Relationships between left ventricular mass and clinical, biohumoral and hemodynamic parameters in human hypertension

The relationships between left ventricular mass (LVM), assessed by echocardiography, and several biohumoral and hemodynamic parameters were studied in 63 mild or moderate hypertensive patients and in an age-matched group of 23 normotensive subjects. In hypertensive patients, but not in normotensives, LVM index was significantly correlated with beta-adrenoceptor responsiveness, as evaluated by the chronotropic response to isoproterenol ( CD25 ) (r = 0.525, p less than 0.001) and with the 24-hour catecholamine urinary output (r = 0.485, p less than 0.001). Both CD25 and the catecholamine urinary output were significantly higher in the hypertensives as compared with the normotensive subjects. Moreover, left ventricular wall thickness (septum + posterior wall) was significantly correlated with CD25 and urinary catecholamines only in hypertensive patients. No significant correlation was found between LVM or wall thickness and body surface area, age, blood pressure, heart rate, cardiac output, total peripheral resistance and left ventricular systolic wall stress, whereas CD25 was correlated with urinary catecholamines only in hypertensive patients (r = 0.606, p less than 0.001). These results seem to support the hypothesis that an elevated adrenergic tone may exert a permissive role in the development of left ventricular hypertrophy in human hypertension.

Predictability of antihypertensive efficacy of selective beta 1 blockers

The possibility that hemodynamic and biohumoral factors may help predict the antihypertensive effectiveness of selective beta 1 blockers was investigated. The effects of 3 wk of treatment with two selective beta 1 blockers, metoprolol and atenolol, were observed in 54 patients with mild or moderate essential hypertension. No significant difference between the hemodynamic effects of the two drugs was found. The percent fall in systolic blood pressure induced by the two correlated strongly with the pretreatment values of the chronotropic response to isoproterenol and with the pretreatment values of cardiac output, heart rate, and plasma renin activity (PRA). There was no correlation between the decrease in systolic blood pressure induced and initial 24-hr urinary catecholamine output, total peripheral resistance, and plasma aldosterone. Percent fall in diastolic blood pressure correlated only with the pretreatment levels of PRA. Our results support the view that the hypotensive effect of beta 1 blockers are predictable on the basis of the pretreatment values of chronotropic response to isoproterenol, PRA, heart rate, and cardiac output.

Anterior S-T changes during acute inferior myocardial infarction

We investigated the clinical course of 57 patients with acute inferior myocardial infarction as regards anterior S-T segment depression. Thirty of them showed S-T segment depression greater than or equal to 0.15 mV in at least 2 precordial leads, and 27 did not exhibit such changes. Twenty-seven patients underwent post-infarction exercise stress test. Furthermore, coronary arteriographic findings and left ventricular performance were evaluated in 8 of these patients with and in 8 without anterior S-T segment depression. Patients with anterior S-T segment depression showed greater inferior S-T segment elevation on admission ECG and deeper Q wave in lead aVF in ECG tracings recorded 1 month later. Higher incidences of in-hospital angina (10/30 vs 2/27, P = 0.01) and of late development of cardiac failure (5/21 vs 0/19, P = 0.03) were found among patients with anterior S-T segment depression. They showed a higher overall coronary score (82.4 +/- 31.0 vs 32.5 +/- 28.9, P = 0.002) and left anterior descending artery score (44.1 +/- 20.7 vs 8.5 +/- 16.1, P = 0.0009) and a reduced ventricular performance, evaluated by ventriculography score (49.5 +/- 2.7 vs 51.8 +/- 2.4, P = 0.05). A higher incidence of mitral regurgitation, secondary to papillary muscle dysfunction, was also found among patients with anterior S-T segment depression (4/8 vs 0/8, P = 0.04). Furthermore, the degree of anterior S-T segment depression in each of these subjects was closely correlated with the corresponding difference from normal ventricular score (r = 0.86, P less than 0.01). Finally, no difference between the two groups of patients was found as to incidence of positive exercise stress tests.

Orthostatic hypotension due to autonomic dysfunction--different therapeutic effects of propranolol

In two patients with orthostatic hypotension, due to autonomic dysfunction, hemodynamic changes induced by the assumption of erect position have been evaluated before and during chronic propranolol treatment. Under control conditions, the change in posture induced in Patient 1 a fall in systolic and diastolic blood pressure by 51.4 and 30.7%, respectively. Cardiac output was reduced by 26.8% and systemic vascular resistance by 23.3%. During propranolol treatment, systolic pressure decreased only by 28% and diastolic pressure by 7.7%. The decline in systemic vascular resistance on standing was abolished, while the reduction in cardiac output remained unmodified. In Patient 2, symptoms of orthostatic hypotension were related to marked decrease in systolic blood pressure, the diastolic pressure remaining unchanged. Moreover, systemic vascular resistance increased and, thus, orthostatic hypotension was exclusively dependent upon the severe fall in cardiac output on standing. As a consequence, propranolol failed to control orthostatic hypotension in this patient. These data suggest that when orthostatic hypotension is secondary to failure in peripheral vasoconstriction, propranolol may act beneficially. When it is secondary to a fall in cardiac output, beta-blockade is ineffective.

Possible role of arachidonic acid and of phospholipase A2 in the control of lysosomal enzyme release from human polymorphonuclear leukocytes

We have studied the role of arachidonic acid (AA) metabolism in the release of lysosomal enzymes (beta-glucuronidase and lysozyme) from human polymorphonuclear leukocytes (PMNs). 5,8,11,14-Eicosatetraenoic acid (ETYA), which inhibits both the cyclo-oxygenase and the lipoxygenase pathways of AA metabolism, was found to cause a dose-dependent inhibition of lysosomal enzyme release from human PMNs induced by immunological (i.e., serum-treated zymosan: Zx) and nonimmunological stimuli (i.e., formyl methionine-containing peptide and the Ca2+ ionophore A23187). In contrast, the non-steroidal anti-inflammatory drugs (indomethacin, meclofenamic acid and aspirin), which only block the cyclo-oxygenase pathway of AA metabolism, had little effect on enzyme release from PMNs induced by the same stimuli. 5,8,11-Eicosatriynoic acid (ETI), a selective inhibitor of the lipoxygenase pathway of AA metabolism, caused a dose-dependent inhibition of lysosomal enzyme release elicited by Zx, f-met peptide, and A23187. p-Bromophenacyl bromide (BPB), which inhibits the phospholipase A2 (PLA2) activity in several tissues, was found to cause a dose-dependent inhibition of lysosomal enzyme release induced by the same immunological and non-immunological stimuli. The inhibitory effect of BPB on enzyme release was irreversible and extremely rapid. It appears that activation of PLA2 and the products of the AA metabolism, generated via a lipoxygenase pathway, play an essential role in the biochemical control of human PMNs activation and secretion.

Inhibition of histamine release from human basophils in vitro by calmodulin antagonists

Calmodulin is a ubiquitous and versatile Ca2+-binding protein that plays a pivoting role in cellular metabolism. We have investigated the possibility that calmodulin plays a role in immediate hypersensitivity reactions by evaluating the effects of two agents, trifluoperazine dihydrochloride (TFP) and the sulfonamide derivative N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) which selectively bind to calmodulin. TFP and W-7 cause a dose-dependent inhibition of histamine secretion from human basophils in vitro induced by several immunological (i.e., antigen and anti-IgE) and nonimmunological (i.e., formyl-methionine-containing peptide and the Ca2+ ionophore A23187) stimuli. These results indicating that two specific calmodulin antagonists are potent inhibitors of the secretory response of human basophils support the hypothesis that calmodulin may play a role in the control of the release of preformed mediators from human inflammatory cells.

Beneficial effect of papaverine plus raubasine in peripheral arterial insufficiency

It has been demonstrated that, in most arteriopathic patients, vasodilators induce the vascular steal phenomenon, i.e. the shunting of blood from the ischemic to the normally perfused areas. It is conceivable, therefore, that vasoconstrictors may improve in the opposite way, reducing the blood flow to the normal zones and increasing it to the ischemic. A "reverse vascular steal" caused by the simultaneous IV injection of a vasodilator and a beta-blocker has been previously shown; however, the chronic treatment of arteriopathic patients with beta-adrenoceptor blocking drugs often results in increased evidence of peripheral arterial insufficiency; therefore, the combination of a vasodilating drug with a beta-blocker is limited in the clinical practice. The aim of this study was to investigate the efficacy of the combination of the vasodilator papaverine hydrochloride with a drug having vasoconstrictive action without the undesirable side effects of beta-blockers. Accordingly, raubasine (40 mg) was given p.o. associated with papaverine (300 mg) in 10 arteriopathic patients, who presented a significant reduction of blood flow in the affected limb after the administration of 300 mg p.o. of papaverine alone. The measurements of blood flow were performed by impedance plethysmographic recordings to evaluate papaverine plasma concentrations. Data obtained by this study indicate that papaverine alone induces a significant reduction of blood flow starting from the time of its maximal plasma concentration. Raubasine alone does not induce any change in blood flow, while the combination of the 2 drugs significantly increases the blood supply to the affected limb. These favorable results, probably related to the ability of raubasine to induce a reverse vascular steal, suggest that the combination of this drug with a vasodilator such as papaverine may represent a new approach in the treatment of peripheral arterial insufficiency.

Studies of the mechanisms underlying impairment of beta-adrenoceptor-mediated effects in human hypertension

To investigate the impairment of beta-adrenoceptor responsiveness in human hypertension, we evaluated the effect of an oral salt load (400 mEq/day of NaCl for 7 days) on plasma catecholamine concentrations and beta-adrenoceptor-mediated effects in 11 young patients with mild essential hypertension. Responses of heart rate and plasma cAMP to isoproterenol administration were used as indices of beta-adrenoceptor responsiveness. Salt loading induced a significant reduction in the dose of isoproterenol required to raise the heart rate by 25 bpm (CD25) (from 7.6 +/- 1.5 to 5.3 +/- 0.9 micrograms, p less than 0.05) and an increase in the slopes of the regression lines for heart rate changes and isoproterenol doses (delta HR/IS) (from 3.3 +/- 0.6 to 4.7 +/- 0.7, p less than 0.05) and for plasma cyclic AMP (cAMP) level changes and isoproterenol doses (delta cAMP/IS) (from 0.3 +/- 0.06 to 1.4 +/- 0.3, p less than 0.05). After salt loading there was a significant reduction in plasma catecholamine concentrations with a significant relationship between changes in upright plasma epinephrine levels and changes in CD25 (r = 0.904, p less than 0.01) and in the slopes for delta HR/IS (r = 0.983, p less than 0.001) and delta cAMP/IS (r = 0.922, p less than 0.001). These results support the hypothesis that the impairment of beta-adrenoceptor sensitivity observed in human hypertension is associated with a beta-adrenoceptor overstimulation due to chronically elevated adrenergic tone.

Protective role of collaterals in patients with coronary artery occlusion

We reviewed the clinical, hemodynamic and angiographic data of 105 patients with right coronary artery occlusion and 82 patients with left anterior descending coronary artery occlusion, subdivided into 3 groups by the presence and quality of collaterals to the occluded coronary (absent, poor or good collaterals). We found that patients with right coronary artery occlusion and good collaterals had a lower frequency of diaphragmatic myocardial infarction (60%) than patients with absent collaterals (100%) (P less than 0.01). In addition, in patients with old diaphragmatic myocardial infarction, both poor and good collaterals were associated with a lower frequency of severe asynergy of the diaphragmatic left ventricular segments at left ventriculography (54% and 14%, respectively), compared to patients with no collaterals to the right coronary artery (92%, P less than 0.02 vs. poor collaterals, P less than 0.001 vs. good collaterals). In contrast, in patients with left anterior descending coronary artery occlusion, the presence of either poor or good collaterals to the left anterior descending coronary artery was not associated with a lower frequency of old anterior myocardial infarction, or, in patients with old anterior myocardial infarction, with a less severe asynergy of the anterior left ventricular segments. Our results suggest that collaterals are effective in protecting the diaphragmatic left ventricular wall in patients with right coronary artery occlusion, but not the anterior left ventricular wall in patients with left anterior descending coronary artery occlusion.

Haemodynamic and clinical effects of long-term treatment of essential hypertension with captopril

Captopril, an orally active inhibitor of angiotensin converting enzyme, was administered for 12 months to 20 patients with mild or moderate essential hypertension who initially responded favourably to this pharmacological treatment. Captopril induced a significant reduction in blood pressure which remained unmodified throughout the study. This fall in blood pressure was mainly due to a significant decrease in total peripheral vascular resistance, since no change in cardiac output was observed. Simultaneously, there was no significant change in left ventricular anatomy and performance evaluated by echocardiographic technique.

Immunofluorescence localization of calmodulin in human polymorphonuclear leukocytes

Human polymorphonuclear leukocytes (PMNs) were purified (approximately equal to 99%) from peripheral blood of normal, adult volunteers. The indirect immunofluorescence technique was used to investigate the presence and the localization of calmodulin in human PMNs. The cellular distribution of calmodulin has been evaluated using an affinity chromatography-purified sheep IgG anti-calmodulin and fluorescein-conjugated rabbit anti-sheep IgG. The anti-calmodulin immunofluorescence pattern suggests that calmodulin is evenly distributed throughout the cytoplasm of human PMNs.

Intropic effects of several antiarrhythmic drugs

The effects of intravenous administration of several quinidine-like antiarrhythmic drugs (bunaftine, monochloroacetyl ajmaline, lidocaine, mexiletine, disopyramide, aprindine, diphenylhydantoin, procainamide) on left ventricular performance, evaluated by systolic time intervals (STI), were studied in 100 patients with atherosclerotic heart disease. The STI were measured: the pre-ejection period (PEP), the isometric contraction time (ICT), the left ventricular ejection time (LVET), corrected LVET (LVETc), and the PEP/LVET ratio. The degree of impairment of left ventricular performance was maximal after aprindine and disopyramide administration. This was demonstrated by significant increases in the PEP, ICT, and PEP/LVET and by significant decreases in LVET and LVETc, in patients in both III-IV and I-II NYHA classes. Bunaftine, monochloroacetyl ajmaline, and lidocaine induced a less marked impairment of myocardial performance, since the PEP, ICT, and PEP/LVET increases were not significant compared to controls in patients in NYHA class I-II, and since no variation of LVET and LVETc were observed. Mexiletine effects on myocardial performance appear to be intermediate between these groups of drugs. Diphenylhydantoin and procainamide, considered separately because of their effects on heart rate and blood pressure which are not possessed by the other drugs, induced significant increases of PEP in NYHA class III-IV patients. However, the effects of these 2 drugs on myocardial performance may have been underestimated, due to the concomitant hemodynamic effect of these drugs.

Transesophageal pacing for prognostic evaluation of preexcitation syndrome and assessment of protective therapy

An esophageal lead was used to perform decremental atrial pacing and elective induction of atrial fibrillation (AF) in 5 patients with the Wolff-Parkinson-White (W-P-W) syndrome before and after amiodarone therapy. In the control state, 1:1 atrioventricular (AV) conduction over the accessory pathway ranged from 220 to 260 ms (mean 232). The shortest R-R interval during AF ranged from 190 to 210 ms (mean 198). The ventricular rate ranged from 175 to 212 beats/min (mean 196). After amiodarone therapy, the shortest cycle length with 1:1 AV conduction increased in all patients, ranging from 290 to 540 ms (mean 370); during AF, no preexcited beat was present in 2 patients, whereas the minimal preexcited R-R interval in the remaining 3 was 290, 240, and 370 ms, respectively. The ventricular response during AF decreased in all patients. Thus, esophageal pacing is a useful method for identifying patients at risk with the W-P-W syndrome and for assessing appropriate management in individual patients. Amiodarone provides protection against life-threatening arrhythmias in these patients.