In myocardial infarction with left-sided heart failure, which statement is true about hemodynamics?

In myocardial infarction with left-sided heart failure, which statement is true about hemodynamics?

• A. Cardiac Output decreases, Stroke Volume decreases, LVSW decreases; Pulmonary Capillary Wedge Pressure may stay normal initially or increase.
• B. Cardiac Output increases, Stroke Volume decreases, LVSW decreases; Pulmonary Capillary Wedge Pressure may decrease.
• C. Pulmonary Capillary Wedge Pressure remains normal and Stroke Volume increases.
• D. Cardiac Output decreases, Stroke Volume increases, LVSW remains the same.

Answer: (A)

When the left ventricle is damaged by a myocardial infarction, its ability to pump forward is reduced. That means less blood is ejected with each beat, so stroke volume falls and, since cardiac output is the product of heart rate and stroke volume, overall forward flow (cardiac output) decreases. Left ventricular stroke work, which reflects the energy the ventricle uses to eject blood against afterload, also falls because contractility is diminished. Backward effects accumulate as blood backs up into the left atrium and pulmonary venous system, raising left atrial pressure and the pulmonary capillary wedge pressure. Initially this wedge pressure may appear normal if the rise hasn’t fully developed yet or if preload dynamics obscure it, but it tends to increase as failure progresses, leading to pulmonary congestion. So the pattern of decreased cardiac output, decreased stroke volume, and decreased LV stroke work, with Pulmonary Capillary Wedge Pressure that can be normal early or increased, correctly describes the hemodynamics.

When the left ventricle is damaged by a myocardial infarction, its ability to pump forward is reduced. That means less blood is ejected with each beat, so stroke volume falls and, since cardiac output is the product of heart rate and stroke volume, overall forward flow (cardiac output) decreases. Left ventricular stroke work, which reflects the energy the ventricle uses to eject blood against afterload, also falls because contractility is diminished. Backward effects accumulate as blood backs up into the left atrium and pulmonary venous system, raising left atrial pressure and the pulmonary capillary wedge pressure. Initially this wedge pressure may appear normal if the rise hasn’t fully developed yet or if preload dynamics obscure it, but it tends to increase as failure progresses, leading to pulmonary congestion. So the pattern of decreased cardiac output, decreased stroke volume, and decreased LV stroke work, with Pulmonary Capillary Wedge Pressure that can be normal early or increased, correctly describes the hemodynamics.