Hemodynamically unstable atrial fibrillation after oral contrast dye instillation in a case of Boerhaave's syndrome.

Sir,

The adverse effects of intravenously injected iodinated contrast dye are dealt seriously in literature.[1] However, adverse events following oral contrast dye are relatively less reported. Here, we report an interesting case of hemodynamically unstable atrial fibrillation (AF) following oral contrast instillation in a case of Boerhaave's syndrome.

A 66-year-old retired teacher was referred to our intensive care unit (ICU) from a private hospital in a state of septic shock. He had a history of left sided chest pain and dyspnea after two bouts of vomiting of food material 5 days ago (suspected Boerhaave's syndrome). Patient was a known hypertensive since 10 years, but was well-controlled on oral antihypertensive medications.

On examination in ICU, he was conscious, oriented, febrile, having tachypnea (30/min), tachycardic (120/min) with hypotension (90/50 mmHg) with patent left intercostal drain (24 Fr) draining serosanguinous material. The patient was intubated and mechanically ventilated and started on broad spectrum antibiotics along with vasopressor and total parenteral nutrition. His baseline hematological (except leukocytosis) and biochemical investigations including arterial blood gas were within normal limit. Electrocardiography and cardiac enzymes were normal. Bedside chest X-ray revealed left sided pleural effusion. Pleural fluid showed high amylase level (>2500 u/l). His shock resolved within next 48 h. We contemplated a contrast enhanced computed tomography (CECT) scanning of chest to confirm our provisional diagnosis and also to see the extent of perforation for early surgical repair. We insert a nasogastric tube up to 15 cm into the esophagus and instilled oral contrast (Iohexol, Omnipaque, GE Health-care) slowly through this tube. Immediately following 20 ml of contrast instillation, the patient developed sudden AF with a ventricular rate of >120/min. He became hemodynamically unstable (BP 80/30 mmHg). A 100 Joule synchronized DC shock had to be given immediately followed by 200 Joule synchronized DC shock. His ventricular rate reduced and hemodynamics improved and his heart rhythm converted into sinus within few minutes. Intravenous 2 g of magnesium sulphate was injected. Intravenous amiodarone infusion (@ 1 mg/kg/h) was also started. Arterial blood gas showed no abnormality in view of electrolytes except mild hypokalemia (K+ =3.8 meq/L). On further questioning of the relatives, we got a history suggestive of tachycardia (? lone AF) 8 years ago (He was not admitted anywhere and advised to take beta blocker). Importantly, beta blocker was stopped for last 8 days and he had no prior history of allergy to any food and drugs or any reactive airway disease. However, we were able to conduct his CECT scan thorax without further dye push. CECT scan thorax showed pneumomediastinum [Figure 1], contrast leak in pleural cavity and most importantly around aorta and pericardium [Figure 2]. After amiodarone infusion for 24 h, we switched over to injection diltiazem. Even after 5 days of contrast exposure, AF recurred intermittently. Patient underwent cervical esophagostomy and gastrostomy. We started diltiazem tablets through gastrostomy. Post-operative period was uneventful. He could be discharged from hospital after definitive surgery. He is now under cardiology follow-up.

Figure 1

Contrast enhanced computed tomography scan thorax mediastinal window showing pneumomediastinum (yellow arrow) and contrast dye around heart (red arrow)

Figure 2

Contrast enhanced computed tomography scan thorax showing contrast near (1) aorta and in (2) pleural cavity

In view of non-specific presentation of Boerhaave's syndrome; CECT scan is essential to “detect the presence, site and size of esophageal perforation” and to guide proper treatment.[23] For CECT scan of thorax and abdomen, iohexol dye is preferred as oral contrast as it has low osmolarity and less adverse effects.[4] Osmotically related nephrotoxicity and anaphylactic-type reactions are the main adverse effects reported after intravenous iodinated dye exposure.[14] To our knowledge, this is the first reported case of adverse reaction like AF following oral contrast dye instillation. We strongly believe that hemodynamically unstable AF, in our case, is due to direct contact of oral contrast dye around aorta and pericardium.[5] Injection of dye over the pericardium might initiated a pericardial inflammatory reaction, which precipitated AF.[6] The physical process of instillation of a viscous solution or lower (room temperature 22°C) temperature of the instillate near the cardiac chambers might triggered AF. Anaphylactoid reaction after oral dye exposure might be a cause.[4] Pneumomediastinum is a known cause of AF and might be a possibility in our patient.[7] Importantly, his old age and a past history suggestive of lone AF, and stoppage of beta adrenergic blocker (first for the suspected esophageal tear and then for septic shock) might make him susceptible for this life threatening episode.[68]

We, in conclusion, want to highlight that oral iodinated dye instillation can cause hemodynamically unstable AF in cases of suspected esophageal perforation may be due to direct mediastinal instillation and stimulation of cardiac structures. Oral dye in those cases should be instilled in presence of hemodynamic monitoring and defibrillator (preferably in ICU setting).