A myocardial infarction is a heart attack; during this, the heart's beat effectively stops and the heart is no longer pumping blood in any useable amount. Therefore, a myocardial infarction causes cardiac output to drop significantly and possibly drop to zero depending on the severity.
Increase in heart rate as Cardiac Output = Heart rate x Stroke volume. As SV will be decreased, HR increases to compensate.
Myocardial infarction (MI) can disrupt the normal cardiac cycle by causing damage to the heart muscle, leading to impaired contraction and relaxation. This can result in diminished cardiac output, arrhythmias, and heart failure. The severity of these effects depends on the location and extent of the heart damage.
because the force of myocardial contraction weakens
Myocardial ischemia results from the temporary lack of oxygen; if ischemia is prolonged, it could result in permanent damage to the heart muscle. This condition is called myocardial infarction, commonly known as a heart attack.ischemia
Inotropes are medications that alter the force or energy of cardiac muscle contractions. Positive inotropes, such as dopamine and dobutamine, increase cardiac output by enhancing myocardial contractility, which can be beneficial in conditions like heart failure. Conversely, negative inotropes decrease contractility, potentially reducing cardiac output. The choice of inotrope depends on the clinical scenario and the underlying cardiac function.
Certainly. Decrease cardiac output would mean a decreased in blood flow to the kidneys, which would lead to reduced filtration, therefore urine output.
It increases intrathoracic pressure which decreases venous return to the heart and causes a decrease in cardiac output.
It increases intrathoracic pressure which decreases venous return to the heart and causes a decrease in cardiac output.
Myocardial infarction (MI) can lead to heart failure in numerous ways. First of all, early on, the heart muscle does not contract well because it is not receiving enough oxygen and other necessary substrates, so stroke volume is decreased, which may lead to congestive heart failure. Later on, if the MI is aborted with thrombolytics or with a cardiac catheterization and thrombectomy, the myocardium may be stunned, or hibernating, because of the lack of oxygen, and may return to normal function over time. If the MI completes, the portion of cardiac muscle that was affected is dead. Depending on how significant a portion that is, losing the muscle alone may result in heart failure. The dead portion of the heart will later turn into a scar, which is noncontractile and also does not allow for the normal stretch, so it may affect preload and contractility in that way as well, decreasing cardiac output and possibly leading to congestive heart failure.
It's decreased ... unless the rate falls, which is the normal cardiac response.
Lowers stroke volume
Myocardial infarction (MI) primarily leads to cardiogenic shock due to impaired heart function and decreased cardiac output. However, it can indirectly contribute to hypovolemic shock if the MI results in complications such as severe bleeding or fluid loss, for instance, from rupture of the heart wall or major blood vessels. Additionally, if the patient experiences significant fluid shifts or dehydration due to stress responses or treatment complications, this could also lead to hypovolemic shock. Overall, while MI is not a direct cause of hypovolemic shock, it can create conditions that may lead to it.