What is the interpretation and treatment plan for a patient with a normal sinus rhythm, no ST-segment deviation, rare premature ventricular contractions (PVCs), and a low-risk Duke Treadmill Score of 12 on an electrocardiogram (ECG) stress test?

Interpretation and Management of Exercise Stress Test Results

Overall Assessment

These results indicate a negative stress test with excellent prognosis, and no cardiac treatment is needed at this time. The Duke Treadmill Score of 12 places this patient in the low-risk category with an annual mortality rate of approximately 0.25%, which approximates the risk in the general population 1.

Detailed Interpretation

Duke Treadmill Score Analysis

• A Duke Treadmill Score of 12 is definitively low-risk, calculated as exercise time minus (5 × ST-segment deviation) minus angina index 1
• Patients with low-risk Duke scores (≥5) have an annual mortality rate of only 0.25%, representing approximately two-thirds of all patients tested for suspected ischemic heart disease 1
• The absence of ST-segment deviation during stress and recovery further confirms the negative result for ischemia 1

Premature Ventricular Contractions (PVCs)

• Rare PVCs during exercise stress testing in the absence of structural heart disease are benign and require no treatment 2
• PVCs occurring during exercise that resolve in recovery (as demonstrated in this case) are not associated with increased mortality risk 2
• Treatment of PVCs is only indicated when they are frequent AND symptomatic, or when they cause left ventricular dysfunction 2, 3
• The threshold for concern is typically a PVC burden >10-20% of total beats, which "rare" PVCs do not approach 3

Clinical Significance

• Both men and women with normal exercise stress tests who achieve age-predicted target heart rate have an annual risk for cardiac death and acute MI of less than 1% 1
• The negative ECG for ischemia combined with the low-risk Duke score indicates a very low likelihood of obstructive coronary artery disease 1
• Individuals exercising >10 metabolic equivalents with a negative exercise ECG and low-risk Duke Treadmill Score have good prognosis with limited need for downstream testing 1

Management Recommendations

No Cardiac Treatment Required

• No anti-ischemic medications (beta-blockers, calcium channel blockers, nitrates) are indicated based on the negative stress test 1
• No antiarrhythmic therapy is needed for rare, asymptomatic PVCs 2, 3
• No further cardiac imaging or invasive testing is warranted at this time 1

Appropriate Follow-Up

• Continue standard cardiovascular risk factor modification (if applicable) including management of hypertension, diabetes, hyperlipidemia, and smoking cessation 1
• Routine clinical follow-up is appropriate, with repeat stress testing only if symptoms develop 1
• The length of time a patient remains at low risk depends on age, sex, and presence of other risk factors such as diabetes 1

Important Caveats

When to Reconsider Testing

• If the patient develops new cardiac symptoms (chest pain, dyspnea, palpitations), repeat evaluation would be indicated 1
• If PVCs become frequent or symptomatic, further evaluation with ambulatory monitoring and echocardiography would be appropriate 2, 3
• The current results do not exclude non-obstructive coronary disease or microvascular dysfunction, but these conditions do not require specific intervention in asymptomatic patients 1

Documentation Note

• The absence of a prior tracing for comparison is not clinically significant given the entirely normal current findings and negative stress test 1
• The normal sinus rhythm at rest and absence of arrhythmias in recovery provide additional reassurance 1