Time-dependent response of both ventricles after septal ablation: Implications for biventricular support after left ventricular assist device placement

Abstract

Acute and chronic hemodynamic responses are distinctly different after septal injury; the acute response demonstrates a paradoxical motion. Resolution of this motion at 4 weeks is suggestive of reduced septal compliance and buttressing. Ventricular interactions after placement of a left ventricular assist device will vary depending on the injury duration.

Nonsurround, nonuniform, biventricular-capable direct cardiac compression provides Frank-Starling recruitment independent of left ventricular septal damage

“…The RV internal septal-lateral end-diastolic (ED) and end-systolic (ES) short-axis dimensions were analyzed as previously described. 17 ED was defined as the interval of the peak electrocardiographic R wave and LV ES and RV ES as the point of zero aortic or pulmonary flow, respectively. Steady state hemodynamic parameters represented the average of 8 to 10 beats.…”

“…Selective percutaneous over-the-wire catheterization of the main septal perforating artery (MSPA) was followed by either sham or active percutaneous transluminal septal myocardial ablation of the artery (PTSMA). 17 After 4 weeks of recovery, the RV hemodynamic and dimensional changes were measured in response to custom-designed HeartPatch DCC placement and its actuation in 5 modes: no device use, passive placement of the DCC device, and LV, RV, or biventricular actuation. 15,18…”

“…Confirmation of the ablation/infarction pathologic features followed selective MSPA perfusion using 1% triphenyltetrazolium solution and simultaneous differential staining through the left main and right coronary arteries. 17…”

“…Ten digital, omnidirectional, transceiver sonomicrometer crystals (2-mm Silastic; Sonometrics, London, Ontario, Canada) were attached in the epicardial and endocardial positions. 17 Other crystals were positioned in an equatorial plane across the cardiac short axis to measure the RV and LV internal dimension and the thickness of the LV, RV free wall, and septum. Their position was confirmed at autopsy.…”

“…To overcome such shortcomings, we used a novel design consisting of independent nonsurround RV-and LV-apposed pumping chambers (HeartPatch-DCC device; Heart Assist Technologies, St Leonards, NSW, Australia; Figure 1), which has been shown to have potent ability to increase cardiac output 15 and restore myocardial efficiency during pharmacologically induced heart failure. 16 This device was implanted in sheep hearts with septal pathologic features, as previously described, 17 to compare the RV in-series, load-independent, and geometric responses to that of previously studied inline mechanical LVAD unloading.…”