Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0033377 (prolapse)
 11,717 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serial non-invasive studies including echocardiography were performed for the evaluation and follow-up of the cardiac lesions in six cases with genetic mucopolysaccharidoses. These cases were classified by the enzyme assay into one case of Scheie syndrome, three of Hunter syndrome, one of Sanfilippo syndrome and one of Maroteaux-Lamy syndrome. The echocardiographic examination revealed the most striking change in the mitral valve, which was progressive with increase of the age in most cases. The mitral valve echo was dense and multilayered with a decreased diastolic descent rate (DDR) in the M-mode echocardiogram, and its thick leaflets showed diminished opening on the two-dimensional echocardiogram. The aortic valve echo was also dense in three cases inducing one case with the prolapse of the non-coronary cusp into the left ventricular (LV) cavity. The pulmonary and tricuspid valves showed an unremarkable change, although the echocardiographic signs of pulmonary hypertension was observed in two cases. Diffuse hypertrophy of the interventricular septum and LV posterior wall was observed in five cases and apical hypertrophy was found in a case of Hunter syndrome (Case 2). Parameters of the LV contractility showed almost normal values but the distensibility of the LV posterior wall was impaired in two cases, suggesting stiffness of the cardiac muscle. Although no ischemic change was observed on the electrocardiogram, the echo density of coronary artery wall was not uniform on the two-dimensional echocardiogram and dilated coronary artery was found in two cases. Phonocardiograms disclosed an aortic regurgitant murmur in one case and an apical mitral regurgitant murmur in two cases. In one case of Scheie syndrome, a pansystolic murmur (Levine 3/6) and a mid-diastolic rumble (Levine 2/6) were present at the age of 15 and 16, but after the transient increase in the loudness these disappeared at the age of 18 and only an ejection systolic murmur is audible at the present time, while the mitral valve showed a progressive limitation of the movement on the two-dimensional echocardiogram. Contrary to the reduced DDR and diminished opening of the mitral valve in 3 cases, neither diastolic rumble nor opening snap was recognized in the phonocardiogram. The echocardiographic findings seemed to reflect the patho-anatomical manifestation of this disease, and thus, the periodical echocardiographic evaluation is rewarding to assess the cardiac lesions and their progression in mucopolysaccharidoses.
 ...
PMID:[Cardiac manifestation of the mucopolysaccharidoses: periodical echocardiographic evaluation in six cases]. 642 63

Myotonia atrophica, a neuromuscular disease marked by autosomal dominant transmission and delayed relaxation of skeletal muscle, has been associated with cardiac failure, conduction abnormality and mitral prolapse (MVP). In order to determine the relaxation rate of cardiac muscle, left ventricular (LV) size and function, and the presence of MVP, 30 patients with myotonia atrophica were studied using digitized M-mode echocardiography (MME). Intracardiac conduction intervals were determined by noninvasive His bundle recording (HBR) from surface electrodes using a high-resolution, R-wave triggered, signal averaging computer. Neurologically unaffected first-degree relatives of the patients with myotonia atrophica were also studied to determine if cardiac abnormalities may be present in the absence of neurologic manifestations of the disease. Peak normalized diastolic endocardial velocity in patients with myotonia atrophica (3.7 +/- 0.8 sec-1) did not differ from unaffected first-degree relatives (3.8 +/- 0.8 sec-1) or normal subjects (3.6 +/- 0.8 sec-1). Systolic LV function and LV dimensions on MME were normal in both groups. However, MVP was present in 7 of 24 (29%) of patients who could be evaluated, but not in unaffected first-degree relatives. Despite normal LV systolic and diastolic function, infranodal intracardiac conduction was prolonged in patients with myotonia atrophica (average HV interval 50 +/- 5 SD msec) but not in neurologically unaffected relatives (average HV interval 40 +/- 5 msec). Delay in proximal intracardiac conduction was also found in patients with myotonia atrophica (average PH interval 140 +/- 20 msec) but not in neurologically unaffected relatives (average PH interval 115 +/- 6 msec). Hence cardiac findings in myotonia atrophica include proximal and distal conduction delay by external HBR even in the absence of abnormality of the standard 12-lead ECG. There may also be an increased frequency of MVP; however, early diastolic relaxation of the LV is unimpaired, and cardiac manifestations of myotonia are not transmitted independently of neurologic abnormality.
 ...
PMID:Left ventricular relaxation, mitral valve prolapse, and intracardiac conduction in myotonia atrophica: assessment by digitized echocardiography and noninvasive His bundle recording. 709 Sep 87

The concept that the mitral valve of the heart is a passive flap that opens and closes like a barn door has been emphasized for decades by medical and biology professors to their students. But experimental findings, which are outlined in this report, support the theory of an active valve. We hypothesize that the two leaflets of the mitral valve are actively contractile; that physical forces generated in the valve itself may stabilize and add precision to the sum of forces that regulate valve movement. This precision could be of critical significance both in the moments preceding, and during, valve opening and closing. Evidence supporting our active valve hypothesis includes the profuse innervation of motor and sensory nerves that are present in the mitral valves of all animals studied. In addition, multiple contractile cell types have been found in the mitral valve, including cardiac muscle cells, smooth muscle cells, and cardiac valvular interstitial cells. In vitro work in our laboratories using the rat mitral valve shows that not only are the valves capable of contraction and relaxation, but that the contractions and relaxations are nerve-mediated. We theorize that the rich innervation and contractile cells in the mitral valve work together to modulate fine-tuning of valve movements and tone, thereby ensuring the integrity of the valve seal. Other investigators have reported that the mitral valve demonstrates contractile activity and that denervation localized to the mitral valve affects valve competence. The evidence for an active mitral valve presented by these and other experimental studies warrant a reexamination of the validity of the passive valve concept. An accurate and full understanding of the precise movements of the valve leaflets and the mechanisms that regulate these movements is likely to provide the information needed to understand and develop treatments for many different cardiac valve problems, including mitral valve diseases such as prolapse and myxomatous degeneration. In view of the available experimental evidence, the concept that the mitral valve functions only as a passive structure is challenged by numerous anomalies. A reinterpretation of the concept of valve function that incorporates active as well as passive roles for the valve leaflets and other components of the valve apparatus would have significant implications both for the directions taken in research involving the cardiac valves and for the approaches to treatment.
 ...
PMID:Is the mitral valve passive flap theory overstated? An active valve is hypothesized. 1505 Jan 15