Posted: March 5th, 2015

Myocardial infarction

Myocardial infarction

Order Description

Explain the progressive pathophysiologic events that lead to and occur during a myocardial infarction (MI). Discuss the risk factors associated with developing an MI (2 pages)

My Question:  Explain the progressive pathophysiologic events that lead to and occur during a myocardial infarction (MI). Discuss the risk factors associated with developing an MI. (2 pages)

Classmate 1
A neonate has a harsh, loud systolic murmur shortly after birth. This is best heard at the left lower sternal border. The neonate is acyanotic and has no other symptoms.
What type of congenital heart disorder does this infant have?
The infant has a ventricular septal defect, which is an abnormal communication between the ventricles. Ventricular septal defects are considered the most common type of congenital heart lesions and are further classified into four types based on their location in the septum. The most common type is the perimembranous type which occurs in the outflow tract of the left ventricle immediately below the aortic valve. The muscular type, which occurs low or anterior in the ventricular septum between the trabecula, is likely to close spontaneously and difficult to close surgically due to their location low in the ventricular apex, besides, most muscular septal defects are hemodinamically insignificant and require no treatment. The supracristal ventricular defect occurs in the right ventricular outflow tract or infundibulum, below the pulmonary valve. The atrioventricular canal or inlet ventricular septal defect occur posterior and inferior to the membranous system, beneath the septal cusp of the tricuspid valve and inferior to the papillary muscles of the conus (McCance & Huether 2014).
Explain why the neonate is not cyanotic.
The neonate is not cyanotic because the direction of the shunting in a ventricular septal defect is from the high-pressure left side to the lower-pressure right side of the heart. Oxygenated blood flows into the pulmonary circulation increasing pulmonary blood flow (McCance & Huether 2014).
When could the infant become cyanotic?
Due to increased pulmonary blood flow caused by the left-to-right shunting, the pulmonary bed undergoes changes leading to a decrease in diameter of the pulmonary vessels which in turn causes increased resistance to blood flow. If pulmonary vascular resistance is severely increased, changes become irreversible, and pulmonary vascular resistance continues to rise. The infant may become cyanotic in the event that pulmonary vascular resistance exceeds systemic vascular resistance, which causes the shunt through the ventricular septal defect to reverse direction causing deoxygenated blood to flow into the systemic circulation. The phenomenon is known as Eisenmenger syndrome (McCance & Huether 2014).

Classmate 2

Hypertension is a systolic blood pressure at or above 140 mm/Hg and/or diastolic pressure at or above 90 mm/Hg. Essential hypertension or primary hypertension is characterized by a chronic elevation in blood pressure that occurs without evidence of other disease, and secondary hypertension by an elevation of blood pressure that results from other diseases, such as kidney disease. “Associated risk factors for primary hypertension are family history of hypertension, high sodium intake, excessive calorie consumption, physical inactivity, excessive alcohol intake and low potassium intake” (Ignatavicius, D. 2010. Pg 798).  Hypertension is known as the silent killer because usually the patient is not aware of this condition until fatal symptoms occur. The most common first signs are headaches, dizziness or fainting. Some patient also may have facial flushing (redness).  Long term uncontrolled hypertension “…increases the workload of the left ventricle by increasing the pressure against which the heart must pump as it ejects blood into the systemic circulation” (Porth, C. 2007. Pg 367). Left ventricle hypertrophy is a major rick factor for ischemic heart disease, cardiac arrhythmias, sudden death, congestive heart failure, stroke or transient ischemic attack, chronic kidney disease, peripheral vascular disease and retinopathy to name the most common.
The main objective for treatment of essential hypertension is to achieve and maintain arterial blood pressure of less than 140/90 mm/HG, with the goal of preventing morbidity and mortality. Lifestyle modification, which include weight reduction, adopting a DASH eating plan, dietary sodium reduction, physical activity and moderation of alcohol consumption plus adhering to a pharmacologic treatment are the most effective way to achieve a stable and control blood pressure.