Initial evaluation: electrocardiogram (ECG)
If the ECG is normal, then the patient is instructed to hyperventilate by breathing deeply and rapidly for a minute or two.
(1) If the chest pain is reproduced by this maneuver, then the hyperventilation syndrome can be diagnosed.
(2) If the chest pain is not reproduced, then consider other causes of chest pain. If no other cause is identified, then repeat the hyperventilation test.
If the ECG is abnormal, then have the patient breathe into a paper bag for 1-2 minutes and then repeat the ECG.
(1) If the ECG initially showed nonspecific ST segment and T wave changes that revert to normal with rebreathing, then the hyperventilation syndrome is likely.
(2) If the ECG does not revert to normal with rebreathing, then consider evaluation for coronary vascular disease (stress testing, angiography, serum troponin, etc.)
Some things to consider in the differential diagnosis:
(1) esophageal disease (spasm, reflux)
(2) mitral valve prolapse
The pattern of arterial blood gases in hyperventilation syndromes:
(1) alkalosis (respiratory)
(2) hypocapnia
(3) low serum bicarbonate
