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Biomedical subjects

R E Rossall

Publications and source records attributed to R E Rossall.

At least 19 recordsLinked to original sources
PubMed1990

Isolated unruptured sinus of Valsalva aneurysm producing right ventricular outflow obstruction.

An unusual case of right ventricular outflow obstruction and right heart failure due to an isolated unruptured congenital sinus of Valsalva aneurysm originating from the right coronary sinus in a 75-year-old-man is described. The diagnosis was made by two-dimensional echocardiography and cardiac catheterization. Successful surgical resection of the aneurysm resulted in dramatic symptomatic improvement.

Aged↗
PubMed1990

Risk stratification after percutaneous transluminal coronary angioplasty.

Approximately 20-30% of patients who undergo elective percutaneous transluminal coronary angioplasty (PTCA) require a second angioplasty within 12 months. A significant proportion of patients develop clinical cardiac events during the first year following the initial procedure. The present investigation was undertaken to establish a statistical model for predicting such events. The study group consisted of 100 patients who underwent elective PTCA at the University of Alberta Hospital. All patients were prescribed nifedipine (10 mg tid) and aspirin (325 mg daily) in addition to other medications determined by the attending cardiologist. The patients were reviewed 10 weeks after the procedure and again at the end of 1 year. The follow-up was completed on 96 patients. Within the first year, forty-five experienced cardiac events (1 death, 5 myocardial infarctions, 4 bypass surgeries, 22 repeat PTCAs). These events occurred in 29 patients. An additional 16 patients experienced significant anginal symptoms. A statistical model based upon the patients' perception of symptoms immediately after the procedure, history of hypertension, vessel subjected to PTCA, ejection fraction pre-PTCA, and occurrence of intimal dissection during PTCA was used to identify patients likely to develop cardiac events. Overall, the model classified 72% of the patients (with and without events). Such a statistical model could be used to identify patients who should be subjected to an enhanced degree of cardiologic surveillance in a rehabilitation program.

Aged↗
PubMed1989

Large air embolus complicating coronary angioplasty.

With the substantial advances in technology and further refinements in the technique of coronary angioplasty, the potential for and manifestations of complications may have changed from those observed in populations studied previously. We describe a rare complication of percutaneous transluminal coronary angioplasty (PTCA), a large air embolus obstructing coronary flow, which is related to the newer technology. The air embolus was successfully extracted by aspiration through the balloon angioplasty catheter.

Angina Pectoris↗
PubMed1989

Unidirectional coronary collateral blood flow in a patient with congenital anomaly of a coronary artery: an angiographic artefact.

A 53-year-old female underwent coronary arteriography for evaluation of chest discomfort. A congenital anomaly of a large interconnecting vessel between the right coronary and circumflex arteries was documented. Selective injection of the right coronary artery resulted in visualization of the circumflex branch of the left coronary through a large interconnecting vessel. Through careful analysis of the left ventriculogram and coronary arteriograms, it appears that retrograde filling of the circumflex artery during right coronary injection is an angiographic artefact.

Adult↗
PubMed1988

Coronary angioplasty at the time of initial diagnostic coronary angiography in patients with unstable angina.

Of the last 200 consecutive patients undergoing PTCA procedures at our institution, 29 (15%) had unstable angina; and angioplasty was performed at the time of diagnostic coronary arteriography. There were 26 males and three females with an age range of 31-82 (mean 57) years. Factors favoring PTCA at the time of initial coronary arteriography included clinical indications for revascularization, appropriate anatomy based on high-quality fluoroscopy, and availability of emergency surgery if required. Of 34 coronary lesions in 29 patients, 19 involved the anterior branch of the left anterior descending coronary artery (LAD), eight the circumflex branch (Cx); and seven the right coronary artery (RCA). Five patients had two vessels dilated (one LAD + RCA, two LAD + Cx, and two RCA + Cx). Of the coronary artery lesions, 19 were concentric, seven were eccentric, 20 were single and discrete, six were long or multiple in the same vessel; eight vessels were totally occluded, and in nine patients there was good collateral circulation. Twenty-nine (85%) arteries were successfully dilated. Of the unsuccessful cases, one was from failure to cross a totally occluded lesion, and three residual lesions and/or postdilatation pressure gradients remained significant. One patient required emergency aortocoronary bypass surgery because of total occlusion of the LAD immediately post-PTCA. There were no postprocedural myocardial infarcts or deaths. It is concluded that, in selected patients with unstable angina, PTCA can be performed successfully and with low risk at the time of initial diagnostic coronary arteriography. This approach offers certain clinical financial advantages.

Adult↗
PubMed1988

Exercise testing after myocardial infarction: relative values of the low level predischarge and the postdischarge exercise test.

This study was undertaken to compare the relative values of the low level predischarge exercise test and the postdischarge (6 weeks) symptom-limited test in 518 consecutive patients admitted with an acute myocardial infarction. Of the patients who did not develop significant ST segment depression or angina during the predischarge test, the symptom-limited test also remained negative in 91.5 and 91.9% of the patients, respectively. Similar results were obtained with ST segment elevation and the systolic blood pressure response during the two exercise tests with only 2.1 and 11.4% changing from normal to abnormal, respectively. Discriminant function analysis was done to predict the occurrence of coronary events (unstable angina, reinfarction, cardiac failure, cardiac death) with use of the data from the exercise tests together with other clinical and investigational data. The jackknife method correctly classified 71.9 and 71.4% of the patients with the data from the predischarge exercise test and symptom-limited test, respectively. Combining the data from the two tests improved the overall predictive accuracy to only 75.0%. It is concluded that the routine performance of a symptom-limited test 6 to 8 weeks after infarction does not reveal any significant additional information in those patients who have undergone a predischarge low level exercise test. Thus the 6 to 8 week test should be restricted to selected patients after myocardial infarction.

Adult↗
PubMed1988

Direct endocardial recording and catheter ablation of an accessory pathway in a patient with incessant supraventricular tachycardia.

A patient presented with incessant supraventricular tachycardia due to a concealed accessory pathway. The His bundle electrocardiogram showed a large discrete accessory pathway potential following ventricular activation and resulting in retrograde atrial activation. Percutaneous catheter ablation in the region of the accessory pathway potential left nodal conduction intact but prevented retrograde activation of the atria. Symptomatic tachycardia has not recurred. Direct endocardial recording of accessory pathway potentials is rare but may offer the opportunity for catheter ablation.

Adult↗
PubMed1987

Response to upright exercise after myocardial infarction.

The left ventricular response to upright bicycle exercise was studied in 39 unselected, non-beta blocked patients (mean(SEM) age 54.2(1.7)yr) (mean(SEM) resting ejection fraction 41.9(2.3)%) 8-10 weeks after myocardial infarction. Nine healthy, age matched, sedentary adult men were studied for comparison (mean(SEM) age 49.8(0.9)yr). The stroke volume and cardiac output were measured by impedance cardiography at rest and after each 3 min workload until symptom limited maximum. The patients were separated into three groups based on stroke volume response to graded exercise. Group 1 (n = 14) had a normal stroke volume response to increasing heart rate. In group 2 (n = 13) stroke volume increased initially then decreased by greater than 15% at a heart rate greater than 100-105 beats.min-1. In group 3 (n = 12) stroke volume failed to increase during exercise. In group 1 cardiac output and mean arterial pressure increased whereas vascular resistance decreased during exercise in a normal fashion. Group 2 had an increased mean arterial pressure and systemic vascular resistance throughout exercise while heart rate increased in a similar fashion to group 1 until work of greater than 70 W was undertaken, at which time heart rate increased in a curvilinear fashion and cardiac output was attenuated. Group 3 had an attenuated cardiac output and a higher heart rate during exercise. In this group of patients systemic vascular resistance failed to decrease normally during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1986

Implication of transstenotic coronary pressure gradient measurement during coronary angioplasty.

The aim of this study was to establish a criterion for the success of an angioplasty based upon pressure gradients across coronary lesions. Sixty-two percutaneous transluminal coronary angioplasties (PTCA) in 56 patients with isolated left anterior descending artery disease were examined. Pressure gradients measured before and after PTCA were expressed as normalized mean pressure gradients (NMPG) computed by dividing mean pressure gradient by mean aortic or proximal coronary artery pressure. Angiographic severity was expressed as percentage area stenosis (AS) calculated from diastolic caliper measurements of diameter of each lesion and the nearest normal adjacent segment in at least two projections. The relationship between AS and NMPG was nonlinear with a steep increase in gradients beyond a critical value of AS of about 60%. This relationship was unaffected by angiographically visualized collaterals. All except one of 65 coronary stenotic lesions with NMPG of more than 0.32 had an AS of more than 60%. Only three of 57 coronary stenoses with NMPG of less than 0.32 had severe AS (p less than 0.001). The results indicate that NMPG is a reliable, practical guide to the severity of coronary stenosis and is therefore a useful measurement for assessing either the success or the residual stenosis during PTCA.

Aged↗
PubMed1986

Prediction of coronary events following myocardial infarction using a discriminant function analysis.

This study was undertaken to derive an index for predicting coronary events in the first year after a myocardial infarction in "low-risk" patients enrolling in a Cardiac Rehabilitation Program. Data from 145 consecutive patients were analysed. The events were classified as follows: angina requiring further therapy, re-infarction and coronary death. Seventy patients had events: Angina--52, Re-infarction--8, Coronary Death--10. A discriminant function analysis was performed to predict such events using data available at the time of discharge from hospital. The following were significant predictors: (1) previous infarction/angina, (2) radiological evidence of cardiomegaly or lung congestion in the Coronary Care Unit, (3) Non-Q wave infarction and (4, 5 and 6) angina, atrial arrhythmias and a decrease in R wave amplitude in V5 during a pre-discharge exercise test. The jack-knife method classified correctly 71.2% of those with events and 72.6% of those without events. In patients with discriminant scores greater than +0.2, 82% developed events.

Adult↗
PubMed1985

Cardiovascular responses to early exercise in inferior wall ST acute myocardial infarction.

The heart rate and blood pressure responses to standardized exercise tests were studied in a group of patients with electrocardiographic evidence of inferior wall acute myocardial infarction (AMI). The tests were done on a bicycle ergometer at 8 to 10 days and 10 to 12 weeks after AMI. At 8 to 10 days after AMI, those with ST AMI (n = 12) had a significantly reduced heart rate response to exercise compared with patients with Q-wave AMI (n = 25). This difference was not evident at 10 to 12 weeks. The systolic blood pressure response in patients with ST AMI was lower than that of Q-wave AMI patients during the first exercise test, although the difference did not attain statistical significance but was significantly lower than the responses of both groups at the second test. The patients with ST AMI had smaller amounts of myocardial damage than those with Q-wave AMI as indicated by plasma creatine kinase values (p less than 0.01). These differences in the heart rate responses appeared to result from the preferential activation of nonmyelinated afferent fibers in the subepicardial region of the inferior wall of the myocardium.

Blood Pressure↗
PubMed1985

Diaphragmatic coronary lesion mimics significant coronary stenosis: a report of four cases.

Diaphragmatic coronary stenosis is a rare coronary angiographic finding. It gives rise to an appearance of relatively severe obstruction and can lead to unnecessary surgical intervention or PTCA. We described four patients with this type of stenosis in whom the lesions proved to be hemodynamically insignificant as judged by the presence of only minor pressure gradients across them.

Adult↗
PubMed1985

Cardiac output measured by impedance cardiography during maximal exercise tests.

The overall accuracy of cardiac output measurements made by impedance cardiography during maximum exercise was studied in man. Initially, the systematic error of the technique was assessed over the range 3.5 to 18 litre . min-1 by comparing with simultaneous measurements of cardiac output made using the direct Fick method. No systemic error was demonstrated in 40 estimations made in 20 subjects. The random error was assessed in 4 subjects in a steady state at rest and during exercise at 80 and 130 W and found to be less than 5% in each subject. The reproducibility of maximum exercise response was assessed in six healthy male subjects (age 26.2 +/- 4.4 years, +/- SEM) who underwent maximum exercise tests twice, 1 week apart, on a bicycle ergometer. Simultaneous recordings of cardiac output and oxygen uptake (VO2) at rest and during each 3 min stage of exercise were made. Highly significant correlations were obtained in the stroke volume (r = 0.84, p less than 0.001), cardiac output (r = 0.98, p less than 0.001) and VO2 (r = 0.98, p less than 0.001) between the two tests. Average maximum cardiac output was 27.0 +/- 1.2 litre . min-1 (+/- SEM) and maximum VO2 was 4.4 +/- 0.2 litre . min-1 (+/- SEM). These results show that measurements of cardiac output were reproducible over one week. Impedance cardiography is non-invasive technique which is as accurate as invasive methods and can be used for maximal exercise testing.

Adult↗
PubMed1985

Use of impedance cardiography in evaluating the exercise response of patients with left ventricular dysfunction.

Invasive studies in patients with left ventricular dysfunction show that data at rest (e.g. ejection fraction-EF) are poor predictors of the changes in cardiac output (CO) which occur with exercise. This investigation was undertaken to determine whether impedance cardiography could be used in such patients to assess CO response to exercise. The method was compared with the direct Fick method. Over a range of COs between 4 and 18 min-1 there was no systematic error. Reproducibility for CO over one week was highly significant (r = 0.94; P less than 0.001). Impedance cardiography was incorporated into routine exercise testing on a bicycle ergometer for a group of 15 patients (mean age 53.2 +/- 3.0 yrs, SEM) who had sustained a major myocardial infarct 6 to 12 months previously, (EF 38.1 +/- 3.5%, SEM). CO was measured at the end of each 3-min stage. In eight patients (EF 40.0 +/- 3.4%, SEM) CO response was abnormal with either a decrease or a failure to increase with increasing workloads. Conventional end-points i.e. angina, attainment of 85% of predicted maximum heart rate, abnormal blood pressure response or excessive dyspnoea did not indicate consistently a need to terminate the test. It is suggested that impedance cardiography is a useful non-invasive method of evaluating patients with left ventricular dysfunction.

Adult↗
PubMed1985

Incremental value of the exercise treadmill test in determining the extent of coronary artery disease: a discriminant function analysis.

This study was undertaken to determine whether it was possible to use a multivariate discriminant function analysis to assess the severity of coronary artery disease in patients with angina pectoris. One hundred and forty-three patients diagnosed as having angina pectoris who formed a 'learning group' were subjected to an exercise test on a treadmill using a Bruce protocol. The items of data from the test least likely to be influenced by beta blockade were considered for the analysis along with two discrete variables (the gender and the use of beta blockers). All the patients subsequently underwent coronary angiography and the severity of the coronary artery disease was graded according to a scoring system. In addition, patients in 'learning group' were classified into two 'Groups', (I) those with normal vessels or with disease in one or two of the major arteries, (II) those with disease in the left main stem or in all three major arteries. The multivariate analysis yielded a score based upon 4 factors: (i) gender, (ii) percentage increase in double product at the highest level of exercise achieved, (iii) duration of ST depression in the recovery period and (iv) the summation of the ST depression in the standard electrocardiogram excluding lead aVR. There was a significant overall correlation between the discriminant function score and the coronary artery score for severity of the disease. In addition, it was found that, of patients having discriminant function score below 0, 96% (69/72) were in Group I. The post-test risk of a positive test was 0.005.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1985

Localization of coronary artery disease with exercise induced ST segment depression: coronary angiographic correlation.

Abnormalities of the 12 lead electrocardiogram (ECG) are often used to localize the anatomic site of myocardial ischemia and vessel involvement in patients (pts) with coronary artery disease. This study is to determine if ischemia of specific vascular segments can be identified by exercise induced ST segment depression (STD) on 12-lead ECG. One hundred and forty three pts with a positive treadmill stress testing (TST) who had coronary arteriography within one month of TST were reviewed. There were 114 men and 29 women, aged 34-74 years (mean 55 years). The Bruce protocol was used for TST. Significant coronary stenosis was defined as obstruction of 70% or greater of the luminal diameter. The pattern of STD on 12 lead ECG during exercise was similar in pts with single vessel disease involving the left anterior descending artery (LAD), right coronary artery (RCA) or circumflex artery (Cx). This pattern of STD in single vessel disease was also comparable to 2-vessel, 3-vessel or left main stem disease. Twenty-two percent of pts with LAD disease had isolated STD in inferior leads. Twenty-five and 29% of pts with RCA and Cx disease respectively had STD in the anterior leads alone during exercise testing. It is concluded that exercise induced STD in 12 lead ECG can not predict ischemia of specific vascular segments or specific vessel involvement.

Adult↗
PubMed1984

Right ventricular infarction: two-dimensional echocardiographic evaluation.

Seventeen patients with predominant right ventricular infarction (RVMI) were studied with two-dimensional echocardiography (2DE). On initial 2DE all had abnormal wall motion (AWM), defined as akinesis plus dyskinesis, in the inferior right ventricle (RV), inferior interventricular septum, and inferior left ventricle (LV). The extent of RV vs LV AWM in short-axis sections at mitral, chordal, and papillary levels was 58% vs 29%, 56% vs 38%, and 59% vs 38%, respectively. The calculated topographic extent of AWM was greater in the RV than in the LV (58% vs 36%, p less than 0.05), and the RV/LV ratio (1.65) exceeded (p less than 0.001) unity. Peak creatine phosphokinase levels correlated significantly (p less than 0.001) with the topographic extent of LV AWM (r = 0.79) or RV + LV AWM (r = 0.75). Although all patients had RV dilatation, eight also had LV dilatation. Serial studies detected the cause of mechanical complications (n = 13), mural echo densities suggesting thrombi (LV in six and RV in seven), and persistent AWM in survivors. Thus, 2DE provided diagnostic data, and assessment of RV and LV AWM confirmed predominant RV involvement.

Adult↗