Evaluation and Management of Left-Sided Chest Pain in a Patient with Stable Diastolic Heart Failure and Ventricular Pacemaker
Immediate Assessment Required
You must obtain a 12-lead ECG immediately and measure high-sensitivity cardiac troponin now, even though this patient has stable heart failure and a pacemaker, because acute coronary syndrome remains a critical differential diagnosis that cannot be excluded by clinical presentation alone. 1
The presence of a ventricular pacemaker rhythm significantly complicates ECG interpretation for acute coronary syndrome, as paced rhythms produce ST-segment and T-wave abnormalities that are the "new normal" for these patients and can mask or mimic ischemic changes. 2 This means you cannot rely on the ECG alone to rule out ACS in this patient.
Why This Patient Requires Urgent Cardiac Evaluation
High-Risk Features Present
Obesity (BMI 31.9) is an independent risk factor for both coronary artery disease and atrial fibrillation, and increases the likelihood of undiagnosed heart failure with preserved ejection fraction (HFpEF). 3, 4
Diastolic heart failure itself increases risk for acute coronary syndrome, as the underlying pathophysiology often involves microvascular dysfunction and myocardial fibrosis that can progress to ischemic events. 5, 3
Left-sided chest pain occurring twice in two days represents new-onset symptoms that must be classified as acute chest pain requiring immediate evaluation, regardless of the patient's otherwise stable clinical status. 1
The combination of obesity, diastolic heart failure, and a pacemaker creates a clinical scenario where typical anginal symptoms may be absent or atypical, yet the risk for ACS remains substantial. 6, 7
Diagnostic Algorithm
Step 1: Immediate Testing (Within 10 Minutes)
Obtain 12-lead ECG within 10 minutes to identify ST-segment elevation, ST-depression, or T-wave inversions, recognizing that the ventricular paced rhythm will make interpretation challenging. 1
Draw high-sensitivity cardiac troponin immediately because it is the most sensitive and specific biomarker for myocardial injury and is not affected by pacemaker rhythm. 1, 6
Repeat troponin at 1–3 hours (or 3–6 hours if using conventional troponin) because a single normal result does not exclude acute coronary syndrome. 6
Step 2: Characterize the Chest Pain
Ask the patient to describe the pain using these specific questions:
Quality: Is it pressure, squeezing, gripping, heaviness, or tightness? (These descriptors increase likelihood of ischemia.) 1, 6 Or is it sharp, stabbing, or fleeting? (These descriptors decrease likelihood of ischemia but do NOT exclude it—13% of patients with pleuritic pain still have acute myocardial ischemia.) 6
Location and radiation: Is it substernal? Does it radiate to the left arm, jaw, neck, or between the shoulder blades? 1, 6
Duration: Does it build gradually over several minutes, or is it instantaneous? (Anginal pain builds gradually, not suddenly.) 1
Precipitating factors: Does physical exertion or emotional stress trigger it? 1, 6
Associated symptoms: Is there dyspnea, diaphoresis, nausea, vomiting, or light-headedness? (These markedly increase the probability of ACS.) 1, 6
Step 3: Physical Examination
Perform a focused cardiovascular examination looking for:
Hemodynamic instability: Heart rate >100 bpm or <50 bpm, systolic blood pressure <100 mmHg. 6 (This patient's HR 70 and BP 126/76 are reassuring but do not exclude ACS.)
Heart failure signs: New crackles, S3 gallop, elevated jugular venous pressure, or new murmurs suggesting mitral regurgitation or aortic regurgitation. 1, 6
Chest wall tenderness: Reproducible pain with palpation suggests costochondritis, but this finding does NOT exclude cardiac causes—you must still complete the cardiac workup. 6, 8
Critical Pitfalls to Avoid
Do NOT assume the pacemaker rhythm makes ECG interpretation impossible. While paced rhythms confound diagnosis, certain findings—such as excessive discordance (ST-segment deviation in the same direction as the QRS complex) or concordant ST-elevation—can still indicate acute myocardial infarction. 2
Do NOT rely on nitroglycerin response to differentiate cardiac from non-cardiac chest pain, as esophageal spasm and other conditions may also improve with nitroglycerin. 6, 9
Do NOT dismiss the pain as musculoskeletal based solely on left-sided location or reproducible tenderness, because cardiac problems still account for 10–34% of chest pain episodes even when musculoskeletal findings are present. 8
Do NOT delay transfer to the emergency department if clinical suspicion for ACS remains high after initial testing, even in an outpatient or office setting. 1, 6
Management Based on Initial Results
If Troponin is Elevated or ECG Shows Acute Changes
Activate emergency medical services immediately and arrange urgent transfer to a facility with 24/7 cardiac catheterization capability. 1, 6
Administer chewed aspirin 162–325 mg unless contraindicated by known allergy or active gastrointestinal bleeding. 6, 9
Provide sublingual nitroglycerin unless systolic blood pressure <90 mmHg or heart rate <50 bpm or >100 bpm. 6, 9
Initiate continuous cardiac monitoring and prepare for urgent coronary angiography with percutaneous or surgical revascularization. 6, 7
If Initial Troponin is Normal and ECG is Nondiagnostic
Observe in a chest-pain unit or emergency department for serial troponin measurements at 1–3 hours and 6–12 hours after symptom onset. 6
Perform serial ECGs every 15–30 minutes if clinical suspicion remains high, as ischemic changes may evolve over time. 1, 6
Consider stress testing or coronary CT angiography within 72 hours if troponins remain negative and the patient remains clinically stable, to definitively exclude obstructive coronary artery disease. 1
Special Considerations for This Patient
Diastolic Heart Failure and Pacemaker Interaction
Diastolic dysfunction increases left atrial pressure and predisposes to both atrial fibrillation and myocardial ischemia, even in the absence of obstructive coronary disease. 5, 3
The absence of recent atrial fibrillation episodes is reassuring but does not eliminate the risk of ischemia, as many patients with diastolic heart failure have latent HFpEF that manifests first as chest pain or exercise intolerance. 3
Obesity as a Compounding Factor
Obesity (BMI 31.9) is associated with epicardial adipose tissue expansion that causes microvascular dysfunction, myocardial fibrosis, and increased risk for both atrial fibrillation and heart failure with preserved ejection fraction. 3, 4
Obese patients with diastolic heart failure are at higher risk for acute coronary syndrome and may present with atypical symptoms, making clinical diagnosis more challenging. 3, 4
Disposition Decision
If you are in an outpatient or office setting and cannot obtain an ECG or troponin immediately, refer the patient to the emergency department now by emergency medical services. 1, 6 Do not delay transfer for additional history-taking or physical examination when clinical evidence of possible ACS exists.
If you are in an emergency department or hospital setting, admit the patient to a monitored unit (coronary care unit or telemetry) for serial troponin measurements and continuous cardiac monitoring until ACS is definitively excluded. 6