Is it bradycardia or something else causing symptoms

Cardiovascular autoregulation is dependent upon a dynamic balance between the sympathetic and parasympathetic branches of the autonomic nervous system.1 Autonomic failure, often present in patients with Parkinson disease (PD) and other neurodegenerative diseases, results in cardiovascular dysfunction that may be evident early in the progression of PD,2, 3 even before the onset of motor symptoms.4 Common manifestations of autonomic dysfunction in PD include neurogenic orthostatic hypotension (nOH), supine hypertension, and attenuated heart rate (HR) variability, all of which are associated with increased morbidity and mortality.5 nOH, a sustained reduction of systolic blood pressure (BP) of ≥ 20 mm Hg or diastolic BP of ≥ 10 mm Hg within 3 minutes of standing or head-up tilt to at least 60°, can result from hypoperfusion of the brain upon standing.6 Supine hypertension, defined as systolic BP ≥ 140 mm Hg and/or diastolic BP ≥ 90 mm Hg while in the supine position (≥5 minutes of rest), is common in patients with nOH.7 Patients with autonomic failure often present with both nOH and supine hypertension, as regulatory BP mechanisms are impaired.8 Normal HR variability and sinoatrial and atrioventricular nodal conduction regulated by both branches of the autonomic nervous system can be disrupted in autonomic dysfunction.9, 10 Patients with suspected autonomic dysfunction can have associated multisystem autonomic abnormalities. A key abnormality is orthostatic intolerance resulting in nOH; however, many patients also have HR abnormalities, including bradycardia. Because symptoms can be nonspecific and mimic other medical conditions, a comprehensive assessment of underlying conditions to determine the cause of symptoms is necessary before making a recommendation for a specific treatment. In this report, we describe the case of bradycardia in a patient with PD who was referred for a pacemaker.