Cardiac ectopy in chronic autonomic failure.

OBJECTIVE: Chronic autonomic failure (CAF), as in Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF), typically entails baroreflex failure, neurogenic orthostatic hypotension (NOH), and supine hypertension. The combination might predispose to cardiac ectopy, which in turn might predispose to syncope and falls during manipulations decreasing venous return to the heart. This study assessed whether CAF is associated with an increased prevalence of cardiac ectopy.
METHODS: Recordings lasting > or = 15 min of the electrocardiogram, beat-to-beat heart rate, and continuous blood pressure were reviewed from a total of 97 CAF patients (34 PD + NOH, 48 MSA, 15 PAF) and 82 control subjects (41 PD without NOH, 33 non-parkinsonian patients, 8 healthy volunteers). Cardiac ectopy was considered present if there were at least two premature beats or an arrhythmia.
RESULTS: Atrial ectopy was found in 74% of patients with PD + NOH, 68% with MSA, and 63% with PAF, prevalences 2-3 times those in PD without NOH (28%, p < 0.0001) or other controls (24%, p < 0.0001). Atrial ectopy was related to subject age (p < 0.0001), supine systolic pressure (p < 0.0001), and the orthostatic fall in systolic pressure (p = 0.0007) and inversely with baroreflex-cardiovagal gain (p = 0.005) and the orthostatic increment in plasma norepinephrine (p = 0.0004). In two PD + NOH patients, atrial ectopy was associated with documented sustained hypotension after the Valsalva maneuver; and in an MSA patient, acute atrial flutter/fibrillation was associated with sudden loss of consciousness.
INTERPRETATION: CAF patients have a relatively high frequency of atrial ectopy, which might interact with baroreflex failure to increase morbidity from orthostatic hypotension.