Practical cardiac hemodynamics.
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Blood Pressure↗
Biomedical subjects
R Gorlin
Publications and source records attributed to R Gorlin.
Echocardiographic diagnosis of left anterior descending coronary artery disease.
To determine the usefulness of the standard echocardiogram in the diagnosis of left anterior descending coronary artery disease proximal or distal to the first septal branch, coronary arteriograms and echocardiograms were performed in 77 patients with a chest pain syndrome. Seventy-nine percent of patients with proximal disease (15 of 19) had an abnormal septal motion measured as a posterior wall/interventricular septal (PW/IVS) excursion ratio greater than or equal to 2.5 compared with 10% of patients with distal disease (2 of 20) who had abnormal septal motion. Only 5% of patients without obstructive disease of the left anterior descending coronary artery (2 of 38) had abnormal septal motion. Proximal disease was found in 79% with abnormal septal motion in the echocardiogram (15 of 19) but in only 7% of patients with normal septal motion (4 of 58). Therefore, abnormal septal motion as measured by the PW/IVS excursion ratio in the echocardiogram is a useful index for the diagnosis of disease of the left anterior descending coronary artery when that disease is proximal to the first septal branch.
Adult↗
Septal perforator compression (narrowing) in idiopathic hypertrophic subaortic stenosis.
Thirteen patients with idiopathic hypertrophic subaortic stenosis were compared with two groups of subjects: 10 patients with chest pain, normal coronary arteries and a normal left ventricle, and 10 patients with left ventricular hypertrophy. Five of the latter had aortic stenosis and five had idiopathic left ventricular hypertrophy. Coronary arteriography revealed that the septal branches of the left anterior descending artery closed or narrowed during systole in patients with idiopathic hypertrophic subaortic stenosis and did not do so in the other patient groups. This narrowing is possibly related to an abnormal position of the septal arteries within the septum in idiopathic hypertrophic subaortic stenosis. Systolic compression of the septal perforator arteries is not a pathognomonic sign of idiopathic hypertrophic subaortic stenosis.
Aged↗
Cardiac shape and function in aortic valve disease: physiologic and clinical implications.
Left ventricular shape and function were studied in 12 normal subjects, 18 patients with pressure overloading secondary to isolated aortic stenosis and 20 patients with volume overloading due to aortic regurgitation. End-diastolic volumes were mildly increased in aortic stenosis but greatly increased in aortic regurgitation. Average ejection fractions were normal in aortic stenosis but depressed in aortic regurgitation. Ventricular shape (eccentricity), normal (elongated) in nearly all patients with aortic stenosis, showed in diastole various degrees of abnormal roundness in patients with aortic regurgitation. As ventricular function declined in aortic regurgitation, the ventricles also became more round in systole. After valve surgery, clinical results were generally better in patients with aortic stenosis than in patients with aortic regurgitation. Among the latter, changes in eccentricity and ejection fraction were the best predictors of surgical outcome. It is postulated that chronic volume loading, as exemplified by aortic regurgitation, may induce basic alterations in architecture and fiber alignment of the left ventricular wall. Such changes may exert significant influence on the clinical course of these patients.
Aortic Valve↗
Correlations of electrocardiography and echocardiography in determination of left ventricular wall thickness: Study of apparently normal subjects.
To examine the usefulness of the surface electrocardiogram in predicting left ventricular wall thickness as determined with echocardiography, standard echocardiograms, electrocardiograms and Frank lead vectorcardiograms were obtained in 30 volunteers. End-diastolic thickness of the interventricular septum and free posterior wall was measured from the echocardiogram and compared with the sum of the S wave in lead V1 plus the R wave in lead V6 (VS1+R6) and the magnitude of the Frank lead vector (Vf), a scalar dunction obtained from a simple analog device. The maximum of Vf, the summated vector (Vf), was highly correlated with VS1+R6 (r=0.84). There was significant correlation between the summated vector and VS1+R6 and the thickness of the interventricular septum (IVS) (r=0.73 and 0.66, respectively). The best least mean square fit for the population was Vf=1.7 IVS-0.39. There was no significant correlation between these variables and the end-diastolic thickness of the posterior wall. Volunteers who were athletically inclined or were joggers tended to have larger summated vector values and evidence of symmetric or asymmetric left ventricular hypertrophy in the echocardiogram. It therefore appears that the thickness of the interventricular septum has a greater influence on the summated vector and VS1+R6 that the echocardiographically assessed thickness of the free posterior wall of the left ventricle. The implications of these findings in the light of recent reports about the incidence of echocardiographically diagnosed left ventricular hypertrophy are discussed.
Adult↗
Postextrasystolic potentiation as a predictor of potential myocardial viability: preoperative analyses compared with studies after coronary bypass surgery.
The ability to predict reversibility of ventricular dysfunction should be important in determining operability. This study examined the usefulness of postextrasystolic potentiation as such a predictor. Left ventricular wall motion was studied using cineventriculography in 31 patients before and after revascularization surgery. Preoperative ejection fraction and wall motion were analyzed during a sinus beat and after a random ventricular extrasystole, whereas postoperative ejection fraction and wall motion were examined only during a sinus beat. Changes in ventricular motion were correlated with changes in vascular supply achieved by operation. Of the 7 patients whose ejection fraction was improved postoperatively, 6 had shown postextrasystolic potentiation compared with only 10 of the 24 patients without such improvement (P less than 0.05). Regional wall motion analysis also showed a significant association between postextrasystolic potentiation and postoperative improvement in wall motion. Of 26 zones judged to have an increased vascular supply after operation, 11 showed increased motion postoperatively. All 11 had shown postextrasystolic potentiation, compared with only 5 of 15 zones with increased vascular supply but without increased postoperative motion (P less than 0.001). Thus, postextrasystolic potentiation seems to be a useful predictor of the ability of asynergic myocardium to respond to successful revascularization surgery.
Adult↗
The effects of left ventricular load and contractility on mitral regurgitant orifice size and flow in the dog.
Acute mitral regurgitation (MR) was produced in 12 dogs by closed chest partial valvulectomy and the relative contributions of MR pressure gradient (MRG), the time for regurgitant flow (VSI), and the MR orifice area (MRA) to mitral regurgitant volume (MRV) assessed. Aortic and left atrial pressures, biplane left ventricular (LV) angiography, forward flow and mitral regurgitant flow (MRF) were measured following MR induction and following augmentation of left ventricular end-diastolic volume (EDV), increased aortic resistance (angiotensin), and in the presence of increased ventricular contractility (calcium or epinephrine). Mitral regurgitation orifice area was determined by calculation and the diameters of the mitral anulus and subvalvular areas measured angiographically. Angiotensin and volume infusion induced a substantial increase in MRF which was largely dependent on an increase in MRA but not MRG, while augmentation of contractility decreased MRF accompanied by a decrease in MRA, relatively independent of MRG. Left ventricular size and shape are major determinants of MRA and resultant MRF in acute mitral regurgitation. These findings may help to explain the effects of such factors as ventricular loading and volume on the clinical course of mitral regurgitation in man.
Animals↗
The myth of acute "mild" myocardial infarction.
Patients with acute myocardial infarction and an uncomplicated early clinical course are often thought to have suffered a mild myocardial infarction. There is also a tendency to link ECG changes suggestive of nontransmural necrosis with such a benign clinical course. Recent work proves that such patients have the same short- and long-term prognosis, similar angiographic and hemodynamic patterns, and deserve management identical to that for patients with transmural myocardial infarction. It is hoped that by combining the older modalities with new diagnostic methods it will be possible to quantitate the magnitude of old and new myocardial ischemic necrosis on which prognosis to a great extent is based.
Acute Disease↗
Incidence of right ventricular asynergy in patients with coronary artery disease.
The effects of coronary artery disease on patterns of left ventricular contractility have been thoroughly investigated. In contrast, little is known about the incidence of right ventricular dysfunction induced by this disease. To evaluate the frequency of right ventricular asynergy, biplane right ventricular cineangiograms were obtained in 26 patients. Seven segmental axes of shortening were analyzed in each end-systolic and end-diastolic frame and normalized as percent decrease (or increase) in axis from end-diastolic length. Of 26 patients, 8 (Group I) served as normal (control) subjects. The remaining 18 patients had significant coronary artery disease; 6 of these (Group II) had no significant disease of the right coronary artery, whereas 12 (Group III) had significant obstruction of this artery. Four patients in Group II had a previous anteroseptal myocardial infarction, and six in Group III had a previous inferior myocardial infarction. There was a progressive decrease in segmental axes of shortening from Group I to II and from Group II to II, but the decrease was not significant at the level P less than 0.01. Only one patient in Group II had frank dyskinetic segmental motion of the interventricular septum (this patient had had a previous anteroseptal myocardial infarction), whereas two patients in Group III had dyskinetic segmental motion of the free right ventricular wall (both had previous inferior myocardial infarction). Therefore, coronary artery disease seldom produces significant right ventricular asynergy. Abnormal septal motion is associated with previous anteroseptal myocardial infarction; however, dyskinetic motion of the free right ventricular wall occurs only in patients with a right coronary arterial lesion and previous inferior myocardial infarction.
Angiocardiography↗
Clinical significance of coronary arterial ectasia.
In a study group of 2,457 consecutive patients undergoing cardiac catheterization, 30 patients had coronary arterial ectasia, an irregular dilatation of major vessels up to seven times the diameter of branch vessels. The frequency of hypertension, abnormal electrocardiogram and history of myocardial infarction was greater than that in a control group with obstructive coronary artery disease. Patients with ectasia did not differ from patients with obstructive disease in sex, age, prevalence of angina or presence of metabolic abnormalities. Six deaths occurred in the group with ectasia during a mean follow-up period of 24 months (annual rate of 15 percent). Extensive destruction of the musculoelastic elements was evident, resulting in marked attenuation of the vessel wall. The short-term prognosis in this group is the same as in medically treated patients with three vessel obstructive coronary artery disease.
Adolescent↗
Regional myocardial blood flow during hyperemia induced by contrast agent in patients with coronary artery disease.
Regional myocardial specific blood flow (regional specific flow) was measured at rest and during contrast hyperemia after the intracoronary injection of xenon-133. The changes in regional specific flow were transient, resulting in some compromise in one of the underlying restraints of the inert gas washout method, namely, the presence of a steady state. Therefore, to determine the clinical utility of this technique, regional specific flow values obtained with this method were correlated with the presence and severity of coronary artery disease as assessed from the coronary arteriogram and left ventriculogram. Regional specific flow during contrast hyperemia was 186+/- 11 (mean +/- 1 standard error of the mean) ml/min per 100 g in control patients and 115+/-5 in patients with coronary artery disease. There was an inverse relation between regional specific flow during contrast hyperemia and the percent coronary stenosis when the stenosis was 40 percent or greater (r = 0.70, P less than 0.001). Regional specific flow was significantly less in patients with asynergy (77 +/- 10 ml/min per 100 g) than in patients with normal ventricular function (105 +/- 5) distal to coronary stenoses of greater than 75 percent. Thus regional specific flow measured during contrast hyperemia using the xenon washout technique and the Anger camera differentiated patients with normal coronary arteriograms from those with coronary artery disease. With this technique, good correlation was shown between regional specific flow and the percent coronary stenosis and presence of ventricular wall abnormalities. The information obtained with this method may provide prognostic information concerning suitability for surgical intervention.
Angiocardiography↗
S-T elevation after infarction.
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Cardiomegaly↗
Problems in echocardiographic volume determinations: echocardiographic-angiographic correlations in the presence of absence of asynergy.
The relation of minor and major axes of the left ventricle was determined in 100 left ventriculograms performed in the right anterior oblique projection. This relation taken over a wide range of volumes was used to derive a theoretically correct equation for determination of ventricular volume by echocardiography. The final equation was: V =[7.0/2.4 +d] (D3), where V = volume and D = the echocardiographically measured internal dimension. In 12 patients without asynergy, this equation accurately and directly calculated end-systolic and end-diastolic volumes whether the left ventricle was small or large. However, in 12 patients exhibiting left ventricular asynergy the correlation between angiographically and echocardiographically determined volumes was poor. Thus, caution is recommended in the use of time-motion echocardiography to calculate ventricular volumes in patients with coronary artery disease and possible left ventricular asynergy.
Angiocardiography↗
Comparison of selective left ventriculograms with levophase ("forward") ventriculograms in patients with coronary artery disease.
In order to compare levophase ("forward") ventriculograms to standard (selective) LV cineangiography, 10 patients with coronary artery disease were studied by (1) selective injection of contrast medium into the LV cavity followed by (2) injection into the right ventricle and filming the levophase. Biplane cineangiograms were used to calculate the end-diastolic volume index (EDVI), end-systolic volume index (ESVI), stroke volume index (SVI), and ejection fraction (EF). Values for the two respective techniques were then compared. Not only were correlation coefficients for the two methods low, but there was also a statistically significant difference between the two SVI (66 +/- 26 ml. for selective and 53 +/- 25 ml. for levophase injection; p less than 0.02) and the two EF (67 +/- 7 per cent for selective and 52 +/- 12 per cent for levophase injection; p less than 0.01). Levophase cineangiograms therefore significantly underestimate the LV ejection fraction when compared to standard (selective) LV cineangiography. These differences must be considered when evaluating greatly divergent interinstitutional survival rates for patients with low EF who undergo coronary artery bypass surgery, and when selecting candidates for bypass surgery on the basis of the angiographic data.
Adult↗
The significance of chest pain occurring with the Master two step test.
This study has assessed whether chest pain occurring during or after a step test could improve the accuracy of exercise testing in the diagnosis of coronary artery disease (CAD). One hundred and fifty-three consecutive men underwent the double Master two-step test prior to diagnostic coronary arteriography. On hundred and twenty-five had CAD, 28 insignificant disease (NCA). The post-exercise ECG showed at least 0-5 mm of ischaemic ST depression in 71 (57%) of the men with CAD and in five (18%) with NCA. Ischaemic ST depression of at least 2-0 mm occurred in 24 men, all of whom had CAD. Chest pain occurred during or after the test in 78 (62%) men with CAD and in nine (33%) with NCA. The accuracy of diagnosis of CAD could be improved by combining the occurrence of chest pain in the test with a positive post-exercise ECG. Either a 2 mm positive post-exercise ECG with or without test angina or 0-5 mm to 1-9 mm positive post-exercise ECG with test angina was found in 56 (45%) of men with CAD and one (4%) with NCA. Thus the concurrence of chest pain during or after a double Master two-step test, together with ischaemic ST segment depression after the test, strongly suggests the presence of CAD.
Angina Pectoris↗
B-scan ultrasonography in idiopathic hypertrophic subaortic stenosis. Study of left ventricular outflow tract and mechanism of obstruction.
Studies were made with standard time motion and B-scan echocardiography on 48 patients including 5 with idiopathic hypertrophic subaortic stenosis (hypertrophic obstructive cardiomyopathy), undergoing diagnostic cardiac catheterization. The dimensions of the left ventricular outflow (O) and inflow (I) tracts were measured on the B-scan images. The outflow tract was significantly narrowed in idiopathic hypertrophic subaortic stenosis at both end-systole (1-1+/-0-1 cm) and end-diastole (1-3+/-0-1 cm) when compared with the average width in other patients (2-6+/-0-1 and 3-0+/-0-1 cm, at end-systole and end-diastole, respectively) (P less than 0-001) or normal subjects (2-4+/-0-3 and 2-9+/-0-2 cm) (P less than 0-01). Furthermore, the O/I ratio differed significantly in idiopathic hypertrophic subaortic stenosis (0-5+/-0-1 at end-systole and 0-6+/-0-1 at end-diastole) from that in all other groups (1-4+/-0-1 at both end-systole and end-diastole) (P less than 0-005). There was no appreciable change in the width of the outflow tract from mid- to end-systole in the two patients in whom this was examined. The data support the contention that the anterior leaflet of the mitral valve assumes an abnormally anterior position in idiopathic hypertrophic subaortic stenosis. Though the systolic anterior movement of the tip of the anterior leaflet of the mitral valve shown by M-mode echocardiography could not readily be confirmed with B-scans, we believe that the narrowed outflow tract found in the present investigation contributes to the obstruction that occurs in this disease. We suggest that this outflow tract narrowing is probably caused by hypertrophy of the ventricular septum which in itself contributes to the narrowing, but which also displaces the papillary muscles and thus produces abnormal traction on the mitral valve and striking anterior displacement of the valve apparatus.
Adult↗
Alterations of myocardial amino acid metabolism in chronic ischemic heart disease.
Arteriovenous differences (A-V) of all naturally occurring amino acids, lactate, and oxygen were measured simultaneously with coronary sinus blood flow (CSBF) in 8 normal subjects and 11 patients with coronary artery disease at rest and during pacing stress. Mean values for CSBF and myocardial oxygen consumptions (MVO2) for the two groups were similar at rest and during pacing, although mean CSBF and MVO2 increased significantly in both groups in the paced as compared to the rest state. Alanine (ala) was the only amino acid released by the myocardium, while only glutamic acid(glu) demonstrated uptake. Mean A-V ala was negative at rest in the control and coronary disease groups (-4.8+/-3.8 vs. -22.0+/-3.0 nmol/ml, respectively), but was significantly more negative in the coronary group (P less than 0.001) and not statistically different than zero in the normals. A-V ala became significantly negative with pacing in the normals (-10.0+/-4.3 nmol/ml), remained unchanged in the coronary group (-23.0+/-2.9 nmol/ml), and was significantly more negative in the coronary group (P less than 0.05). Calculation of data on the basis of net ala flux ([A-V] X [CSBF X hematocrit]) yielded similar results as that obtained with A-V differences. A-V glu was significantly positive in normals (27.7 +/- 8.9 nmol/ml, P less than 0.01) and coronary patients (59.9 +/- 8.9 nmol/ml, P less than 0.01) at rest but significantly greater in the latter group (P less than 0.001). With pacing, A-V glu remained significantly greater than zero in coronary patients (35.3 +/- 6.3 nmol/ml) and decreased to zero in the normals (4.3 +/- 11.8 nmol/ml). Calculation of net glu flux (nmol/min) at rest yielded data similar to that based on A-V difference. With pacing, net glu flux in the coronary patients did not decrease due to the augmentation of CSBF. No relation between A-V glu or ala and CSBF, MVO2 or A-V lactate was noted. The data demonstrate that specific alterations of myocardial amino acid metabolism characterize patients with chronic ischemic heart disease.
Adult↗
Pharmacotherapy of myocardial ischemia.
The cornerstones of pharmacotherapy for myocardial ischemia are the nitrites and the beta-adrenergic blocking agents. These drugs not only inhibit cardiac mechanical activity (and therefore energy requirements) in a variety of ways but also redistribute available blood flow to the potentially ischemic segments of cardiac muscle. The least effective dose of nitroglycerin and the most tolerated (or blocking) dose of propranolol provide the optimum in management. There is increasing evidence that certain orally administered nitrates at larger than usual dosage can further increase the tolerance to effort. Amelioration of hypertension or congestive failure may play a significant role in selected patients.
Adrenergic beta-Antagonists↗