Can Multi-System Atrophy (MSA) cause palpitations?

Can Multi-System Atrophy Cause Palpitations?

Yes, Multiple System Atrophy (MSA) can cause palpitations due to its significant impact on autonomic nervous system function, particularly through dysautonomia and orthostatic hypotension mechanisms.

Autonomic Dysfunction in MSA

MSA is characterized by progressive neurodegeneration affecting multiple systems in the body, with autonomic dysfunction being a central feature of the disease. According to the American College of Radiology guidelines, MSA is classified as a "Parkinson-plus" syndrome with three distinct clinical subtypes 1:

• MSA-P (striatonigral degeneration): Predominant parkinsonian features
• MSA-C (olivopontocerebellar atrophy): Predominant cerebellar symptoms
• MSA-A (Shy-Drager syndrome): Predominant autonomic dysfunction

The autonomic dysfunction in MSA is particularly relevant to cardiovascular symptoms like palpitations. Unlike pure autonomic failure, MSA patients maintain substantial functioning sympathetic and parasympathetic nerves even in advanced disease 2. This persistent autonomic tone can lead to dysregulated cardiovascular responses.

Mechanisms of Palpitations in MSA

Several pathophysiological mechanisms can explain palpitations in MSA patients:

1. Orthostatic Hypotension (OH):

   • MSA is characterized by neurogenic OH, which occurs when standing upright 1
   • The drop in blood pressure triggers compensatory mechanisms including increased heart rate
   • Research shows MSA patients experience an augmented muscle sympathetic nerve activity (MSNA) response during orthostatic stress 3

2. Autonomic Dysregulation:

   • Dysregulation of sympathetic and parasympathetic systems can cause irregular heart rhythms
   • Increased daytime blood pressure variability has been documented in MSA and is associated with mortality 4

3. Compensatory Mechanisms:

   • The body attempts to compensate for blood pressure drops with increased heart rate
   • This can manifest as palpitations when patients change positions

Clinical Presentation

Patients with MSA may experience various symptoms related to autonomic dysfunction:

• Dizziness (83% of MSA patients) 5
• Syncope (45% of MSA patients) 5
• Visual disturbances (53% of MSA patients) 5
• Suboccipital/paracervical "coat-hanger" neck pain (53% of MSA patients) 5
• Palpitations (particularly during positional changes)

Notably, these symptoms are often worse in the morning, with warm temperatures, straining, exertion, arm movements, and after food ingestion 5.

Diagnostic Approach for Palpitations in MSA

For MSA patients experiencing palpitations, the European Society of Cardiology guidelines recommend 1:

1. 48-hour ambulatory ECG monitoring to identify the likely cause
2. Consider implantable loop recorder (ILR) for frequent palpitations where no cause is identified after prolonged ECG monitoring

Management Considerations

Management of palpitations in MSA should focus on addressing the underlying autonomic dysfunction:

1. Orthostatic Hypotension Management 1:

   • Acute water ingestion (≥240 mL) for temporary relief
   • Physical counter-pressure maneuvers (leg crossing, muscle tensing)
   • Compression garments (at least thigh-high, preferably including abdomen)
   • Midodrine may be beneficial but must be used cautiously

2. Caution with Medications:

   • OH treatment has been associated with increased mortality in MSA patients 4
   • Avoid arterial and venous dilators when possible
   • Monitor for supine hypertension when using medications for OH

Important Caveats

1. MSA patients may have substantial orthostatic hypotension but fewer symptomatic episodes compared to pure autonomic failure patients 5.

2. Treatment decisions should consider that OH treatment has been independently associated with mortality in MSA patients 4.

3. The multisystem nature of MSA requires coordinated care focused on the patient's priorities and quality of life 6.

4. Palpitations in MSA patients may be underreported due to the prominence of other symptoms or cognitive limitations in advanced disease.