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Query: UMLS:C0042510 (ventricular fibrillation)
 10,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The systemic hemodynamic and myocardial effects of potent vasodilators administered directly into the left coronary artery were determined and compared with the actions of contrast material in 10 anesthetized dogs in the normal state and in the presence of segmental myocardial ischemia. Contrast material (Renografin 76) caused systemic hypotension, rise in left ventricular diastolic pressure and decreases in LV dp/dt and dp/dt/LVP in both states. Doses of ATP (7.2 microgram/kg and 20 microgram/kg/min) which are maximally effective in augmenting coronary blood flow caused only mild arterial hypotension and minimal inotropic effects in both states. Nitroglycerin (3 microgram/kg and 10 microgram/kg/min) induced no inotropic effects but slightly greater arterial hypotension than ATP in both states. On the other hand, papaverine HCl (300 microgram/kg and 800 microgram/kg/min) induced profound increases in LV dp/dt and dp/dt/LVP, decreases in LVEDP and arterial hypotension in the non-ischemic state. In the presence of segmental ischemia, papaverine HCl caused significantly less increases in LV dp/dt and dp/dt/LVP, paradoxical increases in LVEDP in 5 dogs and ventricular fibrillation in 3 dogs. Thus, maximally effective vasodilatory doses of ATP causes only small alterations in hemodynamics and myocardial contractile state of the normal and ischemic heart. Similar doses of papaverine induce profound positive inotropic effects which are apparently deleterious to the ischemic heart.
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PMID:Comparative hemodynamic effects of coronary vasodilators and contrast material on the normal and ischemic canine myocardium: determination of the optimal agent for clinical augmentation of coronary blood flow. 40 73

The toxicity of Renografin 76% was compared with that of Hypaque 76% by selective injection of each into the right coronary artery of dogs. Renografin contains the chelating agents sodium citrate and disodium edetate, while Hypaque contains calcium disodium edetate and no sodium citrate. Ventricular fibrillation occurred significantly more often with Renografin, suggesting that chelating agents contribute to toxicity in coronary angiography.
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PMID:Ventricular fibrillation from diatrizoate with and without chelating agents. 66 66

Ventricular fibrillation thresholds were measured in anesthetized, closed-chest dogs during the injection of Renografin 76 or Conray 400 into the left coronary artery. Both agents significantly lowered fibrillation threshold--Renografin to 58 +/- 7%; Conray to 20 +/- 5% of control, respectively. The experimental method estimates fibrillatory potential of contrast media more precisely than previous methods. The initial results parallel relative toxicities observed in clinical usage.
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PMID:Contrast agents lower ventricular fibrillation threshold. 69 80

In forty patients with normal coronary arteries, the electrocardiographic changes secondary to Urografin 76 and Hypaque 85 injection into both coronary arteries were monitored. Hypaque caused significantly greater prolongation of the PR interval (p less than 0.001), depression of the ST segment (p less than 0.05) and depth of T wave inversion (p less than 0.05). These effects were more noticeable during right coronary artery injection. Both contrast media slowed the heart rate equally during right and left coronary artery injection. In the absence of coronary arterial disease the ECG changes secondary to contrast media injection probably reflect a direct toxic effect. It is possible that premedication with atropine will reduce these effects. Urografin 76 appears the less toxic of the two media, although one case of ventricular fibrillation occurred with each.
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PMID:Contrast media during coronary arteriography: electrocardiographic changes in the presence of normal coronary arteries. 70 21

Renografin 76 has been shown to have significant calcium-binding properties in vivo and in vitro. Two contrast media solutions were compared by selective injection into the right coronary artery of dogs. One set of injections was made with commercially available Renografin 76 (referred to as stock Renografin) and another set of injections was made with Renografin 76 to which had been added 24 mMols/liter of calcium chloride dihydrate. Ventricular fibrillation occurred significantly more often with the stock Renografin 76. The nature of the calcium binding and its effects are discussed.
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PMID:Reduction in ventricular fibrillation using calcium-enriched Renografin 76. 71 99

Studies that used prolonged contrast media infusion in canine arteries have generated controversy regarding the arrhythmogenic potential of low osmolarity, nonionic contrast agents. In order to establish the relative safety of these agents in the more typical setting of bolus injections, 4 ml intracoronary bolus injections of Hypaque-76 (n = 54), Iohexol-350 (n = 51), and Iohexol-140 (n = 51) were given in random order to 10 anesthetized, open-chest dogs undergoing programmed cardiac stimulation. Hemodynamics and electrocardiogram were monitored during stimulation, both during and for 2 minutes after the end of contrast infusion. Occurrence of evoked single and coupled premature ventricular contractions and nonsustained ventricular tachycardia did not differ statistically among agents. Sustained ventricular tachycardia (five episodes) and ventricular fibrillation (seven episodes) occurred only after Hypaque-76 injections (p less than 0.002). These results differ from those in studies that use continuous contrast infusion and suggest that low osmolarity nonionic contrast agents are as safe as high osmolarity nonionic contrast media. Both appear safer than ionic contrast material.
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PMID:Induction of ventricular arrhythmia by high and low osmolarity ionic and nonionic contrast media. 247 1

To compare the fibrillatory propensity of low concentrations of contrast media (140 mg I/ml) the ionic, ratio 1.5, contrast medium meglumine diatrizoate, the non-ionic, ratio 3, medium iopentol and equimolar glucose (0.37 mol/l) were perfused into 35 isolated rabbit hearts. The three substances were compared at three levels of sodium concentration (0.77 and 154 mmol Na+/l). Meglumine diatrizoate without sodium caused the highest frequency of ventricular fibrillation (91%). Iopentol without sodium caused a significantly lower frequency of ventricular fibrillation (17%). Glucose without sodium caused no fibrillation. The addition of 77 or 154 mmol Na+/l significantly decreased the frequency of ventricular fibrillation of both meglumine diatrizoate (3% and 6%) and iopentol (0%). Meglumine diatrizoate with sodium added caused a lower frequency of ventricular fibrillation than iopentol without sodium. At equal sodium concentrations (0.77 and 154 mmol Na+/l) glucose caused smaller reduction in contractile force and heart rate than iopentol, and iopentol caused smaller reduction in contractile force and heart rate than diatrizoate. It is concluded that addition of sodium to ionic or non-ionic contrast media without sodium decreases the risk of ventricular fibrillation.
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PMID:Reducing the risk of ventricular fibrillation by adding sodium to ionic and non-ionic contrast media with low iodine concentration. Coronary perfusion of the isolated rabbit heart with meglumine diatrizoate or iopentol at 140 mg I/ml and 0-154 mmol Na+/l. 264 14

Electrocardiographic changes induced by ionic contrast media can cause complications during coronary angiography. A conduction delay through various parts of the heart is one factor in the genesis of asystole or ventricular fibrillation. Hypaque-76 (H76) and Renografin-76 (R76) are nearly identical ionic contrast media except that R76 binds more calcium than H76 because of the presence of sodium citrate and EDTA in R76. To determine whether the calcium binding additives in ionic contrast media contribute to the cardiac conduction abnormalities, we examined conduction time through the atrioventricular (AV) nodal tissue (via bipolar His bundle electrograms) and through the distal part of the conduction system (recording the QRS complex from the ECG) during coronary angiography. We injected 10 mL of H76 and R76 in 19 closed chest dogs in a blinded, randomized fashion during coronary angiography. The effects of H76 and R76 on heart rate, AH interval, HV interval, V interval and PR interval, and QRS complex duration were recorded. In 14 nonatrial pacing dogs, compared with H76, R76 produced a greater increase in the AV interval (32.9 +/- 6 milliseconds vs 12.4 +/- 2 milliseconds, P less than .01) and the PR interval (29.6 +/- 6 milliseconds vs 11.9 +/- 4 milliseconds, P less than .02). Additionally, the heart rate decreased 13.9 +/- 3.5 beats/minute from control with R76 compared with a decrease of 4.2 +/- 2.6 beats/minute from control with H76 (P less than .05). There was no significant difference between the prolongation of the HV interval and V interval, or QRS complex duration generated by R76 and H76.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of contrast media on the conducting system of the heart during coronary angiography. A comparison of Renografin-76 to Hypaque-76. 305 71

Contrast media occasionally produce ventricular fibrillation during coronary angiography. We compared the fibrillatory propensity of the conventional ionic contrast medium, Hypaque-76 (H76) to the low osmolar ionic dimer Hexabrix (HB) and to the nonionic agent Omnipaque (OM) in 20 open chest anesthetized dogs. Intracoronary injection of 6 mL of contrast medium produced spontaneous ventricular fibrillation in four of ten dogs with H76, compared with two of ten with HB, and zero of ten with OM (P = .07). The induction of two premature beats by programmed stimulation of the myocardium during injection of 4 mL of contrast medium produced ventricular fibrillation in ten of ten dogs with H76, compared with three of ten with HB, and zero of ten with OM (P less than .001). Both H76 and HB produced ventricular fibrillation in ten of ten dogs when three premature beats were induced, compared with two of ten dogs with OM (P less than .001). Four mL H76 produced a 109 +/- 18 msec increase in the QT interval, compared with an 82 +/- 17 msec increase with HB, and a 45 +/- 12 msec increase with OM. We conclude that both low osmolar HB and OM are less fibrillatory than the conventional ionic medium H76, and that the nonionic medium OM is less fibrillatory than the ionic dimer contrast medium HB.
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PMID:Contrast media-induced ventricular fibrillation. A comparison of Hypaque-76, Hexabrix, and Omnipaque. 340 7

The intracoronary injection of contrast media during coronary angiography occasionally results in ventricular fibrillation. Experimental studies have implicated the calcium sequestering agents, sodium citrate and EDTA in Renografin 76 (RG76), as contributing to this complication. Angiovist 370 (AV370) is a contrast medium similar to RG76 except that it contains disodium calcium EDTA instead of EDTA and sodium citrate. To determine if contrast media lacking sodium citrate and EDTA will result in a lower incidence of ventricular fibrillation in man, this investigation compared the incidence of contrast media-induced ventricular fibrillation in patients undergoing coronary angiography with RG76 to that with AV370. Group A consisted of 2,500 consecutive patients undergoing coronary angiography with RG76 and group B consisted of 2,000 subsequent consecutive patients in whom AV370 was employed as the contrast medium. There was no significant difference between groups A and B with respect to the volume of contrast media used per patient (153 +/- 49 ml vs 154 +/- 45ml), age (58.4 +/- 10 vs 58.6 +/- 10 years), sex (70% male vs 70% male), ejection fraction (59 +/- 17 vs 60 +/- 20), history of mitral valve disease (5.8% vs 7.1%), history of aortic valve disease (6.7% vs 6.5%), prior coronary artery bypass graft surgery (6.6% vs 7.3%), or extent of coronary artery disease. Fifteen episodes of contrast media-induced ventricular fibrillation occurred in group A (incidence 0.6%) whereas two episodes occurred in group B (incidence 0.1%) (p less than 0.02). Each patient was successfully defibrillated and no adverse sequelae resulted. Thus the present investigation suggests that the incidence of ventricular fibrillation during coronary angiography can be significantly decreased by using contrast media lacking sodium citrate and EDTA.
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PMID:Ventricular fibrillation during coronary angiography: reduced incidence in man with contrast media lacking calcium binding additives. 392 Dec 58


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