Hemodynamic and electrocardiographic effects of selective coronary angiography in man

Towards refining of the proposed ECG-based index of coronary microvascular resistance (ECGMVR)

Assessment of the coronary microcirculation via noninvasive indices of coronary microvascular resistance (MVR), based on coronary angiography (AngioMVR) is currently implemented in patients undergoing coronary angiography, and it is employed by many laboratories. Recently, a proposal has been presented of a new index of MVR, based on the duration of the transient electrocardiogram repolarization and depolarization changes emerging during coronary angiography (ECGMVR). It is paramount that the ECGMVR, which does not require any special expertise, new equipment, additional personnel and costs, or prolongation of the catheterization procedure, undergoes correlation with currently utilized indices of AngioMVR, the TIMI frame count index, and the invasive indices assessing the coronary epicardial and microvasculature states, for its validation. Some additional insights are also included in the present communication for the refinement of ECGMVR implementation.

A proposal of a new index of coronary microvascular resistance based on the duration of the transient ECG repolarization changes during coronary angiography

Coronary microvascular dysfunction is present in the majority of patients with acute coronary syndromes, myocardial infarction with nonobstructive coronary arteries, and takotsubo syndrome. Assessment of the coronary microcirculation via a noninvasive index of coronary microvascular resistance (CMVR) based on coronary angiography is currently employed by many laboratories (AngioMVR). A proposal is presented herein of a new index of CMVR, based on the duration of the transient ECG repolarization changes during coronary angiography (ECGMVR), well known to occur in patients with and without coronary artery disease, and specific for the left and right coronary artery contrast injections, which have been widely documented, starting 60 years ago. It will be imperative for the index of ECGMVR to be correlated with the currently implemented AngioMVR and the TIMI frame count index, for the validation of the ECGMVR.

Double-blind comparison of the clinical, hemodynamic, and electrocardiographic effects of sodium meglumine ioxaglate or iohexol during diagnostic cardiac catheterization

The clinical effects and the maximal hemodynamic and electrocardiographic effects of two low-osmolality radiographic contrast media (ioxaglate and iohexol) were directly compared during diagnostic cardiac catheterization in a double-blind, randomized study in 80 patients. Because small changes were expected after injection of both of these agents, sensitive ECG and intracardiac-pressure-monitoring methods were used, and maximal changes, as well as mean changes in variables, were analyzed. Symptoms were absent, mild, or moderate in 67-77% of patients after left ventriculography and in 97-100% of patients after coronary arteriography. After left ventriculography, maximum and minimum left ventricular systolic pressure and end-diastolic pressure, the first derivative of left ventricular pressure (dp/dt), heart rate, were significantly altered over the two-minute observation period but were not different from the preinjection values at two minutes after both agents. Small but significant increases in mean aortic pressure, cardiac output, and pulmonary arterial wedge pressures were seen at two minutes after both agents.

Contrast agents for cardiac catheterization: conceptions and misconceptions

Ionic and nonionic contrast materials are similarly efficacious in providing excellent images with minimal risk to the patient. In comparison with ionic media, the nonionic agents produce minor alterations in intracardiac and peripheral pressures as well as in electrocardiographic intervals and morphology. In addition, nonionic media are less often associated with undesirable symptoms, such as flushing and vomiting. At the same time, ionic and nonionic media are accompanied by a similar incidence of nephrotoxicity, serious arrhythmias, and death. Finally, nonionic contrast material is substantially more expensive than ionic media. In light of this marked difference in cost, one could argue that nonionic media should be reserved for "high-risk" patients, that is, those with a history of a serious adverse reaction to ionic contrast media and those in whom contrast-induced hypotension would be particularly deleterious.

Thrombotic and cardiovascular complications related to nonionic contrast media during cardiac catheterization: analysis of 8,517 patients

The incidence of major complications associated with nonionic contrast media has not been defined in a large study. Accordingly, cardiovascular complications, especially thrombotic events, were prospectively evaluated in 8,517 consecutive patients undergoing diagnostic cardiac catheterization with either iopamidol (n = 6,293) or iohexol (n = 2,224). Thrombotic events were defined as coronary embolus, coronary occlusion, transient ischemic attack or stroke occurring at the time of catheterization. Thrombotic events occurred in 15 patients (0.18%). Coronary thrombus or embolus occurred in 7 patients, a thromboembolus from the ventricular catheter occurred in 1 patients and transient ischemic attack or stroke occurred in 7 patients. Six of 15 patients with thrombotic events were premedicated with heparin. Thrombotic events were unusual in that they tended to occur in clusters within short time intervals. On 1 occasion, a thrombus was observed in the catheter tip before embolization. Other cardiovascular complications were similarly low with an incidence of ventricular tachycardia/fibrillation of 0.1%, profound bradycardia of 0.2% and prolonged angina of 0.3%. There were 2 deaths unrelated to thrombotic events. Although the clinical thrombotic events associated with nonionic contrast have an unusual temporal clustering and may result in major complications, the overall incidence (0.18%) of these thrombotic complications with nonionic contrast agents is quite similar to that reported with ionic contrast media.

Hemodynamic abnormalities during coronary angiography: comparison of Hypaque-76, Hexabrix, and Omnipaque-350

The hemodynamic effects induced by coronary angiography in dogs with low osmolar ionic dimer Hexabrix (HB) and nonionic Omnipaque-350 (OM) were compared to the standard ionic contrast medium, Hypaque-76 (H76), both in the normal heart and in one with simulated severe cardiac disease. Left coronary angiography was performed in 12 "normal" closed-chest dogs with 10-cc injections of H76, HB, and OM in a randomized, blinded fashion. The maximal change in the left ventricular (LV) systolic pressure (SP), mean aortic pressure (MAP), left ventricular end diastolic pressure (LVEDP), and LV dp/dt were recorded. The LVSP and MAP fell 30 +/- 3 mm Hg and 26 +/- 4 mm Hg with H76, 22 +/- 2 mm Hg and 19 +/- 2 mm Hg with HB, and 7 +/- 1.5 mm Hg and 5 +/- 1 mm Hg with OM (P less than .001). The LVEDP increased 4.8 +/- 0.5 mm Hg with H76, 3 +/- 0.5 mm Hg with HB, but only 0.2 mm Hg with OM (P less than .001). The LV dp/dt decreased 392 +/- 63 mm Hg/sec with H76 and 235 +/- 21 mm Hg/sec with HB, but increased 411 +/- 50 mm Hg with OM (P less than .001). In eight additional open-chest dogs, left coronary angiography was performed 1 hr after occlusion of the proximal LAD coronary artery and in the presence of a critical circumflex coronary artery (CX) stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential hemodynamic effects of Hypaque-76 and Renografin-76 during coronary angiography: the role of calcium-binding additives

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 hemodynamic effects of contrast media during coronary angiography, left coronary angiography was performed in anesthetized dogs. In nine closed-chest dogs, 10 cc of H76 and R76 were injected in each dog in a blinded, randomized fashion. The effect of H76 and R76 on left ventricular systolic pressure (LVSP) and left ventricular diastolic pressure (LVDP), on mean aortic pressure (MAP), and on left ventricular (LV) dp/dt was recorded. Compared with H76, R76 produced a greater decrease in the LVSP (77 +/- 25 mmHg vs 48 +/- 17 mmHg P less than .05), MAP (72 +/- 24 mmHg vs 38 +/- 18 mmHg P less than .01), and LV dp/dt (747 +/- 87 mmHg/sec vs 460 +/- 81 mmHg/sec P less than .01). In nine additional open-chest dogs, left coronary angiography was performed 1 hour after occlusion of the proximal LAD coronary artery. Seven cc R76 produced a 35 +/- 15 mmHg decrease in LVSP, compared with 20 +/- 9 mmHg with H76 (P less than .01). The LV dp/dt decreased 720 +/- 387 mmHg/sec with R76, compared with 462 +/- 222 mmHg/sec with H76 (P less than 0.05). Thus, R76 produces significantly greater hemodynamic abnormalities than H76. Contrast media lacking calcium-binding agents may be preferable for coronary angiography.

Hemodynamic effects of contrast media during coronary angiography: a comparison of three nonionic agents to Hypaque-76

Coronary angiography with standard ionic contrast media is associated with marked alterations in cardiac hemodynamics because of the depressant effects of the contrast media on cardiac contractility. Nonionic contrast media have been reported to produce less hemodynamic alteration than standard ionic contrast media. However, there is no information on how one nonionic media compares to another. Thus we compared the hemodynamic effects of three nonionic contrast media, Iopamidol (IOP), Iohexol (IOH), and Ioversol (IOV) to each other as well as to the standard ionic contrast media Hypaque-76 (H76). In 20 closed-chest anesthetized dogs, we recorded the maximal change in left ventricular systolic pressure (LVSP), mean aortic pressure, left ventricular diastolic pressure (LVDP), and left ventricular dp/dt during 10-cc left main coronary artery injections of H76, IOP, IOH, and IOV. The mean aortic pressure and LVSP decreased 36 +/- 17 mm Hg and 46 +/- 21 mm Hg with H76 but only 5 +/- 5 mm Hg and 6 +/- 5 mm Hg with IOP, 5 +/- 4 mm Hg and 6 +/- 6 mm Hg with IOH, and 5 +/- 4 mm Hg and 7 +/- 6 mm Hg with IOV (P less than 0.001). The LVDP increased 6 +/- 5.0 mm Hg with H76 but only 0.2 +/- 0.5 mm Hg with IOP, 0.2 +/- 0.3 mm Hg with IOH, and 0.5 +/- 1.0 mm Hg with IOV (P less than 0.001). The LV dp/dt decreased 545 +/- 261 mm Hg/sec with H76 but increased 886 +/- 477 mm Hg/sec with IOP, 910 +/- 96 mm Hg/sec with IOH, and 473 +/- 335 mm Hg/sec with IOV (P less than 0.001). Whereas each nonionic agent produced significantly less hemodynamic abnormalities than H76, there was no significant difference between any of the nonionic agents on any hemodynamic parameter. Thus, as compared to H76, these nonionic contrast media produced only trivial alterations in hemodynamics and LV dp/dt. These agents may be preferable in patients with LV dysfunction.

Effect of calcium-binding additives on ventricular fibrillation and repolarization changes during coronary angiography

Ventricular fibrillation during coronary angiography with Renografin-76 (meglumine sodium diatrizoate) has been attributed to the calcium-binding additives sodium citrate and sodium ethylenediaminetetraacetic acid (EDTA), which may produce repolarization changes manifested as prolongation of the QT interval. Angiovist-370 is a newer form of meglumine sodium diatrizoate that contains calcium EDTA as its additive and thus has a decreased calcium-binding effect. Eight hundred sixteen patients were prospectively randomized to receive either Renografin-76 or Angiovist-370. Ventricular fibrillation occurred in 10 of 410 patients receiving Renografin-76 and in 0 of 406 patients given Angiovist-370 (p less than 0.0005). Clinical data were analyzed without knowledge of other data in the 10 patients treated with Renografin-76 who had ventricular fibrillation (Group I), 103 randomly selected patients who also received Renografin-76 but had no ventricular fibrillation (Group II) and 108 randomly selected patients given Angiovist-370 (Group III). Of several variables examined, only the QT interval differentiated patients receiving Renografin-76 and Angiovist-370. The mean corrected QT interval (QTc interval) before coronary angiography was slightly but not significantly (p = 0.7) higher in Group I than in Groups II and III. Ten seconds after the first left coronary artery injection it was more prolonged in Groups I and II (0.552 and 0.561 second, respectively) than in Group III (0.448 second) (p less than 0.00005). Similarly, 10 seconds after the first right coronary artery injection it was significantly longer in Groups I and II (0.545 and 0.544 second) than in Group III (0.477 second) (p less than 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic contrast agents: effect of microbubbles and carrier solutions on left ventricular contractility

Recently, there has been a resurgence of interest in the use of contrast-enhanced echocardiography as a means of noninvasively assessing myocardial perfusion. However, if injections of echocardiographic contrast agents are to be used for this purpose it is essential that they are not intrinsically toxic to the heart. In this study, the left ventricular end-systolic wall stress-rate-corrected velocity of fiber shortening relation, a load independent index of contractility, was studied in nine dogs. Two-dimensional and targeted M-mode echocardiographic as well as central aortic pressure tracings were made during echocardiographically gated, pressure- and volume-controlled aortic root injections of nonsonicated and sonicated Renografin-76, saline and dextrose 70% (n = 6), and sonicated and hand-agitated Renografin-76/saline mixture (n = 5). Two of nine dogs received all agents. Off-line computer videodensitometric analysis documented myocardial perfusion. In all cases, data were obtained at control and 5 and 15 seconds after injection. Additional data were collected at 25 seconds after injection for the Renografin-76/saline mixture. Alterations in contractility were measured relative to control as changes in rate-corrected velocity of fiber shortening after afterload (measured as end-systolic wall stress) was eliminated as a confounding variable. Under no condition did saline or Renografin-76 cause alterations in left ventricular contractility. Nonsonicated and sonicated dextrose 70% increased left ventricular contractility at 15 seconds but not at 5 seconds after injection. Hand-agitated Renografin-76/saline mixture induced a negative inotropic effect at 5 and 15 seconds after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial contrast echocardiography in humans: I. Safety--a comparison with routine coronary arteriography

Myocardial contrast echocardiography is a new diagnostic cardiovascular imaging technique capable of defining perfusion zones of coronary vessels in vivo; ultimately, it may be used to measure absolute regional myocardial blood flow. However, before it can be used in humans, its safety must be clearly established. Accordingly, the electrocardiographic and hemodynamic effects of intracoronary injections of 2 cc of sonicated Renografin-76 were compared with 5 to 10 cc of non-sonicated Renografin-76 in 10 subjects with normal coronary arteries. Two cubic centimeters of sonicated Renografin provides optimal myocardial opacification during echocardiography, while 5 to 10 cc of Renografin is required for an adequate coronary arteriogram. During coronary arteriography, heart rate decreased while PR and QT intervals and QRS duration increased as compared with baseline and myocardial contrast echocardiography (p less than 0.01). Similarly, the decrease in aortic pressure and first derivative of left ventricular pressure (dP/dt) was significantly (p less than 0.01) greater during routine coronary arteriography than during myocardial contrast echocardiography. Changes in left ventricular end-diastolic or pulmonary capillary wedge pressure were similar during myocardial contrast echocardiography and coronary angiography. There were no significant differences in the duration of electrocardiographic and hemodynamic changes between myocardial contrast echocardiography and coronary arteriography. It is concluded that intracoronary injection of 2 cc of sonicated Renografin-76 provides optimal myocardial opacification. It is safe in humans, producing transient electrocardiographic and hemodynamic alterations that are less pronounced than those seen during routine coronary angiography.

Functional and pathologic effects of multiple echocardiographic contrast injections on the myocardium, brain and kidney

Myocardial contrast echocardiography can define in vivo the area at risk for necrosis after coronary occlusion. However, if this technique is to be used, it cannot be intrinsically toxic to the heart or other critical organs. To determine the functional and pathologic effects of contrast echocardiography, six intracoronary, six intrarenal and six intracarotid artery injections of 2 to 6 cc of a commonly employed contrast agent (agitated Renografin-saline solution) were performed in five dogs. A sixth dog served as a sham to assess any deleterious effects of the model preparation. Two-dimensional echocardiographic images and electrocardiograms were recorded during intracoronary injections, and heart rate, blood pressure, left ventricular end-diastolic pressure and rate of rise of left ventricular pressure (dP/dt) were continuously monitored. At 24 hours, echocardiographic and hemodynamic measurements were repeated, the dogs were killed and the heart, brain and kidneys were removed and prepared for light microscopic examination. Quantitative analysis of left ventricular wall motion was performed on control, peak contrast, post-contrast and 24 hour studies. With each intracoronary injection, there were transient decreases in blood pressure (p = 0.05 versus control) and increases in left ventricular end-diastolic pressure (p = 0.04 versus control). These were associated with depression of wall motion in contrast-enhanced regions (p = 0.01 versus control) and ST-T segment changes on the electrocardiogram. No significant change in heart rate or left ventricular dP/dt was noted. All variables normalized with the clearance of the contrast effect and remained normal to 24 hours. Light microscopic examination revealed no myocardial or cerebral changes attributable to the contrast agent injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Iohexol in coronary angiography. A double blind investigation

Iohexol 350 mg I/ml (Omnipaque) was compared with the routine contrast medium meglumine, Na-Ca-metrizoate 370 mg I/ml (Isopaque Coronar) in coronary angiography in 30 patients. A randomized, double blind, crossover design was employed. Angiographic image quality, ECG, heart rate, aortic blood pressure and adverse reactions were recorded. Excellent image quality was obtained with both media. Except for one single event of hypotension, only few and minor changes in the parameters measured were recorded. No distinct difference between the two media was found. Iohexol seems to be suitable for selective coronary angiography.

Inotropic effects of ionic contrast media: the role of calcium binding additives

Renografin-76 (RG76) regularly depresses myocardial contractility during coronary angiography. Angiovist-370 (AV370) is a contrast medium similar to RG76 except the calcium sequestering agents sodium citrate and EDTA in RG76 have been replaced by calcium EDTA (an additive that does not bind additional calcium). To determine if the calcium sequestering agents contribute to the mechanical depression produced by ionic contrast media, this study compared the inotropic response of RG76 to that of AV370. Additionally, saline solutions containing sodium citrate + EDTA and calcium EDTA at concentrations found in the respective contrast media were also compared. In 10 open chest dogs the percent change and duration of the inotropic response following intracoronary injections of RG76 and AV370, as well as solutions of sodium citrate + EDTA and calcium EDTA were compared using Walton-Brodie strain gauges. Injections, 2 cc, of RG76 and AV370 produced a biphasic response characterized by an initial negative inotropic response followed by a more prolonged positive inotropic response. The magnitude (67 +/- 3% vs 59 +/- 2%; p less than 0.001) and duration (34 +/- 3 vs 24 +/- 2 sec; p less than 0.001) of the initial negative inotropic response was greater with RG76 than with AV370. The magnitude of the secondary positive inotropic response with RG76 was not different from that obtained with AV370 (31 +/- 12% vs 28 +/- 10%; p greater than 0.3). This positive response was not affected by beta-adrenergic blockage with 0.2 mg/kg of timolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Torsade de pointes: the long-short initiating sequence and other clinical features: observations in 32 patients

The clinical setting, precipitating factors, electrocardiographic features and response to treatment of 32 patients with torsade de pointes were reviewed. Thirty-one patients had underlying cardiac disease and 30 patients had a previous underlying cardiac arrhythmia. Antiarrhythmic medications, often in association with electrolyte abnormalities (such as hypokalemia and hypomagnesemia) were the most common precipitating factors. In 22 of 26 patients, the serum drug levels of the antiarrhythmic agents were found to be within the therapeutic range. However, before the administration of agents known to prolong the QT interval, 20 of the 32 patients had, either alone or in combination, baseline prolongation of the QT interval, hypokalemia or hypomagnesemia. All patients had QTc interval prolongation (mean 0.59 second) immediately before the development of torsade de pointes. Marked lability of T wave morphology was frequently noted. Cardiac pacing was the only consistently effective mode of therapy. A characteristic long-short ventricular cycle length as the initiating sequence was found in 41 of 44 episodes of torsade de pointes. Reported data support the high frequency of this electrocardiographic feature of torsade de pointes in which its onset could be analyzed. It is suggested that this electrocardiographic characteristic will aid in both establishing the diagnosis of torsade de pointes and distinguishing it from other polymorphic forms of ventricular tachycardia.

A survey of contrast media used in coronary angiography

In recent years, various contrast media have been developed for use in coronary angiography. These contrast media may be divided into ionic contrast media of high osmolality, those of low osmolality, and nonionic contrast materials. We conducted our own clinical studies with 40 patients. In random succession a standard contrast medium (ionic, of high osmolality) and a new-generation contrast medium (either nonionic or ionic with low osmolality) were injected into the right and left coronary arteries. After each injection we measured the systolic and diastolic blood pressure using a liquid-filled coronary catheter. In addition, the change in the length of the cardiac cycle was registered in terms of the R-R interval (in ms) and at the same time, leads I, II, and III of the ECG were recorded. We studied the influence of the various contrast media on the activity of ATPase in in vitro experiments, using Lasser and Lang's [30]. When ionic contrast media of low osmolality and nonionic contrast media were utilized the heart rate showed no change. Disturbances of rhythm such as ventricular tachycardia or fibrillation were not observed. All of the contrast media used produced the same ECG changes. These changes can be ascribed to the inhibition of ATPase. The arterial blood pressure was lowered significantly only by ionic contrast media of high osmolality only.

How safe is the coronary angiogram?

The pertinent literature on complications of selective coronary angiography has been reviewed. Three reports that describe the incidence of major complications in large patient groups are presented for comparative analysis of their results and used as a baseline for consideration of factors that may affect variations between the actual and reported rate of complications. It is recommended that agreement be reached on formulating national standards for the performance of the examination, taking into account the best data available.

Symptomatic spontaneous paroxysmal AV nodal block due to localized hyperresponsiveness of the AV node to vagotonic reflexes

Two apparently healthy patients had recurrent syncope with documented paroxysmal AV block. In both patients the site of AV block was demonstrated to be in the AV node. Coronary angiography (in both patients) and sustained deep inspiration (one patient) reproducibly initiated episodes of paroxysmal AV nodal block (identical to spontaneous episodes). Atropine abolished further attempts of AV block induction. Vagal hyperresponsiveness was limited to the AV node, since the interventions provoking paroxysmal AV nodal block produced only appropriate sinus slowing. This syndrome reflects hyperresponsiveness of the AV node to vagotonic reflexes, and exists as a clinically significant entity producing recurrent syncope.

Differential effects of Renografin-76 on the ischemic and nonischemic myocardium

The effects of intracoronary diatrizoate meglumine and diatrizoate sodium (Renografin-76) on regional contraction were examined in the normal coronary circulation and during partial (50 percent) coronary occlusion in 11 dogs using strain and length gauges. Intracoronary injections of Renografin-76 (1.5 cc) (1.690 mosM/liter; 0.19 mEq Na/ml), equiosmolar dextrose solution and 0.19 mEq Na+/ml saline solution were made randomly. Renografin-76 caused a decrease in preejection tension to 87.4 +/- 4.3 percent (p less than 0.025), total tension to 74.6 +/- 3.3 percent (p less than 0.01) and ejection tension to 11.9 +/- 12.6 percent (p less than 0.001) of control value. Segment length increased to 106.7 +/- 7.3 percent of control value. These changes lasted only 12 +/- 2 (range 5 to 20) seconds (mean +/- standard error of the mean). During partial coronary occlusion and after injection of Renografin-76, preejection tension decreased from 91.7 +/- 6.3 to 53.8 +/- 3.9 percent (p less than 0.01), total tension from 89.9 +/- 5.0 to 59.7 +/- 3.5 percent (p less than 0.01) and ejection tension from 22.8 +/- 8.1 to 17.8 +/- 10.9 percent, whereas segment length increased from 112.7 +/- 3.7 to 130.7 +/- 4.6 percent (p less than 0.01) of control value. In contrast to findings in the normal coronary circulation, tension and length changes lasted 54 +/- 16 (range 15 to 180) seconds (p less than 0.05). The hyperemic response during normal coronary circulation was completely abolished during partial coronary occlusion. Prior administration of nitroglycerin did not shorten the duration of the myocardial depressant effects of Renografin. Injections of equiosmolar dextrose or saline solution produced qualitatively similar but quantitatively less marked changes. Thus, intracoronary Renografin-76 has an accentuated and prolonged depressant effect on the ischemic as compared with the normally perfused myocardium; this effect is not solely due to its hyperosmolarity or sodium concentration.

Prevention of contrast-induced bradycardia during coronary angiography

A double-blind study of 90 patients undergoing coronary angiography was performed to determine the safety and efficacy of 0.6 mg atropine sulfate in preventing contrast-induced bradycardia. Coronary angiography performed using the Sones technique resulted in ventricular pauses of greater than 2 seconds in 3 of 49 patients (6%) who received prophylactic atropine and 20 of 41 patients (49%) receiving placebo. Though the pauses were usually due to atrial asystole, 26% of those with greater than 2 second pauses did so because of transient complete heart block. Prophylactic atropine did increase resting heart rate but did not cause other arrhythmias or increase the frequency of angina pectoris despite the presence of severe coronary disease. Our data indicate that contrast-induced asystole is very common, cannot be predicted by consideration of "precatheterization data," and can be prevented effectively and safely by use of prophylactic atropine sulfate.

Role of peripheral vasodilation in the hypotensive response to left ventriculography in anesthetized dogs

Hypotension after left ventriculography (LVG) is believed to result from direct myocardial toxicity, peripheral vasodilation, or a combination of both. The contribution of each has not been established. Thus, LVG was performed in anesthetized dogs under conditions in which peripheral vascular reactivity (PVR) was altered pathophysiologically (aortic coarctation) or pharmacologically (acetylcholine infusion). Ventricular pressure (LVP), its first derivative (dP/dt), aortic pressure (AoP), and carotid and femoral flows were monitored. When PVR was normal, LVG was associated with significant hemodynamic changes which reached a maximum 25-35 seconds after injection. Left ventricular and aortic diastolic pressures were decreased by 22 and 48%, whereas carotid and femoral systolic flows were increased by 41 and 59%. During acetylcholine infusion, LVG did not cause systolic hypotension and peripheral flows were maintained strikingly constant. Similarly, LVG also was associated with insignificant changes in systolic pressures and carotid flow in the presence of aortic coarctation. These results demonstrate that the hypotension attendant with LVG is directly related to the augmentation in peripheral flow, suggesting that the response is mediated almost exclusively by peripheral vasodilation.

Complications of coronary arteriography: a follow-up report

A nationwide survey of complications due to coronary arteriography during 1973--74 yielded responses from 176 hospitals (89,079 coronary arteriograms). The overall mortality rate was 0.14% (brachial, 0.12%; femoral, 0.16%). In the brachial group, the mortality rate was three times as high for non-heparinized as for heparinized patients. In institutions performing fewer than 100 examinations per year, the combined incidence of death, myocardial infarction, and cerebral embolism was five times higher than in institutions performing more than 400 examinations per year. Left main coronary artery or three-vessel disease was present in most patients who died of the procedure. Compared to a previous survey of 1970--71, there was a profound decrease in significant complications (including death, myocardial infarction, and cerebral embolism) and entry site complications such as thrombosis. A reduction in mortality with the femoral technique since 1971 was not accounted for by heparinization and may reflect increasing experience with the method and shorter angiographic times.

Contrast media during coronary arteriography: electrocardiographic changes in the presence of normal coronary arteries

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.

Vectorcardiographic changes at selective coronary angiography. Comparison of two contrast media

Vectorcardiography revealed typical changes following routine selective coronary angiography using Urografin 60% and Isopaque Coronar; the response was dose-dependent. The two contrast media compare well with one another, no statistical difference being recorded, indicating that there is no difference in myocardial toxicity.

Sinus slowing produced by intracoronary arterial injections of hyperosmotic solutions in man

The effect of intracoronary arterial injections of normal saline, contrast agent, hyperosmotic glucose, and mannitol solutions on the sinus rate was studied in 18 patients. Sinus slowing was not produced by isosmotic saline (0.3 Osm. per kilogram of water) when injected into either coronary artery, whereas 76% Urografin (1.9 Osm. per kilogram of water), 20% glucose (1.3 Osm. per kilogram of water), and mannitol (1.2 Osm. per kilogram of water) decreased the sinus rate significantly (P less than 0.001). Among these solutions, Urografin with the highest osmolality produced the most marked sinus slowing, whereas no significant difference was detected between change in the sinus rate with hyperosmotic glucose and mannitol solutions (P greater than 0.5). Moreover, there was no significant difference between the degree of sinus slowing produced by intracoronary injections into the coronary artery of the side which the sinus node artery originated from and the slowing produced by contralateral injections with hyperosmotic solutions (P greater than 0.2). Therefore, it seems unlikely that this sinus slowing would be a result of a direct action on the sinus node including hypoxia and elevated perfusion pressure. Reflex-mediated parasympathetic stimulation may be operative.

Effects of coronary arteriography on atrioventricular conduction. Studies with His bundle electrography

The effect of coronary arteriography on atrioventricular (A-V) conduction was studied in 26 patients with the use of His bundle electrography. Slowing of atrioventricular conduction (prolonged A-H interval) was observed in all 26 pateints following either left or right coronary arteriography without a detectable change in the H-V interval. In four patients with left coronary preponderance in arterial distribution pattern, prolonged A-H inverval was produced only by injecting the contrast material into the left coronary artery. Conversely, in the remaining 22 patiens either with right preponderance or balanced distribution, prolongation of the A-H time was a result of opacification of the right coronary artery. The A-H interval at peak prolongation (133.9 +/- 18.7 [S.D.] msec.) was significantly higher than the control measurement (98.3 +/- 15.7 msec.) (P less than 0.0001). Prolongation of the A-H interval started around 4 seconds after the initiation of injection, reached its peak at an average of 7.7 seconds, and subsided within 20 seconds. When intracoronary injection of 6 ml. of normal saline was made in these 26 patients, no change was observed in the His bundle electrograms. On the other hand, hypertonic (20 per cent) glucose solution, when injected into coronary arteries, had an effect remearably similar to that of contrast material on A-V conduction. These findings suggest that prolonged A-H interval observed during coronary arteriography may be a result of osmotic effect of the contrast material, rather than hypoxia resulting from dilution of coronary blood flow.

Mechanism of the bradycardia during coronary angiography

Bradycardia occurring during coronary angiography may be due to the direct effect of dye or to reflex vagal effects on pacemaker centers. Fifteen patients were classified according to the origin of the sinus nodal and atrioventricular nodal arteries. In patients with type A anatomy, both the sinus and the atrioventricular nodal arteries arose from the right coronary artery. In those with type B anatomy, only the atrioventricular nodal artery arose from the right coronary artery. Heart rate recordings were made during coronary angiography before and after selective infusion of atropine (0.2mg) into the right coronary artery. In type A patients, the sinus bradycardia observed during right coronary dye injection was caused by a combination of both direct and reflex effects on pacemaker tissue. Sinus bradycardia occurring with left coronary dye injections was entirely reflex in nature and was completely blocked with right coronary arterial injection of atropine. In type B patients, sinus bradycardia with right coronary dye injections was produced by reflex suppression of the sinus pacemaker. A junctional rhythm was consistently produced after administration of atropine. Junctional bradycardia in type B patients was caused by direct suppression of the junctional pacemaker. Thus, angiographic dye appears to decrease heart rate by a direct effect on pacemaker tissue and by reflex vagal suppression of the sinus pacemaker.

Mechanisms mediating bradycardia during coronary arteriography

Cardiac slowing occurring during diagnostic coronary arteriography was studied in 78 patients. Comparable degrees of slowing occurred with injections into the right and into the left coronary arteries into the contralateral artery, and with injections into the coronary artery giving rise to the sinus node artery and into the contralateral artery. Rapid intracoronary injections of isosmotic dextrose solution produced significantly less slowing than comparable injections of contrast medium. Slow injections of contrast medium produced cardiac slowing comparable to that caused by rapid injections of contrast medium. However, the cardiac slowing was significantly greater than that produced by rapid injections of dextrose solution. Inhalation of 100% oxygen did not alter the heart rate response to injections of contrast medium. Atropine produced dose-related attenuation of cardiac slowing. Bradycardia persisting after cholinergic blockade was significantly greater after injections into the coronary artery supplying the sinus node than it was after injections into the contralateral artery. Coronary arteriography produced transient, occasionally profound, arterial hypotension in 38 of 41 patients in whom arterial pressures were recorded. Arterial pressure did not change in three patients. This study suggests that the cardiac slowing which occurs during coronary arteriography in man is due primarily to a cholinergic reflex which may be a human counterpart of the Bezold-Jarisch reflex, observed heretofore only in experimental animals. This slowing appears to be mediated primarily by receptors sensitive to contrast medium, rather than by changes of coronary artery pressure, and secondarily, by direct depression of sinus node function by contrast medium.

The complications of coronary arteriography

A nationwide survey was undertaken to determine the rate of complications due to coronary arteriography during 1970-71. The responses from 173 hospitals-including a total of 46,904 coronary arteriograms-were analyzed in relationship to the technique employed and to the number of examinations performed at each hospital during the two-year period. The overall mortality rate was 0.45% (brachial 0.13%, femoral 0.78%). The mortality rate in institutions performing fewer than 200 examinations per two years was eight times higher than in institutions performing more than 800 examinations per two years. Similarly, the incidence of myocardial infarction and cerebral embolism was significantly higher when a smaller number of examinations was performed. The incidence of major complications-including death, myocardial infarction, and cerebral embolism-was higher in examinations using the femoral approach than the brachial approach. The incidence of arterial thrombosis and contrast agent reactions was higher for the brachial approach. Factors which may help to explain these differences are considered and discussed.

Cardiac performance after diagnostic coronary arteriography

Cardiac performance was assessed before and after diagnostic coronary arteriography in 19 patients with heart disease. There was no significant change in cardiac output, heart rate, stroke volume, hemoglobin, hematocrit, and mean systemic arterial pressure. Left ventricular (LV) filling pressure and mean pulmonary artery pressure increased temporarily. The increased left ventricular filling pressure was accompanied by an increase of LV work performed in a few patients; in the remainder the left ventricle performed less work.

In four dogs, selective left coronary arteriography resulting in increased ventricular filling pressure, was accompanied by an increase of left ventricular end-diastolic (V ED ) and stroke volumes; the ejection fraction and heart rate remained unchanged.

If the animal studies (increased V ED accompanying increased ventricular filling pressure) can be applied to patients with heart disease, the alteration of left ventricular function can be considered on the basis of the Frank-Starling mechanism. To cope with the temporary depression of its function, the left ventricle of patients with heart disease utilized the Frank-Starling mechanism resulting in an adequate (essentially unchanged) cardiac output from an increased left ventricular filling pressure. The normal left ventricle of the dog, stressed more than is appropriate clinically, shows an increased stroke volume accompanying the increased end-diastolic volume.

Evaluation of contrast media used in coronary arteriography

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