ABC | Volume 114, Nº2, February 2020

Update Update of the Brazilian Guideline on Nuclear Cardiology – 2020 Arq Bras Cardiol. 2020; 114(2):325-429 Figure 4 – Myocardial perfusion scintigraphy associated with injection of dipyridamole. The moment of maximum vasodilation or coronary hyperemia occurs between 2 and 4 minutes after completing intravenous dipyridamole administration (blue arrow, 4 minutes), at which point the radiopharmaceutical (99mTc-tetrofosmin or MIBI- 99m Tc, orange arrow) is injected. Clinical observation should be continuous throughout the exam, registering blood pressure, heart rate, and electrocardiogram every 2 minutes or in accordance with medical decision, with a typical total exam time of 9 to 10 minutes. 24,46 0.56 mg.Kg in 4 minutes Injection of the radiopharmaceutical 2 to 4 minutes after infusion Dipyridamole IV DIPYRIDAMOLE OPTIONAL Time (minutes) Light exercise Figure 5 – Myocardial perfusion scintigraphy associated with injection of adenosine. The need for continuous intravenous administration is due to the drug’s ultra- short plasma half-life (2 to 10 seconds), with the aim of maintaining coronary hyperemia, which reaches its peak close to the third minute. At this moment, the radiopharmaceutical (MIBI- 99m Tc) is injected. After completing the solution at 6 minutes, frequent monitoring of blood pressure, heart rate, and electrocardiographic registers is maintained for a variable time of 4 to 6 minutes Injection of the radiopharmaceutical Adenosine IV 140 mcg.Kg -1 .min -1 for 6 minutes ADENOSINE Time (minutes) OPTIONAL Light exercise who have contraindications or limitations for stress test, as well as pulmonary obstructive disease with recent crises of bronchial hyperreactivity, arterial hypotension (SBP < 90 mmHg), and significant obstructive carotid artery lesions on both sides. This is also an alternative modality in patients indicated for dipyridamole or adenosine who have ingested substances derived from caffeine or methylxanthines (competitive antagonists) over the past 24 and 12 hours, 341