What is the most common cardiac manifestation of Paget's disease?

High-Output Heart Failure is the Most Common Cardiac Manifestation of Paget's Disease

High-output heart failure is the most common cardiac manifestation of Paget's disease of bone. 1 This occurs due to the increased vascularity and blood flow through pagetic bone lesions, creating arteriovenous shunts that lead to increased cardiac output demands.

Pathophysiology

The mechanism behind high-output heart failure in Paget's disease involves:

• Increased vascularity in affected bones creating arteriovenous shunts
• Increased peripheral blood flow requirements
• Compensatory increase in cardiac output
• Eventually, the heart cannot maintain the high output demands, leading to failure

This is particularly significant in patients with extensive pagetic involvement (polyostotic disease) where the cumulative effect of multiple vascular shunts can substantially increase cardiac workload.

Clinical Presentation

Patients with Paget's disease and cardiac involvement may present with:

• Dyspnea on exertion
• Fatigue and weakness
• Peripheral edema
• Tachycardia at rest
• Bounding pulses
• Wide pulse pressure
• Warm extremities (early in disease)
• Elevated jugular venous pressure
• Pulmonary congestion

Diagnostic Considerations

When evaluating a patient with Paget's disease for cardiac involvement:

• Electrocardiographic abnormalities are common (observed in approximately 60% of cases) 2
• Conduction disorders (seen in about 29% of cases) 2
• Repolarization disorders (seen in about 32% of cases) 2
• Echocardiography may show increased cardiac output, chamber enlargement, and eventually reduced ejection fraction
• Elevated serum alkaline phosphatase correlates with disease activity 3
• Nuclear scintigraphy of bone is the most sensitive test for determining the extent of pagetic involvement 3

Management Approach

The management of cardiac manifestations in Paget's disease focuses on:

1. Treating the underlying Paget's disease:

   • Bisphosphonates are the mainstay of treatment 3
   • Zoledronic acid is the most effective agent 4
   • A single infusion can lead to sustained reduction in bone turnover

2. Managing heart failure symptoms:

   • Standard heart failure therapy including diuretics, ACE inhibitors/ARBs, and beta-blockers as appropriate
   • Careful monitoring of fluid status

Important Considerations

• Bisphosphonate therapy should be reserved for symptomatic patients, as treatment in asymptomatic patients has been associated with increased fracture rates 4
• Cardiac manifestations may be latent and should be systematically evaluated, particularly during active phases of the disease 2
• Other cardiac complications of Paget's disease can include:
  • Calcification of the aortic valve and mitral annulus
  • Conduction abnormalities
  • Rarely, osteosarcomatous degeneration with cardiac metastases

Monitoring

• Regular monitoring of serum alkaline phosphatase levels to assess disease activity 3
• Periodic cardiac evaluation in patients with extensive disease
• Assessment for other complications of Paget's disease (fractures, deformities, neurological complications)

By recognizing and appropriately managing the high-output heart failure associated with Paget's disease, clinicians can significantly improve morbidity and mortality outcomes for these patients.