Systolic dysfunction and dilation

[nm825]

What causes the dilation of the LV you see in systolic heart failure? Is the increased EDV causing it to balloon out and the eccentric hypertrophy occurs in repsonse to this? Or does the dilation occur due to hypertrophic mechanisms?

Further, how do remodeling mechanisms in systolic HF become maladaptive?

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[Instatewaiter]

What causes the dilation of the LV you see in systolic heart failure? Is the increased EDV causing it to balloon out and the eccentric hypertrophy occurs in repsonse to this? Or does the dilation occur due to hypertrophic mechanisms?

Further, how do remodeling mechanisms in systolic HF become maladaptive?

So, dilation is the increase in EDV. This occurs as a way for the heart to maintain cardiac output. It is maladaptive for many reasons. First, because as there is more dilation, you increase wall tension causing subendocardial ischemia and less efficient pumping. Second, this jacks up the mechanics of the heart; as the heart becomes more round as opposed to ellipsoid it is less efficient. In addition to the change in geometry, dilation of the ventricles cause dilation of both the mitral and tricuspid annuli which leads to mitral and tricuspid regurgitation, further worsening the efficiency of the heart as much of the reduced stroke volume is lost to the regurgitation

 

[nm825]

So, dilation is the increase in EDV. This occurs as a way for the heart to maintain cardiac output. It is maladaptive for many reasons. First, because as there is more dilation, you increase wall tension causing subendocardial ischemia and less efficient pumping. Second, this jacks up the mechanics of the heart; as the heart becomes more round as opposed to ellipsoid it is less efficient. In addition to the change in geometry, dilation of the ventricles cause dilation of both the mitral and tricuspid annuli which leads to mitral and tricuspid regurgitation, further worsening the efficiency of the heart as much of the reduced stroke volume is lost to the regurgitation

Thanks. Where does the eccentric hypertrophy come into play? Does the increased wall stress from dilation cause the eccentric hypertrophy as a way of de-stretching the myocytes?

So let's say because of the EDV, your myocytes are really, really stretched. If I start adding more sarcomeres to lengthen each myocytes, they are stretching as much, right?

And this eventually becomes maladaptive because increase mass means an increased oxygen demand, which the heart can't supply?

 

[Instatewaiter]

Thanks. Where does the eccentric hypertrophy come into play? Does the increased wall stress from dilation cause the eccentric hypertrophy as a way of de-stretching the myocytes?

So let's say because of the EDV, your myocytes are really, really stretched. If I start adding more sarcomeres to lengthen each myocytes, they are stretching as much, right?

And this eventually becomes maladaptive because increase mass means an increased oxygen demand, which the heart can't supply?

Eccentric hypertrophy is essentially an increase in LV mass without an increase in thickness. This goes hand and hand with LV dilation.

I am not sure I understand your other questions.