Assessing splenic switch-off in Adenosine stress CMR for patients with atrial fibrillation: a propensity-matched study

Adam Barrishi, John Graby, Ali Khavandi, Amardeep Dastidar, Jonathan C. l. Rodrigues

Research output: Contribution to journalArticlepeer-review


Objectives: Splenic switch-off (SSO) is a validated indi-cator of adequate vasodilator stress unique to adeno-sine stress cardiac MR (CMR). Patients in atrial fibrillation (AF) may have a reduced adenosine response due to lower hyperaemic coronary flow reserve and may achieve SSO less frequently versus sinus rhythm (SR). Methods: 1100 stress CMR studies were identified from a clinical CMR database (2016–2021). 70 patients in AF were propensity score matched to a SR group for age, sex, and body mass index. The adenosine dose admin-istered, symptoms, heart-rate change and scan result were recorded. SSO was evaluated subjectively and semi-quantitatively via changes in splenic and myocar-dial signal intensity (SI) from rest to stress. Results: SSO occurred significantly less frequently in AF than SR (34/70 [49%] vs 53/70 [76%], p = 0.003). Semi-quantitative assessment supported this, with a smaller splenic SI difference between stress and rest in AF vs SR (median splenic stress:rest peak SI ratio 0.92 [IQR:0.61– 1.11] vs 0.56 [IQR:0.45–0.75], p < 0.001). A heart-rate increase >10 bpm predicted visual SSO in SR but not AF. Fewer patients in AF than SR had inducible ischaemia (9/70 [13%] vs 17/69 [25%], p = 0.058). This difference was not driven by inducible ischaemia rates in patients who did not achieve SSO (6/36 [17%] AF vs 4/17 [24%] SR, p = 0.403). Conclusions: SSO occurs significantly less frequently with AF. This may risk the under diagnosis of inducible ischaemia and requires further assessment. Advances in knowledge: SSO, a validated marker of adequate stress in CMR, occurs significantly less frequently in the presence of AF, risking a suboptimal functional assessment of coronary disease.

Original languageEnglish
Article number20220422
JournalBritish Journal of Radiology
Issue number1139
Early online date26 Sept 2022
Publication statusPublished - 1 Oct 2022

Bibliographical note

Funding Information:
We thank the multidisciplinary cardiovascular magnetic resonance imaging team in the Department of Radiology at the Royal United Hospitals Bath NHS Foundation Trust.

Publisher Copyright:
© 2022, British Institute of Radiology. All rights reserved.


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