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Biomedical subjects

P Spirito

Publications and source records attributed to P Spirito.

At least 19 recordsLinked to original sources
PubMed1996

Changes in effective aortic valve area during ejection in adults with aortic stenosis.

Measurements of valve orifice area in aortic stenosis are based on the assumption that orifice area remains constant throughout ejection and is independent of transvalvular gradients and flow. Recent studies, however, have suggested that the calculated valve area of calcific aortic stenosis may change in different flow conditions. Therefore, we tested the hypothesis that in vivo effective orifice area of a stenotic aortic valve changes continuously during ejection, which would make a single area measurement a potentially inadequate indicator of the severity of the stenosis. Doppler measurements of flow velocity in the ascending aorta and in the left ventricular outflow tract at peak velocity, at half-peak velocity during acceleration (midacceleration), and at half-peak velocity during deceleration (mid-deceleration) were obtained in 26 patients with aortic stenosis (mean gradient 50 +/- 19 mm Hg and effective aortic orifice are 0.7 +/- 0.3 dcm2) and in 14 normal subjects of similar age and gender, to calculate instantaneous effective aortic orifice area at midacceleration, at peak velocity and at mid-deceleration. In the 26 patients with aortic stenosis, aortic valve area at midacceleration was 84 +/- 15% of valve area at peak velocity (p < 0.0001), and valve area at mid-deceleration was 113 +/- 17% of that measured at peak velocity (p < 0.01). Conversely, in normal subjects, aortic valve area remained constant during ejection and was 97 +/- 5% and 99 +/- 6% of valve area at peak velocity, respectively, at midacceleration and mid-deceleration (p > 0.05). In addition, in patients with aortic stenosis the percentage of change in effective aortic valve area from midacceleration to mid-deceleration varied widely, from -17% to +49% (mean change +26 +/- 14%). There was no relation between percentage of change in effective valve area and mean transaortic gradient (r = 0.05; p = 0.30) or effective valve area at peak velocity (r = -0.11; p = 0.14). Our results indicate that effective aortic valve area continues to change during ejection in patients with aortic stenosis, and that the magnitude of this change is independent of the usual indexes of severity of the stenosis. Conversely, effective aortic valve area remains constant during ejection in normal subjects.

Aged↗
PubMed1995

A de novo mutation in alpha-tropomyosin that causes hypertrophic cardiomyopathy.

BACKGROUND: Two missense mutations in the gene for alpha-tropomyosin have been described that segregate with hypertrophic cardiomyopathy in single families. To confirm that these mutations are the cause of the disease, we have investigated the origins of one of these mutations, Asp175Asn, in a third and unrelated family. METHODS AND RESULTS: The presence or absence of an alpha-tropomyosin mutation and the haplotypes of the flanking chromosomal regions were determined for members of a family with hypertrophic cardiomyopathy. Haplotypes were constructed by use of an intragenic polymorphism and 10 flanking polymorphisms spanning a region of 35 centimorgans. The Asp175Asn missense mutation was present in the proband and his two affected offspring but not in any of the proband's three siblings. Although both parents were deceased, the haplotypes of the four parental chromosomes could be reconstructed. One parental chromosome was transmitted to two offspring: one bearing the Asp175Asn mutation (the affected proband) and one clinically unaffected sibling who lacked the alpha-tropomyosin mutation. Thus, the Asp175Asn mutation must have arisen de novo. CONCLUSIONS: De novo mutations in the alpha-tropomyosin gene can result in hypertrophic cardiomyopathy that may appear to be sporadic but in subsequent generations gives rise to familial disease. Individuals with sporadic hypertrophic cardiomyopathy should be advised of the risk of transmission to offspring. In addition, these findings provide the strongest genetic evidence that mutations in the alpha-tropomyosin gene are directly responsible for hypertrophic cardiomyopathy.

Adolescent↗
PubMed1995

Mutations in the genes for cardiac troponin T and alpha-tropomyosin in hypertrophic cardiomyopathy.

BACKGROUND: Familial hypertrophic cardiomyopathy can be caused by mutations in the genes for beta cardiac myosin heavy chain, alpha-tropomyosin, or cardiac troponin T. It is not known how often the disease is caused by mutations in the tropomyosin and troponin genes, and the associated clinical phenotypes have not been carefully studied. METHODS: Linkage between polymorphisms of the alpha-tropomyosin gene or the cardiac troponin T gene and hypertrophic cardiomyopathy was assessed in 27 families. In addition, 100 probands were screened for mutations in the alpha-tropomyosin gene, and 26 were screened for mutations in the cardiac troponin T gene. Life expectancy, the incidence of sudden death, and the extent of left ventricular hypertrophy were compared in patients with different mutations. RESULTS: Genetic analyses identified only one alpha-tropomyosin mutation, identical to one previously described. Five novel mutations in cardiac troponin were identified, as well as a further example of a previously described mutation. The clinical phenotype of four troponin T mutations in seven unrelated families was similar and was characterized by a poor prognosis (life expectancy, approximately 35 years) and a high incidence of sudden death. The mean (+/- SD) maximal thickness of the left ventricular wall in subjects with cardiac troponin T mutations (16.7 +/- 5.5 mm) was significantly less than that in subjects with beta cardiac myosin heavy-chain mutations (23.7 +/- 7.7 mm, P < 0.001). CONCLUSIONS: Mutations in alpha-tropomyosin are a rare cause of familial hypertrophic cardiomyopathy, accounting for approximately 3 percent of cases. Mutations in cardiac troponin T account for approximately 15 percent of cases of familial hypertrophic cardiomyopathy in this referral-center population. These mutations are characterized by relatively mild and sometimes subclinical hypertrophy but a high incidence of sudden death. Genetic testing may therefore be especially important in this group.

Adolescent↗
PubMed1994

Morphology of the "athlete's heart" assessed by echocardiography in 947 elite athletes representing 27 sports.

In the present study, we used echocardiography to investigate the morphologic adaptations of the heart to athletic training in 947 elite athletes representing 27 sports who achieved national or international levels of competition. Cardiac morphology was compared for these sports, using multivariate statistical models. Left ventricular (LV) diastolic cavity dimension above normal (> 54 mm, ranging up to 66 mm) was identified in 362 (38%) of the 947 athletes. LV wall thickness above normal (> 12 mm, ranging up to 16 mm) was identified in only 16 (1.7%) of the athletes. Athletes training in the sports examined showed considerable differences with regard to cardiac dimensions. Endurance cyclists, rowers, and swimmers had the largest LV diastolic cavity dimensions and wall thickness. Athletes training in sports such as track sprinting, field weight events, and diving were at the lower end of the spectrum of cardiac adaptations to athletic training. Athletes training in sports associated with larger LV diastolic cavity dimensions also had higher values for wall thickness. Athletes training in isometric sports, such as weightlifting and wrestling, had high values for wall thickness relative to cavity dimension, but their absolute wall thickness remained within normal limits. Analysis of gender-related differences in cardiac dimensions showed that female athletes had smaller LV diastolic cavity dimension (average 2 mm) and smaller wall thickness (average 0.9 mm) than males of the same age and body size who were training in the same sport.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Sixty-six episodes of ventricular fibrillation within four hours: electrical stability restored by propafenone.

Ventricular fibrillation is a complication in patients hospitalized for acute myocardial infarction. We report the case of an unusually high number of episodes of ventricular fibrillation (66 episodes) that occurred within a period of 4 h in a patient with recent anterior myocardial infarction. In patients with acute or recent myocardial infarction and recurrent episodes of ventricular fibrillation, intravenous lidocaine is the antiarrhythmic medication of choice. In our patient, recurrences of ventricular fibrillation were not prevented either by lidocaine, or amiodarone. The rate of recurrence of ventricular fibrillation, however, decreased dramatically, twice, in the minutes following two separate boluses of propafenone, and the arrhythmia did not recur when continuous infusion of propafenone was started. We cannot exclude that were the combined antiarrhythmic effects of lidocaine, amiodarone and propafenone that led to the final control of the arrhythmia.

Amiodarone↗
PubMed1994

Prognosis of asymptomatic patients with hypertrophic cardiomyopathy and nonsustained ventricular tachycardia.

BACKGROUND: In the early 1980s, studies performed in highly selected referral patients with hypertrophic cardiomyopathy reported a strong association between the presence of brief episodes of ventricular tachycardia (VT) on ambulatory ECG monitoring and sudden death. These observations led to antiarrhythmic treatment in many patients with hypertrophic cardiomyopathy and brief episodes of VT. In recent years, however, a growing awareness of the potential arrhythmogenic effects of antiarrhythmic medications has raised doubts regarding such a therapeutic approach, particularly in less selected and lower-risk patient populations. METHODS AND RESULTS: In the present study, we examined the prognostic significance of nonsustained VT in a population of 151 patients with hypertrophic cardiomyopathy who were asymptomatic or had only mild symptoms at the time of their initial ambulatory ECG recording. Of the 151 study patients, 42 had episodes of VT and 109 did not. The runs of VT ranged from 3 to 19 beats, with 35 patients (83%) having < 10 beats. The number of runs of VT ranged from 1 to 12 in 24 hours, with 36 patients (86%) having < or = 5 episodes of VT. Thus, in most patients, the episodes of VT were brief and infrequent. Follow-up averaged 4.8 years. Of the 151 study patients, 6 died suddenly, 3 in the group with VT and 3 in the group without VT. Two other patients, both in the group without VT, died of congestive heart failure. The total cardiac mortality rate was 1.4% per year in the patients with VT (95% CI, 0.4% to 3.5%) and 0.9% in those without VT (95% CI, 0.4% to 2.0%; P = .43). The relative risk of cardiac death for patients with VT was 1.4 compared with patients without VT (95% CI, 0.6 to 6.1). The sudden death rate was 1.4% per year in the patients with VT (95% CI, 0.4% to 3.5%) and 0.6% in those without VT (95% CI, 0.2% to 1.5%; P = .24). The relative risk of sudden death for patients with VT compared with those without VT was 2.4 (95% CI, 0.5 to 11.9). Of the 151 patients included in the study, 88 (58%) remained asymptomatic and were not treated with cardioactive medications during follow-up. Of these 88 patients, 20 were in the group with VT and 68 in the group without VT. None of these patients died. CONCLUSIONS: Our results show that cardiac mortality is low in patients with hypertrophic cardiomyopathy who are asymptomatic or only mildly symptomatic and have brief and infrequent episodes of VT on ambulatory ECG monitoring. Our findings also suggest that brief and infrequent episodes of VT should not be considered, per se, an indication for antiarrhythmic treatment in such patients.

Adolescent↗
PubMed1993

Role of cardiac ultrasound in the assessment of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy is a complex disease characterized by a broad spectrum of morphologic and functional abnormalities and by a great variability in its natural history. Cardiac ultrasound has had a great impact on our understanding of hypertrophic cardiomyopathy and has become the main tool for diagnosis and patient management. This brief review will summarize the main applications of cardiac ultrasound in this disease.

Cardiomyopathy, Hypertrophic↗
PubMed1993

Echocardiographic assessment of mitral valve size in obstructive hypertrophic cardiomyopathy. Anatomic validation from mitral valve specimen.

BACKGROUND: In patients with hypertrophic cardiomyopathy, obstruction to left ventricular outflow is produced by systolic anterior motion of the mitral valve. In many of these patients, the mitral leaflets are elongated and increased in overall size. Mitral valve size may be responsible, in part, for the presence and magnitude of the outflow gradient and the pattern of systolic anterior motion of the leaflets. It may also influence the effectiveness of ventricular septal myotomy-myectomy in relieving subaortic obstruction. Therefore, the present study was undertaken to determine whether mitral valve dimensions could be assessed in quantitative terms from the echocardiogram in patients with hypertrophic cardiomyopathy. METHODS AND RESULTS: A group of 37 patients with hypertrophic cardiomyopathy was selected for this study by virtue of having a high-quality transthoracic or intraoperative echocardiogram suitable for certain quantitative measurements from stop-frame images as well as a morphologically intact mitral valve specimen (removed during surgery). Seven measurements of mitral valve dimensions were obtained from the two-dimensional and M-mode echocardiograms. A univariate regression analysis identified the mitral valve opening area as the best single predictor of actual mitral leaflet area measured from the specimen (r2 = .75; r = .87). The linear relation between mitral valve opening area as assessed by two-dimensional echocardiography and actual mitral leaflet area measured from the mitral valve specimen accounted for approximately 75% of the variability in mitral leaflet area. With such statistical models, it was possible to reliably identify from the echocardiogram enlarged mitral valves (> or = 12.0 cm2) in 16 of 19 patients (84%) and normal-sized valves in 15 of 18 patients (83%). CONCLUSIONS: In a selected group of patients with obstructive hypertrophic cardiomyopathy, a model derived from a regression analysis of quantitative echocardiographic measurements permitted (with good precision) estimation of actual mitral leaflet area and consequently overall mitral valve size and the discrimination of enlarged from normal-sized mitral valves.

Adolescent↗
PubMed1992

Degree of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy and chronic atrial fibrillation.

It has been generally assumed that most patients with hypertrophic cardiomyopathy (HC) who develop atrial fibrillation (AF) have marked left ventricular (LV) hypertrophy and subaortic obstruction. The morphologic and functional features of this subset of patients with HC have not been systematically investigated. The LV morphology and functional profile of 46 patients with HC and chronic AF were compared with those of 81 control patients with HC and normal sinus rhythm. Contrary to expectations, LV hypertrophy (assessed with 2-dimensional echocardiography) was substantially less marked in the patients with AF than in the control patients, and prevalence of subaortic obstruction was similar in the 2 groups. Maximal LV wall thickness and wall thickness index were lower in patients with AF (18 +/- 2 and 56 +/- 7 mm, respectively) than in control patients (22 +/- 6 and 67 +/- 16 mm, respectively; p less than 0.001). Furthermore, mild LV hypertrophy (maximal LV wall thickness less than or equal to 17 mm confined to 1 ventricular segment) was almost twice as frequent in patients with AF (63%) than in control patients (36%; p less than 0.005). Subaortic obstruction was present in 9 patients with AF (20%) and in 28 control patients (35%; p greater than 0.05). In a subgroup of 22 patients with AF who were followed for 4 to 10 years, 5 patients had marked LV wall thinning (greater than or equal to 5 mm, range 5 to 14). In conclusion, these results demonstrate that most patients with HC and chronic AF have the nonobstructive form of HC, and relatively mild LV hypertrophy.

Adult↗
PubMed1992

Usefulness of Doppler echocardiographic assessment of diastolic filling in distinguishing "athlete's heart" from hypertrophic cardiomyopathy.

OBJECTIVE: In some athletes with a substantial increase in left ventricular wall thickness, it may be difficult to distinguish with certainty physiological hypertrophy due to athletic training from hypertrophic cardiomyopathy. The purpose of the present investigation was to determine whether assessment of left ventricular filling could differentiate between these two conditions. DESIGN: Doppler echocardiography was used to obtain transmitral flow velocity waveforms from which indices of left ventricular diastolic filling were measured. Normal values were from 35 previously studied control subjects. SETTING: Athletes were selected mostly from the Institute of Sports Science (Rome, Italy), and patients with hypertrophic cardiomyopathy were studied at the National Institutes of Health (Bethesda, Maryland). PARTICIPANTS: The athlete group comprised 16 young competitive athletes with an increase in left ventricular wall thickness (range 13-16 mm; mean 14). For comparison, 12 symptom free patients with non-obstructive hypertrophic cardiomyopathy were selected because their ages and degree of hypertrophy were similar to those of the athletes. RESULTS: In the athlete group, values for deceleration of flow velocity in early diastole, peak early and late diastolic flow velocities, and their ratio were not significantly different from those obtained in untrained normal subjects; furthermore, Doppler diastolic indices were normal in each of the 16 athletes. Conversely, in patients with hypertrophic cardiomyopathy, mean values for Doppler diastolic indices were significantly different from both normal subjects and athletics (p = 0.01 to 0.003), and one or more indices were abnormal in 10 (83%) of the 12 patients. CONCLUSIONS: Doppler echocardiographic indices of left ventricular filling may aid in distinguishing between pronounced physiological hypertrophy due to athletic training and pathological hypertrophy associated with hypertrophic cardiomyopathy.

Adaptation, Physiological↗
PubMed1991

The upper limit of physiologic cardiac hypertrophy in highly trained elite athletes.

BACKGROUND: In some highly trained athletes, the thickness of the left ventricular wall may increase as a consequence of exercise training and resemble that found in cardiac diseases associated with left ventricular hypertrophy, such as hypertrophic cardiomyopathy. In these athletes, the differential diagnosis between physiologic and pathologic hypertrophy may be difficult. METHODS: To address this issue, we measured left ventricular dimensions with echocardiography in 947 elite, highly trained athletes who participated in a wide variety of sports. RESULTS: The thickest left ventricular wall among the athletes measured 16 mm. Wall thicknesses within a range compatible with the diagnosis of hypertrophic cardiomyopathy (greater than or equal to 13 mm) were identified in only 16 of the 947 athletes (1.7 percent); 15 were rowers or canoeists, and 1 was a cyclist. Therefore, the wall was greater than or equal to 13 mm thick in 7 percent of 219 rowers, canoeists, and cyclists but in none of 728 participants in 22 other sports. All athletes with walls greater than or equal to 13 mm thick also had enlarged left ventricular end-diastolic cavities (dimensions, 55 to 63 mm). CONCLUSIONS: On the basis of these data, a left-ventricular-wall thickness of greater than or equal to 13 mm is very uncommon in highly trained athletes, virtually confined to athletes training in rowing sports, and associated with an enlarged left ventricular cavity. In addition, the upper limit to which the thickness of the left ventricular wall may be increased by athletic training appears to be 16 mm. Therefore, athletes with a wall thickness of more than 16 mm and a nondilated left ventricular cavity are likely to have primary forms of pathologic hypertrophy, such as hypertrophic cardiomyopathy.

Adult↗
PubMed1991

Quantitative assessment of ultrasonic myocardial reflectivity in hypertrophic cardiomyopathy.

The purpose of this study was to investigate the relation between acoustic properties of the myocardium and magnitude of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy. An on-line radio frequency analysis system was used to obtain quantitative operator-independent measurements of the integrated backscatter signal of the ventricular septum and posterior free wall in 25 patients with hypertrophic cardiomyopathy and 25 normal age-matched control subjects. The integrated values of the radio frequency signal were normalized for the pericardial interface and expressed in percent. Tissue reflectivity was significantly increased in the hypertrophied ventricular septum, as well as in the nonhypertrophied posterior free wall, in patients with hypertrophic cardiomyopathy (58 +/- 15% and 37 +/- 12%, respectively) compared with values in normal subjects (33 +/- 10% and 18 +/- 5%, respectively; p less than 0.001). Furthermore, measurements of reflectivity of the septum or posterior free wall, or both, were beyond 2 SD of normal values in greater than 90% of the patients and were also abnormal in each of the five study patients who had only mild and localized left ventricular hypertrophy. No correlation was identified between myocardial tissue reflectivity and left ventricular wall thickness in the patients with hypertrophic cardiomyopathy (correlation coefficient r = 0.4; p = NS). These findings demonstrate that myocardial reflectivity is abnormal in most patients with hypertrophic cardiomyopathy and is largely independent of the magnitude of left ventricular hypertrophy. Moreover, quantitative analysis of ultrasonic reflectivity can differentiate patients with hypertrophic cardiomyopathy from normal subjects independently of clinical features and conventional echocardiographic measurements.

Adolescent↗