Harold Smulyan

The hemodynamics in labile hypertension.

Abstract The hemodynamics have been studied in 73 subjects selected on the basis of an arbitrary definition for an elevated blood pressure. Two hemodynamic patterns were observed: (1) high output and low resistance, and (2) normal cardiac output and elevated total peripheral resistance. There is some theoretical and clinical evidence that the high cardiac output may indicate a more mild hypertension in terms of severity and the likelihood of the development of fixed essential hypertension. Final proof awaits long-term follow-up, and such a study is underway.

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

Tiodazosin, a new antihypertensive, resembles prazosin in structure and α‐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.

The effect of nitroglycerin on forearm arterial distensibility.

Nitroglycerin acts, in part, to reduce arterial impedance, and thus left ventricular work. The reduction in arterial impedance is largely attributable to a fall in systemic vascular resistance, but may also be due to an increased distensibility of the arterial tree. In this study, volume distensibility of forearm arteries was calculated from measurements of pulse-wave velocity before and during intravenous nitroglycerin infusion. Since a fall in blood pressure itself increases arterial distensibility, the induced blood pressure change was controlled as a variable by repeating the measurements with the subjects forearm in a plastic cylinder and repeating the measurements at a variety of altered cylinder pressures. At every studied pressure, nitroglycerin infusion increased forearm arterial distensibility, demonstrating another way in which nitroglycerin reduces left ventricular afterload. Since the pulsatile portion of cardiac work is approximately 10% of total work, the magnitude of this nitroglycerin effect on cardiac function is probably small.

Electrocardiographic criteria for the diagnosis of combined inferior myocardial infarction and left anterior hemiblock

New electrocardiographic (ECG) criteria for diagnosing the combination of inferior myocardial infarction and left anterior hemiblock are proposed. The proposed criteria are based upon the relations between portions of the vectorcardiographic QRS loop in the frontal plane and the corresponding portions of the QRS complexes recorded by the limb leads. The application of the proposed criteria requires that the tracings be obtained with 3-channel ECG machines. The proposed criteria for the diagnosis of inferior myocardial infarction and left anterior hemiblock are as follows: (1) leads aVR and aVL both end in R waves, with the peak of the terminal R wave in lead aVR occurring later than the peak of the terminal R wave in lead aVL, and (2) a Q wave of any magnitude is present in lead II. The performance of the proposed criteria was superior to that of 10 combinations of traditional ECG criteria for inferior myocardial infarction and left anterior hemiblock.

Electrocardiographs criteria for the diagnosis of anterior myocardial infarction: Importance of the duration of precordial R waves

A systematic evaluation of a large number of electrocardiographic (ECG) variables that might be useful for diagnosing anterior myocardial infarction (MI) is reported. Previous anterior MI was shown to be present or absent by cardiac catheterization in 199 patients. The best discriminator between cases and noncases of anterior MI in most patients is the presence of a Q wave of any magnitude or an initial R wave less than 20 ms in lead V2. In patients with ECG evidence of associated left ventricular or type C right ventricular enlargement, the more stringent criterion of a Q wave of any magnitude in lead V2 yielded the optimal combination of sensitivity and specificity for diagnosing anterior MI. The diagnostic performance of the proposed criteria for anterior MI is superior to that of more traditional criteria that use measurements of the absolute and relative amplitudes of precordial R waves.

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.

Comparison of optimal scalar electrocardiographic, orthogonal electrocardiographic and vectorcardiographic criteria for diagnosing inferior and anterior myocardial infarction

A scalar electrocardiogram (ECG), orthogonal ECG and vectorcardiogram (VCG) were recorded in 46 normal persons, 38 patients with inferior myocardial infarction (MI) and 22 patients with anterior MI proved at cardiac catheterization. The diagnostic information provided by the scalar ECG, orthogonal ECG and VCG was quantitatively analyzed and the optimal criteria for diagnosing inferior and anterior MI exhibited by each method were identified. The optimal scalar electrocardiographic, orthogonal electrocardiographic and vectorcardiographic criteria, respectively, are: For inferior MI: initial superior duration in lead aVF greater than 30 ms (sensitivity 63%, specificity 100%), superior/inferior amplitude ratio in lead Y greater than or equal to 0.2 (sensitivity 63%, specificity 96%), initial superior duration greater than 29 ms or initial superior distance greater than 0.4 mV in the frontal plane loop (sensitivity 68%, specificity 100%). For anterior MI: initial anterior duration in lead V2 less than 20 ms or initial anterior duration in lead V3 less than 25 ms (sensitivity 91%, specificity 100%), anterior/posterior duration ratio in lead Z less than 0.3 (sensitivity 73%, specificity 98%), initial anterior duration less than 15 ms in the transverse plane loop (sensitivity 64%, specificity 98%). There were no significant differences among the performances of the optimal scalar ECG, orthogonal ECG and the VCG for diagnosing inferior MI. However, the performance of the optimal scalar ECG was superior to that of the optimal orthogonal ECG and the optimal VCG for diagnosing anterior MI (chi-square = 5.20, p less than 0.02 and chi-square = 7.14, p greater than 0.01, respectively).

Lack of relationship between plasma insulin and glucagon levels and angiographically-documented coronary atherosclerosis☆

In 120 consecutive patients undergoing diagnostic coronary arteriography, fasting blood glucose, plasma insulin, glucagon, serum cholesterol and triglyceride concentrations were measured. The insulin-glucose ratio and insulin-glucagon ratio were calculated. Forty-five patients had normal coronary arteries, 19 had single vessel coronary artery disease and 56 patients had multiple vessel disease. Fasting blood glucose was greater than 120 mg/100 ml in 37 patients (group A) and included 9 of the 10 known diabetics, 3 of whom were being treated with insulin. Seventy-seven patients included in group B had fasting blood glucose concentration less than 120 mg/100 ml. Patients with multiple vessel coronary disease in either group had higher blood glucose and cholesterol concentrations than those with normal coronary arteries or the ones with single vessel disease, but they did not have higher plasma insulin or glucagon levels nor increased insulin-glucose or insulin-glucagon ratios. With comparable extent of coronary artery disease patients in group A had higher plasma insulin levels and insulin-glucagon ratios than those in group B, but no correlation exists between the presence or extent of coronary atherosclerosis and these variables in either group. Thus, neither fasting plasma insulin level nor insulin-glucagon ratio predicts the status of underlying coronary atherosclerosis in either diabetics or nondiabetics.

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.

Importance of the terminal portion of the QRS in the electrocardiographic diagnosis of inferior myocardial infarction

The scalar electrocardiograms of 64 patients with inferior wall myocardial infarction (MI) and 87 normal subjects were quantitatively analyzed to determine the respective contributions of the initial and terminal portions of the QRS to the diagnosis of inferior MI. Of the 10 best individual electrocardiographic criteria for inferior MI, 7 were Q-wave criteria and 3 were criteria that consisted of delayed termination of the QRS in leads II or III. Combining the best terminal QRS criterion (the QRS in lead III ending at least 20 ms later than the QRS in lead I) with the 7 best Q-wave criteria and the best Q-wave criterion (Q wave 40 ms or longer in lead aVF) with the 3 best terminal QRS criteria, resulted in criteria with better sensitivities and overall diagnostic performances than those of the individual criteria. Analyzing the vectorcardiograms that were also available in 26 of the patients with inferior MI and 34 of the normal subjects showed that the delayed inscription of the end of the QRS in leads II and III in patients with inferior MI is due to redirection of the terminal forces of ventricular depolarization. The terminal portions of the QRS complexes in the limb leads, considered both alone and in conjunction with traditional measurements of Q waves, contain information that is useful for diagnosing inferior MI.