From the Guidelines
Yes, a Myocardial Perfusion Scan (MPS) can be performed on a patient with Mobitz type 1 (Wenckebach) block.
Key Considerations
- The procedure typically involves administering a radiopharmaceutical such as Technetium-99m sestamibi (10-30 mCi) or Thallium-201 (2-4 mCi) and acquiring images using a gamma camera, with no specific medication or dose adjustments required for the block itself 1.
- The test can be conducted at rest or with stress, using agents like adenosine (140 mcg/kg/min for 6 minutes) or regadenoson (0.4 mg bolus), to evaluate coronary flow reserve and detect potential ischemia.
- Patients with Mobitz type 1 block generally have a benign prognosis and do not require specific monitoring or treatment for the block itself, making MPS a viable diagnostic option 1.
- The diagnostic accuracy of stress SPECT MPI for detecting angiographically significant CAD is high, with a sensitivity of 87%-89% and specificity of 73%-75% 1.
- MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction 1.
Procedure Details
- The test involves intravenous injection of small amounts of a radioactive tracer, usually during some form of cardiovascular stress 1.
- SPET is the preferred imaging technique, whereby the camera rotates around the patient over 10–20 min and the resulting set of planar projection images are reconstructed into a three-dimensional stack of tomographic slices through the myocardium 1.
- Homogeneous myocardial uptake of tracer indicates normal myocardium and perfusion, while a defect in the stress images that normalises in the rest images indicates an inducible perfusion abnormality 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Myocardial Perfusion Scan (MPS) and Mobitz Type 1 Block
- There is no direct evidence in the provided studies that discusses the feasibility of performing a Myocardial Perfusion Scan (MPS) on a patient with Mobitz type 1 (Wenckebach) block 2, 3, 4, 5, 6.
- The studies primarily focus on the characteristics, prognosis, and management of Mobitz type 1 block, rather than its implications for MPS procedures.
- However, it can be inferred that the presence of Mobitz type 1 block may not necessarily preclude a patient from undergoing an MPS, as the block is often considered a benign condition, especially in asymptomatic individuals 6.
- Nevertheless, the decision to perform an MPS on a patient with Mobitz type 1 block should be made on a case-by-case basis, taking into account the patient's overall clinical condition and the potential risks and benefits of the procedure.
Considerations for MPS in Patients with Mobitz Type 1 Block
- Patients with Mobitz type 1 block may require closer monitoring during the MPS procedure, as the block can potentially lead to hemodynamic instability 3.
- The use of exercise stress testing, which is often a component of MPS, may need to be carefully considered in patients with Mobitz type 1 block, as it can exacerbate the block and lead to symptoms 2, 6.
- The presence of underlying coronary artery disease, which can be a cause of Mobitz type 1 block, may also need to be taken into account when interpreting the results of the MPS 3.