Adding sodium and calcium ions to the contrast medium iodixanol reduced the risk of ventricular fibrillation during perfusion of the left coronary artery in pigs: effects of electrolytes, viscosity, and chemotoxicity of an isotonic perfusate.
OBJECTIVE
The effects of electrolytes, viscosity, and chemotoxicity of a plasma-isotonic iodine contrast medium iodixanol were compared with regard to its propensity to cause ventricular fibrillation (VF).


METHODS
The left coronary artery of pigs was perfused with five isotonic solutions: iodixanol 320 mg I/mL with 19 mmol/L NaCl + 0.3 mmol/L CaCl2, Iod 320+Mann (iodixanol 320 mg I/mL + 50 mmol/L mannitol), Mann+Na/Ca (240 mmol/L mannitol with 19 mmol/L NaCl + 0.3 mmol/L CaCl2), Mann (275 mmol/L mannitol) and Ringer. The first two solutions have at 37 degrees C a viscosity of approximately 13 mPa x s while the others have a viscosity < 1 mPa x s. In eight pigs, each test solution was injected twice into the left coronary artery in random order for 10 seconds (injection volume, 20 mL). In 15 pigs, each of the solutions was injected in random order for 11-40 seconds through the end-hole of a wedged 5F balloon catheter in left coronary artery. Injection rate was 0.5 mL/sec until VF occurred. If VF occurred, injection was stopped and the heart was defibrillated. If VF did not occur, the perfusion period was 40 seconds.


RESULTS
The 10-second perfusions caused no VF. The 40-second perfusions with iodixanol 320 mg I/mL with 19 mmol/L NaCl + 0.3 mmol/L CaCl2 or Ringer caused no VF (0%). Iod 320+Mann caused nine VF (60%) after 35 +/- 4 seconds (SEM). Mann+Na/Ca caused 14 VF (93%) after 30 +/- 2 seconds. Mann caused 15 VF (100%) after 24 +/- 2 seconds. Iodixanol 320 mg I/mL with 19 mmol/L NaCl + 0.3 mmol/L CaCl2 and Ringer caused fewer VF than all other solutions (P < .05-.001). Iod 320+Mann caused fewer VF than Mann (P < .05). Iod 320+Mann caused VF later than Mann+Na/Ca or Mann (P < .02 and P < .01). Mann+Na/Ca caused VF later than Mann (P < .05).


CONCLUSIONS
The results fit with a concept that VF starts when the electrolyte composition of the interstitial fluid in the myocardium is sufficiently nonphysiologic. The more physiologic the electrolyte composition of the perfusion fluid, and the higher its viscosity, the slower the composition of the interstitial fluid will be changed, and VF will occur later (or not at all).
Chai
Chun-Ming
CM
Department of Diagnostic Radiology, University Hospital of Malmö, Medical Faculty, University of Lund, S-20 502 Malmö, Sweden. Chun-Ming.Chai@roentgen.mas.lu.se
Almén
Torsten
T
Bååth
Lars
L
Besjakov
Jack
J
D000818:Animals; D000838:Anions; D002122:Calcium Chloride / Q000737:chemistry / Q000494:pharmacology*; D002404:Catheterization; D003287:Contrast Media / Q000009:adverse effects* / Q000737:chemistry; D005260:Female; D007552:Isotonic Solutions; D008297:Male; D010477:Perfusion; D012965:Sodium Chloride / Q000737:chemistry / Q000494:pharmacology*; D013552:Swine; D014283:Triiodobenzoic Acids / Q000009:adverse effects* / Q000737:chemistry; D014693:Ventricular Fibrillation / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D014783:Viscosity
D000838:Anions; D003287:Contrast Media; D007552:Isotonic Solutions; D014283:Triiodobenzoic Acids; D012965:Sodium Chloride; C044834:iodixanol; D002122:Calcium Chloride