2008 Woodie Awards
Cardiology 101
Alex Kushnir
Issue date: 5/16/05 Section: Science & Tech
- Page 1 of 1
With people living longer then ever before, it's common to have multiple family members suffering from one or more forms of heart disease. It should be no surprise that after 60+ years of beating over 100,000 times a day, the heart begins to show signs of deterioration and weakness. With more treatments today then ever before, it's important to understand what the different types of heart disease are and what treatment options are available for patients with these conditions.
Congestive Heart Failure (CHF)
Congestive Heart failure is a syndrome characterized by the hearts inability to generate an ejection fraction (percentage of blood exiting the heart with each pump) adequate to cover the body's oxygen demands. Affecting over 2 million people in the Unites States, CHF markedly leads as the single largest cause of the death in the western world. CHF is a result of cardiomyopathy, weakening of the myocardium (heart muscle), and for many patients the etiology (cause of disease) remains unknown.
With the heart unable to pump blood efficiently throughout the body, the lungs become congested with fluids resulting in shortness of breath. Many patients discover they have the disease when they complain to their cardiologist about shortness of breath and angina (chest pains). At this point the heart, for whatever reason, has weakened and can no longer pump enough to provide the brain and outer extremities with adequate oxygen and nutrients. The nervous and endocrine system signal the heart to pump harder perpetuating the muscle to weaken even faster. To compensate for the reduced ejection fraction of each pump the left ventricle increases in size. The left ventricle is one of the four chambers in the heart and provides the main force to propel blood out of the heart and into the aorta (main artery leading into the body).One commonly used method to diagnose CHF is the echocardiogram, which uses sound waves to penetrate the skin and provide an image of the heart. This enables cardiologists to measure the size of and determine whether or not the left ventricle has grown.
Some of the common causes of heart failure include previous myocardial infarction (heart attack), obesity, and valve dysfunction. All these conditions weaken and/or place greater stress on the heart resulting in a decreased ability for the heart to function efficiently.
Patients diagnosed with CHF are generally prescribed three/four classes of drugs to lower blood pressure and to reduce stress on the heart: ACE inhibitors, angiotensin receptor blockers, beta-blockers and diuretics. Ace inhibitors and angiotensin receptor blockers interfere with the production and activity of angiotensin II, which normally causes vasoconstriction (blood vessel tightening), thus reducing blood pressure. Diuretics induce the kidneys to uptake more water from the blood, another method of lowering blood pressure. Beta-blockers work by inhibiting the beta-androgenic receptor pathway, which is responsible for up-regulating cardiac activity during periods of high stress.
Myocardial infarction (MI)
Commonly known as heart attack, this nightmare often occurs instantly with little notice and can seriously disable or kill within minutes. Many times a person suddenly feels tight chest pains and cramps. In the body, one of the coronary arteries, blood vessels that supply the heart with oxygen and nutrients has burst or has become clogged resulting in the death of a portion of the myocardium (heart muscle). If the damaged tissue is in the ventricle, then a condition called ventricular arrhythmia develops where the heart is unable to pump blood into the body. If immediate treatment is not administered, the patient may go brain dead as parts of the brain die from insufficient oxygen.
On an electrocardiogram (ECG) a person suffering from an MI has an arrhythmic, tachycardia (fast, non-rhythmic heart beat). The most effective treatment is to shock the patient with a defibrillator. This stops the heart momentarily with the hope that it will restart normally again. Other common treatments include nitroglycerine which dilates the blood vessels and lower blood pressure.
Atrial Fibrillation (AF)
In atrial fibrillation, the upper two chambers of the heart, the atria, quiver instead of beating effectively. However, the ventricles are healthy and strong enough to maintain adequate blood flow. Most people suffering from atrial fibrillation can live normal lives, but find themselves at greater risk for developing blood clots in the heart due to fact that blood remains in the atria over longer periods of time. If left untreated, these clots become embolisms, which can travel to the brain and cause strokes.
AF is generally caused when regular heart muscle cells become pacemaker cells. In the normal heart, only specialized cells located at the top of the heart have the special role of pacemaker cells. These cells are the only ones with the ability to initiate a cardiac contraction. In AF, cells randomly located throughout the atria begin initiating contraction signals so that the atria no longer have a rhythmic beating pattern but rather a series of arrhythmic beats and contractions. What prevents this condition from spreading to the ventricles, where it could lead to ventricular arrhythmia (VA) and sudden cardiac death is the fact that the signal must first pass through the AV node before reaching the ventricles. This allows for the passing of only one signal in a rhythmic fashion preventing the onset of ventricular arrhythmia.
Patients are usually diagnosed with AF during a routine visit to a cardiologist who notices small arrhythmic delays in the generation of cardiac contraction. Other signs are abnormal P-waves. The P-wave is the point on an ECG that represents when the electric impulse of the heart travels across the atria to the AV node before crossing over to the ventricles. Multiple weak contraction signals passing randomly through the atria prevent the generation of one strong electric signal. Depending on the severity of their condition, these patients are usually prescribed blood thinners like aspirin or warfarin, to inhibit the formation of embolisms. In some cases, classic heart failure medications are prescribed to prevent the AF symptoms from weakening the heart leading to more serious forms of heart disease.
Congestive Heart Failure (CHF)
Congestive Heart failure is a syndrome characterized by the hearts inability to generate an ejection fraction (percentage of blood exiting the heart with each pump) adequate to cover the body's oxygen demands. Affecting over 2 million people in the Unites States, CHF markedly leads as the single largest cause of the death in the western world. CHF is a result of cardiomyopathy, weakening of the myocardium (heart muscle), and for many patients the etiology (cause of disease) remains unknown.
With the heart unable to pump blood efficiently throughout the body, the lungs become congested with fluids resulting in shortness of breath. Many patients discover they have the disease when they complain to their cardiologist about shortness of breath and angina (chest pains). At this point the heart, for whatever reason, has weakened and can no longer pump enough to provide the brain and outer extremities with adequate oxygen and nutrients. The nervous and endocrine system signal the heart to pump harder perpetuating the muscle to weaken even faster. To compensate for the reduced ejection fraction of each pump the left ventricle increases in size. The left ventricle is one of the four chambers in the heart and provides the main force to propel blood out of the heart and into the aorta (main artery leading into the body).One commonly used method to diagnose CHF is the echocardiogram, which uses sound waves to penetrate the skin and provide an image of the heart. This enables cardiologists to measure the size of and determine whether or not the left ventricle has grown.
Some of the common causes of heart failure include previous myocardial infarction (heart attack), obesity, and valve dysfunction. All these conditions weaken and/or place greater stress on the heart resulting in a decreased ability for the heart to function efficiently.
Patients diagnosed with CHF are generally prescribed three/four classes of drugs to lower blood pressure and to reduce stress on the heart: ACE inhibitors, angiotensin receptor blockers, beta-blockers and diuretics. Ace inhibitors and angiotensin receptor blockers interfere with the production and activity of angiotensin II, which normally causes vasoconstriction (blood vessel tightening), thus reducing blood pressure. Diuretics induce the kidneys to uptake more water from the blood, another method of lowering blood pressure. Beta-blockers work by inhibiting the beta-androgenic receptor pathway, which is responsible for up-regulating cardiac activity during periods of high stress.
Myocardial infarction (MI)
Commonly known as heart attack, this nightmare often occurs instantly with little notice and can seriously disable or kill within minutes. Many times a person suddenly feels tight chest pains and cramps. In the body, one of the coronary arteries, blood vessels that supply the heart with oxygen and nutrients has burst or has become clogged resulting in the death of a portion of the myocardium (heart muscle). If the damaged tissue is in the ventricle, then a condition called ventricular arrhythmia develops where the heart is unable to pump blood into the body. If immediate treatment is not administered, the patient may go brain dead as parts of the brain die from insufficient oxygen.
On an electrocardiogram (ECG) a person suffering from an MI has an arrhythmic, tachycardia (fast, non-rhythmic heart beat). The most effective treatment is to shock the patient with a defibrillator. This stops the heart momentarily with the hope that it will restart normally again. Other common treatments include nitroglycerine which dilates the blood vessels and lower blood pressure.
Atrial Fibrillation (AF)
In atrial fibrillation, the upper two chambers of the heart, the atria, quiver instead of beating effectively. However, the ventricles are healthy and strong enough to maintain adequate blood flow. Most people suffering from atrial fibrillation can live normal lives, but find themselves at greater risk for developing blood clots in the heart due to fact that blood remains in the atria over longer periods of time. If left untreated, these clots become embolisms, which can travel to the brain and cause strokes.
AF is generally caused when regular heart muscle cells become pacemaker cells. In the normal heart, only specialized cells located at the top of the heart have the special role of pacemaker cells. These cells are the only ones with the ability to initiate a cardiac contraction. In AF, cells randomly located throughout the atria begin initiating contraction signals so that the atria no longer have a rhythmic beating pattern but rather a series of arrhythmic beats and contractions. What prevents this condition from spreading to the ventricles, where it could lead to ventricular arrhythmia (VA) and sudden cardiac death is the fact that the signal must first pass through the AV node before reaching the ventricles. This allows for the passing of only one signal in a rhythmic fashion preventing the onset of ventricular arrhythmia.
Patients are usually diagnosed with AF during a routine visit to a cardiologist who notices small arrhythmic delays in the generation of cardiac contraction. Other signs are abnormal P-waves. The P-wave is the point on an ECG that represents when the electric impulse of the heart travels across the atria to the AV node before crossing over to the ventricles. Multiple weak contraction signals passing randomly through the atria prevent the generation of one strong electric signal. Depending on the severity of their condition, these patients are usually prescribed blood thinners like aspirin or warfarin, to inhibit the formation of embolisms. In some cases, classic heart failure medications are prescribed to prevent the AF symptoms from weakening the heart leading to more serious forms of heart disease.