These data indicate that the reinjection of thallium improves the detection of ischemic myocardium and that myocardial regions with improved thallium uptake on reinjection imaging represent viable but jeopardized myocardium.

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Background Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations. Methods and Results The echocardiography registries from two major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure (PASP) ≥60 mmHg detected echocardiographically. From a total of 10,471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean 77 y, mean PASP 69.4 ± 10.5 mmHg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0-4817 d) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. Pulmonary hypertension was present without substantial left heart remodeling: the mean left ventricular (LV) ejection fraction was 0.50 ± 0.16, LV end-diastolic dimension was 4.9 ± 1.0 cm, and left atrial dimension was 4.4 ± 0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5 ± 11.4 mmHg, pulmonary capillary wedge pressure of 22.6 ± 8.9 mmHg, and pulmonary vascular resistance of 4.6 ± 2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion (V/Q) scan for thromboembolic causes of PH. Conclusions In an at-risk patient population, PH is under-diagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.