ECG Interpretation - Cardiologist-Level Analysis

Measured Intervals

Finding-by-Finding Analysis

1. Rhythm: Sinus Rhythm

• Regular P waves preceding each QRS, positive in leads I, II, aVF - confirmed normal sinus rhythm at 61 bpm
• PR interval of 128 ms is normal, excluding first-degree AV block
• No ectopic beats, no pauses

2. ST Junctional Depression - Nonspecific

• Junctional (J-point) depression differs from true ischemic ST depression. True ischemic ST depression is typically horizontal or downsloping at 80 ms after the J-point, whereas junctional depression involves only the J-point itself with a rapidly ascending ST segment
• "Nonspecific" means the morphology does not fulfill criteria for ischemic ST depression (which requires ≥0.5 mm horizontal/downsloping depression at 60-80 ms post J-point in ≥2 contiguous leads)
• Common causes of nonspecific ST/junctional changes include: tachycardia (rate-related), early repolarization variant, LVH strain pattern, hypokalemia, hypomagnesemia, digoxin effect, or autonomic tone variation

3. Borderline ECG

• The QTc of 423 ms is within normal limits for males (<440 ms) but closer to the upper boundary than ideal
• The nonspecific ST changes
• RV5 at 2.584 mV: this slightly exceeds the Sokolow-Lyon voltage criterion for LVH (RV5 or RV6 >2.5 mV), though the combined Sokolow index (SV1 + RV5 = 1.478 + 2.584 = 4.062 mV) exceeds the threshold of 3.5 mV, raising the possibility of LVH by voltage criteria

4. QRS Duration: 106 ms

• QRS of 106 ms is in the upper normal/borderline range (<120 ms = normal)
• No frank LBBB or RBBB pattern
• Warrants monitoring; if it widens further to ≥120 ms, would represent a bundle branch block

5. QTc: 423 ms (Borderline Prolonged by machine flag)

• Using Bazett's formula, QTc of 423 ms is within the normal range for males (upper limit 440 ms; some sources use 450 ms for males)
• However, any contributing factors should be screened: electrolytes (K⁺, Mg²⁺, Ca²⁺), concurrent QT-prolonging medications
• No features of short QT syndrome or Torsades de Pointes risk at this value

6. Electrical Axis

• P-axis: 66° - Normal
• QRS-axis: 51° - Normal, no left or right axis deviation
• T-axis: 26° - Normal

Differential Diagnosis for Nonspecific ST Changes in This Context

1. LVH with strain pattern - most likely given borderline voltage criteria; strain produces ST depression/T-wave inversions in lateral leads (I, aVL, V5-V6)
2. Early repolarization - benign, common in young males; J-point elevation in precordial leads (but here we have depression, so less likely)
3. Subendocardial ischemia - must be excluded clinically, especially given dyslipidemia on statins; would require stress testing if symptomatic
4. Electrolyte disturbance - hypokalemia classically causes ST depression, flattened T waves, prominent U waves
5. Digoxin effect - "reverse tick" ST morphology; check medication history
6. Autonomic/positional changes - especially in the context of a resting ECG

Actionable Recommendations (for Cardiologist)

Summary for Cardiologist

• Nonspecific ST junctional depression - not meeting ischemic criteria, but not dismissible without clinical correlation
• Possible LVH by Sokolow-Lyon voltage criteria (SV1+RV5 = 4.06 mV, threshold 3.5 mV) - echocardiogram indicated
• Borderline QTc 423 ms - monitor, screen for precipitants
• Borderline QRS 106 ms - watch for progression to BBB
• Patient is on Atorvastatin (dyslipidemia), HbA1c noted - metabolic cardiovascular risk profile warrants full assessment

The machine diagnosis is correct but incomplete. The "nonspecific ST junctional depression" and "borderline ECG" flags are appropriate machine outputs, but the treating cardiologist must integrate these findings with the full clinical picture - particularly blood pressure history, symptoms, and echocardiographic data - before concluding this as a benign tracing.