Background: Implantable cardioverter defibrillators (ICDs) offer effective therapy for the prevention of sudden cardiac death (SCD) due to ventricular arrhythmias. However, inappropriate shocks have detrimental effects on survival and quality of life.The addition of hemodynamic monitoring may be useful in discriminating clinically important ventricular arrhythmias.Objective: In this study, we assess the ability of laser Doppler flowmetry to assess the hemodynamic effect of paced atrial and ventricular arrhythmias using mean arterial blood pressure as the reference. Methods:In this acute human study in patients undergoing an elective electrophysiological study, laser Doppler flowmetry, arterial blood pressure, and surface ECG were acquired during high-rate atrial and ventricular pacing to simulate supraventricular and ventricular tachycardias.Results: Arterial blood pressure and laser Doppler flow signals correlated well during atrial and ventricular pacing (rho = 0.694, p < .001). The hemodynamic impairment detected by both methods was greater during ventricular pacing than atrial pacing (-1.0% vs. 19.0%, p < .001). Laser Doppler flowmetry performed better than rate alone to identify hemodynamic impairments. Conclusion:In this acute study, laser Doppler flowmetry tissue perfusion served as a good surrogate measure for arterial pressure, which could be incorporated into future ICDs.