Backgrounds:
In acute myocardial infarction (AMI), the extent of myocardial damage governs the progression to heart failure in the long-term. Therefore, reducing the myocardial damage is prerequisite to prevent chronic heart failure. Although vagal nerve stimulation (VNS) has been repeatedly demonstrated to have the powerful anti-infarct effect, technical difficulties preclude its clinical applications. Recently we developed an new percutaneous, intravascular VNS (iVNS). In this study, we investigated whether iVNS reduces the infarct size and prevents heart failure one month after ischemia reperfusion (IR).
Methods:
In mongrel dogs, we ligated the left anterior descending coronary artery for 3 hours and reperfused. We transvascularly stimulated the right vagal nerve with a pacing catheter in the superior vena cava. We maximized the intensity of iVNS that did not deteriorate hemodynamics (amplitude; 5.1±2.1 V, pulse width; 0.2ms, frequency; 10 Hz). We started iVNS at the onset of ischemia (iVNS0, n=7) or 90 min after the onset of ischemia (iVNS90, n=7) and continued to 60 min after reperfusion. One month after IR, we compared the infarct size, left ventricular (LV) function and hormonal responses among 3 groups including the no treatment group (IR, n=10).
Results:
Both iVNS0 and iVNS90 significantly reduced the infarct size (IR: 11.6±3.1, iVNS0: 2.4±2.1, iVNS90: 4.5±1.9%, p<0.05, Figure), improved LV ejection fraction (IR: 50±7, iVNS0: 61±6, iVNS90: 60±5.1%, p<0.05) and decreased LV end-diastolic pressure (IR: 14.6±1.9, iVNS0: 4.2±1.0, iVNS90: 5.0±2.8mmHg, P<0.05). The benefits were larger in iVNS0 than iVNS90.
Conclusion:
Short term iVNS delivered prior to coronary reperfusion markedly reduced the infarct size and preserved LV function one month after ischemia. Since we can transvascularly deliver iVNS, it may serve as a new non-pharmacological therapeutic strategy and contribute to improve the long term survival in patients with AMI.
GW26-e2455 Vagal Nerve Stimulation Reverses Cardiac Dysfunction and Subcellular Calcium Handling in Heart Failure Rats After Myocardial Infarction
