The right infarction mentioned here would be a right ventricular myocardial infarction.

It is not absolutely impossible to use nitroglycerin in right heart infarction. It is only the characteristics of the right heart function and the characteristics of the action of nitroglycerin that make the application of nitroglycerin in right heart infarction unsuitable in most cases.

Normally, blood is ejected from the left ventricle into the aorta, then into the systemic arteries, through the capillaries to the venous system, and finally through the large veins back to the right heart. The blood ejected from the left ventricle is balanced with the blood returning to the right ventricle into the pulmonary artery. This maintains normal circulation.

So, the right heart receives blood from the systemic veins back to the heart and then delivers it to the pulmonary arteries. The pressure in the pulmonary arteries is not as high, and the right heart does not need a particularly strong contractile force to eject blood into the pulmonary arteries, so the right ventricular myocardium is relatively thin, and the load on the right heart is mainly a volume load. When the right ventricular myocardium is infarcted, the myocardium has even less power to contract. Then the power to drive circulation depends on the return volume, on the blood that comes back to the heart to fill the heart and drive circulation.

What does nitroglycerin do? It is to dilate blood vessels. However, it is important to realize that nitroglycerin primarily dilates venous blood vessels. One of the mechanisms of action of nitroglycerin in relieving angina and heart failure is to dilate the veins and reduce the volume of return blood, thereby reducing the load on the heart and reducing the tension in the ventricles as they fill with blood (reducing the pressure on the walls of the ventricles within the ventricular chambers), which also improves the blood supply to the myocardium itself (the heart is supplied with blood from the epicardium to the endocardium).

However, in the case of right heart infarction, the myocardium is already not contractile and depends on the filling of blood back to the heart to propel the circulation and ensure perfusion. If nitroglycerin is given at this time, the veins will be dilated, the blood will be stagnant in the venous system, and the blood returning to the right heart will not be sufficient, and the amount of blood continuing to circulate will be reduced. This exacerbates the original problem of infarction of the right ventricle and insufficient propulsion of circulation, resulting in a further reduction in the amount of blood entering the pulmonary circulation and a consequent reduction in the ejection of blood from the heart.

Reduced cardiac ejection leads to lower blood pressure and inadequate systemic perfusion, which can lead to or exacerbate the hypotension associated with myocardial infarction, the development of shock, and ischemia of other organs in the body, such as the kidneys, due to inadequate perfusion.

Therefore, the principle of treatment in the case of right heart (ventricular) myocardial infarction is the need for volume expansion, which ensures that the right heart is able to fill and that enough blood can enter the circulation.

Therefore, nitroglycerin is generally not indicated in right ventricular myocardial infarction.

(Image from the Internet)

There is a story circulating on the Internet that when an acute myocardial infarction occurs, one of the first aid methods is to take nitroglycerin!

Question 1:Contained nitroglycerin is of little significance in relieving normal, as well as vascularizing.

Question 2:Acute right ventricular myocardial infarction without the use of nitroglycerin.

Why should nitroglycerin not be used in acute right ventricular myocardial infarction?

Because hypotension occurs in acute right ventricular myocardial infarction and nitroglycerin lowers blood pressure, when acute right ventricular myocardial infarction occurs, reapplication of nitroglycerin will exacerbate hypotension.

This is why acute myocardial infarction resuscitation starts with an ECG and a blood pressure measurement to determine how to treat it.

Treatment of acute right ventricular myocardial infarction?

All myocardial infarctions should be antiplatelet + anti-inflammatory to stabilize plaque in the first instance, which means that aspirin + tegretol/clopidogrel should be given, and statins should be given orally.

As soon as possible to open the blood vessels, in addition to the treatment of acute right ventricular myocardial infarction and other myocardial infarction treatment is different because acute right ventricular myocardial infarction needs a large number of fluids, so that it can improve the state of low blood pressure, the diagnosis of shock. And the sooner and faster the infusion, the better.

What other conditions should nitroglycerin not be used for?

Every doctor who uses nitroglycerin has a list in their head that clearly says "glaucoma" is prohibited.

2. High intracranial pressure

Nitroglycerin should not be used in many patients who have elevated cranial pressure because it dilates the blood vessels in the head and causes aggravation of the condition.

3、Hypertrophic obstructive cardiomyopathy

In patients with hypertrophic cardiomyopathy with obstruction, the use of nitroglycerin reduces cardiac afterload, which further decreases left ventricular filling, reduces left ventricular pumping, and worsens obstruction.

Nitroglycerin is indeed the most effective first aid drug for angina attacks, but it must be used correctly, used correctly to cure the disease, used wrongly to cause disease!

(Dr. Cardiovascular Wang formally authorized original protection, such as theft must be held legally responsible)

Once encountered such a patient with chest pain, measuring blood pressure is not high, only 90/60mmhg, at that time to it pulled an electrocardiogram, found that may be the right coronary artery problem, the V1 lead is a little bit of mild elevation, at that time the diagnosis is that the blood vessel is blocked in the right coronary artery in a relatively high position, this case is often particularly easy to combine with the right ventricular infarction, and the patient is prone to develop hypotension.

The use of nitroglycerin in this case is especially prudent and even when prohibited!

First of all, we all know that our blood is an internal circulation, and a lack of blood volume leads to a drop in the body's blood pressure! AndBy right heart attack, we actually mean that the right coronary artery is blocked due to inferior posterior wall infarction, which leads to impaired systolic function of the right ventricle, then the blood in the body will be prone to a large number of retention in the peripheral veins and capillary bedsThe main point is that the right ventricle of our body is subordinate to the heart as a whole; its walls are thin and its main role is not to provide sufficient systolic pressure for our heart, but rather to provide the left ventricle with a filling volume to ensure the filling pressure of the left ventricle. ThereforeOnce the right ventricular function is impaired, blood stagnation, it leads to the right ventricle blood volume does not come to be insufficient, the body's effective circulation of blood is also relatively insufficient, this is not the time to expand the overall blood volume, the contraction of blood pressure is right? In order to improve the right ventricular blood volume, right?

Secondly, we all know that nitroglycerin is a relaxation of smooth muscle, especially to relax the role of vascular smooth muscle is the most obvious, can be diastolic systemic veins and arteries, but then diastolic post-capillary venous far more than the diastolic small arteries. Therefore.This is when you dilate the arteries with nitroglycerin, which only exacerbates the lack of circulating blood volume, making the blood pressure drop even further and making the body even more dangerous.

Finally, it has been found clinically that it is not only right ventricular infarcts that are immediate to patients with left coronary infarcts, in other words, thatWhenever a myocardial infarction occurs in a patient with low, not very high, blood pressure, the use of nitroglycerin has been controversial.Because we found out:Nitroglycerin can dilate diseased and narrowed coronary arteries, it can also dilate normal coronary arteries, but it can't dilate occluded arteries, and we all know that infarction is caused by the occlusion of blood vessels.So there is a part of us that believes that nitroglycerin does not improve the blood supply to the infarct site, instead it only further aggravates the ischemia at the infarct site! Therefore, when we are instructing some grassroots or individuals, we areIt is recommended to encounter heart attack patients, you can take oral aspirin, clopidogrel, large amounts of fluids to replenish blood volume, as well as continuous cardiac monitoring, as soon as possible, and then sent to a professional chest pain center, now many hospitals have set up a special chest pain center!

Right ventricular infarction, a type of acute myocardial infarction, is usually caused by occlusion of the right coronary artery and is often clinically combined with an inferior or posterior inferior wall myocardial infarction. Since right ventricular infarction is one kind of infarction, most of the treatments are the same as ordinary myocardial infarction treatments. It is only because right ventricular infarction has some special characteristics that make the medication and treatment program a little different from that of ordinary infarction.

Today, let's discuss why nitroglycerin can't be used in right ventricular infarction. In fact, not can't, but in most cases can't be used, nitroglycerin in specific circumstances, right ventricular infarction is not necessarily can't be used, all we are mainly discussing the right ventricular infarction, why is nitroglycerin used less?

I. Right ventricular infarction is often combined with hypotension

If the right coronary artery blood supply is mainly right ventricular when the infarction is dominated by right ventricular infarction, clinically it can be manifested as severe hypotension, because the contraindication of nitroglycerin is hypotension, so at this time you can not use nitroglycerin. There are several reasons for hypotension after right ventricular infarction, one is because the contractile function of the right ventricle is impaired, which makes the blood in the body stagnate in the peripheral veins and capillary beds, and the amount of circulating blood is relatively insufficient; the second reason is that right ventricular infarction is extremely easy to merge with the atrioventricular block, and the conduction block will make the ventricular rate slow down, which will affect the blood pressure. Therefore, it makes sense not to use nitroglycerin for right ventricular infarction.

II. Limited role of nitroglycerin after heart attack

In fact, whether right ventricular infarction or other heart attacks, the role of nitroglycerin is very limited, because the occluded blood vessels, no matter how to dilate, its impossible to dilate the coronary arteries and recanalization, even the thrombolysis after infarction and emergency PCI can not guarantee that the blood vessels are all recanalized, not to mention the use of nitroglycerin, together with the hypotension and other conditions, the lack of use of nitroglycerin is also to be expected.

Therefore, the use of nitroglycerin is limited in the case of inferior wall myocardial infarction, especially right ventricular infarction. In fact, regardless of the situation, the applicability of a particular drug needs to be considered in a comprehensive manner, and the same is true for nitroglycerin.

The coronary arteries in the heart are divided into left and right branches, which originate from the left and right coronary sinuses of the aorta, respectively. The right coronary artery is generally distributed in the right atrium, most of the anterior wall of the right ventricle, all of the right ventricle side wall and posterior wall, a part of the posterior wall of the left ventricle and the septum of the posterior 1/3 of the ventricle. when the right coronary lumen appears 50% to 75% stenosis, the heart can meet the rest of the blood supply, but after exercise, excitement, the heart oxygen consumption will increase, which will cause myocardial blood supply is insufficient, when the atherosclerosis of the wall of the vascular rupture, vesicles, or bleeding thrombus blockage of the vessel, it can trigger myocardial infarction in the right ventricle. When atherosclerotic plaque ruptures, erodes, or when a thrombus formed after bleeding blocks the blood vessel, it can trigger a myocardial infarction in the right ventricle.

The right heart infarction will often be caused to cause the right heart function is not full, the main problem is the body circulation stagnation, the effective circulation blood volume of the decrease, further lead to the ischemia of the pulmonary circulation, as well as the left ventricular insufficient filling, so that the cardiac output is reduced, resulting in a drop in blood pressure. If nitroglycerin is used clinically at this time, it will make the pulmonary vein dilated, the volume of beat volume will be further reduced, and the effective circulating blood volume will be further decreased, resulting in further decrease of coronary blood supply, aggravating myocardial ischemia, and even shock, so nitroglycerin can not be applied.

Nitroglycerin acts by relaxing smooth muscle, but the effect of relaxing vascular smooth muscle is the most pronounced. Nitroglycerin can diastole veins and arteries throughout the body, and compared with the arteries, nitroglycerin diastoles the veins after the capillaries more strongly. And blood is stored in the storage veins and lower extremity vessels, so the use of nitroglycerin can make the veins dilated, the return of blood to the heart is reduced, reducing preload, ventricular filling and ventricular wall muscle tone.

Therefore, right ventricular infarction should be rapidly rehydrated with CVP monitoring to ensure effective blood volume circulation and avoid cardiogenic shock.

The authoritative interpretation of Pharmaceutical Affairs, unauthorized reproduction, plagiarism will be punished.

Thank you. Acute right heart infarction therapeutic measures and acute left ventricular infarction, there are similarities and differences, right heart ❤ infarction is often accompanied by hypotension and shock, at this time, the key treatment is to maintain sufficient blood volume to ensure that the left ventricle of the heart filling, at this time, although there is is myocardial ischemia, but should not be used nitroglycerin.