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Biomedical subjects

L Ansani

Publications and source records attributed to L Ansani.

At least 19 recordsLinked to original sources
PubMed1994

Long-term reliability of single lead atrial synchronous pacing systems using closely spaced atrial dipoles: five-year experience.

To assess the long-term capability of single atrioventricular (AV) lead VDD pacing systems using close atrial dipoles to assure reliable atrial guided pacing, the safety and efficacy of 86 VDD units implanted in 73 patients at a single center since November 1988 was reviewed. All patients suffered from advanced AV block with normal sinoatrial function. Sixty five patients received a LEM/CCS Twinal 30/30S system, four patients received a Vitatron-Saphir system, and four patients received a Medtronic Thera VDR 8348 system. All patients underwent provocative tests in search of myopotential interference, and Holter recordings; in a group of patients who underwent pacemaker replacement a comparison was made between implant and replacement measurements. The mean follow-up duration was 27.3 months. A high percentage of successfully VDD paced patients and a low incidence of pacemaker malfunction, regularly solved by pacemaker reprogramming, was reported. Atrial signal amplitudes comparable to those measured at implant were found at replacement in all patients. These data support the long-term reliability of single AV lead VDD pacing systems with closely spaced atrial dipoles, as well as stable atrial sensing by floating bipolar atrial electrodes and effective atrial synchronous ventricular pacing over time.

Aged↗
PubMed1994

AV delay optimization and management of DDD paced patients with dilated cardiomyopathy.

Ten DDD paced patients, suffering from dilated cardiomyopathy in the NYHA functional classes III or IV were studied by means of Doppler echocardiography at different programmed values of atrioventricular (AV) delay (200, 150, 120, 100, and 80 msec). The following variables were evaluated: LV diameter, ejection fraction, mitral and aortic flow velocity integrals, and stroke volume. During VDD pacing, a resting AV delay associated with the best diastolic filling and systolic function was identified and programmed individually. Shortening of the AV delay to about 100 msec was associated with a gradual and progressive improvement. Further decrease caused an impairment of systolic function. The patients were clinically and hemodynamically reevaluated after 2 months of follow-up. A reduction of NYHA class and an improvement of LV function were consistently found. The reported data suggest that programming of an optimal AV delay may improve myocardial function in DDD paced patients with congestive heart failure. This result may be the consequence of an optimization of left ventricular filling and a better use of the Frank-Starling law.

Aged↗
PubMed1992

Italian multicenter study on a single lead VDD pacing system using a narrow atrial dipole spacing.

Since November 1988, 514 patients with advanced atrioventricular (AV) block and normal sinoatrial function have received the single lead VDD pacing system Twinal 30 Lem/CCS in 30 Italian centers. At implantation, particular attention was paid to the correct positioning of the atrial dipole in the mid- to mid-high right atrium and to the atrial electrogram characteristics. The follow-up included a chest X ray, to be performed before discharge of the patient from the hospital, telemetric evaluations of the endoatrial potential, provocative tests for interferences by myopotentials, 24-hour ambulatory EGG recordings, and where possible, exercise stress tests. The mean follow-up duration was 15.2 months, ranging from 1 to 42 months. A very low percentage of chronic atrial fibrillation, loss of atrial sensing, and system replacement was reported, most of the patients (93.5%) being paced in VDD mode. All investigations indicated an excellent overall system performance, stable AV synchrony, and infrequent myopotential interference, and a low complication rate throughout the follow-up period.

Aged↗
PubMed1990

The effect of captopril on peripheral hemodynamics in patients with essential hypertension: comparison between oral and sublingual administration.

A comparative study of the effects of oral and sublingual captopril on the hemodynamics of the peripheral musculocutaneous vasculature was carried out on ten patients with essential hypertension. Both routes of administration of captopril lead to lower blood pressure and decreased regional resistance, and to an increased arterial blood flow at rest. The first measurable effect and the peak effect on blood pressure and peripheral hemodynamics appear slightly earlier with sublingual administration. The data provided in this study support the usefulness of the sublingual route in clinical situations in which oral administration of captopril is not feasible.

Administration, Oral↗
PubMed1990

AV delay and exercise stress tests: behavior in normal subjects.

In normal subjects the atrioventricular (AV) conduction is accelerated during exertion. The relationship between heart rate and AV delay is usually described as "linear". Looking at the increasing importance given to an appropriate AV synchrony in permanent dual chamber and P synchronous pacing we present the results of an investigation performed to study the correlation between AV conduction time and heart rate under stress conditions, and disclose some new aspects of this matter, which will possibly be useful for a further improvement of pacemaker technology.

Adult↗
PubMed1990

A new single lead VDD pacing system.

In 24 patients with advanced heart block and normal sinus node function, a new single lead VDD pacing system was implanted. At implantation, the endoatrial, bipolar electrogram was recorded in all patients. The lead position was checked by means of chest X-ray. At discharge and after 1, 3, and 6 months, testing for myopotential inhibition, telemetric evaluation of the endoatrial potential, and Holter recordings were made. After discharge, 18 patients performed two cardiopulmonary exercise tests at two different rate-matched AV intervals. All investigations showed good AV synchrony and a lack of interferences by myopotentials. The maximum rate-matched AV interval provided a significantly improved exercise capacity, which was more evident in patients with signs of myocardial failure.

Aged↗
PubMed1989

Peripheral hemodynamic effects of ibopamine in patients with congestive heart failure. A placebo-controlled, double-blind study.

Under double-blind conditions, 150 mg of ibopamine (di-isobutyric ester of N-methyldopamine) or placebo were given orally to 11 patients with congestive heart failure; after 3 hours, 50 mg of sulpiride were administered intramuscularly. Peripheral hemodynamics were evaluated at the level of the forearm using strain-gauge plethysmography. Ibopamine increased arterial blood flow and venous capacity and decreased arterial peripheral resistance; these effects were counteracted by sulpiride. No significant changes were observed after placebo and sulpiride. These findings confirm the vasodilating effects of ibopamine on peripheral hemodynamics and its utility in patients for the treatment of congestive heart failure.

Aged↗
PubMed1989

[Evaluation of the cardiac and peripheral vascular effects of the administration of single-dose enalapril and captopril in essential arterial hypertension].

The effects of single orally-administered dose of enalapril and captopril on central and district-peripheral circulations have been studied in 20 patients with essential arterial hypertension. Either drug caused a decrease in arterial pressure, telesystolic and telediastolic parietal stress, and a reduction in the peripheral vascular resistance of upper limb district. Furthermore, at the upper limb district level, increases in arterial flow and venous-system capacity have been observed. The entity of these modifications induced by enalapril and captopril appeared comparable, according to the respective peak-time and used dosages. Under this study conditions, the difference between the drugs resulted to be essentially of chronological nature.

Adult↗
PubMed1986

Effects of ibopamine on peripheral hemodynamics: a strain gauge plethysmographic study in patients with congestive heart failure.

Peripheral hemodynamics were studied using strain gauge plethysmography in patients with congestive heart failure after administration of ibopamine (SB-7505), the orally active 3,4-diisobutyryl ester of N-methyldopamine, a dopaminergic agonist, and of sulpiride, a specific dopaminergic antagonist. 50 mg of sulpiride were administered parenterally in 12 patients 3 h after a single oral dose of 150 mg of ibopamine. Ibopamine increased significantly resting arterial blood flow and venous capacity and decreased peripheral resistance. Sulpiride was found to significantly counteract the activity of ibopamine.

Aged↗
PubMed1983

Effect of ibopamine on peripheral haemodynamics.

Peripheral haemodynamics was studied in healthy volunteers by strain gauge plethysmography after administration of ibopamine (IB), diisobutyric ester of N-methyl-dopamine, an orally active dopaminergic agonist. Seven subjects received a single oral dose of ibopamine of 150 mg and 6 received a daily dose of 150 mg (50 mg t.i.d.) for 5 consecutive days. Arterial resting blood flow and venous capacity increased and peripheral resistance decreased significantly. Six further subjects were then studied; 3 h after an oral dose of ibopamine 150 mg, the parenteral administration of Sulpiride 50 mg, a specific vascular dopaminergic antagonist, was found significantly to counteract its peripheral activity. Heart rate and arterial blood pressure were never affected and tolerability was good.

Adult↗
PubMed1983

Phonometric study of the second heart sound in normal man.

The fast Fourier transform (FFT) was employed to analyze the frequency spectra of the second heart sound in 19 healthy subjects. The data obtained show that the second heart sound is mainly composed of low-frequency vibrations, and that the frequency vs. amplitude spectra for the various filters do not exceed 150 Hz. The different spectra obtained can represent a useful reference to compare with pathological acoustical findings.

Adult↗
PubMed1982

Phonometric study of the human first heart sound.

The first heart sound was studied in 20 normal subjects. The phonocardiogram (PCG) was recorded from apical and mid-precordial areas using microphone with a flat response curve from 0.2 to 8,000 Hz. It was stored, together with a simultaneous electrocardiogram, on an FM analog tape recorder (linear frequency response from 0 to 4,000 Hz), fitted with a filter with weighting curve B according to the American National Standard Institute. A linear (SPL) recording was also made. The signal was fed through a digital converter into a minicomputer and the frequency distribution of the first heart sound was analyzed using Fast Fourier Transform. These data were stored and the average spectra were calculated for both B and SPL. The SPL spectra from both apex and mid-precordium showed a maximum intensity of about 80 dB between 12-20 Hz, decreasing progressively to a constant level of 35 dB between 110-120 Hz. The spectra obtained from both areas using filter B showed a maximum intensity of 40-50 dB between 20-60 thereafter. It is important to emphasize that the dB values in B and SPL are absolute, since they refer to a standard reference weighting. It appears that the SPL recording is more valuable in that it allows the study of all components of the PCG signal. The spectra obtained in this study will be used as a standard for future research in various pathological conditions.

Adolescent↗