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Registry data suggests that bifurcation lesions are associated with reduced success during percutaneous revascularization. We studied 1012 CAVEAT patients to compare procedural outcomes in patients with and without bifurcation lesions whose target vessel was treated with either atherectomy or angioplasty. Bifurcation lesions have increased angiographic complexity and interventions on them are associated with lower acute procedural success rates compared to non-bifurcation lesions. Subgroup analysis suggests that atherectomy treatment of bifurcation lesions improves acute procedural success rates and lowers restenosis rates compared to angioplasty treatment of bifurcation lesions but atherectomy of bifurcation lesions is associated with higher acute complication rates than angioplasty of bifurcation lesions.

Exercise-induced bundle branch block is an uncommon electrocardiographic entity said to be associated with coronary heart disease. Thirty-seven patients were studied to determine if exercise hemodynamics and stress/rest thallium scans could identify those patients with coronary heart disease. Eighteen patients of the study group also had coronary angiography. Group I (n = 17) with normal thallium scans and group II (n = 20) with abnormal thallium scans had significantly different maximal heart rate, maximal blood pressure, and double product in exercise as well as duration of exercise. Clinical evaluation of the patient study group permitted a division of the patients into two subgroups: group A, atypical chest pain or abnormal exercise electrocardiogram (n = 12), and group B, definite or probable angina (n = 25). Group B patients had significantly more abnormal thallium scans (17/25) than group A patients (3/12) (p less than 0.04). When compared to coronary angiography, stress/rest thallium scans had a predictive accuracy of 85% for coronary heart disease. While exercise-induced ST-segment depression and R wave amplitude increases are not specific in exercise-induced bundle branch block, exercise hemodynamics and stress/rest thallium scans can help diagnose patients with coronary heart disease. These test findings added to a clinical evaluation permit a more accurate stratification of the patients and indicate which patients need further study.

Spontaneous contrast in the left ventricle is an unusual entity. We retrospectively studied 16 patients who were found to have spontaneous contrast present on two-dimensional echocardiograms, specifically noting their clinical characteristics, the reproducibility of this phenomenon, the presence of thrombi and embolic events, and prognostic implications. Diagnoses included ischemic heart disease in nine patients, dilated cardiomyopathy in six patients, and hypertensive cardiomyopathy in one patient. The mean ejection fraction was 17.6%. There were six thromboembolic events in four patients. The spontaneous contrast was reproducible for periods of time up to 39 months. Patients who had improvement in their left ventricular dysfunction or who underwent aneurysmectomy had disappearance of the spontaneous contrast. Those patients who had spontaneous contrast reproduced on subsequent echocardiograms did not seem to have a worse prognosis than patients with similarly depressed ventricular function, but a larger study is necessary to verify this.

Electrophysiological testing was performed in 100 consecutive patients with spontaneous asymptomatic nonsustained ventricular tachycardia, chronic coronary artery disease, and ejection fraction of less than 40%. Fifty-seven patients without inducible sustained ventricular arrhythmias were discharged on no antiarrhythmic therapy. Sustained monomorphic ventricular tachycardia was induced in 37 patients, and polymorphic ventricular tachycardia or ventricular fibrillation was induced in six patients. Of the 43 patients with inducible sustained ventricular arrhythmias, three had spontaneous cardiac arrest during serial drug testing and were excluded from further analysis. Twenty patients were discharged on drug therapy, resulting in suppression of inducible sustained ventricular arrhythmias. The remaining 20 patients with persistently inducible sustained arrhythmias were discharged on drug therapy, resulting in maximal rate slowing of the induced tachycardia. During a mean follow-up of 16.7 months, there were 10 recurrent cardiac arrests or sudden deaths. The 1- and 2-year actuarial incidence of these events was 2% and 6%, respectively, in patients without inducible sustained ventricular arrhythmias; 0% and 11%, respectively, in patients in whom inducible arrhythmias were suppressed; and 34% and 50%, respectively, in patients with persistently inducible sustained ventricular arrhythmias. Multivariate Cox analysis identified only the persistence of inducible sustained ventricular arrhythmias as a significant independent predictor of sudden death or recurrent sustained arrhythmias (p less than 0.001; relative risk, 3.5; 95% confidence intervals, 2.1-4.9). In this population, therapeutic intervention to prevent sudden death is unnecessary in patients without inducible sustained ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of contrast media on coagulation has an important association with thromboembolic complication during coronary angiography. In this study, whole blood was methodically mixed with nonionic contrast medium, Iohexol (IOH), conventional ionic contrast medium, Hypaque-76 (H76), and low osmolar ionic dimer Hexabrix (HB) in vitro. The thrombotic propensity of contrast agents can be evaluated by measuring the clot formation of the mixtures. The experiments were repeated with whole blood after systemic heparinization. In the in vitro study, 5 ml of canine (N = 10) and 3 ml of human (N = 11) whole blood was incubated for 30 min in glass tubes with equal volumes of IOH, H76, HB, and 0.9% NaCl before heparinization. Clot formation with IOH and 0.9% NaCl were seen both in dogs (4.0 +/- 0.7 gm and 5.6 +/- 0.8 gm) and in patients (1.4 +/- 0.9 gm and 2.9 +/- 1.3 gm), whereas no clot was seen with H76 or XB. Following heparinization, no clot was visualized in any mixture of whole blood with contrast media or 0.9% NaCl. Similar results were observed in the catheter-syringe system with canine blood (N = 11) mixed with the contrast agents. Blood clots found in 15 min and 30 min of IOH were 0.07 +/- 0.08 gm and 0.44 +/- 0.20 gm (P less than 0.01) and of NaCl were 0.29 +/- 0.37 gm and 0.69 +/- 0.38 gm (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The successful use of Fogarty catheter embolectomy combined with aortocoronary vein bypass graft in 4 patients with an acute myocardial infarction is presented. Three patients sustained acute occlusion of the coronary artery secondary to an embolus during cardiac catheterization. In the fourth patient, the left anterior descending coronary artery was occluded with a fragment of calcium debris during aortic valve replacement. All patients survived the operation. Acute occlusion of the coronary artery secondary to an embolus is uncommon, but its early recognition and appropriate surgical management may be lifesaving.

To study the role of the adrenergic nervous system in the genesis of nonlethal reperfusion arrhythmias, the proximal left anterior descending coronary artery was occluded for either 1 or 3 hours in 48 open-chest dogs anesthetized with alpha-chloralose. Heart rate was controlled (90 to 110 beats/min) by bilateral vagotomy and continuous right vagal stimulation. Dogs were treated with either saline, timolol (0.1 mg/kg), or prazosin (0.5 mg/kg) 15 minutes prior to reperfusion. Reperfusion after 1 hour of occlusion in saline-treated dogs evoked sustained polymorphic ventricular tachycardia (204 +/- 9 beats/min) that reverted to sinus rhythm by 15 minutes of reperfusion. The maximum rate of ventricular tachycardia was significantly reduced by both prazosin and timolol. Both drugs also caused about a 50% reduction in the total number of ectopic beats in the first 10 minutes of reperfusion. With a 3-hour occlusion, reperfusion in saline-treated dogs caused sustained polymorphic ventricular tachycardia (135 +/- 15 beats/min) which persisted for several hours. Neither timolol nor prazosin significantly altered the ventricular ectopic rate in these dogs. Furthermore, bilateral stellate transection, left stellate stimulation, isoproterenol (0.5 mg/kg), or methoxamine (100 ug/kg) all failed to alter the ventricular ectopic rate in the saline-treated dogs. Ventricular ectopy induced by reperfusion after a 1- or 3-hour occlusion was overdriven in all dogs by rapid atrial pacing. The results suggest that the nature of reperfusion-induced ventricular ectopy is highly dependent upon the preceeding duration of coronary occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

To determine if the sympathetic nervous system exerts an arrhythmogenic effect on the ischemic myocardium independent of heart rate, the proximal circumflex coronary artery was occluded for 1 h in 62 open-chest, anesthetized dogs. The atrial rate was maintained at 200/min, and the vagosympathetic trunks were transected in all dogs. The total incidence of ventricular fibrillation was 35% in 20 dogs with intact stellates and not significantly different from the incidence of ventricular fibrillation (15%) in another 20 dogs in which both stellate ganglia had been decentralized. Electrical stimulation of the left ansae subclavia (3 Hz, 2 ms, 6-8 V) in the remaining 22 dogs significantly increased the incidence of ventricular fibrillation to 73% (P less than 0.05). The magnitude of S-T segment elevation in the lead II electrocardiogram 90 s after occlusion was 0.69 +/- 0.08 mV in the group with left ansae stimulation and significantly elevated (P less than 0.01) compared with dogs with intact stellates (0.35 +/- 0.06 mV) and with the denervated dogs (0.19 +/- 0.05 mV). The data indicate that the sympathetic nervous system is capable of a direct arrhythmogenic influence on the ischemic myocardium independent of heart rate. The rate-independent arrhythmogenic effects of the sympathetic nervous system may be mediated by an increase in severity of the ischemic insult.

The effect beta blockers (BB) may have on the sensitivity of the thallium treadmill test (Th-TMT) is controversial. The purpose of this study was to test the hypothesis that BB decrease the sensitivity of the Th-TMT. Two hundred three patients over a two-year period were identified who satisfied the following criteria. All had symptom-limited upright treadmill exercise tests with stress and redistribution thallium imaging, as well as coronary angiography within two months of the Th-TMT. Of 58 patients with CAD not on BB, 52 had an abnormal Th-TMT scan (sensitivity 90 percent). In comparison, the sensitivity of the Th-TMT scan in the 88 patients with CAD receiving BB was 76 percent (p less than 0.05). We conclude that BB may significantly decrease the sensitivity of the Th-TMT. Physicians should fully appreciate the higher false negative rate (24 vs 10 percent) for patients on BB and consider cautious withdrawal prior to diagnostic studies.

Intraaortic balloon counterpulsation (IABC) was used in 40 patients who developed left ventricular pump failure following surgery for ischemic heart disease. The IABC was inserted in the operating room in 32 patients, and within 36 hours of surgery in eight patients. Four patients could not be weaned from cardiopulmonary bypass and died in the operating room. Of the other 36 patients, eight died while on IABC. Twenty-eight patients (70%) were successfully weaned from IABC, although six died later in hospital. Twenty-two patients (55%) survived hospitalization. No late deaths have occurred at 5-33 months of follow-up (mean 16-4 months). Twenty (91%) of 22 survivors are Class I or II at time of this report. Postoperative pump failure occurs because of perioperative acute myocardial infarction and/or major preoperative left ventricular dysfunction. Patients with perioperative infarction who have no prior left ventricular dysfunction have a significantly lower mortality (14%) than do those patients with preoperative left ventricular dysfunction who have subsequent acute perioperative infarction (mortality 67%) P less than 0.05.

The effects of orally administered indomethacin or placebo on coronary hemodynamics were studied in 23 patients with coronary artery disease. After indomethacin administration the systemic arterial pressure increased by 12 +/- 4% and the myocardial oxygen consumption by 24 +/- 11%. Coronary sinus flow did not change and coronary vascular resistance increased slightly. Oxygen saturation of the arterial blood did not change, but coronary sinus saturation decreased substantially. Hemodynamic values returned to normal 150 minutes after administration of indomethacin. During rapid atrial pacing, coronary sinus flow increased 79 +/- 14% above the rest value when pacing was done before indomethacin administration; only a 56 +/- 12% increase was seen when pacing was repeated after indomethacin. Peak heart rate achieved during atrial pacing, severity of angina and the degree of ST-segment depression were not altered by indomethacin treatment. Orally administered indomethacin has a mild coronary vasoconstrictive effect that does not interfere substantially with the expected increase in myocardial blood flow during rapid atrial pacing. Anginal threshold is not altered by orally administered indomethacin.

To examine the role of adrenergic influences on genesis of ischemic and reperfusion arrhythmias, the left anterior descending coronary artery (LAD) was cannulated and perfused by a shunt from the left carotid artery in 38 open-chest pentobarbital-anesthetized dogs. Ischemia was produced by shunt occlusion and retrograde diversion of collateral flow from the LAD. The diverted blood was collected and returned to the animal by intravenous (i.v.) injection. The shunt was opened and the ischemic myocardium reperfused after 30 min of ischemia. Microsphere injections in six dogs during shunt occlusion and retrograde bleeding showed that blood flow to the ischemic zone was less than 1.5% of normal zone flow. The remaining 32 dogs were randomized into four treatment groups. Dogs (n = 8) were treated before shunt occlusion with either saline, nadolol (1 mg/kg), prazosin (0.2 mg/kg), or bilateral stellate transection. As compared with saline treatment, nadolol and stellate transection significantly reduced heart rate (HR), and prazosin significantly reduced mean arterial blood pressure (MAP) (p less than 0.05). However, none of the antiadrenergic interventions significantly reduced the number or frequency of ectopic beats during either the 1a or 1b phases of ischemia. None of the 32 dogs developed ventricular fibrillation (VF) during ischemia, but all dogs fibrillated within 30 s of reperfusion. The size of the ischemic zone ranged from 21 to 38% of the left ventricle, and there were no differences among the four treatment groups. The results suggest that when ischemia is severe, the adrenergic nervous system does not play a significant role in genesis of ischemic-induced ectopy or reperfusion-induced VF.

In order to gain understanding of how percutaneous transluminal coronary angioplasty (PTCA) is taught and practiced in the United States, two questionnaires were devised to survey all adult cardiology training programs and all adult cardiac catheterization laboratories in this country. Of the 184 programs that responded to the training questionnaire, 102 (55%) teach PTCA, usually in the form of fellowship training and especially as a specialized year, and less commonly in the form of a preceptorship. Though many programs expose trainees to an adequate number of cases as defined by the program directors, at least 37% do not. Of 388 laboratories responding to the practice questionnaire, 74% perform PTCA. The total number of PTCA's in this country seems to be doubling yearly, but many laboratories do relatively few cases per year, and 79% of physicians doing PTCA do fewer than one case per week. Average laboratory success rate for PTCA is in the range of 80-85%. Though there is now a proliferation of PTCA training programs, 93% of those practicing angioplasty are self- or preceptor-trained, and have not learned the procedure as part of a fellowship.

Thirty-nine patients underwent coronary arteriography 1 to 20 months (mean 7 months) after percutaneous transluminal coronary angioplasty (PTCA). At the time of the repeat study, 35 patients (90%) had recurrent angina or myocardial infarction, and 4 patients (10%) were asymptomatic. Restenosis, defined as greater than 50% loss of PTCA gained diameter, was found in 19 patients (49%). In addition, 20 patients had new lesions or marked progression of existing lesions (defined as greater than 20% or increasing greater than 20% obstruction in coronary diameter) in the previously normal or mildly diseased coronary segments. The new or progressive lesions occurred both in patients with restenosis at the PTCA site (nine of 19) and in patients without restenosis (11 of 20). New or progressive lesions tended to occur more commonly in the artery on which PTCA was performed (13 of 40) than in the artery that did not have PTCA (10 of 77) (p less than 0.02 by chi 2). In arteries that had PTCA, new or progressive lesions occurred more often in the segment proximal to the angioplasty site (seven of 13 or 54%) than in the peri-PTCA segment (two of 13 or 15%) and in the segments distal to it (four of 13 or 31%), but this observation did not reach statistical significance. No other clinical, angiographic, or PTCA procedure variables affected the occurrence of new or progressive lesions. In patients with recurrent angina or myocardial infarction after PTCA, both restenosis and new or progressive lesions are common. New lesions or marked progression of existing lesions tended to occur in the vessel subjected to PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

A total of 145 patients with greater than 50% obstruction of the left main coronary artery (LMC) were studied by coronary arteriography. Of the 140 who survived cardiac catheterization, 121 were considered operable by coronary arteriography, and 19 were inoperable. Of the 121 operable patients, 32 were treated medically, and 89 had aortocoronary bypass surgery. Surgical mortality was 11%. The follow-up was from 1 to 72 months with a mean follow-up of 15 months. A survival table was plotted over a 24-month period. At 90 days survival in surgical patients was 85%, medical patients 72%, and inoperable patients 64%. At one year 82% of surgical patients were alive compared with 61% of medically treated operable patients (P less than 0.05). Thereafter, the survival rate remained stable up to 23 months. Survival in inoperable patients was 38% at one year. Improved surgical survival was associated with the presence of preoperative collateral vessels and a left ventricular stroke index greater than 18 g-m/m2. The study demonstrates that survival is improved significantly by surgery in LMC patients. Since mortality occurs early after coronary arteriography, surgery should be offered early to operable patients.