In hypertrophic obstructive cardiomyopathy, which hemodynamic goals are preferred?

In hypertrophic obstructive cardiomyopathy, which hemodynamic goals are preferred?

• A. High heart rate with high SVR
• B. Low heart rate with high SVR
• C. Low heart rate with low SVR
• D. High heart rate with low SVR

Answer: (B)

In hypertrophic obstructive cardiomyopathy the dynamic LVOT obstruction worsens with tachycardia, low preload, and low afterload, and it improves with a slower heart rate and higher afterload. A slower heart rate lengthens diastole, increasing ventricular filling and LV size, which reduces the obstruction. A higher systemic vascular resistance increases afterload, reducing the pressure gradient across the LVOT and diminishing the obstruction. Clinically, this is why the optimal hemodynamic goal is a low heart rate with a high SVR. Agents such as beta-blockers help slow rate and decrease contractility, while vasoconstrictors like phenylephrine support afterload. Choices with tachycardia or low afterload would worsen the obstruction.

In hypertrophic obstructive cardiomyopathy the dynamic LVOT obstruction worsens with tachycardia, low preload, and low afterload, and it improves with a slower heart rate and higher afterload. A slower heart rate lengthens diastole, increasing ventricular filling and LV size, which reduces the obstruction. A higher systemic vascular resistance increases afterload, reducing the pressure gradient across the LVOT and diminishing the obstruction. Clinically, this is why the optimal hemodynamic goal is a low heart rate with a high SVR. Agents such as beta-blockers help slow rate and decrease contractility, while vasoconstrictors like phenylephrine support afterload. Choices with tachycardia or low afterload would worsen the obstruction.