Differential Diagnosis

The patient's presentation of shortness of breath, recent pacemaker placement, and history of heart failure suggests a complex clinical picture. The following differential diagnoses are categorized based on their likelihood and potential impact:

• Single Most Likely Diagnosis

  • Heart Failure Exacerbation: The patient's history of heart failure, recent episodes of severe shortness of breath, weight loss due to diuretic use, and consistently low heart rate are all consistent with a worsening heart failure condition. The recent hospitalizations for dyspnea further support this diagnosis.

• Other Likely Diagnoses

  • Pacemaker Dysfunction: Given the recent pacemaker placement and the patient's symptoms of shortness of breath, it is plausible that the pacemaker is not functioning effectively, leading to inadequate heart rate and decreased cardiac output.
  • Anxiety Disorder: The patient's reports of feeling nervous and a sense of impending doom during episodes of dyspnea, without chest pain or other symptoms, suggest that an anxiety disorder could be exacerbating her symptoms.
  • Fluid Overload: Despite the use of diuretics, the patient's history suggests potential episodes of fluid overload, which can lead to shortness of breath.

• Do Not Miss Diagnoses

  • Pulmonary Embolism (PE): Although the patient is treated with Apixaban, PE remains a possibility due to the presentation of dyspnea and must be considered to avoid missing a potentially life-threatening condition.
  • Cardiac Tamponade: This is a life-threatening condition that can arise from pacemaker complications, presenting with dyspnea and bradycardia, and must be carefully considered.
  • Myocardial Infarction: Given the patient's cardiovascular history, myocardial infarction should be contemplated, even in the absence of typical chest pain, especially in the elderly.

• Rare Diagnoses

  • Constrictive Pericarditis: This rare condition, involving a thickened pericardium, can lead to heart failure symptoms and deserves consideration given the patient's history, although it is less likely.
  • Cardiac Sarcoidosis: Characterized by granuloma infiltration, it can result in heart failure and arrhythmias. While it is a rare condition, it should be assessed in patients with unexplained cardiac symptoms, including this patient with a history of congenital heart disease and recent pacemaker placement.