Hypertension and Dyslipidemia

Background

The Cardiovascular System

The role of the cardiovascular system is to:

  • regulate blood flow to tissues in the body
  • deliver oxygenated blood and nutrients
  • retrieve waste products
  • regulate the temperature of the body
  • transport hormones
  • maintain fluid volume
  • regulate pH
  • facilitate gas exchange of oxygen and carbon dioxide

The diagram of the heart below provides an overview of the different parts of the heart, and how blood flows through it.

 

A diagram showing the electrical conduction system of the heart. Full text description is below,
“Electrical conduction system of the heart: The figure illustrates the different electrical nodes and muscle fibers that play a role in the electrical conduction system. It also represents the NSR pathway.” Full text description is below.  (Ganesan et al., 2016)

Cardiovascular Disease

Cardiovascular Disease (CVD) is a group of disorders involving the heart and blood vessels.

Common forms of CVD include:

  • Coronary artery disease (CAD)
  • Hypertension (HTN)
  • Heart failure
  • Ischemic heart disease or coronary heart disease (CHD)
  • Peripheral arterial disease (PAD)
  • Dyslipidemia

In this section we will focus on Hypertension and Dyslipidemia.

Hypertension

Hypertension is a medical condition in which the blood pressure in the arteries is persistently elevated.

The cardiac cycle consists of two phases: systolic and diastolic.  Systolic blood pressure measurement is the force exerted on the walls of blood vessels during contraction, and the diastolic blood pressure measurement is the force exerted during relaxation.

Blood Pressure (BP) is regulated by:

  • Cardiac output
  • Sympathetic nervous system
  • Renin angiotensin aldosterone system (RAAS)
  • Renal function

It’s important to understand the various physiological mechanisms involved in blood pressure regulation as cardiac medications act on those systems.

The two phases of the heart cycle, diastole and systole, are shown. Full text description is below.
Human heart shown during systole and diastole. Full text description is below. Source: LadyofHats via Wikimedia Commons.

Dyslipidemia

Dyslipidemia is an abnormal amount of lipids in the blood, which is confirmed using a blood test.

The main lipids involved include:

  • Low-density lipoprotein (LDL)
  • High-density lipoprotein (HDL)
  • Triglycerides (TG)
Dyslipidemia can also be described as:
  • Hyperlipidemia: abnormally high levels of TC, LDL-C or TG
  • Hypercholesterolemia: elevated TC and/or LDL-C
These can lead to CVD as high LDL-C levels are associated with coronary artery disease (CAD) and peripheral artery disease (PAD).

A diagnosis of dyslipidemia can also mean that HDL cholesterol levels are too low.

Atherosclerosis and Coronary Artery Disease

Atherosclerosis refers to the progressive thickening of blood vessels due to an accumulation of plaque. Plaque is built of fatty deposits, fibrous connective tissue and smooth muscle cells, and may lead to blocked blood flow to the:
  • Coronary arteries (CAD)
  • Heart (myocardial infarction)
  • Brain (stroke)
  • Legs (PAD)
Illustration comparing an artery with normal blood flow (top) to one with abnormal blood flow due to plaque build-up along the artery wall, resulting in a narrowed artery (bottom).
Source: National Heart, Lung, and Blood Institute
Background complete! Feel free to review any resources and move to the next section, “Assess”, when you are ready.

 

License

Icon for the Creative Commons Attribution-NonCommercial 4.0 International License

Preparation for Dietetic Practice by Megan Omstead, RD, MPH is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.