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Biomedical subjects

S Betocchi

Publications and source records attributed to S Betocchi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Normalization of left ventricular nonuniformity late after valve replacement for aortic stenosis.

The aim of the present study was to evaluate nonuniformity in pressure overload hypertrophy due to aortic stenosis. Twenty patients were included in the present analysis. Ten patients with severe aortic stenosis were studied preoperatively as well as early (21 +/- 8 months) and (89 +/- 21 months) after aortic valve replacement (AVR) using left ventricular biplane angiograms, high-fidelity pressure measurements and endomyocardial biopsies. Ten normal subjects served as controls. LV systolic function was assessed from biplane ejection fraction, and diastolic function from the time constant of relaxation, the peak filling rate and the constant of myocardial stiffness. Nonuniformity was evaluated from the coefficient of variation of the time to end-systole (systolic asynchrony) and peak filling rate (diastolic asynchrony) of 12 regions in right anterior oblique and left anterior oblique projection. Ejection fraction was comparable in patients with aortic stenosis and in controls, whereas preoperatively diastolic dysfunction with prolonged relaxation and increased stiffness was present in patients with aortic stenosis and was normalized late after AVR. LV systolic asynchrony was present (>25D of controls) in 7 and diastolic asynchrony in 10 of 10 patients with aortic stenosis. Early as well as late after AVR systolic asynchrony was normalized in 9 of 10 patients. Diastolic asynchrony was present early AVR in all but one patient, although there was a significant improvement with respect to the preoperative evaluation. Late after AVR there was a normalization of diastolic asynchrony in 9 of 10 patients with aortic stenosis. Thus, it is concluded that systolic asynchrony is normalized early after AVR probably due to its load-sensitivity, whereas diastolic asynchrony persists probably due to residual LV hypertrophy with increased interstitial fibrosis and myocardial stiffness. Late after AVR, diastolic asynchrony is normalized due to structural remodeling with regression of both myocardial hypertrophy and interstitial fibrosis.

Aortic Valve↗
PubMed1996

Effects of dual-chamber pacing in hypertrophic cardiomyopathy on left ventricular outflow tract obstruction and on diastolic function.

Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function and, in about 1/4 of patients, left ventricular (LV) outflow tract obstruction. Atrioventricular (AV) pacing diminishes LV outflow tract gradient in HC, but impairs diastolic function in the experimental animal and in different categories of patients. To investigate the effects of AV pacing on hemodynamics and LV function in obstructive HC, 16 patients with HC were studied by cardiac catheterization and simultaneous radionuclide angiography during atrial and AV pacing. The resting LV outflow tract gradient decreased with AV pacing from 60 +/- 34 to 38 +/- 37 mm Hg (mean +/- SD; p <0.001). Regional ejection fraction decreased significantly at the septal level from 0.81 +/- 0.21% to 0.69 +/- 0.27% (p <0.01). Pulmonary artery wedge pressure increased from 10 +/- 5 to 15 +/- 6 mm Hg (p <0.001). AV pacing induced asynchrony (i.e., the coefficient of variation of the time to end-systole increased from 7 +/- 4% to 14 +/- 10% (p <0.01). The time constant of isovolumetric relaxation (t) increased from 58 +/- 24 to 74 +/- 33 ms (p <0.02), and peak filling rate decreased from 491 +/- 221 to 416 +/- 184 ml/s (p <0.05). Thus, AV pacing greatly diminishes resting obstruction through a reduction in septal ejection fraction (i.e., an increase in LV outflow tract width in systole), but impairs active diastolic function and increases filling pressures. These latter effects are potentially detrimental in patients with HC in whom diastolic dysfunction is present.

Adult↗
PubMed1996

[Computerized follow-up cards for ambulatory patients with implanted pacemaker or defibrillator].

The follow up of pacemaker and defibrillator dependent patients has a significant role for both the evaluation of pacing effectiveness and check of hemodynamic advantages about patient's quality of life. The bulky paper archives are often inaccurate, hampering the consultation. At present the paper card is the only document which can be utilized to record some data concerning the implant and patient clinical story. Therefore, there is the necessity for a card that can include all patient's data, and the implant and programming pacemaker/defibrillator data during follow up. This new pacemaker card has portable file or data-base including shared data with safety mechanism, which can be utilized in several controls by different users (physicians, hospital ward, primary care units, insurance companies). The pacemaker card includes a chip that permits to store a considerable amount of data; it can be update in every further medical control, in observance of laws. The card Chip Operating System (C.O.S.) consists of a microchip with a memory completely managed by the operating system inside the chip itself. The card can be read by means of a GCR-200 modem linked with a PC IBM-compatible computer and the data can be updated during the follow up. The pacemaker-defibrillator card will appear immediately on screen, and it can be printed, updated and/or modified by a Microsoft Windows operating programme. With this pacemaker card we are able to ensure serviceable medical work, particularly in terms of cost/benefit ratio giving to patient more and more reasoning and safe service.

Database Management Systems↗
PubMed1996

[Left ventricular function in patients with chronic ischemic cardiopathy: relationship with the status of myocardial perfusion].

The aim of this study was the evaluation of left ventricular function compared to myocardial perfusion in patients with chronic coronary artery disease (CAD). Thirty-two patients with chronic CAD (27 men and 5 women, mean age 58 +/- 9 years) underwent radionuclide angiography and rest-redistribution thallium-201 (TI-201) single photon emission Computed Tomography (SPECT). Ejection fraction (EF, %), peak filling rate (PFR, end diastolic volume/second), and the coefficient of variation of the regional time to PFR (CV-TPFR, %) were computed. Patients with severe irreversible defects (i.e. with TI-201 uptake < 50%) had lower EF (42 +/- 7% vs 52 +/- 11%, p < 0.01) and lower PFR (1.9 +/- 0.4 vs 3.1 +/- 1.0, p < 0.0005) than those without. Patients with severe irreversible perfusion defects in the left anterior descending artery territory had lower EF (41 +/- 6% vs 50 +/- 11%, p < 0.01), lower PFR (1.8 +/- 0.3 vs 2.8 +/- 1.0, p < 0.005), and higher CV-TPFR (39 +/- 22 vs 13 +/- 7, p < 0.001) than those without. The results of the present study indicate that in patients with chronic CAD left ventricular systolic and diastolic function is more deteriorated when the left anterior descending artery is involved. Similarly, the presence of severe irreversible perfusion defects is clearly associated with significantly lower EF and PFR.

Adult↗
PubMed1995

Dobutamine echocardiography predicts improvement of hypoperfused dysfunctional myocardium after revascularization in patients with coronary artery disease.

BACKGROUND: In patients with coronary artery disease, dysfunctional hypoperfused myocardium at rest may represent either necrotic or viable hibernating myocardium. The accuracy of inotropic stimulation in identifying hypoperfused, reversibly dysfunctional myocardium has not been extensively investigated. METHODS AND RESULTS: Eighteen patients with stable chronic coronary artery disease underwent, while off drugs, quantitative 201Tl single-photon emission computed tomography after rest injection (2 to 3 mCi), two-dimensional echocardiography at rest and during dobutamine (5 to 10 micrograms/kg per minute i.v.), and radionuclide angiography. Single-photon emission computed tomography and echocardiography at rest were repeated 34 +/- 10 days after coronary revascularization, and radionuclide angiography was repeated 45 +/- 13 days after revascularization. Resting hypoperfusion was defined as 201Tl uptake < 80% of maximal activity. Systolic function was scored from 1 (normal) to 4 (dyskinesia), and functional improvement was defined as a score change > 1 grade. Of 79 dysfunctional hypoperfused segments, 48 (61%) improved function after revascularization. In 42 (88%) of these latter segments, function had improved during dobutamine. Conversely, systolic function after revascularization did not improve in 31 segments, and in 27 (87%), it had not improved during dobutamine. Functional improvement after revascularization was observed in 42 (91%) of 46 segments manifesting an improvement during dobutamine as opposed to 6 (18%) of 33 segments that did not improve during dobutamine. Resting 201Tl uptake (% of maximal activity) before revascularization (65 +/- 9%) significantly increased at follow-up in segments where function improved (70 +/- 12%, P < .005), whereas it did not change significantly in segments with unchanged systolic function after revascularization (from 57 +/- 13% to 60 +/- 17%, P = NS). In 10 patients with prerevascularization ejection fraction < 45%, left ventricular ejection fraction significantly increased from 36 +/- 7% before revascularization to 42 +/- 7% at follow-up (P < .05). CONCLUSIONS: Inotropic stimulation using dobutamine echocardiography identifies hypoperfused reversibly dysfunctional myocardium. Functional improvement during dobutamine is highly predictive of improvement after revascularization.

Aged↗
PubMed1995

Recombinant tissue-type plasminogen activator therapy in prosthetic mitral valve thrombosis: assessment by transthoracic and transesophageal echocardiography.

Prosthetic cardiac thrombosis is a life-threatening complication that needs prompt diagnosis and therapy. We used recombinant tissue-type plasminogen activator (rT-PA), followed by heparin, in three patients with mitral prosthetic thrombosis, which was evident in two and suspect in one. Transthoracic and transesophageal echocardiography were employed in the diagnosis of both thrombosis and its resolution. No complications occurred. Immediately after the end of treatment with rT-PA, clinical status and echocardiographic data improved in all cases: transthoracic echocardiography showed the normalization of prosthetic function and transesophageal echocardiography showed resolution of thrombosis. One patient needed reoperation for rethrombosis due to the presence of prosthetic fibrous clot. rT-PA, followed by heparin, led to a good clinical result without bleeding and embolic complications in selected patients with mitral prosthetic thrombosis. Transthoracic and transesophageal echocardiography are complementary diagnostic tools in the diagnosis and management of patients with prosthetic thrombosis.

Adult↗
PubMed1994

Assessment of left ventricular regional function by radionuclide angiography: effects of number of sectors on repeatability.

Twenty patients were studied by equilibrium radionuclide angiography (RNA) twice in the same day in order to assess the repeatability of quantitative measurements of left ventricular (LV) regional function by using a sector analysis method. RNA was performed in the best septal 45 degrees left anterior oblique projection, acquiring 150,000 counts/frame, at 20 msec/frame with 5% gate tolerance. LV regional analysis was performed using a computer algorithm written by the authors running on Digital PDP 11/34 machine. The algorithm after having identified the center of gravity of the LV, divided it into 4, 5 and 6 equiangular sectors. In the 5, and 6 sector analysis, the region including the mitral and aortic valves was excluded from subsequent analysis. In each sector Ejection Fraction (EF) and Peak Filling Rate (PFR) were computed. In addition, the Time to End Systole (TES) and Time to Peak Filling Rate were also assessed for each region. The coefficient of variation of the regional values of TES (CV-TES) and regional TPFR (CV-TPFR) were then computed and considered as indices of LV systolic (CV-TES) and diastolic (CV-TPFR) asynchrony. Repeatability was firstly assessed by linear regression analysis between the 2 RNA studies. Our data show a high correlation coefficient on regional values of EF and PFR (R: > 0.92). Moreover, the differences in a given parameter between the 2 studies were plotted against their mean value, and the coefficient of repeatability (CR) was calculated as twice the standard deviation of the differences. No significant differences were found between EF and PFR regional values in the 2 RNA studies (EF coefficient of repeatability: < 0.18; PFR coefficient of repeatability: < 0.8). A low value of coefficient of repeatability was found also for CV-TES (< 17) and for CV-TPFR (< 18). In conclusion LV regional analysis is a repeatable method of analysis, and the number of regions does not affect the repeatability.

Angiocardiography↗
PubMed1994

Evaluation of left ventricular asynchrony by radionuclide angiography: comparison of phase and sector analysis.

UNLABELLED: The aim of this study was to assess the optimal method to evaluate asynchrony in equilibrium radionuclide angiography (RNA). METHODS: We studied 20 patients (14 males and 6 females, age range 25-60 yr) with RNA during atrial and sequential atrioventricular (AV) pacing, which increased left ventricular (LV) asynchrony. Both studies were performed at the same heart rate. Asynchrony was assessed either on phase images, by computing the standard deviation of the phase distribution (SD-P) and by sector analysis. Systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end systole (CV-TES) and time to peak filling rate (CV-TPFR) in four sectors. In addition, phase values were computed on time-activity curves from the same sectors, and their standard deviation (SD-Psec) was computed. RESULTS: During atrial pacing SD-P was 32.3 degrees +/- 6.7 degrees and did not change during AV pacing (32.1 degrees +/- 5.6 degrees, p = n.s.). Both CV-TES and CV-TPFR had a significant increase during AV pacing (from 7.7% +/- 3.9% to 11.5% +/- 6.4%, p < 0.01, and from 8.4 degrees +/- 5.8 degrees to 12.9 degrees +/- 6.7 degrees, p < 0.001). AV pacing led to a significant increase in SD-Psec (from 6.3 degrees +/- 4.0 degrees to 12.6 degrees +/- 9.7 degrees, p < 0.05). Moreover, reproducibility was assessed in 15 additional age-matched patients. The results of the reproducibility study indicate a better repeatability for CV-TES and CV-TPFR. CONCLUSIONS: The findings of this study suggest that sector analysis with calculation of indices of LV systolic and diastolic asynchrony is better suited for quantitation of LV temporal nonuniformity.

Cardiac Catheterization↗
PubMed1993

Effects of induced asynchrony on left ventricular diastolic function in patients with coronary artery disease.

OBJECTIVES: This study was designed to increase asynchrony with sequential atrioventricular (AV) pacing and to study its effects on left ventricular isovolumetric relaxation, rapid filling and stiffness. BACKGROUND: Left ventricular nonuniformity is a major determinant of diastolic function. METHODS: Thirteen patients with coronary artery disease were studied by simultaneous equilibrium radionuclide angiography and cardiac catheterization during atrial and AV pacing. Ejection fraction and peak filling rate were measured by radionuclide angiography. Regional analysis was obtained by analyzing time-activity curves of four left ventricular sectors; systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end-systole and, respectively, time to peak filling rate in the four sectors. Cardiac index and left ventricular pressure were measured with high fidelity catheters at cardiac catheterization. The time constant of isovolumetric relaxation was derived from left ventricular pressure. Pressure-volume loops were assembled and constants of chamber stiffness were computed. RESULTS: Atrioventricular pacing led to a decrease in cardiac index (3.7 +/- 0.9 to 3.3 +/- 0.8 liters/min per m2, p = 0.01) and peak filling rate (352 +/- 125 to 287 +/- 141 ml/s, p = 0.03; 2.4 +/- 0.8 to 2.0 +/- 0.8 end-diastolic counts/s, p = 0.02; 4 +/- 1.3 to 3.2 +/- 1.0 stroke counts/s, p = 0.008). The time constant of isovolumetric relaxation increased (57 +/- 10 to 64 +/- 12 ms, p = 0.04) and the global diastolic pressure-volume relation shifted upward. CONCLUSIONS: Atrioventricular pacing induces left ventricular asynchrony, which is associated with a slower rate of isovolumetric relaxation. The isovolumetric relaxation lasts after the filling phase has begun, thereby reducing the rate of rapid filling.

Adult↗
PubMed1993

Effects of sustained training on left ventricular structure and function in top level rowers.

The effects of vigorous training on left ventricular structure and function were evaluated in 15 top level rowers using electrocardiography, Doppler echocardiography and radionuclide angiography. All subjects were studied after 1 month of deconditioning and again after 5 months of vigorous training. After training there was an increase in the ventricular hypertrophy voltage criteria proposed by Sokolow-Lyon and by Friedman but not in that proposed by Casale; T wave amplitude in leads V5 and V6 increased in nine subjects, was unchanged in one and decreased in five; the mean values were also unchanged. Training induced a significant increase in left ventricular end-diastolic and end-systolic diameter and in left ventricular mass index, while peak systolic stress and mean wall stress index decreased. No change was detected after training in the mean values of Doppler echocardiographic and radionuclide angiographic data; nevertheless a significant relationship was found between changes in T wave height in V5 or V6 and in peak filling rate, and between changes in T wave height and ejection fraction. Our study confirms that the effect of vigorous training on left ventricular mass and dimensions does not include changes in mean values of systolic and diastolic function. The relationship between change in T wave amplitude and in peak filling rate values suggests that some metabolic or neurohumoral derangement occurs in the subset of athletes with T wave flattening, that is responsible for the slight reduction in peak filling rate and ejection fraction.

Adolescent↗
PubMed1993

Evaluation of myocardial perfusion and function by technetium-99m methoxy isobutyl isonitrile before and after percutaneous transluminal coronary angioplasty. Preliminary results.

Myocardial perfusion and function were evaluated with Tc-99m MIBI myocardial scintigraphy before and after percutaneous angioplasty in six patients. In addition to conventional stress-rest images (3 projections: 45 degrees left anterior oblique, anterior, and left lateral), gated images were obtained at rest and during stress before and after angioplasty. Improvement in myocardial perfusion after angioplasty was demonstrated in all patients. The increase from rest to stress of radionuclide fractional shortening (an index of global left ventricular function computed on gated images) was greater after angioplasty than before (9% +/- 7% versus--0.5% +/- 8%, respectively, p < 0.05). Systolic wall thickening (an index of regional left ventricular function) showed a significantly greater rest-to-stress increase after angioplasty than before it in the regions supplied by treated vessels. Thus, Tc-99m MIBI myocardial scintigraphy is capable of evaluating myocardial perfusion and function.

Angioplasty, Balloon, Coronary↗
PubMed1993

Effects of calcium antagonists on left ventricular structure and function.

Effects of calcium antagonists on left ventricular hypertrophy: The goals of antihypertensive treatment are to lower systemic blood pressure and to reverse left ventricular hypertrophy. A number of different drugs can induce a decrease in left ventricular mass, some of which are calcium antagonists. In particular, verapamil, diltiazem and a number of dihydropyridines (nifedipine, isradipine, lacidipine) have proved effective in this respect. Left ventricular systolic function: Left ventricular systolic function is often normal at rest in patients with hypertension, but is quite commonly abnormal during exercise. Calcium antagonists therefore do not affect resting systolic function in this category of hypertensive patients. In contrast, in hypertensive patients with heart failure the administration of dihydropyridines improves systolic performance. Left ventricular diastolic function: Isovolumic relaxation and rapid filling are often impaired in patients with hypertension, with or without left ventricular hypertrophy. Verapamil is effective in abolishing this diastolic dysfunction when given intravenously; in contrast, medium-term therapy with calcium antagonists such as diltiazem or dihydropyridines does not improve left ventricular filling properties. However, when antihypertensive therapy achieves a reduction in left ventricular mass, a consistent improvement in diastolic properties occurs.

Antihypertensive Agents↗
PubMed1993

Regional left ventricular mechanics in hypertrophic cardiomyopathy.

BACKGROUND: Nonuniformity is a determinant of diastolic function. In patients with hypertrophic cardiomyopathy, hypertrophy, abnormal calcium handling, and regional ischemia can also play a role. This study was designed to assess regional mechanics, asynchrony, and asynergy in patients with hypertrophic cardiomyopathy. METHODS AND RESULTS: Nine control subjects and 22 patients with hypertrophic cardiomyopathy were studied by biplane left ventriculography and high-fidelity pressure tracings for the assessment of diastolic function by computing the time constant of isovolumic relaxation, peak filling rate, and the constant of passive chamber stiffness. Regional mechanics were evaluated by dividing the left ventricle into six sectors in the right and left anterior oblique projections. Systolic and diastolic asynchrony were assessed from the coefficient of variation of the regional time intervals from end diastole to end systole and to peak filling rate, respectively. Asynergy was evaluated from the coefficient of variation of the regional area reduction. Regional passive elastic properties were estimated by computing the regional constant of chamber stiffness. In patients with hypertrophic cardiomyopathy, isovolumic relaxation was prolonged (time constant of isovolumic relaxation 101 +/- 41 versus 51 +/- 16 milliseconds in control subjects; P < .001) and the constant of chamber stiffness was increased (0.056 +/- 0.038 versus 0.025 +/- 0.010 mL-1; P < .001). Both systolic and diastolic asynchrony as well as asynergy were found. Regional mechanics showed hyperkinesia in the free wall, whereas the septum exhibited normal wall motion and increased constant of chamber stiffness. CONCLUSIONS: Diastolic function is impaired in hypertrophic cardiomyopathy, and such an impairment is the consequence of nonuniformity and hypertrophy. The regions where the myopathic process is more pronounced show normal wall motion but increased stiffness. The inhomogeneity of regional wall motion with regional hyperkinesia and normokinesia of neighboring regions results in left ventricular asynergy.

Adult↗
PubMed1992

Effects of antihypertensive therapy on diastolic dysfunction in left ventricular hypertrophy.

In systemic hypertension, a certain degree of impairment of left ventricular diastolic function is often detectable, and is the consequence of two factors: elevated afterload and left ventricular hypertrophy. The goal of improving diastolic dysfunction can thus be achieved by lowering blood pressure and by inducing a regression in left ventricular hypertrophy. A reduction in blood pressure by intravenous administration of verapamil has proved capable of enhancing left ventricular filling properties in patients with hypertension. This finding has not been corroborated, however, in midterm protocols using an array of drugs (beta-blockers, dihydropyridines, diltiazem, and diuretics). Reduction in left ventricular mass can be achieved by several categories of drugs, and it has been shown that a decrease in mass is accompanied by an improvement in the early diastolic filling pattern. The kind of drug used to accomplish mass reduction seems to be irrelevant as far as the improvement in diastolic function is concerned. The pattern of left ventricular hypertrophy, however, might play a role in influencing the outcome on diastolic mechanics of left ventricular mass decrease.

Adrenergic beta-Antagonists↗
PubMed1992

[Left ventricular systolic and diastolic asynchronism in patients with ischemic cardiopathy: its effects on ventricular filling].

To assess whether left ventricular asynchrony would influence filling in coronary artery disease, 27 patients with coronary artery disease and 39 normal subjects were studied by rest radionuclide angiography. Lower ejection fraction and peak filling rate were found in the coronary artery disease group (56% +/- 17% versus 65% +/- 6%, p less than 0.05; 1.8 +/- 0.7 versus 2.9 +/- 1.4 end-diastolic volumes/s, p less than 0.05). Moreover, the patients with coronary artery disease had a prolonged isovolumic relaxation period (114 +/- 86 ms versus 70 +/- 43 ms, p less than 0.05). Two indices of left ventricular asynchrony were evaluated: the coefficient of variation of regional time to end-systole, and the coefficient of variation of regional time to peak filling rate. The coefficient of variation of regional time to peak filling rate was higher in the coronary artery disease group (10.1% +/- 10%) than in the normal subjects (6.2% +/- 3.7%, p less than 0.05). Both these parameters were inversely related to global peak filling rate in the coronary artery disease group. These findings suggest that in patients with coronary artery disease left ventricular systolic and diastolic asynchrony plays a role in determining left ventricular diastolic properties.

Blood Pressure↗
PubMed1991

Fourier analysis in patients with different pacing modes.

The purpose of this study was to evaluate the usefulness of phase analysis in detecting the altered activation sequence induced by different pacing modes. Radionuclide ventriculography and planar gated blood pool scintigraphy were performed at rest in 56 patients with different pacemakers. This method permitted us to localize the pacemaker impulse site in the right ventricle and its diffusion in the heart. In patients with VVI pacemaker, this technique showed an evident asynchronism of contraction and relaxation of each ventricle and the standard deviation of phase angle (sigma), calculated by computer, is greater during pacing than sinus rhythm for left (LV) and right (RV) ventricles (LV sigma: 17 degrees +/- 4 vs 11 degrees +/- 3, less than 0.001; RV sigma: 31 degrees +/- 7 vs 14 degrees +/- 4, P less than 0.001). In the patients with VVI rate responsive pacemakers, the LV sigma changed from 18.5 +/- 3 under pacing to 11 degrees +/- 3 in sinus rhythm, P less than 0.001, while the RV sigma changed from 30 degrees +/- 8 to 14 degrees +/- 4, P less than 0.001. Instead in the patients with DDD pacemakers, the LV sigma changed from 15.5 degrees +/- 2 under pacing to 11 degrees +/- 3 in sinus rhythm, P less than 0.05, while the RV sigma changed from 29.1 degrees +/- 6 to 14 degrees +/- 4, P less than 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗