Series: Part 3- Acute Heart Failure.

• Centers for Disease Control and Prevention. (CDC). (2022). How the heart works. Centers for Disease Control and Prevention. Retrieved May 3, 2022. Visit Source.
• Colucci, W., & Borlaug, B. (2021). Heart Failure: Clinical manifestations and diagnosis in adults. UpToDate. Retrieved February 20, 2022. Visit Source.
• Gibson, G., Blumer, V., Mentz, J., & Lala, A. (2021). Universal definition and classification of Heart Failure: A step in the right direction from failure to function. American College of Cardiology. Retrieved February 20, 2022. Visit Source.
• Heart Failure Society of America. (HFSA). (2022). Heart Failure facts & information. Heart Failure Society of America. Retrieved February 19, 2022. Visit Source.
• Judeo Christian. (n.d). Congestive Heart Failure overview. Visit Source.
• Newman, T. (2021). What to know about congestive heart failure. Medical News Today. Medical NewsRetrieved February 21, 2022. Visit Source.
• Todd, L. (2021). What to know about systolic heart failure. Medical News Today. Retrieved February 21, 2022. Visit Source.
• Vaidya, Y., & Bhatti, H. (2021). Hepatojugular reflux. StatPearls. Retrieved February 22, 2022. Visit Source.
• Yetman, D. (2021). What are the differences between left- vs. right-sided heart failure? Healthline. Retrieved February 21, 2022. Visit Source.