Nuclear Cardiology in the COVID-19 pandemic.

SARS-CoV-2 infection has a very important relationship with cardiovascular disease. Since the beginning of the pandemic, a close relationship has been observed between cardiovascular comorbidity and a worse prognosis in COVID-19 patients. The study of the pathophysiology of SARS-CoV-2 infection and cardiovascular disease suggests several concomitant hypotheses: direct myocardial damage by the virus, hypoxemia secondary to respiratory failure, inflammatory response to infection and/or thromboembolic phenomena. Cardiovascular damage can manifest in the acute phase of infection with acute myocardial infarction, myocarditis, arrhythmias…, during this phase Nuclear Cardiology procedures have not played a determining role in the diagnosis and management of these patients. On the other hand, in the subacute phase of the infection and in the post-acute COVID syndrome, Nuclear Cardiology seems to shed light on what happens in the cardiovascular system in this phase of the disease. The COVID-19 pandemic has represented a great challenge for health systems, with a significant reduction in non-urgent diagnostic procedures with the aim of reducing the risk of transmission to patients and health personnel. Nuclear Cardiology has not been an exception. In addition to the prioritization of urgent/non-deferrable procedures and general screening, hygiene and distance measures, the main organizations and scientific societies of Nuclear Medicine and Nuclear Cardiology released recommendations and guidelines for safe practice, introducing significant changes in myocardial perfusion SPECT protocols.

Interassay reproducibility of myocardial perfusion gated SPECT in patients with atrial fibrillation.

AIM: The aim of this study was to assess interassay reproducibility of myocardial perfusion gated-SPECT for calculation of end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF) in patients with atrial fibrillation (AF). METHODS: One hundred and fifteen consecutive patients with AF from three participating hospitals (mean age 68.9 years, 39 women) were included in the study. All patients underwent two image gated acquisitions at rest with a 30 minute interval between them. Quantitative data were obtained using the QGS and ECT software algorithms. RESULTS: Heart rate was similar in both studies: 74.94 +/- 15.2 vs 73.03 +/- 15.57. QGS yielded an LVEF of 54.4%/53.8%, an EDV of 100 mL/101.5 mL, and an ESV of 51 mL/52.3 mL; and ECT showed an LVEF of 63.6%/62.9%, an EDV of 125.8 mL/127.4 mL and ESV of 54.1 mL/56.3 mL. Correlation between the two acquisitions was high (>0.948) for both methods for LVEF, EDV and ESV. Regression and Bland-Altman graphics showed a good agreement between all parameters. Interassay variation coefficients for each method (QGS/ECT) were 5.29% vs 4.83% for LVEF, 4.94% vs 5.17% for EDV, and 9.94% vs 12.78% for ESV. CONCLUSIONS: Interassay reproducibility of LVEF and EDV with gated-SPECT in patients with AF is good, whereas for ESV it is suboptimal, particularly when ESV is small.