The most likely diagnosis in this woman who gave birth 2 weeks ago is peripartum cardiomyopathy. Peripartum cardiomyopathy is left ventricular systolic dysfunction identified toward the end of pregnancy or in the months following delivery in the absence of another identifiable cause. This occurs with increased frequency in women with a history of preeclampsia. Patients may be asymptomatic or present with features of heart failure. Prompt initiation of medical therapy is recommended for women with peripartum cardiomyopathy and includes an ACE inhibitor or an angiotensin receptor blocker (after delivery), β-blockers, digoxin, hydralazine, nitrates, and diuretics.

Pulmonary embolism can occur postpartum, particularly if prolonged bed rest is required in the peripartum period. Although both pulmonary embolism and heart failure frequently are marked by dyspnea, this patient's presentation is more indicative of heart failure, with pulmonary congestion and elevated central venous pressure.

Most patients with ischemic cardiomyopathy have symptomatic coronary artery disease, abnormal electrocardiographic findings demonstrating previous myocardial infarction, or regional hypokinesis on echocardiography. These findings are absent in this patient.

Stress-induced cardiomyopathy (takotsubo cardiomyopathy) is characterized by transient cardiac dysfunction with ventricular apical ballooning, usually triggered by intense emotional or physical stress, although in several published cases, no trigger was identifiable. The presenting clinical picture may mimic an acute coronary syndrome, with chest pain, mildly elevated cardiac enzyme levels, and electrocardiographic changes consistent with ischemia. The patient's clinical presentation is not consistent with stress cardiomyopathy.