Cardiovascular disintegration: A conceptual, model-based approach to heart failure hemodynamics

OBJECTIVE
The current understanding of heart failure (HF) largely centers round left ventricular (LV) function; however, disorders in serial integration of cardiovascular system may cause a hemodynamic picture similar to left-sided HF. Therefore, focusing only on LV function may be a limited and misleading approach. We hypothesized that cardiovascular system has four major integration points, and disintegration in any of these points may produce the hemodynamic picture of HF.

METHODS
We used a computational model in which mechanical properties of each chamber were characterized using time-varying elastance, and vascular beds were modeled by series of capacitances and resistances. The required percent changes in stressed volume (Vstressed) was presented as a measure of congestion susceptibility.

RESULTS
As mean systemic pressure is closely correlated with pulmonary capillary wedge pressure (PCWP), arteriovenous disintegration can create a diastolic dysfunction pattern, even without any change in diastolic function. For 10%, 20%, 30%, 40%, and 50% interventricular disintegration, required Vstressed for reaching a PCWP over 20 mmHg was decreased by 42.0%, 31.2%, 22.5%, 15%, and 8.3%, respectively. Systolodiastolic disintegration, namely combined changes in the end-diastolic and systolic pressure-volume curves and ventriculoarterial disintegration significantly decreases the required percent change in Vstressed for generating congestion.

CONCLUSION
Four disintegration points can produce the hemodynamic picture of HF, which indicates that combination of even seemingly mild abnormalities is more important than an isolated abnormality in a single function of a single chamber. Our findings suggest that a “cardiovascular disintegration” perspective may provide a different approach for assessing the HF syndrome.