Immediate Action: ECG with Right Chest Leads
The immediate next step is to obtain an ECG with right chest leads (Option D) to evaluate for right ventricular infarction (RVI), which is strongly suggested by this patient's clinical presentation of elevated JVP with inspiratory increase (Kussmaul's sign), hypotension, and clear lung fields in the setting of acute coronary syndrome. 1, 2
Clinical Reasoning
This elderly diabetic woman presents with a classic acute coronary syndrome requiring immediate ECG evaluation. However, the specific constellation of findings—elevated JVP that increases with inspiration, hypotension (90/55 mmHg), S4 gallop, and clear lung fields—is pathognomonic for right ventricular infarction complicating an inferior myocardial infarction. 1, 2
Why Right-Sided ECG Leads Are Critical
ST-segment elevation ≥0.1 mV in lead V4R is the most readily available and specific electrocardiographic sign for diagnosing RVI, and this must be obtained early as these changes can resolve within hours. 1
RVI complicates 30-50% of inferior-posterior wall myocardial infarctions and defines a high-risk subgroup with considerable immediate morbidity and mortality. 1, 2
Standard 12-lead ECG alone is insufficient to diagnose RVI—right precordial leads (especially V4R) are essential and should be recorded immediately when RVI is suspected clinically. 1, 2
High-Risk Features in This Patient
Diabetes mellitus is a major risk factor for post-infarct mortality (3-5 times greater risk) and qualifies this patient as high-risk requiring urgent invasive strategy. 3, 4
Hemodynamic instability (hypotension) places her in the category requiring coronary angiography "within the first hour" rather than the standard 48-hour window. 3
The combination of hypotension with clear lung fields distinguishes RVI from left ventricular failure—a critical distinction that fundamentally changes management. 1, 2
Why Other Options Are Inappropriate Now
Chest X-ray (Option A): While useful, it does not provide the time-sensitive diagnostic information needed. The clear lung fields on auscultation already suggest absence of pulmonary edema. 3
Echocardiogram (Option B): Although echocardiography can assess RV function, it should follow ECG diagnosis and does not provide the immediate, specific diagnostic information that right-sided ECG leads offer. 3, 1
Coronary CT angiogram (Option C): This is contraindicated in acute MI with hemodynamic instability. The patient needs immediate invasive coronary angiography, not CT imaging. 3
Management Implications of RVI Diagnosis
Once RVI is confirmed by right-sided ECG:
Volume loading is essential to maintain adequate right ventricular preload—this is the opposite of typical left ventricular MI management. 1, 2
Avoid nitrates and diuretics, which can precipitously worsen hypotension by reducing preload. 1, 2
Maintain AV synchrony—loss of atrial contribution can be catastrophic in RVI. 1, 2
Immediate reperfusion therapy (primary PCI preferred) should be initiated at the earliest signs of right ventricular dysfunction. 1, 2
Critical Pitfall to Avoid
The most dangerous error would be treating this hypotensive patient with standard heart failure management (diuretics, nitrates) without first confirming RVI. The elevated JVP might mislead clinicians into thinking the patient is volume overloaded, when in fact she requires aggressive volume loading. 1, 2 The right-sided ECG immediately clarifies this life-threatening diagnostic dilemma.
Antiplatelet Therapy Already Initiated
The aspirin and clopidogrel already administered are appropriate for acute coronary syndrome. 5, 6 Clopidogrel reduces the risk of cardiovascular death, MI, or stroke by 20% when added to aspirin in non-ST-elevation ACS. 6 However, definitive diagnosis with right-sided ECG leads must occur immediately to guide the specific hemodynamic management this patient requires. 1, 2