Type 2 diabetes shares risk factors with cardiovascular diseases (CVDs) for example heart failure (HF). Patients living with diabetes have a 2-4-fold1,2 risk of developing HF, while the risk for hospitalisation is five times higher compared to people without diabetes. As a pharmacist, it is important to revise background information about HF.
HEART FAILURE VS HEART ATTACK
A heart attack, or myocardial infarction, occurs suddenly when coronary arteries to the heart become completely blocked, or the heart is unable to pump blood effectively. 3
These blockages occur when cholesterol plaques or blood clots are formed in the coronary arteries. By restricting blood flow, these blockages can damage the heart muscle. 3
Heart failure (HF), or congestive heart failure, occurs when the heart is weakened and enlarged. This results in:4
- Enlarged heart ventricles, which means that the heart can’t pump the requires amount of blood. This has implications such as failing to deliver oxygen to the rest of the body
- If the ventricles are damaged this results in their inability to fill with enough blood between beats.
In HF the lower left ventricular (which is the main pumping chamber) is first affected although the right ventricle is also affected. In some cases, both ventricles are affected.4
Left-sided HF affects the lower left ventricle. This results in fluid back up in the lungs, causing shortness of breath.4
Right-sided HF affects the lower right ventricle. This results in fluid back up into the abdomen, legs, and feet, causing swelling.4
HOW THE HEART WORKS AND WHAT HAPPENS WHEN YOU HAVE HEART FAILURE?
The heart is one the most vital organs in the body. The function of the heart is to pump the right amount of blood into circulation. The right atrium receives oxygen-depleted blood from the rest of the body and sends it through the right ventricle to the lungs, which provides the body with oxygen. Oxygen-rich blood then circulates from the lungs to the left atrium, thereafter to the left ventricle, which intern pumps it to the rest of the body.5
HF leads to an inability of the heart muscles to pump enough blood for the body’s needs for oxygen.
At first, the heart tries to accommodate, by:
- Enlarging – the heart muscles stretch to contract more strongly to pump more blood in the body
- Developing more muscle mass – this occurs because the contracting heart cells increase. This results in increased heart contractions
- Contracting faster – this helps increase the heart’s output.
The body also tries to compensate in other ways:
- The blood vessels narrow to increase the blood pressure by attempting to compensate for the heart’s loss of contraction
- The kidneys retain more salt and water rather than excreting it in urine. This results in an increased volume of blood, which helps to maintain blood pressure and allows the heart to contract stronger.
WHAT IS EJECTION FRACTION (EF)?
EF is a measurement (expressed as a percentage), of how much blood the left ventricle pumps out with each heartbeat. This is an indication of how well the heart is pumping out blood and can help to diagnose and track HF3 (refer to table 1).
CLASSIFICATION OF HEART FAILURE
The classification of HF is divided according to left ventricular ejection fraction (LVEF)6. Patients with:
- LVEF < 40% = having HF with reduced ejection fraction (HFrEF)
- LVEF between 40-49% = mid-range ejection fraction (HFmrEF)
- LVEF > 50% = HF with preserved ejection fraction (HFpEF).
Table 1: Revised definition and classification of heart failure (HF)2,6
Note: NT-proBNP = N-terminal pro-B-type natriuretic peptide; BNP = brain natriuretic peptide; LVH = left ventricular hypertrophy; LAV = left atrial enlargement
#HF with reduced ejection fraction (HFrEF) (systolic HF) – affects the left side of the heart. This implies that the left ventricle cannot contract normally and results in insufficient oxygen rich blood flow to the body. $HF with preserved ejection fraction (HFpEF) (diastolic HF) – affects the left side of the heart. This implies that the left ventricle cannot dilate and thus be filled with sufficient blood.
HF is a health condition of concern, and the management thereof forms part of that for cardiovascular renal metabolic (CVRM) disorder. The pharmacist plays an important part in understanding CVRM disorder and its integrated management.
- Dr. Julan Trokis. MedTalks ZA. Managing heart failure. Early detection and treatment. 2022. Available at: https://player.vimeo.com/video/716035589 as well as www.denovomedica.com – accessed: 05 June 2023
- Aalbers, J. Early prevention and management of heart failure in type 2 diabetic patients. deNovo Medica, 2021, July, 1-6
- MedicalNewsToday. Heart attack vs. heart failure: What to know. 2023, May 26. Available at: https://www.medicalnewstoday.com/articles/shoveling-snow-heart-attack#summary – accessed: 03 June 2023
- Mayo Clinic. Heart Failure. Symptoms and causes. 2023. Available at: https://www.mayoclinic.org/diseases-conditions/heart-failure/symptoms-causes/syc-20373142#:~:text=Heart%20failure-,Heart%20failure%20occurs%20when%20the%20heart%20muscle%20doesn't%20pump,to%20appear%20blue%20or%20gray. – accessed: 03 June 2023
- American Heart Association. Heart attack and stroke symptoms. What is heart failure? 2023, March 22. Available at: https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure - accessed: 03 June 2023
- MEDTalk presented by Dr. Martin Mpe. MedTalk. Cardiorenal Series 3, Module 3. Type 2 diabetes and the heart. Martin Mpe. 2021. Available at: https://vimeo.com/560385809/a86135cd92 as well as www.denovomedica.com - accessed: 03 June 2023
ADDITIONAL READING MATERIAL
- American Heart Association. Heart attack and stroke symptoms. Classes of heart failure. 2023, March 22. Available at: https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure/classes-of-heart-failure - accessed: 03 June 2023
- American Heart Association. Heart attack and stroke symptoms. Heart failure signs and symptoms. 2023, March 22. Available at: https://www.heart.org/en/health-topics/heart-failure/warning-signs-of-heart-failure - accessed: 03 June 2023 (see self-check infographic plan for the management of HF that can be provided to HF patients, as part of an ‘add on’ service)
- National Heart, Lung and Blood Institute (NIH). Heart failure. Diagnosis. 2022, March 24. Available at: https://www.nhlbi.nih.gov/health/heart-failure/diagnosis - accessed: 03 June 2023
- National Heart, Lung and Blood Institute (NIH). Heart failure. What is heart failure? 2022, March 24. Available at: https://www.nhlbi.nih.gov/health/heart-failure- accessed: 03 June 2023
- Mayo Clinic. Heart Failure. Diagnosis and treatment. 2023. Available at: https://www.mayoclinic.org/diseases-conditions/heart-failure/diagnosis-treatment/drc-20373148 – accessed: 03 June 2023
- American Heart Association. Watch, learn and live. Interactive cardiovascular library. Heart failure. 2023, March 22. Available at: https://watchlearnlive.heart.org/index.php?moduleSelect=hrtflr - accessed: 03 June 2023
- American Heart Association. Heart attack and stroke symptoms. Types of heart failure. 2023, March 22. Available at: https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure/types-of-heart-failure - accessed: 03 June 2023