What Is Cardiac Output?

 Cardiac output is defined as the amount of blood pumped by the ventricles, the lower chambers of the heart, in one minute. Two factors determine cardiac output: stroke volume and heart rate. The equation used is: heart rate x stroke volume = cardiac output. A normal adult heart will have a cardiac output of approximately 4.7 litre( 5 quart) of blood per minute. Exercise wi

ll increase cardiac output, since it increases heart rate.

 

Heart rate

 • The number of times the heart beats in one minute is the heart rate. In adults, the average heart rate is 60 to 100 beats per minute. Heart rates are usually higher in children and women. Differences in gender, size, age and fitness can affect the heart rate, as can some medications and conditions. Very fit people have lower resting heart rates. Heart rates increase when people are upset or excited.

Abdominal Aortic Aneurysm

What Is Abdominal Aortic Aneurysm?

Your aorta is the largest blood vessel in your body, carrying blood from your heart down to your abdomen, legs, and pelvis. If the walls of the aorta become weak, they can swell or bulge out. When this happens in the abdomen, it is called an abdominal aortic aneurysm (AAA).

Abdominal aortic aneurysms will not always cause problems, but a ruptured aneurysm can be life threatening. Therefore, if you are diagnosed with an aneurysm, your doctor will probably want to monitor you closely even if he doesn’t treat you right away.

What are the Types of Abdominal Aortic Aneurysms?

Abdominal aortic aneurysms are usually classified by their size and the speed at which they are growing. These two factors can help to predict the likely health effects of the aneurysm

Small or Slow Growing Abdominal Aortic Aneurysms generally have a lower risk of rupture than larger or fast-growing aneurysms. Often, a doctor will decide that it’s safer to monitor an aneurysm with regular abdominal ultrasounds than it is to treat it.

Large or Fast Growing Abdominal Aortic Aneurysms are more likely to rupture than small aneurysms. This can lead to internal bleeding and other serious complications. The larger the aneurysm is, the more likely it will need to be treated with surgery. Aneurysms also need to be treated if they are causing symptoms or leaking blood.

What Causes an Abdominal Aortic Aneurysm?

The specific causes of abdominal aortic aneurysms are currently unknown. However, certain factors have been shown to increase the risk of an AAA. They include:

•High blood pressure. Blood pressure is exactly what it sounds like, the pressure on the walls of your blood vessels. High blood pressure can weaken the walls of the aorta, making an aneurysm more likely to form.

•Smoking. Smoking can directly damage the walls of your arteries, making them more likely to bulge. It can also increase your risk of high blood pressure.

•Infection (vasculitis). Serious infections within the aorta and other arteries can occasionally cause AAA. However, this happens very rarely.

Aneurysms can form in any blood vessel in your body. However, abdominal aortic aneurysms are considered particularly serious, because of the size of the aorta.

Who Is at Risk for an Abdominal Aortic Aneurysm?

Abdominal aortic aneurysms are more likely to occur if you:

•are male

•are obese or overweight

•have a family history of heart conditions and disease

•have diabetes

•have high blood pressure – especially if you are between 35 and 60 years old

•have high cholesterol or fatty buildup in the blood vessels (atherosclerosis)

•live a sedentary lifestyle

•are over age 60

•experience abdominal trauma or other damage to your midsection

•smoke tobacco products

What are the Symptoms of an Abdominal Aortic Aneurysm?

Most aneurysms have no symptoms, unless they rupture. However, if an AAA does rupture, you may experience one or more of the following symptoms:

•Sudden pain in your abdomen or back. The pain may spread to your pelvis, legs, or buttocks.

•Clammy or sweaty skin

•An increase in your heart rate

•Shock

If you experience any of these symptoms, it is important to talk to a doctor immediately. A ruptured aneurysm can be life threatening.

Diagnosing an Abdominal Aortic Aneurysm

Intact aneurysms are most often diagnosed when a doctor is scanning or examining your abdomen for another reason.

If your doctor suspects that you may have an AAA, he will feel your stomach to see if it is rigid or contains a pulsing mass. He may also check the blood flow in your legs. Doctors can also scan your abdomen for an AAA using one of the following tests:

•CT scan

•Abdominal ultrasound

•Chest X-ray

•MRI

Treating an Abdominal Aortic Aneurysm

Depending on the size and exact location of the aneurysm, your doctor may perform surgery to repair or remove the damaged tissue. This may be done either with open abdominal surgery or endovascular surgery. The surgery performed will depend on your overall health and the type of aneurysm.

Open-Abdominal Surgery is used to remove damaged areas of the aorta. It is an invasive form of surgery and has a longer recovery time. Open-abdominal surgery may be necessary if your aneurysm is very large or has already ruptured.

 

Endovascular Surgery is a less invasive form of surgery. It uses a graft to repair the weakened walls of the aorta.

 

For a small abdominal aortic aneurysm (less than 1.6 inches in size), your doctor may decide to monitor the aneurysm regularly instead of performing surgery. Surgery has risks, and small aneurysms generally do not rupture.

 

Prognosis: What Is to Be Expected in the Long Term?

If your doctor recommends open-abdominal surgery, it may take up to six weeks to recover. Endovascular surgery has a shorter recovery time – up to two weeks.

The success of surgery and recovery greatly depends on whether or not an AAA is found before it ruptures. Prognosis is usually good if the AAA is found before it ruptures.

Prevention

Focusing on heart health can also help you prevent AAA. That means watching your diet, exercising, and avoiding other cardiovascular risk factors such as smoking. Your doctor might also prescribe medicines to treat high blood pressure or cholesterol or to help you control your diabetes.

If you have ever smoked, or have other risk factors, your doctor may want to screen you for AAA when you turn 65. If so, don’t worry. The screening test uses an abdominal ultrasound to scan your aorta for bulges. It is painless, and it only needs to be performed once.

Abdominal Aortic Aneurysm