The role of atria in ventricular fibrillation after continuous-flow left ventricular assist device implantation in ovine model

Abstract

ObjectivesThis study attempted to explore the hemodynamics and potential mechanisms driving pulmonary circulation in status of ventricular fibrillation (VF) following continuous-flow left ventricular assist device (CF-LVAD) implantation.MethodsAn ovine CF-LVAD model was built in small-tailed Han sheep, with the pump speed set as 2,400 rpm. VF was induced following ventricular tachycardia using a temporary pacemaker probe to stimulate the right and left ventricular free walls. The central venous pressure (CVP), pump flow (PF), pulmonary artery flow (PAF) and other major indicators were observed and recorded after VF.ResultsLow-flow systemic and pulmonary circulation could be sustained for 60 min under VF with sinus atrial rhythm after CF-LVAD implantation. The CVP gradually increased. The mean PF declined from 1.80 to 1.20 L/min, and the mean PAF decreased from 1.62 L/min to 0.87 L/min. Under VF with atrial fibrillation, the systemic and pulmonary circulation couldn’t be sustained. The CVP jumped from the 5 mmHg baseline to 12 mmHg, the mean PF rapidly decreased from 3.45 L/min to 0.79 L/min, and the PAF declined from 3.94 L/min to 0.77 L/min.ConclusionThe atrial rhythm and function might be essential for the circulation maintenance in patients with VF after CF-LVAD implantation.

Catheter Ablation for Tachyarrhythmias in Left Ventricular Assist Device Recipients: Clinical Significance and Technical Tips

“…If a rapid ventricular response is the sole risk factor for intolerable hemodynamics, atrioventricular nodal ablation with ventricular pacing may represent a potential solution for LVAD recipients. Nevertheless, it is important to note that an animal model supported by a continuous-flow LVAD illustrated the necessity of atrial systolic function in preserving hemodynamic stability during ventricular fibrillation (VF) [21]. The LVAD effectively provided support for 60 min during VF with sinus rhythm; however, it was noted that AF was unable to sustain both systemic and pulmonary circulation in the presence of elevated central venous pressure [21].…”

“…Nevertheless, it is important to note that an animal model supported by a continuous-flow LVAD illustrated the necessity of atrial systolic function in preserving hemodynamic stability during ventricular fibrillation (VF) [21]. The LVAD effectively provided support for 60 min during VF with sinus rhythm; however, it was noted that AF was unable to sustain both systemic and pulmonary circulation in the presence of elevated central venous pressure [21]. This result may, in part, be influenced by right ventricular failure associated with AF; nonetheless, it underscores the significance of maintaining sinus atrial rhythm in such a specific scenario [16,22].…”

“…Further studies are warranted to better clarify the clinical implication of the presence of AF during durable LVAD supports. however, it was noted that AF was unable to sustain both systemic and pulmonary circulation in the presence of elevated central venous pressure [21]. This result may, in part, be influenced by right ventricular failure associated with AF; nonetheless, it underscores the significance of maintaining sinus atrial rhythm in such a specific scenario [16,22].…”