Coronary Arteriography In Dogs Research Articles

Coronary arteriography with an oxygenated contrast medium: Cardiac effects in dogs with and without acute ischemic heart failure

We investigated the possible cardiac effects of oxygen addition to contrast media (CM) during coronary arteriography in dogs that did and did not have ischemic heart failure. Acute ischemic heart failure was induced by injecting small plastic microspheres into the left coronary artery of 18 dogs. Hemodynamic and electrophysiologic measurements were performed during a single injection before and during heart failure and during a single injection and five rapidly repeated CM injections during heart failure. Iohexol supplemented with electrolytes (iohexol + electrolytes = IPE), oxygenated IPE (IPE+O), Ringer acetate, and oxygenated Ringer acetate were injected into the left coronary artery. Single injections of IPE and IPE+O induced small hemodynamic and electrophysiologic effects. However, repeated injections of IPE and IPE+O increased left ventricular inotropy (maximum value of the first derivative of the left ventricular pressure) by 36% and 39%, reduced heart rate by 7% (for both), and lengthened QTc time (corrected QT interval) by 39 and 38 msec, respectively. A comparison of IPE and IPE+O revealed no statistically significant differences. Although electrolyte addition to nonionic CM may reduce the risk of cardiac complications during coronary arteriography, oxygenation does not seem to significantly further reduce this risk.

Role of sodium addition to nonionic contrast medium in preventing ventricular fibrillation during coronary arteriography in dogs

We studied the effect of the addition of sodium to nonionic contrast medium (CM) on the incidence of ventricular fibrillation (VF) during coronary arteriography in dogs. We infused 20 ml (0.5 ml/sec) of iohexol, iohexol plus 30 mmol of Na+ per liter, and NaCl-Ringer's acetate in randomized order through a wedged catheter placed in the right coronary artery (RCA) or in the left anterior descending coronary artery (LAD) in 12 anesthetized dogs. In addition to electrocardiographic and hemodynamic measurements, epicardial monophasic action potential durations and ventricular activation times were recorded during infusions into the LAD. All infusions with iohexol into the RCA and the LAD (n = 16) caused VF. Seven of 19 infusions with iohexol plus 30 mmol of Na+ per liter caused VF. Infusions with iohexol plus 30 mmol of Na+ per liter that did not cause VF lengthened monophasic action potential durations and increased ventricular activation times more in the CM-perfused area than in the control area. The addition of sodium to iohexol reduces the incidence of VF when infused through a wedged catheter. The protective mechanisms may be attributable to a lengthened repolarization phase and an increased activation time in the CM-perfused area.

Sodium Addition to Nonionic Contrast Media

In order to study the electrophysiologic and hemodynamic effects of sodium addition to low-osmolality contrast media during coronary arteriography, eight dogs with surgically opened thoraces were studied. Epicardial monophasic action potentials (MAP) were recorded from the contrast perfused area, using suction electrodes. Six milliliters of iohexol, iohexol with addition of 20 to 80 mmol/L Na+ and ioxaglate, were selectively administered into the left coronary artery. Only minor hemodynamic alterations occurred with the iohexol solutions, whereas ioxaglate decreased left ventricular (LV) inotropy and pressures initially. Iohexol and iohexol containing less than 40 mmol/L Na+ did not change MAP duration significantly. The addition of 80 mmol/L Na+ to iohexol lengthened MAP duration at 25%, 50%, and 90% repolarization by 14 +/- 2, 18 +/- 3, and 18 +/- 5 mseconds, respectively. Ioxaglate lengthened MAP duration by 14 +/- 3, 17 +/- 3, and 26 +/- 8 mseconds, respectively. Thus, during coronary arteriography in dogs, iohexol with sodium added, like ioxaglate, induced regional electrophysiologic changes in the contrast-perfused area of the myocardium, while sodium-free iohexol did not.

Effect of Contrast Media on Left Ventricular Function during Left Coronary Arteriography in Dogs

The effect of contrast media on the left ventricular function of the heart was assessed by left coronary administration of contrast media using canine models. Following insertion of the catheter into the left coronary artery, 0.5 ml/kg of a test solution was injected at a rate of 1 ml/s. The test solutions included isotonic saline, meglumine/sodium diatrizoate, iopamidol and ioxaglate. The mean systemic pressure, left ventricular end-systolic and end-diastolic pressures and the first derivative of left ventricular pressure were continuously measured until five min post-injection. Left ventricular function decreased immediately by 15 s post-injection and recovered quickly by one min. The inhibition of myocardial contractility was observed with diatrizoate and ioxaglate to the same degree. These changes were statistically more pronounced than those with iopamidol, which showed changes similar to those with saline in all parameters except for the positive inotropic effects. These observations suggest that not only hyperosmolality but also ionic composition and chemotoxicity are the factors responsible for the myocardial depression and that no single factor dominates in their effects.

Effect of Contrast Media on Left Ventricular Function during Left Coronary Arteriography in Dogs

The effect of contrast media on the left ventricular function of the heart was assessed by left coronary administration of contrast media using canine models. Following insertion of the catheter into the left coronary artery, 0.5 ml/kg of a test solution was injected at a rate of 1 ml/s. The test solutions included isotonic saline, meglumine/sodium diatrizoate, iopamidol and ioxaglate. The mean systemic pressure, left ventricular end-systolic and end-diastolic pressures and the first derivative of left ventricular pressure were continuously measured until five min post-injection. Left ventricular function decreased immediately by 15 s post-injection and recovered quickly by one min. The inhibition of myocardial contractility was observed with diatrizoate and ioxaglate to the same degree. These changes were statistically more pronounced than those with iopamidol, which showed changes similar to those with saline in all parameters except for the positive inotropic effects. These observations suggest that not only hyperosmolality but also ionic composition and chemotoxicity are the factors responsible for the myocardial depression and that no single factor dominates in their effects.

The importance of sodium concentration on the incidence of fibrillation during coronary arteriography in dogs.

Coronary arteriography is known to produce electrical disturbances including conduction disturbances, arrhythmias, and ventricular fibrillation. A canine model for studying ventricular fibrillation has been developed that uses relatively long injections in the right coronary artery. In experiments in 49 dogs over a five-year period, the authors have consistently observed that with low osmolality contrast media, the incidence of ventricular fibrillation becomes quite high when the formulation contains less than 3.2 mmol/L sodium. This effect seems independent of the concentration of the contrast media molecules. High concentrations of the ionic monomer diatrizoate cause fibrillation despite high sodium concentrations.

The Importance of Sodium Concentration on the Incidence of Fibrillation During Coronary Arteriography in Dogs

The Importance of Sodium Concentration on the Incidence of Fibrillation During Coronary Arteriography in Dogs

Coronary arteriography in dogs following blunt cardiac trauma: a longitudinal assessment.

The purpose of the study was to examine the effects of blunt cardiac trauma on the epicardial coronary arteries of dogs by using sequential coronary arteriographic studies. A direct impact to the anterior surface of the heart at a velocity of 12 m/sec was delivered by an air pressurized impactor in eight of ten dogs with the chest open and the pericardium intact. Selective coronary arteriograms were performed percutaneously with the chest closed starting just before trauma and repeated afterward at intervals of 3 hours, 3 days, 2 weeks, and 5 weeks. Two of ten dogs were sham operated and did not undergo impact to the heart. The coronary arteries in these two dogs remained angiographically normal throughout the study period. In dogs that underwent impact and were maintained for the entire duration of the study (seven of eight dogs), injury to the epicardial coronary arteries occurred in every instance. Injury was limited mostly to branches of the left anterior descending and right coronary arteries. The left circumflex coronary artery, which was posterior to the site of impact, was always spared. The types of injury included complete branch occlusion, partial coronary obstruction, extravasation, and in one instance, an arteriovenous fistula. In nearly all instances, these injuries became evident angiographically between 3 hours and 3 days after impact and usually were completely resolved after 2 to 5 weeks. These observations indicate that the epicardial coronary arteries may be compromised by nonpenetrating cardiac impact. The resulting coronary pathology, however, resolved within a few weeks after injury.

Effects of contrast media on coronary vascular resistance during coronary arteriography in dogs

Effects of contrast media on coronary vascular resistance during coronary arteriography in dogs

ECG Changes and Arrhythmias Induced By Ionic and Non-Ionic Contrast Media During Coronary Arteriography in Dogs

Metrizamide (non-ionic, Nyegaard Co., Oslo, Norway), diatrizoate (ionic) and metrizoate (ionic) were selectively injected into the right or the left canine coronary artery. ECG was recorded and external defibrillation was performed whenever ventricular fibrillation occurred. During left coronary injections metrizamide prolonged the PQ and QT intervals less than did the diatrizoate. During right coronary injections metrizamide affected the QT interval less than either diatrizoate and metrizoate. During right coronary infusions metrizamide caused significantly fewer incidences of ventricular fibrillation than diatrizoate. In clinical coronary arteriography it is assumed that metrizamide would generate fewer AV blocks than diatrizoate and fewer incidences of ventricular fibrillation after right coronary injections than diatrizoate. Changes in the PQ and QT intervals during coronary arteriography can be used as tests to predict the safety of new contrast media.

Mechanism of production of cardiac conduction abnormalities due to coronary arteriography in dogs.

Left coronary arteriography and left coronary artery injections of Tyrode's solution and glucose solutions were performed in 12 anesthetized dogs. The contrast medium was found to prolong the conduction time through the AV junctional tissue and through the most distal part of the conduction network as verified by His-bundle electrogram and by surface ECG (lead II). The results indicate that for evaluation of the effects on conductivity of various media, it is most reliable to measure the altered conduction velocity in the AV nodal region. The prolongation of conduction time produced by contrast medium explains heart conduction blocks and may contribute to the genesis of ventricular fibrillation, frequent complications to coronary arteriography. The data suggest that anoxemia does not cause this delayed conduction. Hyperosmolarity contributes to the alterations of the conductivity, but the ionic composition and anion toxicity of the contrast medium also may be of importance.

Hemodynamic responses of selective coronary arteriography in dogs.

Hemodynamic responses of selective coronary arteriography in dogs.

Electrocardiographic changes during coronary arteriography in dogs.

Electrocardiographic changes during coronary arteriography in dogs.