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Biomedical subjects

H Smulyan

Publications and source records attributed to H Smulyan.

At least 55 records · Page 3Linked to original sources
PubMed1983

Improved electrocardiographic criteria for the diagnosis of left anterior hemiblock.

New electrocardiographic (ECG) criteria for the diagnosis of left anterior hemiblock are proposed. The proposed criteria are based upon the relation between portions of the vectorcardiographic (VCG) QRS loop in the frontal plane and the corresponding portions of the ECG QRS complexes recorded by the limb leads. The application of the proposed criteria requires that the tracings be obtained with 3-channel ECG machines so that the temporal relation between the QRS complexes in simultaneously recorded limb leads can be inspected. This type of analysis of the electrocardiogram permits prediction of features of the VCG QRS loop that are important for the diagnosis of left anterior hemiblock. The proposed ECG criteria for the diagnosis of left anterior hemiblock are (1) the QRS complexes in leads aVR and aVL each end in an R wave (terminal R wave), and (2) the peak of the terminal R wave in lead aVR occurs later than the peak of the terminal R wave in lead aVL. The sensitivity and specificity of the proposed criteria were empirically evaluated using series of electrocardiograms obtained under clinical circumstances during which the occurrence of left anterior hemiblock was, respectively, likely and unlikely. The performance of the proposed criteria was statistically superior to that of 2 sets of frontal plane QRS axis criteria.

Adult↗
PubMed1983

Systolic hypertension. Direct and indirect BP measurements.

The BPs of each of 26 patients with systolic hypertension were simultaneously measured indirectly by the cuff-mercury sphygmomanometer (cuff) and directly by intra-arterial recording from a brachial artery. The systolic BPs recorded by the two methods were comparable, indicating that systolic hypertension can be reliably diagnosed by readings from the cuff alone. However, the average diastolic BP was significantly overestimated by the cuff. This error in turn led to an underestimation by the cuff of the pulse pressure and overestimation of the mean arterial pressure. Thus, the low intra-arterial (true) diastolic BP and wide pulse pressure make increased arterial stiffness a plausible contributing factor in the pathophysiology of systolic hypertension.

Adult↗
PubMed1983

Acute effects of captopril on cardiopulmonary hemodynamics and renin-angiotensin-aldosterone and bradykinin profile in hypertension.

Hemodynamic variables were measured and plasma renin activity (PRA), angiotensin II (AII), aldosterone, and bradykinin assays performed in 21 hypertensive men on regular diet and thiazide diuretics before and 60 to 90 minutes after 25 mg oral captopril. Heart rate, right and left ventricular filling pressures, mean cardiac index (CI), and pulmonary vascular resistance (PVR) remained unchanged. The mean intra-arterial pressure (MAP) fell from 140 +/- 5 to 116 +/- 6 mm Hg (p less than 0.001) correlating with reduction of systemic vascular resistance (SVR) (r = 0.87, p less than 0.001), control PRA (r = 0.59, p less than 0.01), and All levels (r = 0.72, p less than 0.005) but not with control bradykinin or its postcaptopril rise (p less than 0.01). The fall in SVR correlated with reduction in plasma All (r = 0.80, p less than 0.001) and aldosterone concentrations (r = 0.53, p less than 0.05). Of four patients (19%) with precipitous fall in MAP after captopril, three needed volume expansion for circulatory support. We conclude: (1) All reduction by captpril and not bradykinin potentiation explains most of the agent's hemodynamic response in hypertensive circulation, (2) endogenous All may have a supportive role for SVR and possibly for CI but not for PVR, and (3) extra precaution is warranted while captopril is being started in patients taking diuretics.

Adult↗
PubMed1983

Effects of tiodazosin, a new antihypertensive, hemodynamics and clinical variables.

Tiodazosin, a new antihypertensive, resembles prazosin in structure and alpha-adrenergic-blocking activity, and it also exerts a direct vasodilator effect. We evaluated its long-term hemodynamic and systemic effects in patients with essential hypertension. Our data show that after 10 wk of therapy with tiodazosin, 7 of our 10 patients had significant reduction in intra-arterial mean blood pressure as a result of a fall in systemic vascular resistance. Heart rate, cardiac output, and plasma volume did not change. Systemic effects were minor and included a gain in weight and a reduction in hemoglobin, hematocrit, platelet count, serum protein, albumin, bilirubin, and specific gravity of urine. No patient initially developed orthostatic symptoms after the first dose, but there were transient episodes of light-headedness in three patients, palpitations in two, increased urinary frequency in one, and drooping of eyelid in another during the trial period. One patient developed profound orthostatic hypotension, which could be attributed to the drug. Because of such side effects and the failure to lower blood pressure in 30% of patients with essential hypertension, tiodazosin appears to have several important drawbacks and little advantage over currently available antihypertensives.

Adult↗
PubMed1983

Arterial oxygenation and pulmonary function with Saralasin in chronic lung disease.

During our earlier saralasin infusion study in hypertensive patients, we found a drug-induced rise in arterial oxygen tension (PaO2) associated with unchanged mixed venous PO2 or the PaCO2 and unrelated to cardiopulmonary hemodynamic changes. To test the hypothesis that saralasin improved pulmonary mechanics, blood gases, lung mechanics, lung volumes, diffusing capacity, and distribution of ventilation were analyzed and cardiac output (CO) measured in 12 normotensive men with chronic pulmonary disease before and during a 2 1/2 hour infusion of Saralasin (5 micrograms/kg/min). The PaO2 increased from a mean of 63 +/- 3 (SEM) to 70 +/- 3 mm Hg (p less than 0.001), while the CO decreased from 6.81 +/- 0.52 L/min to 6.18 +/- 0.48 L/min (p less than 0.005). The change in (delta)CO correlated with delta PaO2 (r = -0.67, p less than 0.05). Total systemic vascular resistance rose from 1,201 +/- 134 to 1,353 +/- 147 dynes X sec X cm5 (p less than 0.001). The PaCO2 and other measurements remained unchanged. We conclude that saralasin raised the PaO2 not by changing pulmonary function or mechanics, but by redistributing pulmonary blood flow and improving the ventilation-perfusion relationship.

Adult↗
PubMed1982

Continuous propranolol infusion following abdominal surgery.

Thirteen patients given long-term propranolol hydrochloride therapy for heart disease required 15 abdominal surgical procedures. On each occasion, propranolol therapy was maintained postoperatively by continuous intravenous infusion. Duration of infusion ranged from one to nine days, and each infusion was monitored with frequent measurements of serum propranolol concentrations. In patients with normal hepatic and renal function, therapeutic serum propranolol levels were attained with a narrow dose range averaging 3.0 mg/hr, irrespective of body weight. All patients had postoperative courses free of complications attributable to beta-blockade. This form of therapy appears to protect against sympathetic stimulation during the perioperative period and to prevent the propranolol withdrawal syndrome in such patients. Continuous propranolol infusion might also be useful in other clinical situations, such as acute aortic dissection or severe thyrotoxicosis, where predictable therapeutic serum propranolol levels could be maintained when oral therapy was contraindicated.

Abdomen↗
PubMed1982

Detection of experimental right ventricular necrosis using vectorcardiograms obtained during artificial pacing.

This study was carried out to evaluate the possible usefulness of the VCG obtained during right ventricular pacing in the diagnosis of right ventricular necrosis. Myocardial necrosis was produced by injecting 40% formalin into the ventricular walls of 18 open-chest mongrel dogs. The injections were made in the inferior wall of the left ventricle in nine dogs (Group A) and in the inferior wall of the right ventricle in the remaining nine dogs (Group B). Analysis of vectorcardiographic QRS loops obtained during artificial pacing of the right ventricular apex was made before and 60 minutes after the injections. In Group B, but not in Group A, the injections resulted in superior displacement of initial QRS forces as indicated by measurements of time, distance, amplitude and angle. The pacing VCG, performed in serial fashion, is a specific and sensitive means of detecting right ventricular inferior wall necrosis in the experimental animal. Application of these findings to the diagnosis of myocardial infarction in humans requires further investigation.

Animals↗
PubMed1982

Improved electrocardiographic criteria for the diagnosis of inferior myocardial infarction.

New electrocardiographic (ECG) criteria for the diagnosis of inferior myocardial infarction (IMI) are proposed. The criteria are based upon the relationships between portions of the vectorcardiographic (VCG) QRS loop in the frontal plane and the corresponding portions of the ECG QRS complexes recorded in leads II and III. The application of the proposed criteria requires that the tracings be obtained with three-channel ECG machines so that the temporal relationships between the QRS complexes in lead II and those in simultaneously recorded lead III can be inspected. This type of analysis of the ECG permits important features of the contour of the VCG QRS loop to be predicted. The proposed ECG criteria for the diagnosis of IMI are: in the absence of counterclockwise rotation in the frontal plane, (1) Q waves of 30 msec or longer in lead II or (2) regression of initial inferior forces from lead III to lead II. The proposed ECG criteria were evaluated in an initial series of 333 patients and, using a blind experimental design, in a confirmatory series of 94 patients. The performance of the proposed criteria was statistically superior to that of two sets of ECG Q-wave criteria and comparable to that of the VCG criteria of Starr et al.

Adult↗
PubMed1981

Vectorcardiographic manifestations of experimental right ventricular necrosis.

This study was carried out to evaluate the possible usefulness of the VCG in the diagnosis of right ventricular necrosis. Myocardial necrosis was produced by injecting 40% formalin into the ventricular walls of 21 open-chest mongrel dogs. The injections were made in the inferior wall of the left ventricle in eight dogs (Group A) and in the inferior wall of the right ventricle in 13 dogs (Group B). Analysis of vectorcardiographic QRS loops obtained before and two hours after the injections revealed that both left and right ventricular necrosis resulted in a decrease in: maximum inferior amplitude, inferior amplitude at 10 and 20 msec. and maximum frontal plane angle. In Group A, six dogs had counterclockwise initial forces in the frontal plane before the injections and these became clockwise following the injections. In Group B, nine dogs had counterclockwise initial forces in the frontal plane before the injections and these remained counterclockwise following the injections. The only consistent QRS change in scalar ECGs that occurred after the injections was the development of small Q waves in the six dogs in Group A that manifested clockwise initial forces in the frontal plane. The VCG performed in serial fashion may be more sensitive than the 12 lead ECG for detecting right ventricular inferior wall necrosis in the experimental animal. Application of these findings to the diagnosis of myocardial infarction in humans requires further investigation.

Animals↗
PubMed1979

Effects of a portacaval or peritoneovenous shunt on renin in the hepatorenal syndrome.

Ten patients with hepatorenal syndrome were evaluated before and after creation of a side-to-side portacaval shunt or insertion of a peritoneovenous shunt, procedures which produced an increase in plasma volume and cardiac output. In the seven patients who survived surgery, renal function improved significantly, plasma renin activity fell from high to normal levels, and low levels of plasma renin substrate increased. Prior to surgery, blockade of angiotension II by saralasin produced hypotension and an increase in plasma renin activity, whereas after surgery, saralasin had no effect on blood pressure or renin. Our findings suggest that decreased "effective" plasma volume may be important in the stimulation of renin release and possibly in the pathophysiology of renal failure in the hepatorenal syndrome.

Angiotensinogen↗
PubMed1979

Improvement in arterial oxygenation by saralasin infusion in man.

Simultaneous hemodynamic and blood gas measurements were performed in 26 hypertensive adults, who were cigarette smokers, before and after a 30-minute infusion of saralasin (5 microgram/kg/min) which is a highly specific competitive antagonist of angiotensin II (AII). The arterial pressure fell in nine, rose in seven and was unchanged in ten patients. The mean cardiac index for the entire group remained unchanged. Pulmonary arterial or wedge pressure, pulmonary vascular resistance, arterial PCO2 and pH did not change. Unrelated to the hemodynamic changes, the mean arterial oxygen pressure (PaO2) increased from 68.6 +/- 2.2 mm Hg to 73.9 +/- 2.1 mm Hg (P less than 0.001). In the absence of a significant increase in alveolar ventilation as indicated by an unchanged mean PCO2 and lacking a hemodynamic explanation, the mechanism for the rise in PaO2 is speculative at this stage. The possibility of an improvement in the distribution of ventilataion by saralasin infusion is under investigation.

Adult↗
PubMed1978

Elevated ejection fractions in patients with the anginal syndrome and normal coronary arteriograms.

The etiology of chest pain in patients with the anginal syndrome and normal coronary arteriograms has not been established. There has been no explanation for the association of electrocardiographic, hemodynamic, and myocardial metabolic abnormalities consistent with myocardial ischemia observed in some patients with this disorder. Historical, clinical, laboratory, and hemodynamic data of 45 patients (24 females, 21 males), mean age 47.5 years, with chest pain and normal coronary arteriograms are reviewed. Left ventriculograms were analyzed utilizing the single-plane cineangiographic measurement of left ventricular volume. Systolic ejection fractions for the 45 patients ranged from 0.66 to 0.91 (mean 0.80 +/- 0.01 SEM). Ventricular volumes determined angiographically revealed mean end-diastolic and end-systolic volumes of 83 +/- 5 ml and 18 +/- 2 ml, respectively. The mean changes in longitudinal and transverse segmental axis shortening that occurred during ventricular systole were 28.8% and 50.7%, respectively. These elevated values for ejection fraction, and reduced measurements of ventricular volumes, indicate that some patients with chest pain and normal coronary arteriograms may have small hearts with hyperdynamic ventricular contraction. These findings suggest that hyperdynamic ventricular contraction may play a causative role in the development of transient, angina-like chest pain in these patients. The etiology of the proposed hyperdynamic ventricle is unknown, but it may be attributable to increased beta-sympathetic stimulation of the myocardium.

Adult↗
PubMed1978

Sodium nitroprusside therapy in congestive cardiomyopathy-variability in hemodynamic response.

Twelve of 17 patients (group A) with congestive cardiomyopathy improved hemodynamically during sodium nitroprusside (NP) infusion. Five patients (group B) failed to increase their cardiac output. The two groups were identical in clinical presentation and had comparable cardiomegaly and left ventricular filling pressure (LVFP). However, group A had a baseline cardiac index (CI) lower than 2.5 L/min/m2 and high peripheral systemic (PSR) and total pulmonary vascular resistance (PR). In contrast, group B had a control of CI of higher than 2.5 L/min/m2 and near normal PSR and PR. Furthermore, a highly significant correlation was observed between the calculated levels of control PSR and their subsequent reduction during NP infusion. The higher the initial resistance, the more marked was its fall on NP as documented in group A. In group B, the PSR was probably not high enough for NP to be effective in increasing the cardiac output further by vasodilatation. We conclude that NP infusion may not increase cardiac output in congestive cardiomyopathy, in spite of a high LVFP, if the PSR is near normal.

Adult↗
PubMed1978

An evaluation of the results of left ventricular aneurysmectomy: use of a simplified method for analysis of the left ventriculogram.

Twenty-three patients underwent left ventricular aneurysmectomy without coronary artery bypass or other surgical procedure. Fourteen patients (Group 1) benefitted from surgery, and nine fared poorly (Group 2), including the four postoperative deaths. Among the 19 survivors, 17 had postoperative catheterizations. Pre- and postoperative left ventriculograms in the right anterior oblique projection were analyzed by planimetry of the aneurysmal and non-aneurysmal areas. This method provided data favorably altered by surgery in the improved patients and unchanged in the others. None of the preoperative ventriculographic measurements effectively separated the postoperative patient groups. The poor results in the Group 2 patients were of heterogeneous origin arising from pre-, peri- and postoperative factors. The more important factors were the largest and smallest aneurysms, surgically induced mitral insufficiency, and progressive coronary artery disease. Thus, the improvement in surgical results from better angiographic preoperative case selection is possible, but limited.

Adult↗
PubMed1978

Systemic and pulmonary hemodynamic effects of saralasin infusion in hypertension. Predictability of plasma renin status from hemodynamic changes.

Hemodynamic measurements were obtained before and after 30 minutes of saralasin infusion in 26 fasting adults with hypertension (25 men and 1 woman). Nine showed a depressor response with a decrease in mean intaarterial pressure greater than 20 mm Hg. Ten were nonresponders and seven had an agonistic response with an increase in mean arterial pressure of greater than 10 mm Hg. Heart rate, pulmonary arterial and wedge pressures and pulmonary vascular resistance were nearly identical in the three groups and remained unchanged. Cardiac index decreased from a mean of 2.76 +/- 0.14 (standard error of the mean) to 2.48 +/- 0.1 liters/min per m2 in the nonresponders (P less than 0.02) but remained unchanged in the groups with a depressor or an agonistic response. The mean systemic vascular resistance decreased from 2,406 +/- 303 to 1,839 +/- 265 dynes sec/cm5 in the group with a depressor response (P less than 0.001) and increased in nonresponders (less than 0.02) and those with an agonistic response (P less than 0.01). However, regardless of the response of mean arterial pressure, systemic vascular resistance decreased only in the 10 patients with a plasma renin activity greater than 5 ng/ml per hour (8 from the depressor response group and 1 each from the nonresponse and agonistic response groups). It is concluded that (1) classification based soley on the response of aterial pressure to saralasin ignores important hemodynamic changes; (2) the response of cardiac index--no change in the patients with a depressor response and a reduction in nonresponders--suggests that endogenous angiotension II supports cardiac output in these groups; (3) a decrease in systemic vascular resistance is better than a decrease in mean arteiral pressure as a predictor of the status of the plasma renin activity; and (4) lack of change in pulmonary vascular resistance suggests that endogenous angiotension II plays an insignificant role in maintaining the resistance of the pulmonary vasculature.

Adult↗