Detection of coronary artery disease in patients with severe aortic stenosis with noninvasive methods.

Exercise stress ECG testing is not generally recommended in patients with severe aortic stenosis. Analysis of the utility of exercise testing, both with and without the use of myocardial thallium-201 scintigraphy for the diagnosis of coronary artery disease (CAD), yielded low specificity. A noninvasive, safe, and accurate diagnostic modality to ascertain the presence of CAD is not available to date for patients with severe aortic stenosis. The aim of this study was to assess the safety and diagnostic accuracy of adenosine stress echocardiography (A-Stress-Echo) and of adenosine stress myocardial perfusion scintigraphy (A-SPECT), for the detection of CAD in patients with severe aortic stenosis. The study included 50 patients with severe aortic stenosis (maximal instantaneous aortic valve gradient >80 mmHg, range 81 to 144 mmHg, and aortic valve area <0.75 cm2). All patients were submitted to A-Stress-Echo, after a 6-minute infusion of adenosine (140 microg/kg body weight/min), and then (>3 days later) A-SPECT with the same dosage of adenosine as above. Coronary angiography was performed in all patients. No major complications were observed. The unpleasant symptoms were brief and did not necessitate cessation of the test. Both modalities showed the same sensitivity (85% for A-SPECT and 85% for A-Stress-Echo) angiographically diagnosed CAD while A-Stress-Echo yielded much higher specificity (96.7% vs 76.7%). Concordance of the two methods was found in 40 cases and the specificity for those patients was 100%. A-Stress-Echo and A-SPECT, either separately or in combination, constitute excellent and safe noninvasive diagnostic methods in detecting CAD in patients with severe aortic stenosis.

Transesophageal echocardiographic Doppler study of coronary flow in a patient with myocardial bridging--a case report.

A case report of myocardial bridging of the left anterior descending artery is described. Coronary flow proximal to the myocardial bridge was studied with transesophageal echo Doppler. The patient, a 62-year-old farmer who sustained an anterior myocardial infarction, underwent thrombolysis and was admitted. He subsequently underwent coronary angiography and left ventriculography, which showed a severe myocardial bridge of the midshaft of the left anterior descending artery. The ejection fraction improved from 25 to 48% after thrombolysis, as measured by using echocardiography. Transesophageal Doppler study proximal to the myocardial bridge revealed a relative increase of the diastolic coronary flow velocity (increased acceleration), which reached its peak value in early diastole. Despite the presence of severe myocardial bridging, coronary flow reserve increased substantially two minutes after the infusion of dipyridamole (0.56 mg/kg iv for 4 minutes). Transesophageal Doppler study of coronary blood flow proximal to the myocardial bridge in the left anterior descending artery showed a characteristic waveform that may prove to be indicative of this condition.

Echocardiographic detection of the extent of coronary artery disease in the elderly using dobutamine and adenosine infusion.

BACKGROUND: The high prevalence of asymptomatic multivessel disease in the elderly and the fact that most of them can not carry out an exercise stress testing renders the application of other stress modalities necessary. The aim of this study is to compare the diagnostic value of dobutamine and adenosine stress echocardiography and their accuracy in determining the extent of coronary artery disease in elderly people. METHODS: Dobutamine and adenosine stress echocardiography were performed in 128 consecutive patients > or = 70 years-of-age with known or suspected coronary artery disease. All patients underwent coronary angiography within 2 weeks of the stress tests. RESULTS: The presence of any echocardiographic abnormality on dobutamine (odds ratio 30.8) and adenosine (odds ratio 18.1) test, the need for cessation of dobutamine test and the ST depression during dobutamine infusion, were independent predictors of significant coronary artery disease. Both tests proved more sensitive for detecting multivessel disease (89% for dobutamine, 74% for adenosine test), than one-vessel disease (74 and 39%, respectively). This difference was statistically significant only for the adenosine echocardiography test (P = 0.008). In patients with localized resting wall motion abnormalities, the accuracy of dobutamine test to predict a remotely diseased vessel (70%), was statistically superior to the accuracy of adenosine test (57%, P = 0.008). Patients with multivessel disease showed delayed resolution of test-induced wall motion abnormalities, during the recovery period after both tests, compared with those who suffered from one-vessel disease. CONCLUSIONS: Dobutamine echocardiography was more sensitive and accurate than adenosine echocardiography in detecting and determining the extent and the severity of coronary artery disease in the elderly. A positive adenosine echocardiography result reflected the presence of advanced coronary artery disease. The two tests, combined with clinical data, could classify the elderly into low- and high-risk subgroups for ischemic heart disease.

Torsades de pointes following radiofrequency catheter His ablation.

A case of polymorphic ventricular tachycardia torsade de pointes type, appearing in a 70-year-old female following radiofrequency catheter His ablation, is presented. The substrate was slow rate with ventricular bigeminy and QT prolongation which appeared after ablation. The same phenomenon reappeared after permanent VVIR pacemaker implantation with a basal rate of 55 beats/min. One episode of polymorphic ventricular tachycardia deteriorated into ventricular fibrillation, requiring a 360-J DC shock. Raising the pacemaker rate to 80 beats/min abolished the arrhythmias.

Detection of myocardial viability in the prediction of improvement in left ventricular function after successful coronary revascularization by using the dobutamine stress echocardiography and quantitative SPECT rest-redistribution-reinjection 201TI imaging after dipyridamole infusion.

The aim of this study was to assess the feasibility, safety, and respective diagnostic accuracy of low-dose dobutamine infusion and rest-redistribution-reinjection thallium 201 single photon emission computed tomography (SPECT) after dipyridamole infusion (Th-DIP), in the prediction of functional improvement of asynergic infarcted zones, after successful revascularization in patients with chronic ischemic heart disease. Thirty-one patients with a previous myocardial infarction and left ventricular dysfunction (mean ejection fraction: 41 +/- 5.8%) were studied. The regional wall motion of the left ventricle was evaluated by basic echocardiography before and 14 +/- 1.7 weeks after successful revascularization (19 by percutaneous transluminal coronary angioplasty and 12 by coronary artery bypass grafting). Dobutamine stress echocardiography (DSE) was performed in all patients with dobutamine infusion of 5 and 10 micrograms/kg/minute over five minutes. Within three days after DSE and prior to revascularization, all patients underwent Th-DIP for myocardial viability assessment. A 16-ventricular-segment model was used for basic, DSE, and Th-DIP images. Viability was assessed by applying the standard criteria for each technique. In the 31 patients, 496 segments were analyzed. By basic echocardiography, 164 (33%) of them were classified as asynergic. The DSE detected viable tissue in 69/496 (14%) segments, whereas Th-DIP identified viability in 95/496 (19%) segments. When the postrevascularization basic echocardiographic study was used as the gold standard in identifying myocardial viability, the sensitivity and specificity for the DSE and Th-DIP were 86.5%, 94.4% and 90.5%, 69%, respectively. No major side effects were observed with both techniques. In conclusion, DSE seems to be an accurate method for identifying viable but asynergic myocardium in patients with chronic ischemic heart disease, whereas Th-DIP overestimates the postrevascularization recovery. Detection of hibernating myocardium can be obtained by these two noninvasive methods. However, DSE seems to be more useful in determining the prospective selection of patients who are going to benefit from revascularization.

Stress echocardiography in elderly patients with coronary artery disease: applicability, safety and prognostic value of dobutamine and adenosine echocardiography in elderly patients.

OBJECTIVES: Our aim was to determine the applicability, safety and prognostic value of adenosine and dobutamine stress echocardiography in patients > or = 70 years old. BACKGROUND: These tests are sometimes mandatory because of difficulties and inaccuracies in interpreting traditional electrocardiographic stress tests. Furthermore, if these tests could be used to avoid coronary arteriography and cardiac catheterization, they would become essential in the care of the elderly, whose numbers are increasing. METHODS: We performed coronary arteriography and dobutamine and adenosine stress echocardiographic tests in 120 patients (72 men) > or = 70 years old who entered the hospital because of chest pain and had known or suspected coronary artery disease. The stress tests were performed on separate days, within 2 weeks of coronary arteriography. Both the arteriograms and the echocardiograms were analyzed by two experts who had no knowledge of the patients' other data or the other interpreter's report. Tests were judged to have positive or negative results, and the patients were followed up for the development of cardiac events. Univariate and multivariate analyses and other statistical modalities were applied for comparisons. RESULTS: Documented coronary artery disease was found in 89 patients. During the 14 +/- 7 of follow-up, cardiac events developed in 50 patients, including 3 (7.9%) of 38 patients with negative dobutamine and 12 (20.7%) of 58 patients with negative adenosine test results. Demonstration of any abnormality on stress echocardiography was an independent factor for cardiac events, both for dobutamine (relative risk 7.3) and for adenosine (relative risk 3.0). Both cessation of dobutamine or adenosine tests and diagnosis of disease in two or more coronary vessels were also independent predictors. ST segment depression > or = 1mm was related to future events only with the dobutamine test. CONCLUSIONS: These echocardiographic stress tests proved safe and well tolerated. They successfully stratified this cohort of elderly patients with coronary artery disease to low or high risk subgroups for subsequent cardiac events.

Dobutamine-induced transmural myocardial ischemia in a patient with mild coronary lesions.

A 70-year-old man was admitted for evaluation of retrosternal pain at rest. During infusion of dobutamine (25 micrograms/kg/min) the patient developed angina, ST-segment elevation in the inferior leads, and echocardiographic hypokinesia in the inferior-basal myocardial wall. Coronary angiography revealed insignificant (20-30%) stenosis of the right coronary artery and a normal remaining tree. This case suggests that dobutamine may induce transmural myocardial ischemia in patients with mild coronary lesions, probably by producing occlusive coronary spasm on a substrate of arterial endothelial dysfunction.

Effects of magnesium and potassium on Wolff-Parkinson-White syndrome.

To investigate the effects of electrolytes on anterograde conduction via accessory pathways, 12 patients with Wolff-Parkinson-White syndrome received, while in sinus rhythm, intravenous KCl (7 mEq in 200 mL of 0.9% NaCl), MgSO4 (10 mL 20% in 200 mL of 0.9% NaCl), NaCl (0.9%, 200 mL), and procainamide (maximal dose, 10 mg/kg of body weight over a 5-minute period) in a randomized fashion. NaCl had no effect on preexcitation. Procainamide abolished preexcitation in seven patients, of whom five had a similar response with MgSO4 and four with KCl. The finding that potassium and magnesium transiently abolish preexcitation in some Wolff-Parkinson-White patients deserves further study, especially during tachyarrhythmias in patients with accessory pathways.

Acute aortic regurgitation caused by non-bacterial thrombotic endocarditis.

A case of non-bacterial thrombotic endocarditis, which caused acute aortic regurgitation in a middle-aged, otherwise healthy woman, is presented. The diagnosis was confirmed with echocardiography and documented by a histopathological study of the excised aortic valve after operation for valve replacement.

Intracardiac balloon pump for the relief of acute mitral regurgitation.

The goal of this study was to test the hypothesis whether a small balloon placed within the mitral orifice and pulsed in a synchronous manner could reduce the degree of acute mitral regurgitation. Previous experimental studies had shown that a similar balloon within the aortic orifice relieved satisfactorily aortic regurgitation. Acute mitral regurgitation was created in 14 dogs, and a catheter with a small polyurethane balloon on its distal end was introduced to the mitral ring through the left ventricular apex. The balloon was connected to a Datascope pump for intermittent, synchronous pulsation. Left atrial, left ventricular and aortic pressures were monitored. In three animals transesophageal echocardiography was used in addition to monitor the regurgitant transmitral flow with color Doppler image. Intermittent inflation of the balloon during systole decreased the maximum left atrial pressure from 31.83 mmHg +/- 3.48 mmHg to 23.16 +/- 3.3 mmHg (p < 0.001) and the mean left atrial pressure from 21.66 +/- 2.8 mmHg to 17.25 +/- 2.76 mmHg (p < 0.001). The systolic gradient across the mitral valve increased from 59 +/- 14.53 mmHg to 77.11 +/- 12.44 mmHg (p < 0.01). Transesophageal echocardiography showed an almost 50% decrease of the transmitral regurgitant flow. It is concluded that intermittent, systolic, synchronous balloon pulsation within the mitral orifice reduces the degree of experimental, acute mitral regurgitation.

On line echocardiography in evaluating left atrial changes in acute mitral regurgitation and in monitoring a catheter-mounted balloon for its correction.

The purpose of this study was to evaluate changes in the left atrial size in acute mitral regurgitation (AMR) and monitor its correction by a catheter-mounted balloon (B). In 16 dogs, pressure changes in the left atrium (LA) were related to LA size and regurgitant mitral flow after the production of AMR by severing the mitral cusps. TEE was used for evaluating LA area (ALA) and the mitral regurgitation flow area (AMRF). TEE was also used in monitoring the position of a catheter-mounted B inserted through the LV apex and positioned on the mitral ring to relieve AMR. The B was inflated during systole and deflated during diastole. The ALA increased by 4.89 +/- 1.21 cm2 (mean +/- 1 SD) (p < 0.001) after AMR, the AMRF increased by 3.01 +/- 0.85 cm2 (p < 0.001) and the mean atrial pressure (LAP) by 9.38 +/- 2.43 mmHg (p < 0.001). In all experiments the position of the B could be confirmed in the 2D image and in 4 the reduction of AMRF by the function of the B was documented by the colour flow Doppler. It is concluded that after AMR the size of the LA increases along with the increase in LA pressure and a phasically inflated balloon and its effect on AMR can be easily identified and monitored by TEE.

Doppler echocardiographic study of pulmonary venous flow in mitral stenosis and early after mitral valve replacement.

The aim of the study was Doppler echocardiographic assessment of the effect of mitral stenosis (MS) on pulmonary venous flow (PVF), and of any changes occurring after mitral valve replacement. Fifty patients with MS (22 in atrial fibrillation (AF)) and 28 healthy subjects (control group) underwent transthoracic echocardiographic evaluation of PVF. Fourteen of the 22 patients in AF were submitted in addition to transesophageal echo study before and after mitral valve replacement. Pulmonary wedge pressure was measured in 18 patients. Patients in sinus rhythm (SR) and more than mild MS showed significantly decreased peak velocity and flow velocity time integral of the systolic forward PVF. This finding was more exaggerated in MS with AF. Concerning diastolic forward PVF, patients in SR showed significantly decreased peak velocity and velocity time integral, irrelevant of the degree of MS, while patients with AF exhibited adequate signs of flow. In all patients duration, deceleration time (D-DT) and pressure half-time (D-PHT) of the diastolic forward PVF were significantly increased. The last two parameters correlated with the corresponding variables of mitral flow and with echocardiographically determined mitral valve area and the D-DT of the pulmonary wedge pressure. Concerning reversed PVF, patients with more than mild MS exhibited significantly increased peak velocity and velocity time integral. After mitral valve replacement, a significant increase of diastolic forward peak velocity and velocity time of the PVF were detected. The duration of diastolic forward peak velocity of PVF, D-DT and D-PHT decreased. The systolic forward phase did not change significntly after the valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary heart disease risk factors in Hansen's disease sufferers.

In the frame of an epidemiologic study of Hansen's disease (HD) sufferers, several risk factors have been investigated which might explain the high prevalence of coronary heart disease (CHD) among HD patients. The data analyzed in the present study are derived from 293 HD patients (157 men and 136 women). The patients, after having completed a WHO adopted questionnaire, were given a complete physical examination, a resting and an exercise electrocardiogram, and biochemical as well as hematological examinations. Coronary HD patients, when compared to noncoronary HD patients, showed statistically significant differences in the following parameters: (1) mean age, (2) mean concentration of the electrophoretic fraction of alpha-lipoproteins, (3) deviation from mean weight, (4) prevalence of hypertension, and (5) prevalence of the borderline lepromatous form of HD. However, the differences found when comparing other parameters, such as blood pressure, smoking, diabetes mellitus, total cholesterol, triglycerides, pre-beta and beta-lipoproteins, uric acid, erythrocyte sedimentation rate, ABO blood groups, etc., did not reach the level of significance. These findings suggest that HD sufferers are a special population subgroup with reference to CHD risk factors, differing in many ways from the general population.

Effect of acute changes in aortic pressure on the coronary reserve.

STUDY OBJECTIVE: The aim was to evaluate the effect of acute changes in aortic pressure on the coronary reserve and hyperaemic response. DESIGN: Aortic pressure changes were induced either by intra-aortic balloon pumping or by the production of acute aortic regurgitation. A transient 20 s occlusion of the left anterior descending coronary artery was used as the hyperaemic stimulus. EXPERIMENTAL SUBJECTS: The experiments were performed on 19 open chest anaesthetised dogs, weight 13-32 kg. MEASUREMENTS AND MAIN RESULTS: During intra-aortic balloon pumping the mean diastolic aortic pressure increased by 24.7(SEM 2.9) mm Hg (p less than 0.001), while in aortic regurgitation it decreased by 47.7(11.1) mm Hg (p less than 0.01). At the peak hyperaemic response the driving coronary pressure was 121.4(2.8) mm Hg during intra-aortic balloon pumping and 59.8(11.5) mm Hg during aortic regurgitation. The peak hyperaemic flow increased by 12.0(3.8) ml.min-1 (p less than 0.01) during intra-aortic balloon pumping, compared to the values before pumping and decreased by 14.9(4.2) ml.min-1 (p less than 0.01) during aortic regurgitation, compared to the values before aortic regurgitation. The coronary reserve, expressed as the ratio of the hyperaemic to the resting flow, increased by 0.7(0.1) (p less than 0.001) during intra-aortic balloon pumping and decreased by 0.4(0.2) (p less than 0.05) during aortic regurgitation. A positive significant correlation coefficient was found at the peak hyperaemic response between the mean aortic pressure and the total forward effective coronary flow, and between the mean diastolic aortic pressure and the diastolic component of the coronary flow, during both intra-aortic balloon pumping and aortic regurgitation. CONCLUSIONS: The results suggest that coronary reserve increases during intra-aortic balloon pumping and decreases during aortic regurgitation; these changes could be attributed to the effect of the pressure changes on the hyperaemic flow.

Intraventricular pumping at the mitral ring in mitral regurgitation.

This study aims at evaluating the effect of a small spherical balloon functioning during acute mitral regurgitation. Acute mitral regurgitation was produced in 11 mongrel dogs with a specially designed curved blade introduced through the left ventricular apex. Left atrial pressure, electrocardiogram, left ventricular pressure (in 8 dogs) and aortic flow (in 7 dogs) were monitored. The mean left atrial pressure increased by 9.45 +/- 2.44 mmHg (p less than 0.01) and the v wave by 14.09 +/- 2.94 mmHg (p less than 0.001). The systolic left ventricular pressure and the aortic flow decreased. The heart remained in sinus rhythm & the rate did not change significantly. After the production of mitral regurgitation, a small spherical balloon (9 to 16 cc capacity) mounted on a catheter was introduced to the left ventricle through the apex and positioned in the mitral ring. The balloon was inflated by means of a pump during systole and deflated during diastole. During its function the mean left atrial pressure decreased by 4.37 +/- 0.84 mmHg (p less than 0.001) and the v wave by 8.64 +/- 1.23 mm Hg (p less than 0.001). The systolic left ventricular pressure and the aortic flow increased. The peak systolic gradient across the mitral valve increased by 20.5 +/- 3.86 mmHg (p less than 0.01). The heart rate did not change. It is suggested that in acute mitral regurgitation the function of a small balloon could improve the hemodynamic condition by acting as a valve at the mitral ring for reduction of regurgitation and possibly by improving systolic function in severe heart failure.

Effect of the positioning of a balloon valve in the aorta on coronary flow during aortic regurgitation.

The coronary artery flow changes relative to the function of a catheter-mounted balloon valve used for relief of aortic regurgitation were studied in 10 mongrel dogs. Acute aortic regurgitation was produced by severing the aortic cusps with a long needle. Coronary flow was recorded from the left anterior descending coronary artery through an electromagnetic flowmeter. When the balloon was functioning within the cavity of the left ventricle there were no significant changes in the coronary flow and aortic pressure, except for a slight decrease in the aortic end-diastolic pressure. When it was functioning in the aortic ring the coronary flow increased 6.52 +/- 1.65 ml/min/100 gm of myocardium (p less than 0.001) and became predominantly diastolic. When it was functioning in the ascending aorta the coronary flow decreased 6.22 +/- 1.16 ml/min/100 gm of myocardium (p less than 0.001) and remained predominantly systolic. Finally, when the balloon was functioning in the thoracic aorta the coronary flow did not change significantly. With the balloon functioning in the aortic ring, ascending aorta, or thoracic aorta, there was a significant increase in the aortic end-diastolic pressure and decrease in the pulse pressure distal to the location of the balloon. It is concluded that the location of the balloon valve inserted for relief of aortic regurgitation influences the effect on coronary arterial flow.

The use of a small intra-aortic balloon to increase coronary flow.

A small spherical balloon, mounted on a catheter, was positioned, via an arteriotomy, in the ascending aorta 1 cm above the aortic valve in 10 dogs. The balloon was inflated for 60 ms, through the equipment of the intra-aortic balloon pump, during various parts of the cardiac cycle. When the inflation occurred during the rapid ejection phase, the systolic component of the coronary flow increased by 32.57 +/- 5.4 per cent (P less than 0.001), resulting in a 6.69 +/- 1.14 per cent (P less than 0.001) increase of the total (effective forward) flow. The tension time index increased by 9.01 +/- 0.85 per cent (P less than 0.001). The left ventricular end-diastolic pressure and indexes of contractility did not change. When the inflation occurred during the reduced ejection phase the increase in coronary flow and tension time index was less. When the inflation occurred during the first third of diastole, there were no significant changes in the pressures and flow. In the middle third of diastole, the inflation of the balloon produced a 6.5 +/- 0.99 per cent (P less than 0.001) increase of the total flow, without significant changes in the pressures, except for a small increase in the mean diastolic aortic pressure. When the inflation occurred in the last third of diastole, the total coronary flow increased by 10.47 +/- 1.06 per cent (P less than 0.001). There was a decrease in the aortic end diastolic pressure and a 1.08 +/- 0.42 per cent (P less than 0.02) increase in the time tension index. In five dogs, additional observations were made using another mode of inflation. The balloon remained inflated during the entire diastolic period. The total coronary flow increased by 17.46 +/- 4.8 per cent (P less than 0.01), along with a small increase in the diastolic aortic pressure. Indexes of contractility did not change. In conclusion, a small spherical balloon functioning as a pump in the ascending aorta, in close proximity to the coronary ostia, can significantly increase the coronary blood flow.

Intra-aortic ballon pump for relief of aortic regurgitation. Experimental study.

Backflow from the aorta to the left ventricle during diastole in aortic regurgitation can be reduced by expanding, during diastole, a small air balloon positioned in the ascending aorta downstream to the regurgitant valve. A spherical catheter-mounted balloon, acting as a prosthetic aortic valve for the correction of acute aortic regurgitation, was tested in 12 dogs. This "valve" was actively inflated and deflated by means of a common intra-aortic balloon pumping system (Datascope). A significant increase of end-diastolic pressure in the descending aorta, from 51.72 +/- 1.72 to 70.35 +/- 1.92 mm Hg (mean +/- standard error, p less than 0.001), was obtained, without a significant pressure gradient across the "valve". The "valve" prevented the backward flow of the descending aorta by up to 100%, so that there was a mean increase in t-e effective forward flow of 12.61 +/- 5.27% (mean +/- standard error, p less than 0.05). Coronary arterial flow changes varied during the application of the "valve." They depended directly on the changes of the diastolic component of the flow velocity wave, and this relationship was significant (x2 = 33.04, p less than 0.0001). Contractility indices were not significantly affected during the function of the "valve." It is suggested that the spherical "valve" mounted on a catheter may easily be inserted without thoracotomy for a temporary satisfactory correction of the aortic regurgitation.

Epidemiology of coronary artery disease among Hansen's patients.

The prevalence of coronary heart disease (CHD) and its risk factors were studied in 475 Hansen's patients (HP's) by a special questionnaire, physical examination, electrocardiogram at rest and after exercise, and biochemical and hematologic investigations. It was found that the prevalence of CHD (Minnesota codes 1-1 to 1-3 and 4-1) was 10.92%, which is higher than that found in epidemiologic studies of nonHansen's populations. The only CHD risk factors detected were age, obesity, and hypertension. There was no statistically significant difference in the prevalence of CHD between HP's living confined in the institution and those living in their homes. Factors enhancing the development of CHD in this group may include hypertension and obesity as well as psychological factors, which particularly common in these patients, and of course old age.