Abstract 3251: Acute Changes in Bio-reactance Based Non Invasive Cardiac Output Measurements Following Biventricular Pacing Predict Left Ventricular Reverse Remodeling at 3 months: A Novel Tool to Guide CRT?
Introduction Non invasive cardiac output monitoring (NICOM) based on bio-reactance is a reliable, portable method for hemodynamic assessment and offers the potential to aid the assessment and the treatment of patients with heart failure. The purpose of our study was to assess to what extent acute changes in NICOM measurements are related to LV reverse remodeling following cardiac resynchronization therapy (CRT).
Methods In forty-two heart failure patients (age 69 +/− 9 yrs, EF 23 +/− 7%, QRS 154 +/− 12ms, NYHA III/IV- 21/3) acute CO recordings were made using NICOM within 7 days of the implantation and echocardiographic optimization of CRT. NICOM measurements were made by placing four electrodes on the skin surface of each patient’s chest allowing beat to beat assessment of CO at baseline (CRT OFF) and during optimized biventricular pacing (CRT ON). All patients underwent echocardiography prior to CRT and after 3 months and response was defined as a >15% reduction in left ventricular end systolic volume (LVESV).
Results Response to CRT was seen in 24/42 (57%) patients. There was a significant difference in CO readings within 7 days during CRT ON between responders and non responders (6.23 +/− 1.21 vs 5.19 +/− 0.96 L/min, p<0.01). The mean increase in acute CO between baseline and CRT ON amongst all patients was 36 +/− 33% with significant differences between responders and non responders (54 +/− 35 vs 16 +/− 14%, p<0.01). There was a good correlation between the extent of LVESV reduction at 3 months and the acute change in CO from baseline to CRT ON within 7 days of implant (r=0.47, p<0.001). Receiver operating characteristic curve analysis demonstrated that a cut off of 20% improvement in CO acutely (AUC 0.91) could predict LV reverse remodeling at 3 months with a sensitivity of 86% (95% CI: 57–98%) and a specificity of 100% (95% CI: 82–100%).
Conclusion: NICOM is a simple method for assessing CO non-invasively and an acute improvement in NICOM recordings following CRT can accurately predict LV reverse remodeling at 3 months. NICOM is safe, reliable and portable and this validation study suggests potential use in the optimization of CRT devices and in the guidance of lead placement at the time of implant. Both these areas deserve further evaluation with NICOM.