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Patients with severe aortic stenosis are increasingly treated with transcatheter aortic valve implantation (TAVI) as a safer option to surgical aortic valve replacement (sAVR).  Similar to many other heart diseases, after the specific therapeutic intervention patients are eligible for cardiac rehabilitation (CR) for the purpose of functional recovery. Thus far, CR after both sAVR and TAVI has been used to a limited extent, as shown by the availability of only two meta-analyses including 5 studies and 6 studies, respectively. Recent observational studies reported a significant improvement in functional indexes such as the Barthel scale and the 6-minute walk test (6MWT). We evaluated the outcome of CR in patients after TAVI treatment by measuring changes in the commonly used Barthel scale and 6MWT and adding the short physical performance battery (SPPB) scale as an index to assess lower extremity function. All indexes demonstrated a significant improvement, namely p<0.001 with the Barthel scale, p=0.043 for the 6MWT, and p=0.002 for SPPB. These results confirm the significant improvement of the Barthel scale and 6MWT reported in the previous meta-analysis and suggest the utility of SPPB as a further index of efficacy of CR in patients with severe aortic stenosis treated with TAVI.

Although the first non-imaging nuclear probe for clinical application was already available 25 years ago, this technique is still underused for the assessment of ventricular function. Over the years substantial technological progress rendered nuclear probes more accurate and easier to use, and so far the applicability of these devices has been evaluated in several experimental and clinical contexts. Bedside devices can be used in the evaluation of hemodynamically unstable patients and of drug therapy. In patients with several heart diseases, particularly with ischemic cardiomyopathy, accurate information on the changes in ventricular function occurring during routine activities, as well as during structured activities, can be provided using the ambulatory probes. This review will focus on the development and clinical application of these diagnostic tools.

Background: The aim of this study was to evaluate the accuracy of low-dose dobutamine echocardiography (DE) and resting thallium 201 single photon emission computed tomography (SPECT) alone and in combination for prediction of functional recovery at late follow-up (1 year) after revascularization., Methods and Results: Twenty-six patients with coronary artery disease and ventricular dysfunction (ejection fraction, 42% +/- 9%) underwent DE and Tl-201 SPECT 14 +/- 9 (mean +/- SD) days before revascularization and repeated echocardiography 12 +/- 5 months thereafter. Discriminant analysis was applied to combine Tl-201 SPECT and DE data to classify dysfunctional segments as viable or nonviable. In 78 akinetic/dyskinetic revascularized segments, Tl-201 SPECT provided a sensitivity of 83% and a specificity of 55%, whereas DE showed a sensitivity of 60% and a specificity of 91%, for prediction of improvement in regional function at follow-up. The combination of data through use of discriminant analysis provided a sensitivity of 80% and a specificity of 86%, with an overall accuracy of 82%, significantly higher than DE (71%; P <.05) and Tl-201 SPECT (73%; P <.05) alone. Moreover, discriminant analysis identified 12 (75%) of 16 patients with and 8 (80%) of 10 patients without significant improvement in ejection fraction at follow-up, with an accuracy of 77%., Conclusions: The combination of Tl-201 SPECT and DE data provides higher accuracy than either technique alone for prediction of recovery of regional and global function after revascularization.

Accurate assessment of myocardial viability permits selection of patients who would benefit from myocardial revascularization. Currently, rest-redistribution thallium-201 scintigraphy and low-dose dobutamine echocardiography are among the most used techniques for the identification of viable myocardium. Thirty-one consecutive patients (all men, mean age 60 +/- 8 years) with chronic coronary artery disease and reduced left ventricular ejection fraction (31% +/- 7%) were studied. Rest 201Tl single-photon emission tomography (SPET), low-dose dobutamine echocardiography and radionuclide angiography were performed before revascularization. Radionuclide angiography and echocardiography were repeated after revascularization. An a/dyskinetic segment was considered viable on 201Tl SPET when tracer uptake was >65%, while improvement on low-dose dobutamine echocardiography was considered a marker of viability. Increase in global ejection fraction was considered significant at > or = 5%. In identifying viable segments, rest 201Tl SPET showed higher sensitivity than low-dose dobutamine echocardiography (72% vs 53%, P<0.05), while specificity was not significantly different (86% vs 88%). In 17 patients, global ejection fraction increased > or = 5% (group 1) while in 14 it did not (group 2). A higher number of a/dyskinetic segments were viable on 201Tl SPET in group 1 than in group 2 (2.6 +/- 1.9 vs 0.6 +/- 1.2, P < 0.005), while no significant differences were observed on low-dose dobutamine echocardiography (1.7 +/- 1.6 vs 1.1 +/- 1.6). A significant correlation was found between the number of a/dyskinetic segments viable on 201Tl SPET and post-revascularization changes in ejection fraction (r = 0.52, P < 0.05), but such a correlation was not observed for low-dose dobutamine echocardiography. Using as the cut-off the presence of at least one viable a/dyskinetic segment, rest 201Tl SPET had a higher sensitivity (82% vs 53%, P = 0.07) and showed a trend towards higher accuracy and specificity (77% vs 58%, and 71% vs 64%, respectively) as compared with low-dose dobutamine echocardiography. In conclusion, these findings suggest that when severely reduced global function is present, rest 201Tl SPET evaluation of viability is more accurate than low-dose dobutamine echocardiography for the identification of patients who will benefit most from revascularization.