Myocardial Infarction, Case Study Example

A myocardial infarction (MI)occurs when the circulation of blood to the heart is blocked, causing damage to the muscle.Immediate treatment is vital, but obtaining an accurate diagnosisto the root cause is necessary to provide the best treatment.Electrocardiograms (ECG), biomarker elevations, andextensive cardiac imaging increase patients’ chances of optimal recovery (Thygesen, Alpert, White, Jaffe, Apple, Galvani,… & Al Atar, 2007).

An MI is usually caused by the occlusion of the coronary artery. When the heart cannot receive oxygen and vital nutrients, significant portions of the heart die. A commonsymptom is sudden death, so it is important to recognize prodromal symptoms such as fatigue, malaise, dizziness, chest pain, and feelings of indigestion and anxiety. The classic presentation isintense, unremitting, anddiffuse chest pain, whichradiatesto the neck, shoulders, jaw, and left arm.The pain is unaffected by movement and described as pressure. Patients may experience shortness of breath, coughing, and wheezing.Otherindicators include an increased and irregular heart rate and hypertension.

An ECG distinguishesthe type of MI. AnST-segment elevation myocardial infarction (STEMI)occurs when the coronary artery is completely occluded, causing large portions of the heart to die. A non-ST segment elevation myocardial infarction (NSTEMI)causes only partial occlusion of the coronary artery and less damage to the heart. NSTEMIs do not produce the ST-segment elevation on an ECG, but account for greater than 70% of all MIs. Though they are not as acute as STEMIs, NSTEMIs have worse long-term outcomes (Chang, Min, Rao, Patel, Simonetti, Ambrosio & Raman, 2012).

Cardiac enzymes are measured to determine the phase, and to distinguish between a heart attack and unstable angina. In a healthy heart, cardiac enzymes are contained; necrosis causesthe biomarkers to leak into the blood stream. Cardiac enzymes include troponin, creatine kinase (CK-MB), and lactate dehydrogenase (LDH); however, troponinis the best indicator of an MI.An MI is diagnosed if troponins are elevated one value above the 99^th percentile, measured at 14ng/L in the general population. Troponins can even predict future cardiovascular events (Koenig, Breitling, Hahmann, Wusten, Brenner & Rothenbacher, 2012). Other biomarkers lack the specificity of troponins and should be used only with other studies in the detection of an MI.

Other laboratory tests are helpful in the diagnosis and management of an MI. A complete blood count (CBC) can indicate underlying pathologies and measure the count of platelets, and red and white blood cells. Levels of C-reactive proteins and creatine should be observed prior to prescribing medications. Blood oxygenation should be checked repeatedly for hypoxemia. Further cardiac imaging can detect wall motion abnormalities in the heart (Thygesen, Alpert, White, Jaffe, Apple, Galvani,… & Al Atar, 2007). Imaging includesradionuclide ventriculography, myocardial perfusion scintigraphy (MPS), and magnetic resonance imaging (MRI).

Initial treatments include oxygen therapy, blood thinners, and nitroglycerin. STEMI patients often receive treatments to restore arterial flow such as thrombolytic medications or angioplasty. NSTEMI patients have different requirements, as they are caused by an underlying pathology. Further treatments for an MI may include medications such as beta blockers or ACE inhibitors, bypass surgery, and cardiac rehabilitation. Lifestyle modifications such as reducing stress, quitting smoking, and working with diet and exercise may be recommended.

An MI is an indicator of a deeper malfunctioning in the body. Though the initial treatment must be performed to keep the patient alive, a specific diagnosis must be made. When the cause of the MI is accurately diagnosed, patients may have the best chance of recovery.

References

Chang, H., Min, J., Rao, S., Patel, M., Simonetti, O., Ambrosio, G., & Raman, S. (2012).

Advances in cardiovascular imaging: Non-ST-segment elevation. Circulation: Cardiovascular Imaging, 5, 536-546. Retrieved from http://circimaging.ahajournals.org/content/5/4/536.full

Koenig, W., Breitling, P., Hahmann, H., Wusten, B., Brenner, H., & Rothenbacher, D. (2012). Cardiac troponin T measured by high-sensitivity assay predicts recurrent cardiovascular events in stable coronary heart disease patients with 8-year follow-up. Clinical Chemistry, 58(8), 1215-1224. Retrieved from http://www.clinchem.org/content/58/8/1215.full

Thygesen, K., Alpert, J., White, H., Jaffe, A., Apple, F., Galvani, M., … Al Atar, N. (2007). Expert consensus document: Universal definition of myocardial infarction. Circulation, 116, 2634-2653. Retrieved from http://circ.ahajournals.org/content/116/22/2634.long