Total internal reflection fluorescence microscope is a new optical microscopic system based on near-field optical theory. Its character of illumination by evanescent wave, together with the great signal-to-noise ratio and temporal resolution achieved by high quality CCD, allows us to analyze the spatiotemporal details of local Ca<sup>2+</sup> dynamics within the nanoscale microdomain surrounding different Ca<sup>2+</sup> channels. We have recently constructed a versatile objective TIRFM equipped with a high numerical aperture (NA=1.45) objective. Using fluo-4 as the Ca<sup>2+</sup> indicator, we visualized the near-membrane profiles of Ca<sup>2+</sup> waves and elementary Ca<sup>2+</sup> sparks generated by Ca<sup>2+</sup> release channels in rat ventricular myocytes. Different from those detected using conventional and confocal microscopy, Ca<sup>2+</sup> waves observed with TIRFM exhibited fine inhomogenous substructures composed of fluctuating Ca<sup>2+</sup> sparks. The anfractuous routes of spark recruitment suggested that the propagation of Ca<sup>2+</sup> waves is much more complicated than previously imagined. We believe that TIRFM will provide a unique tool for dissecting the microscopic mechanisms of intracellular Ca<sup>2+</sup> signaling.