Diaphragmatic Flutter: Intermittent vs. Constant Pattern
Diaphragmatic flutter is characteristically an intermittent condition, not constant, with episodes triggered by specific activities or occurring spontaneously with periods of normal diaphragmatic function between episodes. 1, 2
Clinical Pattern and Episodic Nature
Diaphragmatic flutter manifests as episodic involuntary contractions of the diaphragm at rapid rates (0.5-8.0 Hz in classic cases, or 9-15 Hz in high-frequency variants), rather than continuous dysfunction 1, 3
Episodes can be triggered by specific activities such as increasing the depth of breathing or electrical stimulation of the diaphragm, demonstrating clear intermittent provocation rather than constant presence 2
Between episodes, patients typically experience periods of normal diaphragmatic function, which is fundamentally incompatible with a constant disorder 2
Evidence Supporting Intermittent Nature
In documented cases, flutter can be instantaneously halted with interventions such as noninvasive ventilatory support, with resolution lasting for months before recurrence—this start-stop pattern definitively establishes intermittency 2
Treatment with carbamazepine (200-400 mg three times daily) leads to disappearance or great improvement of flutter episodes, indicating the condition occurs in discrete episodes that can be prevented rather than being continuously present 3
The clinical presentation includes longstanding symptoms like esophageal belching, hiccups, and retching that wax and wane, rather than being unremitting 3
Diagnostic Implications
Electromyography demonstrates repetitive discharges during symptomatic periods, with spirographic tracings showing high-frequency oscillations superimposed on normal tidal respiratory movements—the presence of underlying normal breathing confirms intermittent superimposed flutter rather than constant dysfunction 3
Respiratory inductive plethysmography can confirm the diagnosis by capturing the episodic high-frequency pulsatile contractions of the thorax and abdominal wall associated with breathlessness 4
Clinical Caveat
A critical pitfall is that patients may experience rare episodes (such as when getting out of bed) that resolve with brief intervention (up to 40 minutes of noninvasive ventilatory support), emphasizing the episodic rather than continuous nature of this disorder 2
The diverse etiology (hypocalcemia, striatal necrosis, idiopathic causes) all share the common feature of intermittent episodes rather than constant dysfunction, regardless of underlying cause 5