Specific Objectives
By the end of this lesson, the learner will be able to:
- State modifiable and non-modifiable risk factors
- Describe the pathophysiology of myocardial infarction
- List the symptoms of myocardial infarction
- Describe the list of drugs that treat myocardial infarction
Lecture: Myocardial Infarction
Also called a heart attack, myocardial infarction is a cardiac disease that occurs due to the death of myocardial cells because of hypoxia (Frangogiannis, 2014). Hypoxia is secondary to the lack or insufficient supply of oxygenated blood to the heart muscle.
Risk Factors for Myocardial Infarction
Non-modifiable risk factors are those that an individual cannot manipulate to increase or reduce the probability of developing the disease. They comprise of increasing age, male gender, African American race, history of the disease in the family (Vakil et al., 2014). Conversely, modifiable risks are the behavioral lifestyle issues that individuals have the power to control in an attempt to prevent the development of cardiovascular diseases. They comprise of excessive consumption of alcohol, cigarette smoking, overweight and obesity, and physical inactivity (Vakil et al., 2014). Other risks include diseases such as diabetes mellitus, high blood pressure.
Pathophysiology
The heart muscle requires an adequate supply of oxygen through the uncompromised perfusion of the myocardium. However, the occurrence of hypoxia results in not only myocardial injury but also myocardial cell death (Frangogiannis, 2014). The pathogenesis begins from the coronary blood vessels. The vessels start to accumulate fats that fill the lumen. Also, calcium deposition narrows the lumen of blood vessels. Fröbert et al. (2013) explain that thrombosis, which is the clotting of blood, can result in the narrowing or blockage of the coronary artery. Sometimes, the blood vessels may undergo spasms, which disrupt the normal flow of blood resulting in an insufficient supply of oxygen to the myocardium (Frangogiannis, 2014). Irrespective of the cause of coronary artery blockage, cardiac cells that are distal to the blockage lack oxygen resulting in hypoxia (Frangogiannis, 2014). Finally, the cells undergo permanent death due to the lack of oxygen. Symptoms of the disease occur because of this pathological process.
Symptoms of Myocardial Infarction
The classic symptoms are chest pain and shortness of breath.
Other common symptoms include:
- Tightness in the chest
- Pain in the chest that radiates to the jaw, back, arms, and the neck (Frangogiannis, 2014)
- Sweating
- Nausea and vomiting
- Anxiety
- Dizziness
- Tachycardia
- Coughing
Classes of Drugs Treating Myocardial Infarction
Analgesics
Morphine sulfate is the analgesic of choice in the treatment of myocardial infarction. It reduces both pain and anxiety as well as cardiac overload due to the reduction of heart overload and afterload (Reddy, Khaliq, & Henning, 2015).
Thrombolytic agents
These drugs aim at dissolving thrombi that block the coronary artery to bring about the disease symptoms (Steg et al., 2012).
Angiotensin-converting enzyme (ACE) inhibitors
These drugs inhibit the physiological conversion of angiotensin I to angiotensin II resulting in reduced renal excretion of sodium. Such a thing reduces cardiac overload. According to Evans et al. (2016), these drugs are effective in improving left ventricular ejection fraction, which is associated with improvement in patient survival.
Lesson Activity
Effective Questioning
The teacher will engage learners by asking them questions concerning various aspects of myocardial infarction. For example, the teacher will ask learners to define myocardial infarction and state its symptoms. Learners will answer the questions appropriately and the teacher will determine whether their responses are right or wrong.
Assignment
Describe the investigations a clinician should carry out to diagnose myocardial infarction. Information acquired from other sources should be cited and a reference list included using APA style.
References
Evans, M., Carrero, J. J., Szummer, K., Åkerblom, A., Edfors, R., Spaak, J.,…Jernberg, T. (2016). Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in myocardial infarction patients with renal dysfunction. Journal of the American College of Cardiology, 67(14), 1687-1697.
Frangogiannis, N. G. (2014). The inflammatory response in myocardial injury, repair, and remodeling. Nature Reviews Cardiology, 11(5), 255-265.
Fröbert, O., Lagerqvist, B., Olivecrona, G. K., Omerovic, E., Gudnason, T., Maeng, M.,…Erlinge, D. (2013). Thrombus aspiration during ST-segment elevation myocardial infarction. New England Journal of Medicine, 369(17), 1587-1597.
Reddy, K., Khaliq, A., & Henning, R. J. (2015). Recent advances in the diagnosis and treatment of acute myocardial infarction. World Journal of Cardiology, 7(5), 243-276.
Steg, P. G., James, S. K., Atar, D., Badano, L. P., Lundqvist, C. B., Borger, M. A.,… Gershlick, A. H. (2012). ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. European Heart Journal, 33(20), 2569–2619.
Vakil, K., Taimeh, Z., Sharma, A., Abidi, K. S., Colvin, M., Luepker, R.,…Adabag, S. (2014). Incidence, predictors, and temporal trends of sudden cardiac death after heart transplantation. Heart Rhythm, 11(10), 1684-1690.