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Biomedical subjects

M Condorelli

Publications and source records attributed to M Condorelli.

At least 253 records · Page 14Linked to original sources
PubMed1982

[Mexiletine in the treatment of lidocaine-resistant ventricular tachycardia. Preliminary results].

Intravenous mexiletine (3 mg/Kg as bolus) was given to 7 patients with sustained ventricular tachycardia. Previous lidocaine administration in standard doses failed to suppress ventricular tachycardia. Mexiletine successfully suppressed the episodes of ventricular tachycardia in 6 of the 7 patients at a dose of 250 mg. Minimal non-cardiac toxicity occurred after mexiletine administration in the majority of patients. Mexiletine appears to be a promising alternative to lidocaine in the management of ventricular arrhythmias.

Drug Resistance↗
PubMed1981

His bundle electrogram recording using a multipolar electrode catheter via the arm veins.

In eighteen patients with atrioventricular conduction disturbance, His bundle electrograms were studied via the arm vein. A 6F Berkovits-Castellanos USCI hexapolar electrode catheter was introduced into the right atrium and looped across the tricuspid valve in a "golf club" shape. The main aim was to leave the two distal electrodes in contact with the atrial endocardium to perform atrial pacing, while displaying the other four electrodes along the superior angle of the tricuspid valve for proximal and distal His bundle recordings. His bundle electrograms were successfully obtained in all cases. The arm approach provides an alternate route whenever the femoral approach is not feasible. Moreover, the use of an hexapolar electrode catheter provides some practical advantages: 1) it enables atrial pacing to be performed, as well as proximal and distal His bundle recording to be obtained, by using the same multipolar electrode catheter; and 2) it allows long-term monitoring of His bundle potentials, in view of the stability of His bundle recordings. Finally, the arm approach could be the method of choice for the study of His bundle electrograms during leg supine exercise in selected patients.

Arm↗
PubMed1981

Development of cardiac hypertrophy in rats exposed to acute hypobaric hypoxia. - Studies with protein synthesis inhibitors.

The study is based on the experimental model of myocardial hypertrophy in rats. Male Sprague-Dawley adult rats were exposed to acute hypoxia in a hypobaric chamber (0.40 atmospheres of air for 24 hours). Myocardial hypertrophy was detected by wet and dry heart weight values when calculated on the basis of total body weight; i.e., ratio heart weight in mg to body weight in 100 g. The behaviour of myocardial hypertrophy was assessed after treatment of intact animals with Puromycin (10 mg/rat i.p.) or Actinomycin-D (100 micrograms/rat i.p.). The experimental results showed the following dry heart weight values (mean +/- SEM): room pressure 60.5 +/- 1.5; hypoxia 69.2 +/- 0.9; Actinomycin-D + hypoxia 63.5 +/- 0.6; Puromycin + hypoxia 62.4 +/- 1.5, (P less than 0.001). From the comparison of data reveals that inhibitors of protein synthesis completely inhibit the myocardial hypertrophy due to hypoxia. Thus it is documented that acute hypobaric hypoxia is able to induce in the rat an actual myocardial hypertrophy condition as expressed of the enhanced protein synthesis.

Animals↗
PubMed1981

The reflex control of arginine-vasopressin release in essential hypertension.

1. The reflex control of arginine-vasopressin release was studied in 12 essential established hypertensive patients and in 12 age-matched normal subjects by comparing the effects of head-up tilt and a variable-pressure neck-chamber. 2. After 45 min 85 degrees head-up tilt, normal subjects showed an increase in plasma arginine-vasopressin and in plasma renin activity, while plasma volume decreased. In hypertensive patients, plasma arginine-vasopressin showed changes after tilt opposite to those of controls, while the changes in plasma renin activity and plasma volume were similar to those observed in the normal group. In both groups the changes in systolic and diastolic blood pressure were not statistically significant. A reduction in carotid sinus transmural pressure obtained by increasing neck-tissue pressure (+50 mmHg) by means of a neck-chamber, evoked different responses in mean blood pressure in the two groups, but failed to induce any significant change in plasma arginine-vasopressin concentration both in the normal and in the hypertensive subjects. 3. These results seem to suggest that carotid sinus baroreceptors, though active in blood pressure control, do not play a direct role in arginine-vasopressin release and, therefore, the opposite response of arginine-vasopressin observed after tilt in the two groups of subjects should be ascribed to more complex mechanisms.

Adolescent↗
PubMed1981

Baroreflex responsiveness in borderline hypertensives: a study with neostigmine.

The baroreflex response to changes in transmural pressure throughout the arterial tree or limited to the carotid sinus was evaluated in ten borderline hypertensives and compared with that observed in ten normal subjects and in ten established hypertensives. Baroreceptor sensitivity was tested by evaluating both heart rate response to phenylephrine-induced increase in arterial pressure and heart rate and blood pressure changes induced by increased neck tissue pressure by means of a neck chamber. The heart rate response to phenylephrine (evaluated by the regression of the R-R interval versus the systolic blood pressure) was depressed both in borderline and established hypertensives as compared with controls. Similarly, the heart rate and the pressor response to increased neck tissue pressure were depressed in both groups of hypertensives. In borderline, but not in established hypertensives, neostigmine administration improved consistently the pressor baroreflex response to increased neck tissue pressure and the heart rate reflex response to both the employed stimuli. These findings indicate that a reduced parasympathetic activity is one of the components involved in the altered baroreflex sensitivity in borderline hypertensives.

Adult↗
PubMed1981

Echocardiographic evaluation of acute administration of oxyfedrine in patients with coronary artery disease.

In order to assess the effects of oxyfedrine in ischaemic heart disease, echocardiographic evaluation of left ventricular function was performed 2,5,10,15 and 20 minutes after the intravenous administration of 12 mg oxyfedrine in 15 patients with coronary artery disease without angiographic abnormalities of left ventricular wall motion. The following parameters were measured: heart rate, mean arterial blood pressure, internal dimension in diastole (LVIDd) and in systole (LVIDs) of the left ventricule and the percentage shortening of the LVID (%LVID). There was a significant increase in %LVID (peak 10 minutes after drug administration; p less than 0.001) indicating improved left ventricular function, associated with slight changes in pre-load (LVIDd) and in heart rate, and no variation in mean blood pressure. No abnormalities of contraction were observed after the administration of oxyfedrine. These results suggest that oxyfedrine exerts a direct positive inotropic effect of the myocardium in patients with significant coronary artery stenoses.

Aged↗
PubMed1981

Non-invasive evaluation by thermistor plethysmography of left ventricular performance during dynamic exercise. Comparison with echocardiography.

The purpose of this study was to evaluate the reliability of two non-invasive techniques (STI and echocardiography) in assessing cardiovascular response during exercise. STI were obtained using a new carotid pulse transducer (thermistor pulse) proved to be reliable in exercise recording. The study population included 12 male rowers (age 15-20 years), who performed supine bicycle exercise; STI and echocardiographic recording of left ventricle were simultaneously obtained at rest and continuously throughout the exercise period. A negative linear correlation (r=-0.782; p less than 0.001) was found between PEP (pre-ejection period) and %LVID (fractional shortening of left ventricle), reliable indexes of cardiac contractility measured by the two techniques. A lower, but significant correlation (r=0.643; p less than 0.001) was present between ETI (left ventricular ejection time corrected by heart rate) and SV (stroke volume) indexes of pump function. The present study shows that STI measured with this new technique, can be employed in evaluating left ventricular function in those patients in whom a good echocardiogram is difficult to record during exercise.

Adolescent↗
PubMed1981

Mechanisms underlying systemic hemodynamic responses to experimental coronary artery occlusion. A preliminary study with hexamethonium.

The hemodynamic changes induced by coronary occlusion were investigated in anesthetized dogs. Coronary occlusion elicited an immediate but transient increase in the systemic blood pressure and in the vascular resistance of the hind limb perfused at constant flow. Thereafter, systemic hypotension and vasodilatation in the perfused region were observed. Vagotomy abolished the initial increase of the systemic and perfusion pressure and reduced significantly the late vasodilator response both systemically and in the perfused hind limb. After the subsequent administration of hexamethonium the vasodilatation in the hind limb was no longer manifest but the fall in blood pressure was unmodified. These results seem to suggest that multiple mechanisms are involved in the hemodynamic response to coronary occlusion.

Animals↗
PubMed1981

Clinical hemodynamic and angiographic findings in 94 patients with old myocardial infarction. Comparison with 79 patients with coronary artery disease and no myocardial infarction.

Clinical, hemodynamic, coronary arteriographic, and ventriculographic findings of 94 patients (pts) with coronary artery disease (CAD) and old myocardial infarction (MI) have been described and compared with those of 70 pts with CAD and no previous MI. Pts with old MI presented a more compromised functional and hemodynamic status, with a higher incidence of NYHA class III-IV pts (40%), symptoms of left ventricular (LV) failure (31%), cardiomegaly (70%), higher left ventricular end-diastolic pressure (LVEDP) (19.6 +/- 9.6 mmHg, p less than 0.05), compared with 32%, 22%, 54% and 16.0 +/- 6.8 mmHg respectively in CAD pts with no MI. MI pts presented more severe CAD, higher incidences of three vessel disease (56%, p less than .005) and of left anterior descending (LAD) (34%) and right coronary artery (RCA) (36%) occlusions, compared with 34%, 6%, and 9% respectively in pts with no MI. Furthermore, pts with old MI showed more diffused and severe LV segmental wall contraction abnormalities, with higher frequencies of LV aneurysm (31%) and of pts with asynergy of more than 2 LV segments (26%), compared with 1% and 3% respectively in pts with no MI. Within the group with old MI, LVEDP was higher in pts with anterior (A) (22.0 +/- 11 mmHg, p less than .02) and anterior ł diaphragmatic (AłD) (21.5+/- 7.9 mmHg, p less than .05) MI, compared with pts with diaphragmatic (D) MI (16.6 +/- 7.1 mmHg); furthermore, LVEDP increase was significantly correlated with the severity and the extent of LV asynergy. In A and D MI, LAD and RCA stenoses or occlusions were prevalent respectively; pts with AłD MI showed larger numbers of coronary stenosis (3.05) and occlusions (1.05) per patient. The coronary artery supplying the infarcted area showed stenosis (greater than 75%) in 95.6% and was normal in 2.2% of cases. Thus, pts with CAD and old MI, and particularly of AłD and A MI, show a more compromised hemodynamic status and more severe degrees of CAD and of LV segmental wall contraction abnormality, which are responsible for their poor prognosis, compared to pts with CAD but no old MI.

Adult↗
PubMed1981

Severity of mitral regurgitation assessed by echocardiography. Reliability and limitations.

To assess whether echocardiography may represent a useful mean to evaluate the degree mitral regurgitation (DR), left ventricular diastolic internal dimension (LVIDd), left atrial dimension (LAD), and velocity of circumferential fiber shortening (Vcf) were compared to DR assessed by left ventriculography in 48 patients with primary (n = 21) and cardiomyopathic (n = 27) valvular incompetence. In patients with good left ventricular contractility, i.e. with Vcf values above 1.02, a significant positive linear correlation was found between LVIDd and DR (LVIDd = 5.38 + 0.45DR; r = 0.72; p less than 0.001). In contrast, in patients with depressed left ventricular function, i.e. with Vcf values below 1.02, LVIDd did not correlate to DR. In either group LAD and Vcf did not correlate to DR. Thus, echocardiography may provide useful semiquantitative information concerning DR only in patients with preserved left ventricular performance.

Cardiomegaly↗
PubMed1981

Arrhythmia control by cardiac stimulation.

Cardiac programmed stimulation in the control of tachyarrhythmias offers encouraging prospectives. We describe two devices which utilize radiofrequency as a means of synchronization and stimulation and can be triggered by the patient himself when tachycardia occurs. In addition we introduce a third anti-tachycardia device, completely automatic, which can be used in cardiologic departments. The first device described permits critical stimulation and can be programmed to deliver a single or double synchronized impulse. The second device, which utilizes the same implanted unit and electrode as used for critical stimulation, when activated searches the tachycardia interruption zone by scanning. The third device, based on the same principles, has a rate discriminator that activates the scanning stimulation. We treated 12 patients: 8 suffering from paroxysmal supraventricular tachycardia (4 with Wolff--Parkinson--White syndrome, 2 with intranodal reentry, 2 with brady--tachy syndrome); 2 patients with ventricular recurrent tachycardia; 1 with atrial flutter; and another with iterative junctional tachycardia. The follow-up varied for every patient from 6 yr to 3 mth.

Arrhythmias, Cardiac↗
PubMed1981

[Coronary artery disease (CAD) in females. Coronary arteriographic findings in 34 women and comparison with 184 males with cad].

We studied the clinical, hemodynamic and angiographic findings of 34 women (W) and of 184 men (M) with significant (greater than or equal 50%) CAD. W, compared to M, presented a higher incidence of systemic hypertension (p less than .025), while less frequent were among W smoking habits (p less than .001), history of old myocardial infarction (MI) (p less than .005), and patients in III-IV NYHA class (p less than .025). Left ventricular (LV) dP/dt was higher in W than in M (p less than .005). At coronary arteriography, single vessel disease (SVD) was more frequently found in W than in M (70% vs 23%, respectively, p less than .001); this findings was more evident in patients under 50 years of age (100% vs 30%, respectively, p less than .055). Prevalence of left anterior descending (LAD) over right (RCA) and circumflex (Cx) coronary artery stenoses was more marked in W than in M, especially in patients under 50 years of age (SVD of the LAD in 67% and of RCA in 33% of young W). Poor angiographic run-off of LAD was found in 21% of W, and only in 10% of M. In 2 of the 3 W with poor run-off of LAD operated on, a coronary bypass on the distal LAD was no technically feasible. At left ventriculography, a lower frequency of LV segmental wall motion abnormalities was found in W than in M, especially in patients with no history of MI (p less than .001). In summary, W with significant CAD, compared to age matched M, presented in our experience with a higher frequency of SVD and of LAD stenoses, and with a better LV contractile performance at left ventriculography. Furthermore, in W LAD more frequently showed a poor angiographic run-off. Such findings may bear important implications on the indication and results of coronary surgery in W with CAD.

Adult↗
PubMed1981

[Long-term electrical stimulation of tachycardias: control by ambulatory electrocardiographic monitoring (author's transl)].

The Authors suggest a new method, elaborated by their own, for long-term antiarrhythmic stimulation. They used ambulatory electrocardiography in order to evaluate the results. It consists of a radio frequency device for synchronization and stimulation, and allows the scanning stimulation of all the cycle of tachycardia, with automatic search for the zone of interruption. The stimulatory is carried by the patient, who must set it in motion at the onset of the tachycardia. Preliminary results show the efficacy of the method; Holter monitoring seems to be the best guide to the development of a satisfactory implantable automatic tachycardia-terminating pacemaker.

Ambulatory Care↗
PubMed1981

[Familial sudden death in preexcitation syndrome. Surgical interruption of the anomalous pathways in two brothers (author's transl)].

We describe the results of surgical dissection of multiple accessory pathways in two brothers. A significant family history of pre-excitation syndrome was present: two children died suddenly and at the autopsy of one of them an accessory atrioventricular connection was found. In the first patient the preoperative electrophysiologic study showed anterior septal and posterior septal accessory pathways, and enhanced conduction in the A-V node. The second patient had the following anomalous connections: enhanced conduction in the A-V node; anterior septal, posterior septal and right lateral accessory pathways; Mahaim fiber. Intraoperative mapping, performed during pacing from different sites at different cycle length, was used to define the atrial and ventricular insertions of the accessory pathways as well as to confirm the surgical success.

Adolescent↗