ABSTRACT
BACKGROUND: In patients undergoing regadenoson stress SPECT myocardial perfusion imaging (MPI), the impact of the regimented administration of aminophylline on the cardiac-to-extracardiac photon activity ratio is unknown. METHODS: This is a substudy of the ASSUAGE trial (NCT01250496); a double-blinded, randomized, placebo-controlled clinical trial which investigated the attenuation of regadenoson-related adverse effects using 75 mg of intravenous aminophylline vs placebo, administered 90 seconds following (99m)Tc-tetrofosmin injection in patients undergoing regadenoson stress SPECT-MPI. In subjects with normal MPI enrolled in the trial, we sampled from the antero-posterior planar projection of the post-stress scintigraphic data the mean photon activity in the myocardium, liver, bowel, and lungs. The mean cardiac-to-extracardiac activity ratios were compared between patients randomized to aminophylline vs placebo. RESULTS: We studied 158 eligible subjects, randomized to receive aminophylline (n = 86) or placebo (n = 72). The means of photon activity ratios of the heart-to-liver, heart-to-bowel, heart-to-lungs, inferior wall of the heart-to-liver, and inferior wall of the heart-to-bowel were not statistically different between those who received aminophylline vs placebo (P values > .30). Only the time lapse between stress (99m)Tc-tetrofosmin injection and stress SPECT acquisition independently correlated with higher heart-to-liver and heart-to-bowel activity ratios (P values ≤ .01). Patients' body mass index independently correlated with lower heart-to-lung ratio (P = .009). CONCLUSION: The regimented intravenous aminophylline use following regadenoson stress does not significantly improve the cardiac-to-extracardiac photon activity ratio in patients undergoing regadenoson stress (99m)Tc-tetrofosmin SPECT-MPI.
Subject(s)
Aminophylline/administration & dosage , Hyperemia/chemically induced , Hyperemia/prevention & control , Myocardial Perfusion Imaging/methods , Purines/adverse effects , Pyrazoles/adverse effects , Tomography, Emission-Computed, Single-Photon/methods , Adenosine A2 Receptor Agonists/adverse effects , Cardiotonic Agents/administration & dosage , Double-Blind Method , Exercise Test/adverse effects , Exercise Test/methods , Female , Humans , Image Enhancement/methods , Male , Middle Aged , Myocardial Perfusion Imaging/adverse effects , Placebo Effect , Reproducibility of Results , Sensitivity and Specificity , Tomography, Emission-Computed, Single-Photon/adverse effects , Vasodilator Agents/adverse effectsABSTRACT
Cardiac tumors can lead to distinct electrocardiographic changes and ventricular arrhythmias. Benign and malignant cardiac tumors have been associated with ventricular tachycardia. When possible, benign tumors should be resected when ventricular arrhythmias are intractable. Chemotherapy can shrink malignant tumors and eliminate arrhythmias. We report the case of a 52-year-old woman with breast sarcoma whom we diagnosed with myocardial metastasis after she presented with palpitations. The initial electrocardiogram revealed sinus rhythm with new right bundle branch block and ST-segment elevation in the anterior precordial leads. During telemetry, hemodynamically stable, sustained ventricular tachycardia with right ventricular localization was detected. Images showed a myocardial mass in the right ventricular free wall. Amiodarone suppressed the arrhythmia. To our knowledge, this is the first report of ventricular tachycardia associated with radiation-induced undifferentiated sarcoma. We discuss the distinct electrocardiographic changes and ventricular arrhythmias that can be associated with cardiac tumors, and we review the relevant medical literature.
