Transient pseudo-P pulmonale unmasking cardiopulmonary interactions in cardiogenic shock

The "pseudo-P pulmonale" mimics right atrial enlargement, often mimicking acute pulmonary embolism (PE). We report a 70-year-old male with cardiogenic shock and elevated D-dimer post-thrombolysis, initially suggesting massive PE. However, dynamic ECG monitoring revealed extreme pseudo-P pulmonale (0.55 mV) temporally uncoupled from the D-dimer peak. Postural experiments and extubation confirmed this alteration was the electrophysiological projection of severe backward pressure from acute left ventricular failure, exacerbated by high positive end-expiratory pressure (PEEP 14 cmH2O). This case highlights the value of dynamic ECG analysis in unmasking complex cardiopulmonary hemodynamics in intensive care.