Coronary or Left Ventricular Pacing, the Easy and Obvious Way Out of Asystole During Cardiac Catheterization

The authors of the preceding study¹ have to be commended on a clean set of experiments re-invigorating an all-but-forgotten easy and safe modality to treat bradycardia or even save lives in the catheterization laboratory. While the emphasis of the paper is on the fact that the novel VisionWire perfects the technique of coronary pacing, the message is consistent that coronary pacing, per se, is a good thing to have. In the early 1980s,² when exploring the intracoronary electrocardiogram (also evaluated in the paper discussed) as a more sensitive and selective assessment of ischemia during percutaneous coronary intervention (PCI), it came to mind that the electrical setup via the coronary guidewire could also be used for pacing. This happened in an era when every PCI was preceded by prophylactic pacemaker insertion into the right ventricle. This not only made PCI more complex, but also increased the risk of tamponade, as correctly reiterated by the authors of the discussed article. Some people used the availability of coronary pacing as a convenient reason to abandon preventive pacemaker insertion. Since then, the transition to smaller coronary guiding catheters, inducing less flow obstruction in the coronary orifice, the use of nonionic contrast medium inducing less bradycardia, and the reduced need for prolonged balloon inflations with the transition from balloon angioplasty to stenting have shrunk the need for pacing during PCI to almost nothing. Nonetheless, bradycardia, and even asystole, still occur in the catheterization laboratory. Vasovagal episodes can usually be swiftly reversed by atropine. Obstruction of a sinus node artery by the guiding catheter or true ischemia-induced bradycardia are more difficult to treat. All the physician has to do is to remember that pacing-ready equipment is already in place. The authors point out that there is no need to jump from the wrist to the groin or, if already working from the groin, to hectically look for the femoral vein while the patient is pulseless. Simply connect the wire hanging out of the patient to the cathode (- pole) of the pacemaker device and the anode (+ pole) to some exterior part of the patient. A large skin electrode (according to the current paper best applied to the back of the chest) is ideal and the patient will feel no pinching even when high pacing output is used. In an emergency situation, one may just stick a needle into the anesthetized groin or even into the nonanesthetized chest wall to be ready for unipolar pacing. Not all guidewires conduct equally well, and the one proposed by the authors clearly excels. However, physicians will not select a coronary guidewire based on the best pacing threshold to be expected in the unlikely event that coronary pacing were to be required, let alone done. First, it is important to know that the tip of the coronary guidewire has to be advanced deeply into a coronary side-branch feeding muscle (e.g., septum) rather than epicardium. Second, as much of the guidewire length as possible should be insulated, up to the coronary orifice, and the guiding catheter should take care of that. Within the coronary artery, advancement of the balloon catheter to the vicinity of the tip will help. A Monorail catheter will do this as well as an over-the-wire catheter. Third, the pacing output should first be set at maximum and only reduced once pacing is accomplished. Pacing may also become necessary during cardiac catheterization procedures when there is no coronary guidewire in place. Any guidewire inserted into the left ventricle and insulated by a plastic catheter will serve as a left ventricular pacing electrode.^3–5 In fact, the mere irritation by the guidewire flipping around in the left ventricle is likely to mechanically produce some kind of cardiac rhythm. After finding a stable position for the wire, the pacemaker will take over. Finally, the upsurge of percutaneous aortic valve implantation requiring rapid pacing during balloon inflation to avoid the balloon being pushed away from the intended site (the same holds true for dilatation of coarctation) invites the use of left ventricular pacing over the guidewire.⁶ The message should be clear: interventional cardiologists need to utilize the obvious tools at hand rather than panicking when the patient’s heart stops beating. The patient’s brain will enjoy the re-establishment of a normal cardiac output as fast as it can be done, which is best possible by pacing with equipment that is already in place.

References

1. Heinroth KM, Unverzagt S, Buerke M, et al. Transcoronary pacing in a porcine model — Impact of guidewire insulation. J Invasive Cardiol 2011;23:108–114.
2. Pande AK, Meier B, Urban P, et al. Intracoronary electrocardiogram during coronary angioplasty. Am Heart J 1992;124:337–341.
3. de la Serna F, Meier B, Pande AK, et al. Coronary and left ventricular pacing as standby in invasive cardiology. Cathet Cardiovasc Diagn 1992;25:285–289.
4. Meier B. Pacing in the left heart — Often forgotten because rarely needed. Cathet Cardiovasc Diagn 1997;42:33.
5. Meier B. Left ventricular pacing for bradycardia in the cardiac catheterization laboratory. Catheter Cardiovasc Interv 2004;62:31.
6. Navarini S, Pfammatter JP, Meier B. Left ventricular guidewire pacing to simplify aortic balloon valvuloplasty. Catheter Cardiovasc Interv 2009;73:426–427.

———————————————————— From the Swiss Cardiovascular Center Bern, University Hospital Bern, Switzerland. The author reports no conflicts of interest regarding the content herein. Address for correspondence: Bernhard Meier, MD, FACC, Professor and Head of Cardiology, Swiss Cardiovascular Center Bern, University Hospital Bern, CH-3010 Bern, Switzerland. E-mail: bernhard.meier@insel.ch