What is the recommended management plan for a patient with intermediate risk for future cardiac events, who developed 1mm horizontal ST depressions in leads II, III, and VF during a cardiac stress test, has a normal left ventricular (LV) size and ejection fraction, moderately enlarged right ventricular (RV) size, mildly reduced RV systolic function, and mild mitral valve regurgitation, despite a negative stress echocardiogram (echo) for ischemia?

Management of Discordant Stress Test Results with Intermediate-Risk Duke Treadmill Score

This patient requires coronary angiography based on the discordant findings between ECG ischemia and negative stress echocardiography, combined with the intermediate-risk Duke treadmill score and concerning RV findings. 1

Risk Stratification Analysis

Duke Treadmill Score Classification

• Intermediate-risk Duke treadmill score (–11 to 5) places this patient in the 1% to 3% annual mortality rate category, which by ACC/AHA guidelines warrants further evaluation beyond the stress test alone 1
• The presence of 1mm horizontal ST depressions in inferior leads (II, III, aVF) during stress represents ECG evidence of ischemia that cannot be dismissed despite the negative imaging 1

Critical Discordance Requiring Resolution

• The discordance between positive ECG findings (ST depressions) and negative stress echo imaging is a red flag that demands invasive evaluation 1
• ACC/AHA guidelines classify patients with intermediate-risk treadmill scores as requiring additional risk stratification, and when ECG changes suggest ischemia but imaging is negative, coronary angiography becomes the definitive next step 1

Right Ventricular Findings Add Complexity

• Moderately enlarged RV with mildly reduced systolic function is an unexpected finding that may indicate:
  • Chronic pulmonary hypertension (though PA systolic pressure is reported as normal)
  • Prior RV infarction (which can occur with inferior wall ischemia affecting the RCA territory)
  • Intrinsic RV pathology
• The inferior ST depressions (leads II, III, aVF) suggest right coronary artery (RCA) or left circumflex territory ischemia, which could explain both the ECG changes and potentially contribute to RV dysfunction 1

Recommended Management Algorithm

Immediate Actions

1. Refer for coronary angiography within 2-4 weeks (not emergent given hemodynamic stability and resolved symptoms) 1
2. Initiate or optimize medical therapy immediately:
   • High-intensity statin therapy
   • Aspirin 81mg daily (if not already on)
   • Beta-blocker therapy (particularly given the intermediate risk)
   • Consider ACE inhibitor/ARB given the RV dysfunction 1
3. Provide sublingual nitroglycerin with clear instructions for recurrent chest pain or dyspnea 1

Rationale for Angiography Over Conservative Management

• ACC/AHA guidelines specifically state that patients with intermediate-risk stress test results who have ECG evidence of ischemia should undergo coronary angiography to definitively assess for obstructive CAD 1
• The negative stress echo does not exclude significant coronary disease when ECG changes are present—stress echocardiography can miss single-vessel disease or non-transmural ischemia, particularly in the RCA/inferior territory 2, 3
• The combination of intermediate Duke score + ECG ischemia + unexplained RV dysfunction creates a clinical picture where the pretest probability of significant CAD remains high enough to warrant invasive assessment 1

Why Not Repeat Stress Testing with Different Modality?

• Repeating stress testing with nuclear imaging would delay definitive diagnosis and is not recommended when ECG ischemia is already documented 1
• The patient has already demonstrated adequate cardiac workload, so exercise capacity is not the issue 1
• Nuclear perfusion imaging might provide additional information, but given the discordance and intermediate risk, proceeding directly to angiography is more appropriate 1

Common Pitfalls to Avoid

Do Not Falsely Reassure Based on Negative Echo Alone

• Stress echocardiography has limitations in detecting single-vessel disease or subendocardial ischemia, particularly when wall motion abnormalities are subtle or transient 2, 3
• The sensitivity of stress echo is operator-dependent and can miss ischemia in up to 15-20% of cases with significant CAD 3

Do Not Ignore the ST Depression Pattern

• 1mm horizontal ST depression in multiple inferior leads is a significant finding that meets criteria for ECG-positive stress test 1
• Horizontal or downsloping ST depressions are more specific for ischemia than upsloping depressions 1

Do Not Overlook the RV Dysfunction

• The moderately enlarged RV with reduced function requires explanation—this is not a normal finding and may indicate chronic ischemia, prior infarction, or pulmonary vascular disease 1
• Even with normal PA pressures reported, RV dysfunction in the context of possible CAD warrants investigation 1

Do Not Delay Angiography for Outpatient Stress Testing

• Patients with intermediate-risk features and ECG ischemia should not be sent home with plans for outpatient repeat testing—they require definitive evaluation 1
• The development of dyspnea during stress (symptom #5 in your report) combined with ECG changes suggests clinically significant ischemia 1

Clinical Context and Prognosis

Risk Quantification

• Intermediate Duke treadmill score confers 1-3% annual mortality risk, but this increases when ECG ischemia is present 1
• The normal LV function (EF 65-70%) is reassuring but does not exclude significant CAD 1, 3
• Patients with peak WMSI of 1.0 (normal stress echo) typically have 0.9% annual cardiac event rate, but this patient's ECG findings place them in a higher risk category 3

Expected Angiographic Findings

• Given the inferior ST depressions, expect possible RCA or left circumflex disease 1
• The negative stress echo suggests that if CAD is present, it may be single-vessel disease or non-flow-limiting stenosis that becomes significant under stress 2, 3
• Approximately 25-35% of patients with intermediate-risk stress tests and ECG ischemia will have obstructive CAD requiring revascularization 1, 2

Follow-up Regardless of Angiography Results

• If angiography shows no obstructive CAD, consider:
  • Coronary vasospasm (Prinzmetal's angina)
  • Microvascular dysfunction
  • Alternative causes of RV dysfunction (intrinsic cardiomyopathy, prior myocarditis)
• If angiography shows obstructive CAD, revascularization decisions should be based on anatomy, symptoms, and ischemic burden 1, 2

The key principle is that discordant stress test results in an intermediate-risk patient require definitive anatomic assessment with coronary angiography rather than additional functional testing. 1