Systemic Infection
Serious infections increase total body metabolism and thus impose hemodynamic burden on the heart. Increased heart rate associated with infections is an additional burden. Circulating inflammatory cytokines are known to impair myocardial function and thus precipitate heart failure. The infectious process may also have an element of myocarditis.
Pulmonary Embolism
Patients with heart failure are at a higher risk of developing deep vein thrombosis and pulmonary embolism. Pulmonary thrombo-embolism exerts hemodynamic stress on the right side of the heart.
Other Factors
Stress in any form be it physical, emotional or environmental, development of unrelated illness, exposure to cardiac depressants drugs (cancer chemotherapy, negative inotropic drugs), cardiac toxins (alcohol, cocaine), pregnancy, anemia, thyroid disorders are some of the common conditions that may precipitate heart failure.
Non-compliance
Inappropriate reduction of therapy or noncompliance of therapy is an important cause to be kept in mind when encountered with worsening heart failure. One should make a diligent and systematic search for these precipitating factors and they should be treated adequately and appropriate steps should be taken to avoid recurrences. Identifying precipitating factors generally denotes better prognosis for the patients.