Misdiagnosis of a Massive Pulmonary Thromboembolism in A Patient With Dextrocardia and a Pacemaker

Pulmonary thromboembolism (PTE) is the third most common cause of acute cardiovascular disease, which can lead to high morbidity and mortality if left untreated. Anatomical and electrophysiological variations and obesity may complicate timely diagnosis and delay required management. While computed tomography pulmonary angiography (CTPA) remains the most accurate diagnostic tool, initial assessments using electrocardiography (ECG) or echocardiography can be helpful in early suspicion. However, anatomical and electrophysiological variations, like dextrocardia and a permanent pacemaker (PPM), can obscure key ECG findings like right ventricular (RV) strain patterns. Moreover, obesity can distort echocardiographic estimations, particularly of RV function, due to increased chest wall thickness and suboptimal acoustic windows. We report a case of a 52-year-old obese woman with situs inversus dextrocardia and a PPM who presented with dyspnea. Diagnostic challenges were significant, as both echocardiography and ECG were compromised due to her obesity, anatomical variation, and PPM device, leading to an initial misdiagnosis and treatment for decompensated heart failure (DHF) with diuretics and vasodilators. Given her worsening condition and elevated D-dimer levels, a CTPA was performed, revealing PTE. Due to delayed PTE treatment, the patient experienced hemodynamic deterioration and impaired organ perfusion, leading to acute kidney injury requiring dialysis. Following PTE management and a few dialysis sessions, her hemodynamics and overall condition improved, with recovery of urine output. The patient was ultimately discharged in stable condition. This case emphasizes the diagnostic complexities in patients with rare anatomical conditions (e.g., dextrocardia with PPM) presenting with nonspecific symptoms like dyspnea. In such cases, clinicians should maintain a high index of suspicion for urgent conditions like PTE, especially when factors like obesity, anatomical variations, and device-related artifacts hinder conventional diagnostic tools. Enhancing clinical vigilance, developing tailored algorithms for unique populations, using advanced imaging modalities earlier (such as CTPA), and engaging in interdisciplinary consultations are critical in these complex cases to help avoid delays in definite diagnosis and treatment.