Cardiovascular Disorders

Introduction

The heart is a complex organ vital to human life. Disorders associated with the cardiovascular system are so serious and prevalent, they're the leading cause of death in the United States. It's important to learn about these disorders so you'll know how to prevent them from happening or how to treat them if they arise.

 

Hypertension

Most people think hypertension simply means "high blood pressure." Actually, the condition of hypertension is determined only if the patient has had elevated blood pressure readings over a significant period and under varied conditions.

Hypertension is known as a "silent killer." A person with hypertension may not feel ill. However, elevated blood pressure over a long period causes progressive damage to many organs of the body. 

Hypertension is a major risk factor for atherosclerosis, which is the buildup of plaque in the arteries. In turn, atherosclerosis of the renal arteries (arteries feeding blood to the kidneys) can lead to hypertension because the kidneys play a central role in blood pressure regulation. Uncontrolled hypertension leads to strokes, heart attacks (myocardial infarctions), peripheral vascular disease, chronic kidney disease, and retinal disease. Most hypertensive people have idiopathic hypertension, the cause of which is unknown.

 

Decades ago, hypertension was thought to be a normal and acceptable process of aging. Now, physicians know that hypertension at any age is a serious disease that needs to be treated. Normal resting blood pressure is 120/80 mmHg (120 systolic over 80 diastolic).

Remember: Systolic blood pressure is a measure of the amount of pressure that blood presses against the arteries and vessels as the ventricles of the heart contract. Diastolic blood pressure is a measure of the same pressure when the heart is relaxed. Another way to think of these measures is that systolic is the "peak" pressure and diastolic is the "minimum" pressure.

Blood pressure levels

Normal | Systolic: less than 120 mmHg

                 Diastolic: less than 80 mmHg 

At risk | Systolic: 120-139 mmHg

               Diastolic: 80-89 mmHg

High | Systolic: 140 mmHg or higher

            Diastolic: 90 mmHg or higher

 

Risk factors for high blood pressure include:

1. Increased age
2. High salt and saturated fat intake
3. Hyperlipidemia (high level of lipids, such as fats, cholesterol, and triglycerides, in the blood)
4. Being overweight or obese
5. Not having an active lifestyle (also called a sedentary lifestyle)
6. Smoking
7. Family history of high blood pressure

The best treatment for high blood pressure is changing your lifestyle. These changes include:

• Losing weight
• Drinking less or no alcohol
• Decreasing salt intake
• Exercising 
• Quitting smoking
• Eating a healthy diet

 

Different classes of medication are used to treat hypertension, including

1. Diuretics 
2. Beta blockers
3. ACE inhibitors 
4. ARBs
5. CCBs
6. Vasodilators 

Each class of medication comes with its own side effects and special precautions.

 

Diuretics are also known as "water pills." Diuretic medications stop kidneys from reabsorbing water and electrolytes. This leads to increased loss of water and electrolytes in the form of urine. Increased water loss lowers the blood volume, which lowers the blood pressure.

Medications: 

• Spironolactone (Aldactone)
• Furosemide (Lasix)
• Bumetanide (Bumex)
• Hydrochlorothiazide (Esidrix)

Side effects:

• Hypotension (low blood pressure)
• Dehydration 
• Electrolyte deficiencies 
• Arrhythmias 

Special precautions:

• Avoid taking at bedtime 
• May need electrolyte supplements
• Spironolactone, a potassium-sparing diuretic, may not require a potassium supplement

 

Beta blockers are beta receptor antagonists that act on the beta receptors in the heart. This causes decreased heart rate and cardiac output and lowers the blood pressure. These drugs are particularly helpful in patients with increased heart rate at rest. Note that beta blocker names end in the suffix –lol.

Medications:

• Metoprolol (Lopressor)
• Atenolol (Tenormin)
• Metoprolol XL (Toprol XL)
• Carvedilol (Coreg)
• Labetalol (Normodyne)
• Propranolol (Inderal)

Side effects:

• Hypotension
• Dizziness
• Syncope
• Bradycardia
• Fatigue
• Hepatic toxicity

Special precautions:

• Don't abruptly discontinue
• Major drug-drug interactions occur with certain asthma medications

 

Angiotensin Converting Enzyme (ACE) inhibitors inhibit (that is, restrain) the conversion of Angiotensin I to Angiotensin II (a potent vasoconstrictor). ACE inhibitors decrease the fluid volume and also cause peripheral vasodilation, resulting in lower blood pressure. Most ACE inhibitor medications end with the suffix –pril.

Medications:

• Captopril (Capoten)
• Lisinopril (Prinivil)
• Enalapril (Vasotec)
• Benazepril (Lotensin)

Side effects:

• Hyperkalemia (increased blood potassium)
• Hypotension 
• Dry, persistent cough
• Angioedema (swelling of tongue, lips, and mouth—a serious adverse event requiring immediate treatment)
• Increased serum creatinine (indicator of kidney failure)

Special precautions:

• If a cough is intolerable, may need to switch to different class of antihypertensive
• Monitor kidney function

 

Angiotensin II receptor blockers (ARBs) inhibit the binding of Angiotensin II to the Angiotensin II receptor. ARBs produce similar end results as ACE inhibitors to lower the blood pressure. Most ARB medications end with the suffix –sartan.

Medications:

• Losartan (Cozaar)
• Valsartan (Diovan)
• Irbesartan (Avapro)

Side effects:

• Hyperkalemia (increased blood potassium)
• Hypotension
• Dry, persistent cough
• Angioedema (swelling of tongue, lips, and mouth—a serious adverse event requiring immediate treatment)
• Increased serum creatinine (indicator of kidney failure)

Special precautions:

• If a cough is intolerable, may need to switch to different class of antihypertensive
• Monitor kidney function

Calcium channel blockers (CCBs) hinder the calcium ion influx (calcium is required during contraction) in the vascular smooth muscle of the heart, resulting in heart muscle relaxation—decreasing blood pressure. Most CCB medications end with the suffix –pine.

Medications:

• Diltiazem (Cardizem)
• Verapamil (Calan)
• Amlodipine (Norvasc)
• Felodipine (Plendil)

Side effects:

• Hypotension
• Dizziness
• Flushing
• Headache

Tachycardia

• Exacerbation of CHF (congestive heart failure)

Special precautions:

• Monitor for signs of peripheral or pulmonary edema

Vasodilators work by directly dilating the blood vessels o produce rapid and significant reduction in blood pressure. Vasodilators are commonly used to treat dangerously high blood pressure in emergency situations due to their rapid effect on lowering blood pressure. All medications beginning with the prefix nitro– are vasodilators.

Medications:

• Hydralazine (Apresoline)
• Nitroprusside (Nitropress)
• Nitroglycerin (Nitrostat)
• Isosorbide Mononitrate (Imdur)

Side effects:

• Tachycardia
• Edema or fluid retention
• Lupus
• Postural hypotension

Special precautions:

• Don't abruptly stand up
• Monitor for signs of swelling

 

Congestive Heart Failure

Congestive heart failure (CHF) happens when the heart can't pump blood efficiently to deliver an adequate supply of blood to the metabolizing tissues, usually because of water and sodium retention. CHF is often confused with a "heart attack." However, it may precede or follow a heart attack. It also may be associated with other cardiovascular problems, such as high blood pressure, aortic stenosis, and coronary artery disease.

 

The word congestive is used to imply the edematous state commonly associated with fluid retention. CHF most commonly occurs in the elderly but could also occur in people of any age due to underlying cardiovascular problems such as coronary artery disease, pulmonary embolism, and infection.

Symptoms of CHF include fatigue, increased urination at night, swelling, shortness of breath, tachycardia, and nausea/vomiting.

Medications are used to help relieve these symptoms, prevent further damage, and prolong survival. Damaged heart muscle after heart failure can't be repaired.

Risk factors for congestive heart failure include

• Increased age
• Infections
• Valve disease
• Arrhythmia 
• Trauma to heart muscle
• Chemotherapy and certain illicit medications
• Congenital heart disease

Nonpharmacologic therapy for congestive heart failure may include

• Bed rest to decrease the cardiac load
• Progressive ambulation
• Dietary control with small, frequent meals
• Salt restriction

 

Medications used to treat congestive heart failure include the following.

Digoxin (Lanoxin). Digoxin is a medication that's been proven to be very effective in treating CHF symptoms and reducing hospitalization. It's important to monitor digoxin levels closely to avoid digoxin toxicity due to its narrow therapeutic index.

Diuretics. Diuretics are slowly titrated to minimize or eliminate fluid retention. Diuretics increase urination and odium excretion. 

Beta Blockers. Beta blockers reduce heart rate and prevent arrhythmias to help reduce CHF symptoms. Beta blockers are known to reduce the risk of mortality and hospitalization and improve the overall clinical status of CHF patients. Sometimes beta blockers are used in conjunction with diuretics. 

ACE Inhibitors and ARBs. These medications are generally used for long-term management of chronic CHF.

 

Hyperlipidemia 

Hyperlipidemia (or high cholesterol) is the increase in circulating concentration of cholesterol, cholesterol esters, triglycerides, or phospholipids. Cholesterol is classified as steroid-based and is a primary component of the cell membrane. There are two main types of cholesterol in the blood.

1) HDL (High-Density Lipoprotein) is also known as "good cholesterol." High HDL is associated with a decreased risk of heart disease.

2) LDL (Low-Density Lipoprotein) is also known as "bad cholesterol." High LDL is associated with an increased risk of heart disease and stroke.

 

*Triglycerides are provided by dietary fats and hepatic conversion of carbohydrates. Triglycerides are also considered "bad" because too many also increase the risk of heart disease.

 

Risk factors for hyperlipidemia include

• A genetic defect in the receptor and/or enzyme abnormality or deficiency
• Obesity
• High fat and cholesterol dietary intake
• Certain medications that cause increased cholesterol

Treatment for hyperlipidemia may include

• Dietary restrictions to avoid fatty foods
• Exercise
• Weight reduction
• Smoking cessation 

 

Statins that are used to treat hyperlipidemia include

• Atorvastatin (Lipitor)
• Simvastatin (Zocor)
• Pravastatin (Pravachol)
• Rosuvastatin (Crestor)

Common side effects of statins include

• Nausea
• Headache
• Abdominal pain
• Muscle pain (May be an indicator of a serious side effect of statins, called rhabdomyolysis, which is a breakdown of skeletal muscle. Routine monitoring of CK [creatine kinase] is recommended for high-risk patients.) 
• Liver damage (Liver function tests are recommended periodically while patients are on statins.)

*Other medications used to treat hyperlipidemia include

• Niacin (Niaspan)
• Fenofibrate (Tricor)
• Gemfibrozil (Lopid)
• Ezetimibe (Zetia)

 

Coronary Artery Disease

Coronary artery disease (CAD) is one of today's leading health problems for both men and women and effects millions of people in the United States. CAD is a condition in which plaque builds up inside the coronary arteries—also known as atherosclerosis. This narrows the arteries and limits the amount of blood and oxygen that the heart can receive. The lack of oxygen to the heart is called ischemia, and the resulting pain is called angina. 

The most feared outcome associated with CAD is a myocardial infarction (MI), more commonly known as a heart attack. MI is one possible form of acute coronary syndrome (ACS), the name for a rupture of coronary arteries due to plaque buildup. 

Specifically, MI occurs when a thrombus (blood clot) develops in a coronary artery that's already narrowed by atherosclerosis. The complete blockage of blood flow through the coronary artery prevents the surrounding heart muscle from receiving any blood and oxygen. One proven measure to decrease the incidence of CAD and myocardial infarction is controlling cholesterol levels.

 

Risk factors for coronary artery disease include

• Hyperlipidemia
• Hypertension
• Smoking
• Obesity
• Age
• Family history
• Sedentary lifestyle

The goal of treatment is to reduce the risk of sudden death due to MI, and treat underlying conditions such as hypertension and cholesterol with therapies previously listed.

 

Medications commonly used to prevent MI or treat ACS are:

• Aspirin reduces the risk of another heart attack by keeping blood thinner.
• Nitroglycerin or other nitrates are used as vasodilators to prevent chest pain by increasing blood supply to the ischemic arteries.
• Blood thinners are used to prevent clot formation or dissolution of a clot to prevent further damage.

 

Dysrhythmia 

Dysrhythmia is a commonly used term to define disorganized or abnormal heart rhythm. Common causes of dysrhythmias include hypertension, ACS, and heart failure. Dysrhythmias may be fatal if not treated.

Medications used to treat cardiac dysrhythmia include:

• Amiodarone (Cordarone)
• Disopyramide (Norspace)
• Dofetilide (Tikosyn)
• Propafenone (Rythmol)

 

Key Points

 

• Cardiovascular diseases are preventable with lifestyle modifications such as diet, exercise, and weight reduction.
• Beta blockers are commonly used medications to control high blood pressure and treat CHF symptoms.
• One way to recognize which medication is a beta blocker is to remember that these medications end with the suffix –lol.
• Most ACE inhibitor medications end with the suffix –pril.
• Most ARB medications end with the suffix –sartan.
• CCB medications generally end with the suffix –pine.
• All nitro– medications are vasodilators.
• Most cholesterol-lowering medications end with the suffix –statin.