Health and medicine
- Overview of heart failure
- What is heart failure?
- Systolic heart failure pathophysiology
- Diastolic heart failure pathophysiology
- Compensation and decompensation in heart failure
- Symptoms of left sided heart failure
- Symptoms of right sided heart failure
- Heart failure diagnosis
- Heart failure treatment - Early stages
- Heart failure treatment - Late stages
- Heart failure treatment - Devices and surgery
Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Tanner Marshall.
Want to join the conversation?
- If nitrates reduce BP in veins, hence reduce venous return and pre-load, then would it cause the blood retain in body? or edema?
Btw, would nitrates cause any effect on urine output?(7 votes)
- The most common side effect of nitrates is a headache. This headache is caused by vasodilation in the vessels supplying the brain. There is a limit to how many nitrates on person can take in a specific time frame (3 in 15 minutes), which prevents some of the side effects that you have listed. Nitrates are also short-acting. However, if one were to take more than the recommended dose, edema could occur for the reason that you have listed..(7 votes)
- when you do exercise, the heart pumps faster, so, if you have coronary artery disease, won't it lead to a heart attack?(4 votes)
- Potentially, yes. In exercise (or on exertion) the heart pumps faster and harder, which means the muscle is working harder and needs more energy. The circulation in the heart muscle only works when the ventricles are relaxed, because systole squeezes the vessels and stops the blood flow. If there's an underlying cause for ischaemia, some of the heart muscle can be starved of oxygen and nutrients for long enough that the cells start dying, resulting in a myocardial infarction or heart attack.(6 votes)
- How exactly does exercise improve the efficiency of the heart? For skeletal muscle, if I understand right, you gain strength by gaining muscle mass, but that isn't what we want in the heart right?(3 votes)
- Exercise is important for many different reasons. Exercise can help improve blood flow and circulation. If you have a healthy heart, then you are better able to pump blood throughout your body. Exercise is also good for you lungs, which oxygenate the blood. Oxygen is important for our tissues and required for our survival. If you exercise you reduce the risk for cardiovascular disease, which causes the heart to work harder and in many cases insufficiently. Healthy heart=happy, healthy body(3 votes)
- how can a patient with heart failure instructed to do exercise because as it is told that heart failure means heart cannot meet the demands of the body.so when exercising we are giving extra work load to the heart which can result in hypertrophy and finally worsening the heart failure.anticipating reply,thanks in advance(2 votes)
- Well, this is actually in the early stages which means at risk, so heart failure isn't currently present yet, but there are risk factors. When you exercise, like any muscle, you improve the heart muscle. It is true that your heart beats faster, but when you exercise more frequently, your heart gets used to meeting the high oxygen demands that exercise cause. Therefore, the heart can pump blood more efficiently.(3 votes)
Are there associated risks to using vasodilators on other parts of the body and in certain situations (e.g. pregnant)?
Thank you(2 votes)
- In the early stages of Heart Failure the patient might not even have symptoms. And they might only have risk factors for Heart Failure. This means that they probably have some kind of pre-existing condition that might, if you leave it unchecked, will lead to Heart Failure in the future. Or lead to worsening Heart Failure if it's already present. But these conditions haven't led to full blown Heart Failure with, with symptoms. So patients are likely still able to go about their daily lives. Some example of Risk Factors might include something like hypertension, or high blood pressure, or coronary artery disease, or diabetes. The doctor might recognize these conditions as red flags for Heart Failure. And even though they're just seeing it as these preliminary signs and risk factors, they'll emphasize the importance of improving these conditions before Heart Failure gets worse. Because most of the time especially with structural changes to your heart, where it starts to look different, these tend to be unidirectional. Meaning that those changes only tend to get worse not better. So with that said, a very important early stage treatment that's recommended is exercise. With exercise your cardiovascular fitness increases. This increases your heart's efficiency so your heart gets better at pumping blood. And we know that a reduced pumping efficiency is a main theme in Heart Failure. And in addition to exercise another lifestyle change that might be recommended is a change in diet. And reducing salt intake is a common and important change. And doing this tends to reduce your blood pressure, making it easier to pump blood out. And this lowers the chances of the heart to start to compensate and start making structural changes to the heart's ventricles which, like we said, is a one way street. The doctor might also decide to prescribe medications. And these will often be targeted at reducing blood pressure which, like we said, makes it easier for the heart to pump blood out. And reduces the chance of compensation and structural changes to the heart. So the first class of medications are ACE inhibitors or A-C-E inhibitors. This stands for angiotensin-converting-enzyme and these are vasodilators. And from this word we've got vaso which means vessels so your blood vessels. And then you've got dilator which is to widen so these cause your blood vessels to dilate or get bigger. And when they dilate they aren't squeezing the blood inside them as much and so the pressure in your blood vessels goes down. And if the pressure in your blood vessels goes down your heart's going to have an easier time pumping blood out to this lower pressure system. Just remember that analogy about trying to blow air through a really small straw and then a really big tube. Which one's more difficult? It's the straw, right? Well, in the same way your heart's going to have an easier time pumping blood through these dilated blood vessels. And another set of medications that might be prescribed are Hydralazine and Nitrates. And these also tend to reduce your blood pressure. Hydralazine specifically acts as a vasodilator for arteries and arterials. Which are the blood vessels going away from the heart, right? And like we just mentioned this makes it easier for your heart to pump blood out. Nitrates, on the other hand, although they can act on your arteries as well mostly act on your veins. So they act to reduce your venous blood pressure. And this reduces the pressure in getting blood back to the heart. Which also reduces your Preload. Remember, that the Preload is one of those mechanisms of compensation. So if we reduce the Preload we can limit the structural changes that might start to happen as a result. Finally, the last class of medications are called Beta Blockers. And these help inhibit the activation of the sympathetic nervous system. Remember how the sympathetic response in the heart is activated, with these receptors on the heart. Well these receptors are generally known as Beta Receptors. So Beta Blockers tend to block these receptors from being activated. That makes sense. So if they were activated, the heart rate and pumping force increases, right? But if they're blocked this tends to slow down the heart rate and limits that sympathetic response. And limiting this is important because just like increased Preload, we remember that over activation of the sympathetic nervous system is a method of compensation which can lead to structural changes to the heart. And so we want to try to reduce the chances of any structural changes.