What is the clinical significance of a normal myocardial perfusion study with Lexiscan (regadenoson) and a normal ejection fraction (EF) of 67% with a hypokinetic mid inferolateral segment on echocardiogram?

From the Guidelines

The patient's cardiac evaluation indicates a need for further assessment due to the presence of a hypokinetic mid inferolateral segment despite normal overall heart function and perfusion, suggesting potential prior myocardial injury or underlying coronary artery disease. The myocardial perfusion study with Lexiscan on 4/2/2025 was normal, indicating adequate blood flow to the heart muscle during stress, as per the guidelines for heart failure management 1. However, the echocardiogram on 4/25 revealed a normal overall heart function with an ejection fraction of 67%, which falls into the category of heart failure with preserved ejection fraction (HFpEF) as defined by the 2022 AHA/ACC/HFSA guideline for the management of heart failure, where HFpEF is characterized by an LVEF ≥50% 1. The presence of a hypokinetic mid inferolateral segment of the heart wall, despite the normal ejection fraction, warrants further evaluation to determine the cause and potential impact on long-term cardiac outcomes.

Key considerations in this patient's evaluation include:

• The classification of heart failure based on left ventricular ejection fraction (LVEF), with this patient's LVEF of 67% placing them in the HFpEF category 1.
• The importance of evaluating the trajectory of LVEF over time, especially in patients with mildly reduced ejection fraction, although this patient's EF is preserved 1.
• The need for objective measures of cardiac dysfunction to support the diagnosis of HFpEF, which may include elevated natriuretic peptide levels or evidence of increased LV filling pressures 1.
• The potential for regional wall motion abnormalities to indicate prior myocardial injury or underlying coronary artery disease, even in the presence of normal perfusion studies.

Given these considerations, I recommend a cardiology consultation to further evaluate the hypokinetic segment and assess for any underlying conditions that may be contributing to this finding, such as coronary artery disease or prior myocardial infarction. Additionally, optimal management of cardiovascular risk factors, including blood pressure, cholesterol, diabetes if present, smoking cessation, and weight management, is crucial. Daily aspirin 81mg would be reasonable if not contraindicated, as part of a comprehensive approach to reducing cardiovascular risk. The patient should continue any current cardiac medications while awaiting this consultation, and further testing or evaluation may be necessary based on the cardiology consultation findings.

From the Research

Patient's Condition

The patient underwent a myocardial perfusion study with Lexiscan, which was normal. Additionally, an echocardiogram showed a normal EF at 67% with mid inferolateral segment being hypokinetic and no obvious valvular pathology.

Relevant Studies

• The study 2 discusses the use of metoprolol in treating hypertension and angina pectoris, but does not directly relate to the patient's condition.
• The study 3 focuses on titration of beta-blockers in heart failure, which may not be directly applicable to this patient's situation.
• The study 4 investigates the effectiveness of ranolazine in improving coronary microvascular function in patients with nonobstructive coronary artery disease, which could be relevant to the patient's hypokinetic mid inferolateral segment.
• The study 5 examines the dosing of beta-blocker therapy in patients with heart failure, but may not be directly relevant to this patient's condition.
• The study 6 provides an overview of ranolazine and its possible role in primary microvascular angina management, which could be relevant to the patient's condition.

Key Findings

• Ranolazine has been shown to improve coronary microvascular function in patients with nonobstructive coronary artery disease 4.
• Ranolazine may be useful in managing primary microvascular angina 6.
• Beta-blocker therapy is commonly used in heart failure patients, but the dosing and titration may vary 3, 5.
• Metoprolol is a widely used beta-blocker for treating hypertension and angina pectoris, but its use in this patient's condition is unclear 2.