Physiology and Histology of Acute Myocardial Channels Made with Different Lasers

There is growing acceptance of the use of transmyocardial laser revascularization (TMLR) to treat patients with angina that is refractory to conventional therapies [1– 3]. This acceptance is largely based upon the fact that ongoing clinical trials have consistently shown that TMLR provides a significant reduction in angina [1, 4–9]. Importantly, this rather dramatic effect on chest pain is not short-lived as might be expected with either a placebo effect or with the previously observed transient relief of angina seen after thoracotomy [10]. Furthermore, there is also evidence that over time, regional blood flow is improved in myocardium treated with TMLR [5,6,9]. Despite these encouraging clinical results, there is still significant controversy over the mechanisms of both the relief of angina and improved blood flow.