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Imaging
Radionuclide Imaging for Assessment of Patients with Atrial Fibrillation
Todd D Miller and J Wells Askew
Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester
Abstract
Atrial fibrillation is a common arrhythmia affecting more than 2 million adults in the US. There is a well-recognized association between
atrial fibrillation and cardiovascular disease. Associated cardiovascular conditions include coronary artery disease (CAD), hypertension, left
ventricular dysfunction (systolic and/or diastolic), valvular heart disease, pericardial disease, congenital heart disease and pulmonary
embolus. Single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) can be useful for assessment of
underlying CAD in patients with atrial fibrillation. The decision to employ SPECT MPI in an individual patient with atrial fibrillation should
depend on the clinical characteristics of the patient that generally would warrant the use of a SPECT study and not solely on the presence
of atrial fibrillation.
Keywords
Atrial fibrillation, arrhythmia, coronary artery disease (CAD), single-photon-emission computed tomography (SPECT), myocardial perfusion imaging
(MPI), radionuclide imaging
Disclosure: Todd D Miller receives research grants from Lantheus Medical Imaging and Molecular Insight Pharmaceuticals and has consulting agreements with TherOx, Inc.
and The Medicines Company. J Wells Askew receives research grants from General Electric and has consulting agreements with TherOx, Inc.
Acknowledgements: The authors would like to thank Pamela McCabe for secretarial preparation of the manuscript.
Received: 16 March 2009 Accepted: 16 April 2009
Correspondence: Todd D Miller, Gonda 5, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, US. E:
miller.todd@
mayo.edu
Case Study helpful for the management of this patient? Should a SPECT study be
A 47-year-old male truck driver with no previous history of heart disease performed for evaluation of possible underlying CAD? If a SPECT MPI
presents for his annual Department of Transportation physical. He has study is performed, should the study be gated or ungated? Can a
noticed mild dyspnoea when climbing stairs but not with other activities gated SPECT study in this patient provide a reliable measurement of
of daily living. He denies chest discomfort, palpitations, orthopnoea, left ventricular ejection fraction (LVEF)?
paroxysmal nocturnal dyspnoea or ankle oedema. His risk factors for
coronary artery disease (CAD) include a prior history of cigarette This case study illustrates the potentially useful but uncertain
smoking, having stopped 10 years ago. He does not drink alcohol and application of radionuclide imaging in the assessment of patients with
does not take any medications. A general physical examination reveals atrial fibrillation.
a middle-aged obese (body mass index [BMI] 32) male in no acute
distress. His vital signs are as follows: blood pressure 138/88mmHg in Background
the right arm while sitting; heart rate measured at the apex 140bpm, Atrial fibrillation (AF) is a common arrhythmia. Currently, there are an
irregular; and lungs clear to auscultation. In terms of cardiovascular estimated 2.2 million adults in the US with AF.
1
The prevalence of AF
state, the jugular venous pressure is normal; the carotid upstrokes are increases with age and reaches 8% in octogenarians.
2
Although
normal without bruits; the peripheral pulses are normal; the apical AF can occur as an isolated entity (lone AF), in most patients AF
impulse is not palpable in the supine position; there is no right is associated with some other form of cardiovascular disease. These
ventricular lift; the intensity of the first heart sound is variable; the associated conditions include CAD, hypertension, LV dysfunction
second heart sound is physiologically split; and there are no third or (systolic and/or diastolic), valvular heart disease (especially mitral
fourth heart sounds or murmurs. The abdomen is normal, other than valve disease), pericardial disease (either acute or chronic),
obesity, and the extremities demonstrate no oedema. His laboratory congenital heart disease (e.g. atrial septal defect) and pulmonary
data are as follows: total cholesterol 242mg/dl; high-density lipoprotein embolus. AF can also be associated with non-cardiovascular
(HDL) cholesterol 32mg/dl; low-density lipoprotein (LDL) cholesterol conditions, including drugs (alcohol), endocrine disorders
146mg/dl; triglycerides 320mg/dl; and glucose 107mg/dl. His (hyperthyroidism), changes in autonomic tone (increased
electrocardiogram is shown in Figure 1. parasympathetic or sympathetic activity), metastatic disease
involving or adjacent to the atrium, pulmonary disease, post-
The following questions arise: Would stress single-photon-emission operative status, neurogenic conditions (subarachnoid haemorrhage
computed tomography myocardial perfusion imaging (SPECT MPI) be or non-haemorrhagic major stroke) and sleep apnoea. The American
20 © TOUCH BRIEFINGS 2009
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