Exertional syncope in a patient with aortic stenosis and right coronary artery disease

A female with advanced aortic valvular stenosis and moderate right coronary artery disease experienced an exertional syncope during 24-h ambulatory electrocardiographic monitoring. A progressive bradycardia with 90-s sinus node arrest (cardio-inhibitory response) and premonitory angina pectoris with significant ST segment changes were demonstrated. Our report supports the concept of a neurocardiogenic (vasovagal) mechanism of exertional syncope in patients with aortic stenosis. The predominant left ventricular inferior-wall myocardial ischaemia in our patient might be an additional stimulus to left ventricular mechanoreceptors, resulting in a profound cardio-inhibitory response.     

Effects of prostacyclin on myocardial hemodynamics and metabolism after coronary artery bypass grafting

OBJECTIVE: To evaluate the impact on clinical behavior of a 3-day workshop designed to increase trainees' rates of smoking cessation counseling and reminders about Pap smears in routine consultations. DESIGN: Randomized control trial. SETTING: Accredited teaching practices of the Royal Australian College of General Practitioners' Training Program. SUBJECTS: Thirty-four trainees and 1,500 consecutive adult patients ages 16-65 years. METHOD: Trainees randomly allocated to the experimental group participated in a 3-day interactive workshop on disease prevention during their 13-week family medicine term. Audiotapes of consultations with adults conducted by trainees at the beginning and end of the rotation were analyzed blind to compare assessment of patients' smoking status and, for women, date of last Pap smear. A questionnaire mailed to each patient after the consultation also allowed identification of smokers and women overdue for a smear. Consultations with these patients at risk were analyzed for preventive counseling. Inter- and intrarater reliability was calculated for audiotape analysis. RESULTS: Preworkshop rates of questions about smoking were low, occurring in 22% of consultations. While trainees allocated to the experimental workshop were more likely to ask a routine question about smoking at the end of the term than those in the control group (P = 0.01), two-thirds of smokers remained undetected irrespective of trainee group and fewer than one in five were advised to stop smoking. Reminders about Pap smears did not change as a result of training and remained low in fewer than 20% of consultations. kappa values demonstrated high reliability of audiotape analysis. CONCLUSION: This direct measurement of clinical behavior revealed that low levels of preventive care provided by trainees are resistant to skills training without reinforcement in clinical practice. In view of the importance of prevention in routine consultations, we recommend continued evaluation of more intensive educational programs. Those withstanding rigorous evaluation could be considered for implementation in similar training contexts seeking to improve the frequency and quality of disease prevention in primary medical care.     

The dose-dependent effects of halothane on right ventricular contraction pattern and regional inotropy in swine

The right ventricle (RV) is comprised of two embryologically distinct units, the inflow and outflow tracts, which normally contract sequentially and differ in the magnitude of increased inotropy during sympathetic nervous stimulation. The present study examined the dose-response effects of halothane on the RV contraction pattern and regional contractility in seven open-chest pigs instrumented for measurement of inflow and outflow tract pressures and segment lengths. The RV contraction pattern was evaluated by comparing the phase of inflow and outflow tract shortening, and regional contractility was determined by calculation of preload recruitable stroke work (PRSW) slope. Using this methodology, an inflow-outflow tract contraction phase difference of -27 degrees (inflow tract shortened earlier) was evident at baseline, but was abolished by 1.0 and 1.5 minimum alveolar anesthetic concentration (MAC) halothane; PRSW slope of both the inflow and outflow tracts, however, demonstrated similar dose-related change. To determine whether alterations in cardiac sympathovagal balance played a role in the RV response to halothane, an additional four animals were studied after pretreatment with hexamethonium, propranolol, and atropine. In these animals, there was no difference in the regional contraction phase either at baseline or during halothane administration, and dose-related depression of PRSW by halothane was again similar in both regions. However, when halothane effects on regional PRSW in animals with autonomic blockade were compared to those of neurally intact animals, a 20% greater depression of outflow tract PRSW by 0.5 MAC halothane was evident. This study demonstrates that halothane abolishes the normal sequential pattern of RV contraction without exerting markedly variant negative inotropic effects within different regions of the RV, and provides evidence to suggest that alterations in cardiac sympathovagal balance may contribute to the effect of halothane on RV contraction dynamics.     

Enhanced detection of proximal right coronary artery stenosis with the additional analysis of right ventricular thallium-201 uptake in stress scintigrams

The value of right ventricular thallium-201 analysis in detecting proximal right coronary artery stenosis in exercise myocardial scintigraphy was analyzed in 52 patients, 27 with and 25 without proximal right coronary artery stenosis. For the detection of proximal right coronary artery stenosis, the sensitivity and specificity of thallium scintigraphic analysis were 59 and 88% for a right ventricular abnormality, 67 and 68% for a left ventricular inferior wall abnormality, and 93 and 56% for an abnormality of either. When both right and left ventricular thallium images were abnormal, all 9 patients had proximal right coronary artery stenoses, and when both were normal, 26 of 28 patients had a normal proximal right coronary artery. The sensitivity and specificity of blood pool scintigraphic variables during exercise (right ventricular ejection fraction and left ventricular inferior wall motion) were not significantly different for detection of proximal right coronary artery stenosis. Thus, the additional analysis of the right ventricle on thallium-201 stress scintigrams can improve the detection of proximal right coronary artery stenosis. When both right ventricular and left ventricular thallium scintigrams are abnormal (or normal), the ability to predict the presence (or absence) of proximal right coronary artery stenosis is very high.     

Effects of critical coronary stenosis on global systolic left ventricular function quantified by pressure-volume relations during dobutamine stress in the canine heart

OBJECTIVES: In this study we quantified the effects of a critical coronary stenosis on global systolic function using pressure-volume relations at baseline and during incremental dobutamine stress. BACKGROUND: The effects of coronary stenosis have previously been analyzed mainly in terms of regional (dys)function. Global hemodynamics are generally considered normal until coronary flow is substantially reduced. However, pressure-volume analysis might reveal mechanisms not fully exposed by potentially load-dependent single-beat parameters. Moreover, no systematic analysis by pressure-volume relations of the effects of dobutamine over a wide dose range has previously been presented. METHODS: In 14 dogs left ventricular volume and pressure were measured by conductance and micromanometer catheters, and left circumflex coronary flow by Doppler probes. Measurements in control and with left circumflex stenosis were performed at baseline and at five levels of dobutamine (2.5 to 20 microg/kg/min). The end-systolic pressure-volume relation (ESPVR) dP/dtMAX vs. end-diastolic volume (dP/dtMAX - V(ED)) and the relation between stroke work and end-diastolic volume (preload recruitable stroke work [PRSW]) were derived from data obtained during gradual caval occlusion. RESULTS: In control, dobutamine gradually increased heart rate up to 20 microg/kg/min, the inotropic effect blunted at 15 microg/kg/min. With stenosis, the chronotropic effect was similar, however, contractile state was optimal at approximately 10 microg/kg/min and tended to go down at higher levels. At baseline, the positions of ESPVR and PRSW, but not of dP/dtMAX - V(ED), showed a significant decrease in function with stenosis. No differences between control and stenosis were present at 2.5 microg/kg/min; the differences were largest at 15 microg/kg/min. CONCLUSIONS: Pressure-volume relations and incremental dobutamine may be used to quantify the effects of critical coronary stenosis. The positions of these relations are more consistent and more useful indices than the slopes. The positions of the ESPVR and PRSW show a reduced systolic function at baseline, normalization at 2.5 microg/kg/min and a consistent significant difference between control and stenosis at dobutamine levels of 5 microg/kg/min and higher.     

Effects of morphine and halothane anesthesia on coronary blood flow

This study was undertaken to determine the relative effects of morphine and halothane anesthesia on coronary blood flow. Right heart bypass was instituted in 20 dogs by draining the vena cava blood into a cardiotomy reservoir and returning it to the main pulmonary artery. Coronary sinus drainage was measured by a right ventricular cannula. Group I (10 dogs) was sequentially given 0.5, 1, 1.5, 2.0, and 2.5% halothane. Group II (10 dogs) was given 1, 2, 3, 4, and 5 mg per kilogram of morphine intravenously. Arterial pressure, coronary sinus blood flow, cardiac output, arterial pH, PCO2, and PO2 were determined and repeated at each dose level of anesthesia and compared to the control values. Morphine significantly increased coronary flow at 3, 4, and 5 mg/kg without pressure adjustment and at 2 mg/kg after pressure adjustment. Coronary flow with halothane was unchanged from control values except for a decrease at 2.5%. Coronary flow was significantly greater with 3, 4, and 5 mg/kg of morphine than with 1.0 and 1.5% halothane.     

Anomalous origin of the right coronary artery from the left anterior descending coronary artery

A 77-year-old male presented with a recent posterior myocardial infarction for coronary angiography. This angiogram revealed a rare, previously unreported anomalous origin of the right coronary artery from the proximal left anterior descending coronary artery distal to the first major diagonal branch.     

Effects of intraaortic balloon pumping on septal arterial blood flow velocity waveform during severe left main coronary artery stenosis

OBJECTIVES: We sought to evaluate the effect of intraaortic balloon pumping on the phasic blood velocity waveform into myocardium with severe coronary artery stenosis. BACKGROUND: In the presence of severe coronary artery stenosis, it is not clear whether intraaortic balloon pumping augments intramyocardial inflow during diastole or changes systolic retrograde blood flow from the myocardium to the extramural coronary arteries. METHODS: Using anesthetized open chest dogs (n=7), we introduced severe stenosis in the left main coronary artery to reduce the poststenotic pressure to approximately 60 mm Hg (>90% diameter stenosis). Septal arterial blood flow velocities were measured with a 20-MHz, 80-channel ultrasound pulsed Doppler velocimeter. Left anterior descending arterial flow, aortic pressure and poststenotic distal coronary pressure were measured simultaneously. The diastolic anterograde flow integral and systolic retrograde flow integral were compared in the presence and absence of intraaortic balloon pumping. RESULTS: Although intraaortic balloon pumping augmented diastolic aortic pressure, this pressure increase was not effectively transmitted through stenosis. Septal arterial diastolic flow velocity was not augmented, and left anterior descending arterial flow was unchanged during intraaortic balloon pumping. CONCLUSIONS: In the presence of severe coronary artery stenosis, intraaortic balloon pumping failed to increase diastolic inflow in the myocardium and did not enhance systolic retrograde flow from the myocardium to the extramural coronary artery. Thus, the major effect of intraaortic balloon pumping on the ischemic heart with severe coronary artery stenosis may be achieved by reducing oxygen demand by systolic unloading.     

Anomalous right coronary artery from the pulmonary artery in Taussig-Bing anomaly

The presence of associated anomalies in patients with double-outlet right ventricle can significantly alter surgical intervention. Preoperative delineation of these anomalies can facilitate surgical planning and improve outcome. We describe a case in which the right coronary artery and anterior descending coronary artery arose from the pulmonary artery in a patient with double-outlet right ventricle with subpulmonary ventricular septal defect (Taussig-Bing anomaly). Recognition of this important anomaly prevented significant intraoperative myocardial damage by altering techniques of cardioplegia administration for myocardial preservation.     

Anomalous origin of the right coronary artery from the pulmonary artery

Anomalous origin of a coronary artery from the pulmonary artery is a relatively rarer congenital anomaly which almost exclusively involves the left coronary artery. A previously healthy 25-year-old woman had a cardiopulmonary arrest. Following resuscitation, investigations revealed an even rarer anomaly, an anomalous right coronary artery arising from the pulmonary artery. Successful surgical repair was accomplished by reimplanting the right coronary artery into the aortic root. The patient is currently asymptomatic 2 years postoperatively. The pertinent literature is reviewed.     

Renal hemodynamics in the rat before and during inhibition of angiotensin II

Renal blood flow (RBF) was measured with a noncannulating electromagnetic flow transducer in anesthetized rats which had been maintained for 3-5 wk on low, normal, or high salt plus deoxycorticosterone diets. After base-line observations, one of two dissimilar inhibitors of the renin-angiotensin system, angiotensin I converting enzyme inhibitor SQ 20881 or the structural analogue [Sar1,Ala8]angiotensin II was administered intravenously. The employed doses of SQ 20881 and [Sar1,Ala8]angiotensin II effectively inhibited the pressor and renal vasoconstrictor responses induced by exogenous angiotensin I and II, respectively, in each dietary group. Both inhibitors vasodilated kidneys in salt-restricted rats; however, neither affected base-line renal hemodynamics in salt-loaded rats. Pressure-flow relationships were evaluated by clamping the aorta to reduce renal perfusion pressure. Renal blood flow was autoregulated between 100 and 140 mmHg with the same efficiency before and during inhibition of angiotensin II in each dietary group. These data indicate that angiotensin II modifies base-line RBF and renal vascular resistance and are consistent with the view that the renin-angiotensin system is not an essential mechanism responsible for autoregulation of RBF in the rat.     

The effect of hemodilution on regional myocardial function in the presence of coronary stenosis

Hemodilution decreases blood viscosity and circulatory input impedance and thus reduces afterload. Its use in treatment of LV power failure has been advocated, but the safe limits of isovolemic hemodilution are not known. Compensation of the reduced O2-capacity of the blood was therefore studied with normal and impaired coronary reserve. In 20 dogs the LAD was stenosed to a degree just not affecting the supplied region and central and coronary hemodynamics were studied. Regional myocardial function was assessed by ultrasound transit time between transducers implanted in the LV wall. Lowering the hematocrit to 15% by isovolumic exchange of blood for Dextran 60 increased CVP (18%), PAP (47%), LAP (64%), LVedP (46%), CO (67%), and flow to the intact area (LCA: 211%). Flow in the stenosed LAD increased slightly. Enddiastolic length (EDL) of LAD dependent muscle segments rose to 120% and their contraction amplitude deltaL was decreased by 46%. Whereas non-ischemic segments showed compensatory rise in deltaL (38%) at almost constant EDL (+9%). After release of the LAD stenosis EDL and deltaL returned to normal. During progressive anemia myocardial O2-demand is not adequately met if coronary reserve capacity is depleted. Reversion of hypokinesia after removal of the stenosis shows unimpaired myocardial function at a hematocrit as low as 15% provided the coronary circulation is intact.     

Effects of acetylcholine and nitroprusside on systemic and regional hemodynamics in hypertensive rats

This study was performed to investigate the in vivo effects of acetylcholine, a stimulator of endogenous NO production, and nitroprusside, an exogenous NO-donor, on hemodynamics in the normotensive (WKY) and the hypertensive (SHR) rat. Anesthetized rats were given microspheres for the measurement of cardiac index (CI), total vascular resistance (TPRI), regional blood flow and vascular resistance. Infusion of acetylcholine (2 microg/kg/min) caused a marked decrease in TPRI by (-35+/-5%, +/-SEM) in the WKY (n=8), whereas in the SHR (n=8) a less pronounced reduction was seen (-14+/-3%, p<0.01 between groups). CI increased by 27+/-9% in the WKY, but was unaltered in the SHR. Blood pressure decreased similarly (17-20%). Acetylcholine significantly increased blood flow by about 40% in the kidneys and the heart in the WKY, but had no significant effect in the SHR. Other tissues, such as skeletal muscle and cerebral tissues, showed no major changes. Infusion of nitroprusside (1 microg/kg/min) reduced blood pressure by 5 to 10% in the strains. The regional effects of nitroprusside did not differ between the strains. In conclusion, the acetylcholine-induced vasodilation in the kidney and the heart was attenuated in the SHR compared to the WKY. These findings might suggest a difference in the endothelial response between the SHR and the WKY in some, but not in all, tissues.     

Anatomical types of coronary circulation and various lesions of the right coronary artery

The data on coronarography, conducted in clinic to 1249 patients in 1994-1996 yrs., and intraoperative data, obtained in the patients with a coronaris dextra (ACD) affection and its concurrent affection with a coronaris sinistra (ACS) operated on in clinic in 1974-1996 yrs., were analyzed. It was established that the frequency of severe affection of endothelium of ACD while the existence of the left coronary blood circulation (CBC) type 2.5 times as higher than that while the presence of its right or balanced kinds. The most frequent atherosclerosis occurrence in the proximal ACD portion creates the anatomical prerequisites for the broad application of surgical treatment methods of coronary insufficiency.     

Combined carotid endarterectomy and coronary artery bypass grafting in asymptomatic carotid artery stenosis

The role of combined carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) in patients with severe asymptomatic carotid artery disease and concurrent symptomatic coronary artery disease is controversial. The objective of this report is to investigate the safety of combined CEA/CABG. The medical records of 30 patients who underwent combined CEA/CABG for coexistent asymptomatic carotid and symptomatic coronary artery occlusive disease were reviewed. All patients were scheduled for either elective or urgent myocardial revascularization due to their symptomatic coronary artery disease. Color-flow duplex scanning identified internal carotid artery stenosis of 80 to 99 per cent in 28 patients (93%) and 50 to 79 per cent in 2 patients (7%). Seventeen patients (57%) were male. The mean age was 64 +/- 10 years (range, 42-84 years). Contralateral internal carotid artery occlusion was present in four patients. Severe left main coronary artery disease was present in 12 patients (40%) and 7 patients (23%) had an ejection fraction of less than 50 per cent. There were no perioperative deaths or strokes. One patient suffered a myocardial infarction on postoperative day 1. This study demonstrates the safety of combined CEA/CABG for coexistent coronary and asymptomatic carotid disease. Using this surgical approach for critical coexistent disease may minimize the incidence of perioperative cerebrovascular complications in patients undergoing CABG.     

Elective stenting of carotid artery stenosis in patients with severe coronary artery disease

AIMS: To evaluate the feasibility and safety of elective carotid stent implantation in patients with carotid stenoses and concomitant coronary artery disease, as an alternative to combined carotid and coronary surgery. METHODS: We treated 50 patients with >70%, stenoses in 53 carotid arteries with balloon angioplasty followed by elective stent implantation. All patients had severe coronary artery disease, and/or mitral insufficiency, aortic stenosis, rhythm disorders or generalized arteriosclerosis. In three patients the opposite carotid artery was occluded; nine patients had bilateral stenoses of which two received stents bilaterally. RESULTS: Fifty-six successful stent implantations (42 Wallstents, eight BeStents, two AVE-Microstents, one Palmaz Schatz stent, three Sito stents) were performed, reducing the baseline percent stenosis from 78 +/- 18%, to 13 +/- 11%. Complications included three transient ischaemic attacks, one minor and one major stroke. Follow-up was available for 46 patients over a mean of 10 months. Three asymptomatic restenoses and one deformation of a BeStent occurred. CONCLUSION: Our preliminary results indicate that carotid artery stenting in patients with concomitant severe coronary artery disease is feasible, safe, and may be an alternative to combined carotid and coronary surgery.     

Mid-term results in coronary revascularization using the right gastroepiploic artery graft

We studied the mid-term results in 191 patients (including emergent operation in 27 patients) who have performed coronary artery bypass grafting (CABG) using the right gastroepiploic artery (REGA) for 74 months (mean follow up period was 37 months). We evaluated the postoperative results in terms of 1. mortality and survival rate, 2. graft angiography, 3. cardiac event free rate and 4. abdominal complications. We had operative death in 6 patients (3.1%) including 3 patients of emergent operations. Late deaths were found in 11 patients (5.9%): 2 patients were cardiac death and 9 were non-cardiac. The actual survival rates were 94.2% at one year, 90.0% at three years and 85.9% at five years. Early patency rate of the RGEA was 98.9% (n = 178). However flow competition between the RGEA and native coronary artery was seen in 42 patients (24.0%). Mid-term patency rate was 96.4% (n = 28). According to mid-term graft angiography, 1 patient improved and 5 patients got worse in comparison with early control. Cardiac event free rates were 98.2% at 1 year, 94.8% at 3 years and 92.7% at 5 years. Abdominal complications were observed in 5 patients (1 patient of bleeding from the RGEA, 1 of gastric perforation, 2 of bleeding from gastric ulcer and 1 of pyloric stenosis) at early period and in 7 patients (2 patients of incisional hernia and 5 of gastric cancer) at long-term period. Early and mid-term results of CABG using the RGEA were quite good. However, the RGEA had a tendency of flow competition against native coronary artery and a problem of gastric cancer after the operation.     

Glomerular haemodynamics during renal artery clamping and haemorrhage in the dog

The influence of gradual decline in renal perfusion pressure (RPP) due either to renal artery clamping (C) or to haemorrhagic hypotension (HH) was studied using micropuncture techniques in anaesthetized dogs. The decrease in renal blood flow (RBF) was more profound and set in earlier during HH than during C, where perfect autoregulation was observed down to a mean arterial blood pressure of 85 mmHg. Glomerular filtration rate (GFR) was also only slightly decreased during C, with no change in filtration fraction (FF); again, a much greater decrease in GFR with an increase in FF was seen in HH. The excretion of water, electrolytes and urea were also more decreased during HH than during C. Similar changes were seen at the single nephron (SN) level. Opposite changes were observed in arteriolar resistances: during C a decrease in total arteriolar resistance (RT) amounting to -22% at a RPP of 84 mmHg and -13% at 60 mmHg was seen, due exclusively to a drop in afferent resistance (RA), but during HH there was a significant increase in RT by +36% at RPP of 110 mmHg, +39% at 85 mmHg and +68% at 60 mmHg. This increase was mainly due to an increase in efferent resistance (RE) rather than in RA: +42 vs. +31%, respectively, at 110 mmHg and +67 vs +19% respectively, at 85 mmHg. It was not until a RPP of 60 mmHg was reached that this difference between RE and RA disappeared, being +67% for RE and +69% for RA. The ultrafiltration coefficient, Kf, did not change during C and only decreased slightly with the biggest drop in RPP during HH (2.84 microliters mmHg-1 min-1 during HH vs. 4.19 microliters mmHg-1 min-1 before HH). The SNGFR/GFR ratio remained unchanged during C but declined with decreasing RPP during HH, which probably indicates a 'redistribution' of RBF to the deeper regions of the renal cortex. In conclusion, major differences in renal function were observed between C and HH whose cause is unknown.     

Echocardiographic diagnosis of single coronary artery in double-outlet right ventricle

A 90-year-old woman was admitted to our hospital in December 1993 because of dyspnea on exertion and malaise. She had been well until October 1993, when she first noticed Raynaud's phenomenon, skin tightening, digital ulceration and scarring of her hands. On physical examination, generalized edema was found, along with acrosclerosis with contracture, especially in the fingers, wrists, and elbows. Inspiratory crackles were noted. A roentgenogram of the chest and an echocardiogram revealed pulmonary fibrosis, pulmonary congestion, and massive pleural and pericardial effusions. The pleural effusion was a transudate. Progressive systemic sclerosis was diagnosed, and furosemide and isosorbide were given. The edema and pulmonary congestion resolved, but the pleural and pericardial effusions did not. Prednisolone was given, which reduced the pleural effusion but not the pericardial effusin. The pleura and the pericardium are not usually involved in progressive systemic sclerosis, and this disease rarely occurs in patients over 70 years old. To the best of our knowledge, this was one of the oldest patients with progressive systemic sclerosis. The combination of massive pleural and pericardial effusions, and the advanced age of onset make the present case unusual.     

Severe stenosis of the right coronary artery in a 15-year-old girl with type IIa hypercholesterolemia: successful treatment with stent implantation

Coronary artery stenosis with need for therapy is rarely seen in childhood. A 15-year-old girl with hypercholesterinaemia type II a was undergoing lipid aphereses therapy (once or twice a week) since she was 6 years old. The girl was seen in our hospital with stenocardia and depression of the ST-segment in the inferior ECG leads at rest. Myocardial scintigraphy with technetium 99 showed an ischemia of the infero-lateral left ventricular myocardium. During selective coronary angiography a 90% stenosis of the proximal right coronary artery over a distance of approximately 5 mm close to the ostium was found. Post stenotic dilatation of the vessel was obvious. In addition a diffuse 10% stenosis in the proximal and middle part of the right coronary artery was found. The left coronary artery appeared angiographically normal. After balloon dilatation, stent implantation was performed without complications with a 6 mm microstent. Reduction of the stenosis from 90% to 40% could be achieved. Ticlopidin 2 x 250 mg was started for thrombocyte aggregation inhibition. During the following 12 months the patient has been free of symptoms. Lipidaphareses has been continued as before. Stent implantation seems to be a successful treatment for coronary artery stenosis also in young patients.