What causes a subendocardial infarction?
Usually a subendocardial infarct is the result of a partially occluded epicardial coronary artery (i.e. NSTEMI).
What is a subendocardial infarction?
Subendocardial infarction was defined as typical chest apin (greater than 15 minutes), serum enzyme elevation and persistent (greater than 48 hours) new T wave inversion and/or S-T segment depression in the absence of new pathologic Q waves.
Why Subendocardial portion of left ventricle is more prone to MI?
This is because the high intracavitary pressure in systole squeezes the intramyocardial blood vessels of the left ventricle in systole. Left ventricular epicardial region gets perfusion in both systole and diastole while the subendocardial region gets solely during diastole.
What is the pathophysiology of a myocardial infarction?
In the clinical context, myocardial infarction is usually due to thrombotic occlusion of a coronary vessel caused by rupture of a vulnerable plaque. Ischemia induces profound metabolic and ionic perturbations in the affected myocardium and causes rapid depression of systolic function.
What is the difference between a transmural and subendocardial infarction?
Discussion. The results of this study are that subendocardial infarction is associated with a significant reduction in longitudinal S and SR, whereas radial and circumferential function are relatively preserved. In contrast, transmural infarction is associated with a reduction of both long-axis and short-axis function.
Why is the Subendocardium more prone to ischemia?
In conclusion, subendocardial vulnerability to a acute reduction in perfusion pressure stems primarily from differences in vascular compliance induced by transmural differences in both extravascular loading and vessel wall thickness.
What are the 4 types of myocardial infarction?
ST segment elevation myocardial infarction (STEMI) non-ST segment elevation myocardial infarction (NSTEMI) coronary spasm, or unstable angina.
What is the difference between transmural MI and subendocardial MI?
The transmural type usually consisted of yellowish-brown coagulation necrosis in the center of an infarcted focus and coagulative myocytolysis at the marginal zone. The subendocardial type was characterized by coagulative myocytolysis throughout the entire focus.
Why does Mi cause left ventricular failure?
Heart failure developing after MI hospitalization is a consequence of cardiomyocyte death and scar formation, which triggers chronic neurohumoral activation (renin–angiotensin–aldosterone and sympathetic nervous system up-regulation) and ventricular remodelling.
What is the pathophysiology behind heart failure?
Pathophysiology of Heart Failure. In heart failure, the heart may not provide tissues with adequate blood for metabolic needs, and cardiac-related elevation of pulmonary or systemic venous pressures may result in organ congestion.
What are the 5 types of myocardial infarction?
| The Third Universal Definition of Myocardial Infarction | |
|---|---|
| Type 4b: | Myocardial infarction related to stent thrombosis |
| Type 4c: | Myocardial infarction related to restenosis |
| Type 5: | Myocardial infarction related to coronary artery bypass grafting (CABG) |
Which type of myocardial infarction type is most severe?
An ST-elevation myocardial infarction (STEMI) is a type of heart attack that is more serious and has a greater risk of serious complications and death.
Where is the Subendocardial conducting network?
The Purkinje fibers (Purkyne tissue or subendocardial branches) are located in the inner ventricular walls of the heart, just beneath the endocardium in a space called the subendocardium.
What is the difference between infarction and ischemia?
The term ischemia means that blood flow to a tissue has decreased, which results in hypoxia, or insufficient oxygen in that tissue, whereas infarction goes one step further and means that blood flow has been completely cut off, resulting in necrosis, or cellular death.
What is transmural and subendocardial infarction?
How does myocardial infarction affect heart failure?
Clinical impact of heart failure after myocardial infarction
Among patients with a history of MI, HF development increases total mortality risk three‐fold and cardiovascular mortality four‐fold. The timing of HF development also has an impact on adverse events.
What causes heart failure after MI?
Several overlapping mechanisms contribute to HF after MI (Figure 1). HF during the index MI occurs due to a combination of myocardial stunning, myocyte necrosis, decompensation of pre-existing HF or acute mitral regurgitation due to papillary muscle dysfunction.
What are the pathological changes in congestive heart failure?
As the heart fails, patients develop symptoms which include dyspnea from pulmonary congestion, and peripheral edema and ascites from impaired venous return. Constitutional symptoms such as nausea, lack of appetite, and fatigue are also common.
What is the main cause of congestive heart failure?
The most common cause of congestive heart failure is coronary artery disease. Risk factors for coronary artery disease include: high levels of cholesterol and/or triglyceride in the blood.
What are 4 signs of myocardial infarction?
What are the symptoms of acute myocardial infarction?
- pressure or tightness in the chest.
- pain in the chest, back, jaw, and other areas of the upper body that lasts more than a few minutes or that goes away and comes back.
- shortness of breath.
- sweating.
- nausea.
- vomiting.
- anxiety.
- feeling like you’re going to faint.
Why is it called Purkinje fibers?
Purkinje fibers are named after the Czech scientist Jan Evangelista Purkyně, who discovered them in 1839.
What are the 5 components of the cardiac conduction system?
These muscle cells send signals to the rest of the heart muscle causing a contraction. This group of muscle cells is called the cardiac conduction system. The main parts of the system are the SA node, AV node, bundle of HIS, bundle branches, and Purkinje fibers.
How do you distinguish between myocardial ischemia and myocardial infarction?
Myocardial ischemia occurs when blood flow to the heart muscle (myocardium) is obstructed by a partial or complete blockage of a coronary artery by a buildup of plaques (atherosclerosis). If the plaques rupture, you can have a heart attack (myocardial infarction).
Which comes first hypoxia or ischemia?
Ischemia always results in hypoxia; however, hypoxia can occur without ischemia if, for example, the oxygen content of the arterial blood decreases as occurs with anemia.
What is the pathophysiology of congestive heart failure CHF )?
Congestive heart failure is a syndrome that can be caused by a variety of abnormalities, including pressure and volume overload, loss of muscle, primary muscle disease or excessive peripheral demands such as high output failure. In the usual form of heart failure, the heart muscle has reduced contractility.