Left-to-right systolic ventricular interaction in patients undergoing biventricular stimulation for dilated cardiomyopathy

Abstract

Left-to-right systolic ventricular interaction (i.e., the phenomenon by which the left ventricle contributes to most of the flow and to two-thirds of the pressure generated by the right ventricle) originates from transmission of systolic forces between the ventricles through the interventricular septum and from the mechanical effect of the common muscle fibers encircling their free walls. As a consequence, any reduction of left ventricular free wall function translates in lower right ventricular pressure or function. We investigated whether systolic ventricular interaction could be evidenced in nine patients with dilated cardiomyopathy in whom a biventricular pacemaker was implanted. Changes in right and left ventricular pressures were measured with high-fidelity catheters, before and after periods of biventricular pacing from the right atrium with different stimulation intervals to the right and left ventricles, respectively. The steady-state changes of left and right ventricular systolic pressure obtained from any single pacing interval combination were considered. We then calculated, with a two-level mixed regression analysis of the entire data set, the relation between changes in left and right systolic pressures: the presence of a statistically significant slope was assumed as evidence of ventricular interaction. The slope of the regression replaced the crude pressure ratio as an estimate of the gain of the interaction; its value compared with values observed in experimental studies. Moreover, its dependence on septal elastance and on right ventricular volume was similar to that already demonstrated for ventricular interaction gain. In conclusion, the linear relationship we found between systolic pressure changes in the two ventricles of patients with dilated cardiomyopathy during biventricular pacing could be explained in terms of ventricular interaction.

Left ventricular–right ventricular interaction in paediatric idiopathic dilated cardiomyopathy

“…1 They found that the tricuspid annular plane systolic excursion and the tricuspid annular peak systolic velocity were significantly lower in these patients than in the control group as a possible sign of relevant left ventricular-right ventricular interaction. Given the known left ventricular-right ventricular interaction in patients with tetralogy of Fallot 2 or dilated cardiomyopathy, 3 we support the notion of Groner et al 1 that right ventricular dysfunction is under-recognised in children with dilated cardiomyopathy. To be able to fully assess changes in systolic right ventricular function in patients with congenital heart defects, sufficient reference data of normal patients are required.…”

Radiofrequency Catheter Ablation for Dyssynchrony-induced Dilated Cardiomyopathy in an Infant

“…Mechanical dyssynchrony has been described as the root of left bundle branch‐induced cardiomyopathy, which reverses with cardiac resynchronization therapy . Left‐to‐right systolic ventricular interaction accounts for much of the hemodynamic work performed by the right ventricle via fibers of the interventricular septum and via those common fibers that encircle their combined free walls . Unusual variations of the distribution and orientation of those common fibers may put individuals with electrical dyssynchrony at unique risk of mechanical inefficiency and increased energy requirements.…”

Applicability of Automated Functional Imaging for Assessing Right Ventricular Function

“…However, it is now recognized that left‐to‐right systolic ventricular interaction is the phenomenon by which the LV can contribute to as much as 80% of the flow and 68% of the pressure generated by the RV . This phenomenon originates from the transmission of systolic forces between the two ventricles through the interventricular septum and from the mechanical effect of common muscle fibers encircling their free walls . Therefore, these interventricular segments should be included in the overall RV analysis, particularly as we have previously documented that TAPSE also depends on LV function …”

“…28 This phenomenon originates from the transmission of systolic forces between the two ventricles through the interventricular septum and from the mechanical effect of common muscle fibers encircling their free walls. 29 Therefore, these interventricular segments should be included in the overall RV analysis, particularly as we have previously documented that TAPSE also depends on LV function. 19 Even though it can be argued that instead of using RVFAC, RVOT systolic excursion, TAPSE, and TA TDI systolic velocity to establish RV AFI sensitivity and specificity, cardiac magnetic resonance or three-dimensional echocardiography should had been used as a reference standard of RV function.…”