Aim: Development of the CardioVascLas-System® (CVLS) for cardiovascular laser catheter application. 
Materials: The CVLS consists of a compact 1064nm Nd:YAG medical diode laser with its accessory, the IriFlowLas® roller pump, and the versatile laser catheter RytmoLas® and its variants. It was designed for high density or anatomically mapping guided, selective ablation of arrhythmogenic or hypertrophic obstructive myocardium, of retrocardiac, periarterial renal and pulmonary nerve modulation, and varicose vein ablation by using a non-contact, open-irrigated, electrode-laser catheter, all in one. In addition, side selective atrial septal laser puncture by using the variant ISPunctureLas®, and esophageal photon/temperature sensing by using the esophageal probe PhotonSensoLas®.
Methods: Over 1000 transcatheter laser applications were performed in over 150 animal experimental studies in dog, pig, and ovine models to test the laser effects the system was designed for. In addition, over 500 laser applications in over 150 patients with various tachyarrhythmias including inappropriate sinus tachycardia, atrial, atrio-ventricular nodal, ventricular focal and reentry tachycardias, atrial flutter and fibrillation were performed. Left heart access was achieved by side selective interatrial septal laser puncture. Laser applications are performed under normothermic conditions, the catheter is not heated up. Experimental lesions were evaluated acutely, 2-3h, subacutely, 3-4 days, after 3 and 6 months, and in 2 years. Patients were controlled clinically, surface lead ECG, Holter monitoring after 6, 12 months.
Results: Except for two animal experiments laser tests and treatments in humans were without any kind of complications. Experimentally clear-cut homogenous lesions of coagulation necrosis spreading gradually from deep intramurally and irreversible transmural atrial or ventricular lesions were achieved in the atria in 5-10s and in the ventricles in 15-30s respectively. Photons are absorbed selectively by the myocardium, without interfering with electrophysiologic monitoring principles, without electrical hum, during laser application, what allows for a real-time verification of the initial success of treatment on the monitor. After abolishment of potential amplitudes in the bipolar high-density (HD) left ventricular laser mapping electrograms (LEG1-3 A) laser lesions were transmural; correlation coefficient 0.9. Laser lesions are healing to a fibrous scar without shrinking or aneurysm formation. Lesions are not arrhythmogenic and as reflected by D-Dimer serum levels are not thrombogenic. Contact pressure, and catheter orientation upon the endocardial surface are not major determinants for laser lesion formation. Among other arrhythmias laser ablation of long-lasting drug resistant persistent atrial fibrillation was attempted in 48 patients with various comorbidities. Laser applications at 15W/10-20s abolished local electrical potential amplitudes in the HD laser mapping electrograms permanently and sinus rhythm was achieved. Procedure duration: 82-175min (118 ± 72 min), 14-26 lesions (19 ± 4) per patient, X-ray exposure time 15-82 min (23.2 ± 12 min). Interventions were without complications. After a follow-up 8.2 ± 6.5 years patients’ quality of life improved significantly and all except two were off medication and in sinus rhythm; success rate = 96% (JAFIB Aug-Sep 2017| Volume 10| Issue 2, 1-10). With the RytmoLas® selective perirenal nerve modulation (J Vet Scie & Animal Husbandry Vol 9(1), 2348-9790) and pulmonary artery nerve modulation (Int. J. Mol. Sci. 2021, 22, 8788.https://doi.org/10.3390/ijms22168788) is practicable as promising methods for the treatment of systemic and pulmonary resistant hypertension. By using the ISPunctureLas® for side selective interatrial septal laser puncture at 10 W/2-3s successful left heart access was achieved in 45 patients without complications (J Innovations CRM, 4 (2013), 1481–1485).
Conclusions: The laser method is a safe and effective alternative catheter ablation technique for the treatment of various cardiovascular diseases with the potential for becoming an all-pervasive procedure.

TBA