Author + information
- Received February 21, 2017
- Revision received March 9, 2017
- Accepted March 10, 2017
- Published online May 15, 2017.
- Alessandro Colombo, MD∗ (, )
- Paolo Danna, MD,
- Alessandro Cialfi, MD,
- Davide Sala, MD and
- Maurizio Viecca, MD
- ↵∗Address for correspondence:
Dr. Alessandro Colombo, Divisione di Cardiologia, Ospedale “Luigi Sacco”, 20157 Milano, Italy.
Previous studies have shown that reducing intrathoracic pressure during inspiration significantly increases right atrial volume (through an increase in venous return) with a slight reduction of right atrial pressure (1). In patients with an atrial septal defect, the same phasic, inspiration-related pressure variations were noted, but right atrial volume did not change, thus indicating substantial volume shift from the right to left atrium (2). Experimental findings in mammals also suggest that right-to-left shunting does occur in inspiration when a defect is opened in the interatrial septum (3,4). These observations are convincing proof that right-to-left shunting might preferentially occur during inspiration also in patients with a patent foramen ovale (PFO). Indeed, the Valsalva maneuver increases the diagnostic yield of PFO diagnosis because its release phase exacerbates the hemodynamic consequences of inspiration.
A 62-year-old man with a recent transient ischemic attack and diagnosis of PFO with interatrial septal aneurysm was admitted at our center for percutaneous PFO closure.
At the beginning of the procedure, he was spontaneously hiccupping. When we injected standard saline contrast from the right femoral vein for baseline assessment of PFO, the hiccups were seen to cause 3 simultaneous phenomena: a sudden increase in right atrial volume, a major leftward shift of the interatrial septum, and a massive right-to-left shunt through the PFO (Figure 1, Online Video 1).
We proceeded to PFO catheterization and were able to record the left atrial pressure during subsequent hiccups. What we saw was a series of sudden, hiccup-related sharp falls of left atrial pressure (Figure 2). We did not insert an additional catheter into the right atrium, and therefore could not gauge the simultaneous pressure changes in both atria during hiccups. Anyway, massive leftward interatrial shunting concomitant to sharp pressure falls in the left atrium convincingly proves that the hiccup produces the same variations in atrial physiology as respiration does, though on higher scale, and with striking consequences.
For a supplemental video and its legend, please see the online version of this article.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received February 21, 2017.
- Revision received March 9, 2017.
- Accepted March 10, 2017.
- 2017 American College of Cardiology Foundation
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