Radionuclide monitoring of left ventricular function

The development of continuous left ventricular (LV) function–monitoring devices has allowed monitoring of several physiologic parameters in a number of cardiovascular disorders. This interesting application of radionuclide angiography relates to the use of miniaturized equipment suitable for evaluating patients during routine activities by means of nonimaging probes. In contrast to gamma cameras, these probes do not produce an image of the heart, but are used specifically to record count variations within its field of view. Because the systems are not designed to generate images, the detectors are simpler than a standard scintillation camera. The simplicity in detector configuration makes the systems portable and less expensive than gamma cameras. Several devices have been evaluated and validated for continuous monitoring of LV function. The diagnostic and prognostic roles of these techniques appear to be predominant in patients with CAD. Silent myocardial ischemia may be widely evaluated by these systems, which allow the clinician to predict ischemic cardiac events, perform risk stratification, and guide treatment in patients with CAD more accurately than can be done with exercise test results. In fact, it has been demonstrated that adverse cardiac events are more commonly observed during routine daily activities. The continuous improvement in miniaturizing these devices and the capability of online processing of data could make this technique useful and widely acceptable, facilitating simultaneous assessment of hemodynamic and metabolic changes in silent LV dysfunction and continuing to play an important role in noninvasive evaluation of ventricular performance.