Erroneous Left ventricular cavity size measurements on myocardial perfusion SPECT resulting from transient
Iain D C Kirkpatrick1, William D Leslie
1Department of Radiology, University of Manitoba, Winnipeg, Manitoba, Canada. kirkpatrick_iain@hotmail.com
Insights
Transient ischemic dilatation (TID) during stress imaging can indicate severe coronary artery disease. However, supraventricular tachyarrhythmias can alter left ventricular size, leading to misleading TID ratios in myocardial perfusion scans.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Transient ischemic dilatation (TID) of the left ventricle during myocardial perfusion imaging (MPI) is a recognized indicator of severe coronary artery disease.
- Accurate interpretation of TID ratios is crucial for diagnosing significant coronary artery disease.
Observation:
- Factors unrelated to ischemia can transiently affect left ventricular dimensions.
- Four cases demonstrated that supraventricular tachyarrhythmias can influence TID ratios.
- These arrhythmias reduced cardiac filling time, impacting left ventricular volumes.
Findings:
- Abnormally high and low TID ratios were observed in patients with transient supraventricular tachyarrhythmias during Tc-99m sestamibi SPECT MPI.
- Supraventricular tachyarrhythmias can mimic or mask true ischemic findings by altering ventricular size.
Implications:
- Clinicians must consider the potential impact of supraventricular tachyarrhythmias when interpreting TID ratios in stress MPI.
- Recognizing these arrhythmias is essential to avoid misdiagnosis of coronary artery disease severity.
- This highlights the importance of correlating imaging findings with the patient's clinical status and rhythm during the scan.
Abstract:
Transient ischemic dilatation (TID) of the left ventricle during stress on myocardial perfusion imaging is a sign of severe coronary artery disease. Factors other than ischemia can transiently influence left ventricular size, however, and TID ratios can be misleading if these factors are not properly identified. We describe 4 cases of stress-rest Tc-99m sestamibi SPECT myocardial perfusion imaging in which both abnormally high and low TID ratios were seen as a result of the presence of transient supraventricular tachyarrhythmias that reduced cardiac filling time and corresponding left ventricular volumes.
