Prevalence and clinical outcome of mitral-valve prolapse

Adult women with mitral valve prolapse are more flexible

BACKGROUND

Mitral valve prolapse (MVP) is common in women. Other clinical features such as flexibility and hyperlaxity are often associated with MVP, as there is a common biochemical and histological basis for collagen tissue characteristics, range of joint motion, and mitral leaflet excursion.

OBJECTIVE

To confirm whether adult women with MVP are more flexible and hypermobile than those without.

METHODS

Data from 125 women (mean age 50 years), 31 of them with MVP, were retrospectively analysed with regard to clinical and kinanthropometric aspects. Passive joint motion was evaluated in 20 body movements using Flexitest and three laxity tests. Flexitest individual movements (0 to 4) and overall Flexindex scores were obtained in all subjects by the same investigator.

RESULTS

Women with MVP were lighter, less endomorphic and mesomorphic, and more linear. The Flexindex was significantly higher in the women with MVP, both absolute (48 (1.6) v 41 (1.3); p<0.01) and centile for age (67 v 42; p<0.01) values. In 13 out of 20 movements, the Flexitest scores were significantly higher for the women with MVP. Signs of hyperlaxity were about five times more common in these women: 74% v 16% (p<0.01). Scores of 0 and 1 in elbow extension, absence of hyperlaxity, and a Flexindex centile below 65 were almost never found in women with MVP.

CONCLUSION

Flexitest, alone or combined with hyperlaxity tests, may be useful in the assessment of adult women with MVP.

[Mitral regurgitation]

Mitral regurgitation is the second most frequent reason for valve surgery. The most important causes of mitral regurgitation are degenerative valve disease (mitral valve prolapse), left ventricular impairment and dilatation (in coronary artery disease or dilated cardiomyopathy), and infective endocarditis. The regurgitation of blood from the left ventricle into the left atrium leads to dilatation of the left atrium, increase in pulmonary capillary pressure and pulmonary congestion. In chronic severe mitral regurgitation, the left ventricle dilates and becomes impaired over time. Key symptoms are fatigue and dyspnea on exertion. The most prominent physical sign is the characteristic systolic murmur. Echocardiography identifies severity, delineates morphology, and estimates the impact of mitral regurgitation on left ventricular function. Importantly, echocardiography identifies candidates for mitral valve repair. Symptomatic patients and asymptomatic patients with impaired left ventricular function should be operated. If possible, valve repair is preferred over valve replacement to better preserve left ventricular function and to avoid the need for postoperative anticoagulation (except if atrial fibrillation persists).

Incidence and outcomes of acute lung injury

BACKGROUND

Acute lung injury is a critical illness syndrome consisting of acute hypoxemic respiratory failure with bilateral pulmonary infiltrates that are not attributed to left atrial hypertension. Despite recent advances in our understanding of the mechanism and treatment of acute lung injury, its incidence and outcomes in the United States have been unclear.

METHODS

We conducted a prospective, population-based, cohort study in 21 hospitals in and around King County, Washington, from April 1999 through July 2000, using a validated screening protocol to identify patients who met the consensus criteria for acute lung injury.

RESULTS

A total of 1113 King County residents undergoing mechanical ventilation met the criteria for acute lung injury and were 15 years of age or older. On the basis of this figure, the crude incidence of acute lung injury was 78.9 per 100,000 person-years and the age-adjusted incidence was 86.2 per 100,000 person-years. The in-hospital mortality rate was 38.5 percent. The incidence of acute lung injury increased with age from 16 per 100,000 person-years for those 15 through 19 years of age to 306 per 100,000 person-years for those 75 through 84 years of age. Mortality increased with age from 24 percent for patients 15 through 19 years of age to 60 percent for patients 85 years of age or older (P<0.001). We estimate that each year in the United States there are 190,600 cases of acute lung injury, which are associated with 74,500 deaths and 3.6 million hospital days.

CONCLUSIONS

Acute lung injury has a substantial impact on public health, with an incidence in the United States that is considerably higher than previous reports have suggested.

Silent cerebral infarct in patients with mitral valve prolapse

It is still not clear whether mitral valve prolapse (MVP) is a risk factor for ischemic stroke. The aim of this study was to evaluate whether uncomplicated MVP is a risk factor for silent cerebral ischemic events. Fifty-two patients with uncomplicated MVP and 46 control subjects without MVP were included in the study. All subjects were evaluated for silent cerebral infarct (SCI) with a magnetic resonance imaging. Five (9.6%) of the patients who had MVP but no other risk factors for ischemic cerebral events had SCI. The results suggest that uncomplicated MVP is a risk factor for SCI, and that patients with MVP should receive anti-platelet-aggregating drugs.

Mitral Annular Disjunction in Advanced Myxomatous Mitral Valve Disease: Echocardiographic Detection and Surgical Correction

Mitral annular disjunction is a structural abnormality of the mitral annulus fibrosus described by pathologists in association with mitral leaflet prolapse and defined as a separation between the atrial wall-mitral valve (MV) junction and the left ventricular attachment allowing for hypermobility of the MV apparatus. The transesophageal echocardiographic characteristics of this abnormality have not been previously described. In patients undergoing MV repair for myxomatous MV degeneration and evaluated using a standardized transesophageal echocardiographic protocol, annular disjunction (mean value 10 +/- 3 mm) was seen at the base of the posterior leaflet in 98% of patients with advanced, and in 9% of patients with mild/moderate MV degeneration. There was a significant correlation between the magnitude of disjunction and the number of segments with prolapse/flail (r = 0.397, P = .001). We found annular disjunction to be a common component of MV apparatus in advanced MV degeneration. Its recognition on transesophageal echocardiography is important to facilitate optimal MV repair. The modification of the repair technique allows surgical correction of the annular disjunction, which seems to optimize long-term results in these challenging cases.

New locus for autosomal dominant mitral valve prolapse on chromosome 13: clinical insights from genetic studies

BACKGROUND

Mitral valve prolapse (MVP) is a common disorder associated with mitral regurgitation, endocarditis, heart failure, and sudden death. To date, 2 MVP loci have been described, but the defective genes have yet to be discovered. In the present study, we analyzed a large family segregating MVP, and identified a new locus, MMVP3. This study and others have enabled us to explore mitral valve morphological variations of currently uncertain clinical significance.

METHODS AND RESULTS

Echocardiograms and blood samples were obtained from 43 individuals who were classified by the extent and pattern of displacement. Genotypic analyses were performed with polymorphic microsatellite markers. Evidence of linkage was obtained on chromosome 13q31.3-q32.1, with a peak nonparametric linkage score of 18.41 (P<0.0007). Multipoint parametric analysis gave a logarithm of odds score of 3.17 at marker D13S132. Of the 6 related individuals with mitral valve morphologies not meeting diagnostic criteria but resembling fully developed forms, 5 carried all or part of the haplotype linked to MVP.

CONCLUSIONS

The mapping of a new MVP locus to chromosome 13 confirms the observed genetic heterogeneity and represents an important step toward gene identification. Furthermore, the genetic analysis provides clinical lessons with regard to previously nondiagnostic morphologies. In the familial context, these may represent early expression in gene carriers. Early recognition of gene carriers could potentially enhance the clinical evaluation of patients at risk of full expression, with the ultimate aim of developing interventions to reduce progression.

Anxiety and medical disorders

Anxiety symptoms and disorders are associated with a range of general medical disorders. This association may be a physiologic consequence of the general medical disorder, a psychologic reaction to the experience of having a medical illness, a side effect of treatment, or a chance occurrence. This article briefly reviews the associations of panic disorder with seizure disorder, Klüver-Bucy syndrome, mitral valve prolapse, and respiratory disorders; of generalized anxiety disorder with chronic obstructive airway disease and cardiovascular and endocrine disorders; of social anxiety disorder with Parkinson's disease; of obsessive-compulsive disorder with striatal disorders; and of posttraumatic stress disorder with head injury and pain. Such associations provide important clues for understanding the neurobiology of anxiety disorders.

Prevention of Systolic Anterior Motion After Repair of the Severely Myxomatous Mitral Valve With an Anterior Leaflet Valvuloplasty

BACKGROUND

Systolic anterior motion after mitral valve repair of severely myxomatous valves is due to excess tissue or anterior displacement, or both, of the leaflet coaptation point. Our series of anterior leaflet valvuloplasty, an alternative to the sliding leaflet technique to prevent systolic anterior motion, is presented.

METHODS

Between January 1, 1996 and January 6, 2003, we performed elliptical excisions of the base of the anterior leaflet in 47 patients with a mean age of 66 years (range, 29 to 86). All patients had an anterior leaflet height of 3.0 cm or more and an annular diameter of 4.0 cm or more. Repairs included posterior leaflet (37; 80%), and anterior leaflet (28; 61%) resections, with occasional transposition flaps (9; 19%). All 47 (100%) had an annuloplasty ring (9, Physio; 37, Seguin). Four (8%) included tricuspid repair, 6 (13%) aortic valve replacement, and 9 (19%) coronary artery bypass. Follow-up was between 2 months and 8 years.

RESULTS

There was no systolic anterior motion or in-hospital (30-day) mortality. Postoperative echocardiography revealed an average anterior leaflet height of 2.2 +/- 0.3 cm, with an annular diameter of 3 +/- 0.2 cm. The anterior/posterior leaflet ratio decreased from 1.6 +/- 0.2 to 1.4 +/- 0.1 cm while the coaptation point-annular plane distance decreased from 1.2 +/- 0.2 to 0.9 +/- 0.1 cm. There were 4 late noncardiac deaths. Two patients have required mitral valve replacement owing to progressive disease and 6 patients were lost to follow-up. The 35 patients remaining have trace-mild mitral regurgitation.

CONCLUSIONS

Our anterior mitral valve leaflet valvuloplasty, regardless of the ring, results in a decrease in surface area and excursion of the anterior leaflet without systolic anterior motion.

Abnormalities of ventricular repolarization in mitral valve prolapse

OBJECTIVES

Mitral valve prolapse (MVP) is associated with arrhythmias and sudden death. Some studies suggest that abnormalities of the autonomic nervous system (ANS) may contribute to these arrhythmias. In a family investigation with genetic analysis of patients carrying a MVP, we performed a Holter study to define the autonomic profile of MVP.

METHODS AND RESULTS

A 24-hour digitized 3-lead Holter ECG was recorded in 30 patients with MVP and in two control groups, a group of 30 healthy relatives and a group of 31 healthy volunteers. We studied especially heart rate variability (HRV) and QT dynamicity. The slope of the relationship between ventricular repolarization and heart rate was studied separately during day and night. There was no difference in HRV (SDNN, rMSSD) among the three groups. On the contrary, QT interval duration was increased in patients with MVP as compared to healthy relatives (QT end: 409+/-52 ms vs 372+/-23 ms, P<0.05; QT apex: 319+/-42 ms vs 286+/-23 ms, P<0.01) and to healthy volunteers (QT end: 409+/-52 ms vs 376+/-25 ms, P=0.004; QT apex: 319+/-42 ms vs 289+/-23 ms, P<0.01). Nocturnal ventricular repolarization rate dependence was increased in MVP as compared to healthy relatives (0.16+/-0.06 vs 0.13+/-0.04, P<0.05) and to healthy volunteers (0.16+/-0.06 vs 0.11+/-0.06, P<0.001) whereas the 24-hour and diurnal QT-R-R slope was not disturbed.

CONCLUSION

In MVP, QT is increased and the circadian modulation of QT end/RR slope is disturbed with an increased nocturnal rate dependence. These abnormalities of ventricular repolarization might explain the risk of arrhythmic events in MVP.

Cardiac valves and valvular pathology

We summarize herein selected contributions over the past several decades by pathologists and others to the diagnosis, understanding, and management of valvular heart disease, including the structural basis of valve function, the pathology/pathobiology of common naturally occurring and iatrogenic lesions, developments in valve substitution, and novel approaches to valve repair, replacement, and regeneration.

Marfan syndrome and mitral valve prolapse

Mitral valve prolapse (MVP), an abnormal displacement into the left atrium of a thickened and redundant mitral valve during systole, is a relatively frequent abnormality in humans and may be associated with serious complications. A recent study implicates fibrillin-1, a component of extracellular matrix microfibrils, in the pathogenesis of a murine model of MVP. This investigation represents an initial step toward understanding the mechanisms involved in human MVP disease and the development of potential treatments.

Epidemiology of reflex syncope

Cost-effective diagnostic approaches to reflex syncope require knowledge of its frequency and causes in different age groups. For this purpose we reviewed the available literature dealing with the epidemiology of reflex syncope. The incidence pattern of reflex syncope in the general population and general practice is bimodal with peaks in teenagers and in the elderly. In the young almost all cases of transient loss of consciousness are due to reflex syncope. The life-time cumulative incidence in young females ( congruent with 50 %) is about twice as high as in males ( congruent with 25 %). In the elderly, cardiac causes, orthostatic and postprandial hypotension, and the effects of medications are common, whereas typical vasovagal syncope is less frequent. In emergency departments, cardiac causes and orthostatic hypotension are more frequent especially in elderly subjects. Reflex syncope, however, remains the most common cause of syncope, but all-cause mortality in subjects with reflex syncope is not higher than in the general population. This knowledge about the epidemiology of reflex syncope can serve as a benchmark to develop cost-effective diagnostic approaches.

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.

Heart failure and death after myocardial infarction in the community: the emerging role of mitral regurgitation

BACKGROUND

In case series, mitral regurgitation (MR) increased the risk of death after myocardial infarction (MI), yet the prevalence of MR, its incremental prognostic value over ejection fraction (EF), and its association with heart failure and death after MI in the community is not known.

METHODS AND RESULTS

The prevalence of MR and its association with heart failure and death were examined among 1331 patients within a geographically defined MI incidence cohort between 1988 and 1998. Echocardiography was performed within 30 days after MI in 773 patients (58%), and MR was present in 50% of cases, mild in 38%, and moderate or severe in 12%. Among patients with MR, a murmur was inconsistently detected clinically. After 4.7+/-3.3 years of follow-up, 109 episodes of heart failure and 335 deaths occurred. There was a graded positive association between the presence and severity of MR and heart failure or death. Moderate or severe MR was associated with a large increase in the risk of heart failure (relative risk 3.44, 95% CI 1.74 to 6.82, P<0.001) and death (relative risk 1.55, 95% CI 1.08 to 2.22, P=0.019) among 30-day survivors independent of age, gender, EF, and Killip class.

CONCLUSIONS

In the community, MR is frequent and often silent after MI. It carries information to predict heart failure or death among 30-day survivors independently of age, gender, EF, and Killip class. These findings, which are applicable to a large community-based MI cohort, suggest that the assessment of MR should be included in post-MI risk stratification.

Antithrombotic and Thrombolytic Therapy for Ischemic Stroke

This chapter about treatment and prevention of stroke is part of the 7th ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al). Among the key recommendations in this chapter are the following: For patients with acute ischemic stroke (AIS), we recommend administration of i.v. tissue plasminogen activator (tPA), if treatment is initiated within 3 h of clearly defined symptom onset (Grade 1A). For patients with extensive and clearly identifiable hypodensity on CT, we recommend against thrombolytic therapy (Grade 1B). For unselected patients with AIS of > 3 h but < 6 h, we suggest clinicians not use i.v. tPA (Grade 2A). For patients with AIS, we recommend against streptokinase (Grade 1A) and suggest clinicians not use full-dose anticoagulation with i.v. or subcutaneous heparins or heparinoids (Grade 2B). For patients with AIS who are not receiving thrombolysis, we recommend early aspirin therapy, 160 to 325 mg qd (Grade 1A). For AIS patients with restricted mobility, we recommend prophylactic low-dose subcutaneous heparin or low molecular weight heparins or heparinoids (Grade 1A); and for patients who have contraindications to anticoagulants, we recommend use of intermittent pneumatic compression devices or elastic stockings (Grade 1C). In patients with acute intracerebral hematoma, we recommend the initial use of intermittent pneumatic compression (Grade 1C+). In patients with noncardioembolic stroke or transient ischemic attack (TIA) [ie, atherothrombotic, lacunar or cryptogenic], we recommend treatment with an antiplatelet agent (Grade 1A) including aspirin, 50 to 325 mg qd; the combination of aspirin and extended-release dipyridamole, 25 mg/200 mg bid; or clopidogrel, 75 mg qd. In these patients, we suggest use of the combination of aspirin and extended-release dipyridamole, 25/200 mg bid, over aspirin (Grade 2A) and clopidogrel over aspirin (Grade 2B). For patients who are allergic to aspirin, we recommend clopidogrel (Grade 1C+). In patients with atrial fibrillation and a recent stroke or TIA, we recommend long-term oral anticoagulation (target international normalized ratio, 2.5; range, 2.0 to 3.0) [Grade 1A]. In patients with venous sinus thrombosis, we recommend unfractionated heparin (Grade 1B) or low molecular weight heparin (Grade 1B) over no anticoagulant therapy during the acute phase.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

The relationship between echocardiographic features of mitral valve and elastic properties of aortic wall and Beighton hypermobility score in patients with mitral valve prolapse

The present study was designed to investigate the incidence of benign joint hypermobility syndrome (BJHMS) in mitral valve prolapse (MVP) and the correlation between the echocardiographic features of the mitral valve and elastic properties of the aortic wall and Beighton hypermobility score (BHS) in patients with MVP and BJHMS. Fourty-six patients with nonrheumatic, uncomplicated, and isolated mitral anterior leaflet prolapse (7 men and 39 women, mean age; 26.1 +/- 5.9) and 25 healthy subjects (3 men and 22 women, mean age, 25.4 +/- 4.3) were studied. Patients were divided into two groups according to their BHS (group I, MVP+BJHMS; group II, MVP-BJHMS). Individuals with accompanying cardiac or systemic disease were excluded. Echocardiographic examination was performed in all subjects. The presence of BJHMS was evaluated according to Beighton's criteria. The incidence of BJHMS in patients with MVP was found to be significantly higher than that of controls (45.6%, (21/46) vs 12% (3/25), P < 0.0001). Group I (MVP + BJHMS) had significantly increased anterior mitral leaflet thickness (AMLT, 3.4 +/- 0.4 vs 3.1 +/- 0.3; P < 0.005), maximal leaflet displacement (MLD, 2.4 +/- 0.4 vs 1.7 +/- 0.4; P < 0.005), and degree of mitral regurgitation (DMR, 17.1 +/- 7.2 vs 11.2 +/- 4.4; P < 0.01) compared to group II. However, the index of aortic stiffness (IAOS) was found to be lower (17.6 +/- 6.9 vs 23.9 +/- 7.6; P < 0.005) and aortic distensibility (AOD) to be higher (0.0035 +/- 0.007 vs 0.0024 +/- 0.005; P < 0.005) in group I. There was a significant correlation between AMLT, MLD and DMR, and BHS (r = 0.57/P = 0.007, r = 0.55/P < 0.009, r = 0.51/P < 0.01, respectively). In addition, AOD correlated positively with BHS (r = 0.53/P < 0.005), but the index of aortic stiffness correlated inversely with BHS (r = -0.49/P < 0.007). The incidence of BJHMS in patients with MVP was more frequent than the normal population and there was a significant correlation between the severity of BJHMS (according to BHS) and echocardiographic features of the mitral leaflets and elastic properties of the aortic wall.

Panic disorder

BACKGROUND

This article reviews the clinical features, epidemiology, pathophysiology, dental findings, and dental and medical management of the care of patients with panic disorder, or PD.

TYPES OF STUDIES REVIEWED

The authors conducted a MEDLINE search for the period 1998 through 2003, using the key term "panic disorder" to define the pathophysiology of the disorder, its epidemiology and dental implications. The articles they selected for further review included those published in peer-reviewed journals.

RESULTS

PD is a common and debilitating psychiatric disease in which a person experiences sudden and unpredictable panic attacks, or PAs, with symptoms of overwhelming anxiety, chest pain, palpitations and shortness of breath. Persistent concern about having another attack and worry that it may indicate a heart attack or "going crazy" impairs the person's social, family and working lives. Frequently accompanying the disorder is agoraphobia, depression and mitral valve prolapse, or MVP.

CLINICAL IMPLICATIONS

In patients with PD, the prevalence of dental disease may be extensive because of the xerostomic effects of psychiatric medications used to treat it. Dental treatment consists of preventive dental education and prescribing saliva substitutes and anticaries agents. Precautions must be taken when prescribing or administering analgesics, antibiotics or sedative agents that may have an adverse interaction with the psychiatric medications. Because there is a connection between PAs and MVP, the dentist needs to consult with the patient's physician to determine the presence of MVP and whether there is associated mitral valve regurgitation. Patients with MVP and accompanying mitral valve regurgitation require prophylactic antibiotics when undergoing dental procedures known to cause a bacteremia and heightened risk of endocarditis.

Chest pain in adult congenital heart disease: where does it come from?

Chest pain is common in adolescents and in young adults and usually not associated with a severe underlying cardiovascular disorder. However, in adults with congenital heart disease, residua or sequellae of previous interventions may provoke potential complications. Moreover, chest pain may be the first sign of a life-threatening condition. Basic knowledge is mandatory and will lead to the correct diagnosis and treatment. Data in literature, which focus on this issue, are scarce and motivated to summarize the experience of daily practice from the eye point of the clinician.

Decreased Platelet Function in Cavalier King Charles Spaniels with Mitral Valve Regurgitation

With aggregometry, increased platelet activity has been reported in Cavalier King Charles Spaniels (CKCS) without mitral regurgitation (MR). In contrast, dogs with MR have been found to have decreased platelet activity. The purpose of this study was to test an easy bedside test of platelet function (the Platelet Function Analyzer [PFA-100]) to see if it could detect an increase in platelet activity in CKCS without MR and a decrease in platelet activity in CKCS with MR. This study included 101 clinically healthy dogs > 1 year of age: 15 control dogs of different breeds and 86 CKCS. None of the dogs received medication or had a history of bleeding. The PFA-100 evaluates platelet function in anticoagulated whole blood under high shear stress. Results are given as closure times (CT): the time it takes before a platelet plug occludes a hole in a membrane coated by agonists. The CT with collagen and adenosine-diphosphate as agonists was similar in control dogs (median 62 seconds; interquartile interval 55-66 seconds) and CKCS with no or minimal MR (55; 52-64 seconds). The CT was higher in CKCS with mild MR (regurgitant jet occupying 15-50% of the left atrial area) (75; 60-84 seconds; P = .0007) and in CKCS with moderate to severe MR (jet > 50%) (87: 66-102 seconds; P < .0001). CKCS with mild, moderate, and severe, clinically inapparent MR have decreased platelet function. The previous finding of increased platelet reactivity in nonthrombocytopenic CKCS without MR could not be reproduced with the PFA-100 device.

Glycosaminoglycan profiles of myxomatous mitral leaflets and chordae parallel the severity of mechanical alterations

OBJECTIVES

This biochemical study compared the extracellular matrix of normal mitral valves and myxomatous mitral valves with either unileaflet prolapse (ULP) or bileaflet prolapse (BLP).

BACKGROUND

Myxomatous mitral valves are weaker and more extensible than normal valves, and myxomatous chordae are more mechanically compromised than leaflets. Despite histological evidence that glycosaminoglycans (GAGs) accumulate in myxomatous valves, previous biochemical analyses have not adequately examined the different GAG classes.

METHODS

Leaflets and chordae from myxomatous valves (n = 41 ULP, 31 BLP) and normal valves (n = 27) were dried, dissolved, and assayed for deoxyribonucleic acid, collagen, and total GAGs. Specific GAG classes were analyzed with selective enzyme digestions and fluorophore-assisted carbohydrate electrophoresis.

RESULTS

Biochemical changes were more pronounced in chordae than in leaflets. Myxomatous leaflets and chordae had 3% to 9% more water content and 30% to 150% higher GAG concentrations than normal. Collagen concentration was slightly elevated in the myxomatous valves. Chordae from ULP had 62% more GAGs than those from BLP, primarily from elevated levels of hyaluronan and chondroitin-6-sulfate.

CONCLUSIONS

The GAG classes elevated in the myxomatous chordae are associated with matrix microstructure and elastic fiber deficiencies and may influence the hydration-related "floppy" nature of these tissues. These abnormalities may be related to the reported mechanical weakness of myxomatous chordae. The biochemical differences between ULP and BLP confirm previous mechanical and echocardiographic distinctions.

Mitral valve prolapse in systemic lupus erythematosus patients: clinical and immunological aspects

Mitral valve prolapse (MVP) has been reported to be associated with systemic lupus erythematosus (SLE). The aim of the present study was to determine the prevalence of MVP in SLE patients, assess its clinical significance and examine the possible association of this entity with other autoimmune indices. Eighty-seven consecutive SLE patients attending the rheumatology clinic and 73 normal control subjects were examined by M-mode, two-dimensional color-Doppler echocardiography. Serum samples were examined for various organ and non-organ specific autoantibodies. MVP was detected in 19/87 patients with SLE and in four of the healthy controls(P = 0.0057). SLE patients with MVP were younger (33.6 +/- 12.4 years) than those without MVP (41. +/- 12.9, P = 0.04) and with shorter duration of the disease (P = 0.03). We found a statistically higher prevalence of anticardiolipin antibodies (aCL) in SLE patients with prolapse (11/19) compared with SLE patients without prolapse (15/68, P = 0.04). This association was independent of age. The aCL-lgG levels were significantly higher in SLE patients with MVP (32.37 +/- 43.26) compared with SLE patients without MVP (22.24 +/- 29.95, P = 0.04). Thyroid autoantibodies tended to be more common in S LE patients with MVP. Th e prevalence of MVP is increased in SLE patients. The presence of aCL and of organ-specific autoantibodies in SLE patients with MVP might indicate the autoimmune origin of MVP. The possibility that SLE patients with MVP may be predisposed to further autoimmune diseases should be considered.

Cerebral ischemic events after diagnosis of mitral valve prolapse: a community-based study of incidence and predictive factors

BACKGROUND AND PURPOSE

Association of mitral valve prolapse (MVP) with ischemic neurological events (INEs) is uncertain.

METHODS

In the community of Olmsted County (Minn), we identified all MVP diagnosed (1989 to 1998) in patients in sinus rhythm with no prior history of INE. We measured INE rates and compared them with expected rates in our community to define the excess risk of INE.

RESULTS

Among 777 eligible subjects (age, 49+/-20 years; 66% female; follow-up, 5.5+/-3.0 years), 30 patients had at least 1 INE during follow-up (at 10 years, 7+/-1%). Compared with expected INEs in the same community, subjects with MVP showed excess risk of lifetime INE (relative risk [RR], 2.2; 95% CI, 1.5 to 3.2; P<0.001) and during follow-up under purely medical management (RR, 1.8; 95% CI, 1.1 to 2.8; P=0.009). Independent determinants of INE were older age (RR, 1.08 per year; 95% CI, 1.04 to 1.11; P<0.001), mitral thickening (RR, 3.2; 95% CI, 1.4 to 7.4; P=0.008), atrial fibrillation (AFib) during follow-up (RR, 4.3; 95% CI, 1.9 to 10.0; P<0.001), and need for cardiac surgery (RR, 2.5; 95% CI, 1.1 to 5.8; P=0.03). INE 10-year rates were low in patients <50 years of age (0.4+/-0.4%, P=0.60 versus expected) but were excessive in patients >50 years of age (16+/-3%, P<0.001 versus expected) or with thickened leaflets (7+/-2%, P<0.001 versus expected). Predictors of follow-up AFib were age, mitral regurgitation, and left atrium diameter (all P<0.01).

CONCLUSIONS

In the community, subjects with MVP display a lifetime excess rate of INE compared with expected. Clinical (older age) and echocardiographic (leaflets thickening) characteristics define patients with MVP at high risk for INE, and subsequent AFib or need for cardiac surgery, both related to the degree of mitral regurgitation, increase the risk of INE.

JS, Dai D, Leyne M, Marshall JE, Nesta F, Levine RA, Slaugenhaupt SA. A locus for autosomal dominant mitral valve prolapse on chromosome 11p15.4

Mitral valve prolapse (MVP) is a common cardiovascular abnormality in the United States, occurring in approximately 2.4% of the general population. Clinically, patients with MVP exhibit fibromyxomatous changes in one or both of the mitral leaflets that result in superior displacement of the leaflets into the left atrium. Although often clinically benign, MVP can be associated with important accompanying sequelae, including mitral regurgitation, bacterial endocarditis, congestive heart failure, atrial fibrillation, and even sudden death. MVP is genetically heterogeneous and is inherited as an autosomal dominant trait that exhibits both sex- and age-dependent penetrance. In this report, we describe the results of a genome scan and show that a locus for MVP maps to chromosome 11p15.4. Multipoint parametric analysis performed by use of GENEHUNTER gave a maximum LOD score of 3.12 for the chromosomal region immediately surrounding the four-marker haplotype D11S4124-D11S2349-D11S1338-D11S1323, and multipoint nonparametric analysis (NPL) confirms this finding (NPL=38.59; P=.000397). Haplotype analysis across this region defines a 4.3-cM region between the markers D11S1923 and D11S1331 as the location of a new MVP locus, MMVP2, and confirms the genetic heterogeneity of this disorder. The discovery of genes involved in the pathogenesis of this common disease is crucial to understanding the marked variability in disease expression and mortality seen in MVP.

Association between atrial septal aneurysm and patent foramen ovale in young patients with recent stroke and normal carotid arteries

BACKGROUND

Atrial septal aneurysm (ASA) has been considered a potential source of cardiogenic embolism for many years. The ASA Multicenter Italian (ASA-MI) Study evaluated the prevalence and characteristics of ASA in patients with stroke and normal carotid arteries compared with control patients without stroke. The purpose of the present study was to evaluate the frequency of ASA and the association with patent foramen ovale (PFO) in the subgroup of younger patients (aged less than 55 years) included in the ASA-MI Study.

METHODS

The ASA-MI Study included 606 patients, enrolled between November 1990 and December 1996: 245 patients with a previous cerebral embolic attack and normal carotid study and a control group of 316 patients. They all underwent transthoracic and transesophageal echocardiography. The subgroup of younger patients aged less than 55 years included 90 patients (61 men and 29 women of mean age 49 +/- 5 years) (group AY). This group was evaluated and compared with an age- and sex-matched control population (61 men; of mean age 48 +/- 6 years) (group BY).

RESULTS

The prevalence of ASA was 48.8% (95% confidence interval 40-61) in group AY and 22.2% in the group BY (95% confidence interval 18-33) (chi(2) = 5.968; p = 0.01). Morphological features were similar in the 2 groups of patients. ASA involved the entire septum in 52% of patients of group AY, and in 47.2% of group BY. The prevalence of PFO was 58.8% (95% confidence interval 43-62) in group AY and 28.8% in group BY (95% confidence interval 17-35) (chi(2) = 5.811; p = 0.01). A strong association was found between ASA and PFO. Of the 90 younger patients with stroke, 39 of 44 (88.6%) with ASA also had PFO, compared with 14 of 46 (30.4%) without ASA (chi(2) = 7.370; p = 0.007).

CONCLUSION

We found that ASA and PFO were independent predictive factors for stroke in younger patients with stroke and normal carotid arteries and that the association between ASA and PFO bore an increased odds risk.

[Prognosis of organic mitral regurgitation and implications for surgical indications]

The term organic Mitral Regurgitation (MR) relates to MR secondary to anatomic alteration of the valvular or subvalvular mitral apparatus and refers to rheumatic MR and degenerative MR, i.e. mitral valve prolapse, which has become in the past 20 years the 1st cause of severe MR leading to surgery in western countries. Recent publications on the prognosis of patients with MR secondary to flail leaflet, showed that these patients incur excess mortality rates as compared to expected and that ten years after diagnosis, 90% of those will either be dead or operated on for severe symptoms. On the other hand, analysis of postoperative prognosis showed that the best results of surgical correction were observed in asymptomatic patients with normal pre-operative left ventricular function. The prognosis of these patients was then similar to that expected if a valvular repair was performed, making of mitral repair the hinge point of early surgical strategies.

[Use of echocardiography in mitral regurgitation for the assessment of its mechanism and etiology for the morphological analysis of the mitral valve]

Echocardiographic assessment of mitral regurgitation allows the diagnosis of its mechanism and cause which are major determinants in the feasibility of mitral valve repair. This assessment is based on a systematic analysis of the different structures of the mitral valve apparatus: mitral annulus (enlargement, calcification), mitral valve morphology (thickening, calcification, floppy valve, vegetations, perforation), mitral valve motion (restriction, identification of the prolapsed leaflets and scallops in patients with mitral valve prolapse or flail leaflets), subvalvular apparatus (ruptured chordae, thickening), papillary muscles, and left ventricular wall. This analysis can diagnose the mechanism of mitral regurgitation according to the Carpentier classification, and can clarify its cause: degenerative lesions (prolapse or flail leaflet with or without ruptured chordae), rheumatic lesions (thickened valves with restricted motion), endocarditis (vegetations, perforation, ruptured chordae), ischemic mitral regurgitation (restricted valve motion with inferior or posterior left ventricular wall asynergy), or functional mitral regurgitation (annular dilatation, displacement of papillary muscles with restricted leaflet motion). Transthoracic echocardiography with harmonic imaging usually allows a comprehensive assessment of functional anatomy of mitral regurgitation. Transesophageal echocardiography is indicated if transthoracic echocardiography is inadequate. It is also indicated just before surgery and as an intraoperative procedure. Real time 3D echocardiography should probably complete the evaluation of mitral regurgitation in the near future.

The Stickler syndrome: genotype/phenotype correlation in 10 families with Stickler syndrome resulting from seven mutations in the type II collagen gene locus COL2A1

PURPOSE

To evaluate a cohort of clinically diagnosed Stickler patients in which the causative mutation has been identified, determine the prevalence of clinical features in this group as a whole and as a function of age, and look for genotype/phenotype correlations.

METHODS

Review of medical records, clinical evaluations, and mutational analyses of clinically diagnosed Stickler patients.

RESULTS

Patients with seven defined mutations had similar phenotypes, though both inter- and intrafamilial variability were apparent and extensive. The prevalence of certain clinical features was a function of age.

CONCLUSION

Although the molecular determination of a mutation can predict the occurrence of Stickler syndrome, the variability observed in the families described here makes it difficult to predict the severity of the phenotype on the basis of genotype.

Mechanism of higher incidence of ischemic mitral regurgitation in patients with inferior myocardial infarction: quantitative analysis of left ventricular and mitral valve geometry in 103 patients with prior myocardial infarction

OBJECTIVE

The mechanism of higher incidence of ischemic mitral regurgitation in patients with inferior compared with anterior myocardial infarction despite less global left ventricular remodeling and dysfunction is controversial. We hypothesized that inferior myocardial infarction causes left ventricular remodeling, which displaces posterior papillary muscle away from its normal position, leading to ischemic mitral regurgitation.

METHODS

In 103 patients with prior myocardial infarction (61 anterior and 42 inferior) and 20 normal control subjects, we evaluated the grade of ischemic mitral regurgitation on the basis of the percentage of Doppler jet area, left ventricular end-diastolic and end-systolic volumes, midsystolic mitral annular area, and midsystolic leaflet-tethering distance between papillary muscle tips and the contralateral anterior mitral annulus, which were determined by means of quantitative echocardiography.

RESULTS

Global left ventricular dilatation and dysfunction were significantly less pronounced in patients with inferior myocardial infarction (left ventricular end-systolic volume: 52 +/- 18 vs 60 +/- 24 mL, inferior vs anterior infarction, P<.05; left ventricular ejection fraction: 51% +/- 9% vs 42% +/- 7%, P <.0001). However, the percentage of mitral regurgitation jet area and the incidence of significant regurgitation (percentage of jet area of 10% or greater) was greater in inferior infarction (percentage of jet area: 10.1% +/- 7.5% vs 4.4% +/- 7.0%, P =.0002; incidence: 16/42 (38%) vs 6/61 (10%), P <.0001). The mitral annulus (area = 8.2 +/- 1.2 cm2 in control subjects) was similarly dilated in both inferior and anterior myocardial infarction (9.7 +/- 1.7 vs. 9.5 +/- 2.3 cm2, no significant difference), and the anterior papillary muscle-tethering distance (33.8 +/- 2.6 mm in control subjects) was also similarly and mildly increased in both groups (35.2 +/- 2.4 vs 35.2 +/- 2.8 mm, no significant difference). However, the posterior papillary muscle-tethering distance (33.3 +/- 2.3 mm in control subjects) was significantly greater in inferior compared with anterior myocardial infarction (38.3 +/- 4.1 vs 34.7 +/- 2.9 mm, P =.0001). Multiple stepwise regression analysis identified the increase in posterior papillary muscle-tethering distance divided by body surface area as an independent contributing factor to the percentage of mitral regurgitation jet area (r2 = 0.70, P <.0001).

CONCLUSIONS

It is suggested that the higher incidence and greater severity of ischemic mitral regurgitation in patients with inferior compared with anterior myocardial infarction can be related to more severe geometric changes in the mitral valve apparatus with greater displacement of posterior papillary muscle caused by localized inferior basal left ventricular remodeling, which results in therapeutic implications for potential benefit of procedures, such as infarct plication and leaflet or chordal elongation, to reduce leaflet tethering.

Cardiovascular MR imaging: technique optimization and detection of disease in clinical practice

Magnetic resonance (MR) imaging has emerged as an important and growing means of cardiovascular imaging, with many advantages over other radiologic modalities, including excellent spatial and temporal resolution, lack of ionizing radiation, and noninvasiveness. In this article, the utility of MR imaging in cardiovascular imaging and in the diagnosis of cardiovascular disease will be discussed. MR techniques for evaluating the heart and vasculature will be described, and troubleshooting techniques will be presented. Imaging findings in congenital anomalies such as septal defects, patent ductus arteriosus, transposition of the great arteries, and tetralogy of Fallot will be identified. Valvular lesions and methods for evaluating valvular function will be discussed. MR imaging findings in acquired disorders such as aneurysms and pericardial disease will be described.

Mitral valve prolapse in the general population: the benign nature of echocardiographic features in the Framingham Heart Study

OBJECTIVE

The aim of this study was to examine the echocardiographic features and associations of mitral valve prolapse (MVP) diagnosed by current two-dimensional echocardiographic criteria in an unselected outpatient sample.

BACKGROUND

Previous studies of patients with MVP have emphasized the frequent occurrence of echocardiographic abnormalities such as significant mitral regurgitation (MR) and left atrial (LA) enlargement that are associated with clinical complications. These studies, however, have been limited by the use of hospital-based or referral series.

METHODS

We quantitatively studied all 150 subjects with possible MVP by echocardiography and 150 age- and gender-matched subjects without MVP from the 3,491 subjects in the Framingham Heart Study. Based on leaflet morphology, subjects were classified as having classic (n = 46), nonclassic (n = 37), or no MVP.

RESULTS

Leaflet length, MR degree, and LA and left ventricular size were significantly but mildly increased in MVP (p < 0.0001 to 0.004), with mean values typically within normal range. Average MR jet area was 15.1 +/- 1.4% (mild) in classic MVP and 8.9 +/- 1.5% (trace) in nonclassic MVP; MR was severe in only 3 of 46 (6.5%) subjects with classic MVP, and LA volume was increased in only 8.7% of those with classic MVP and 2.7% of those with nonclassic MVP.

CONCLUSIONS

Although the echocardiographic characteristics of subjects with MVP in the Framingham Heart Study differ from those without MVP, they display a far more benign profile of associated valvular, atrial, and ventricular abnormalities than previously reported in hospital- or referral-based series. Therefore, these findings may influence the perception of and approach to the outpatient with MVP.

Impact of atrial fibrillation on tricuspid and mitral annular dilatation and valvular regurgitation

To investigate the effects of atrial fibrillation (AF) on the mitral and tricuspid valves, the corresponding annular dilatation and valvular regurgitation were compared with 2-dimensional and Doppler echocardiography in 31 consecutive patients with lone AF and 28 normal controls. Mid-systolic mitral and tricuspid annular areas were measured from 2 diameters in 2 orthogonal apical echocardiograms. Percent (%) mitral regurgitant (MR) or tricuspid regurgitant (TR) jet area to the left or right atrial area was evaluated and % MR or TR jet area >20% was considered moderate or significant. Both the mitral and tricuspid annular areas in patients with lone AF were significantly larger compared with the controls (mitral: 9.5 +/- 1.2 vs 6.6 +/- 0.9 cm2, lone AF vs control, p < 0.01) (tricuspid: 12.0 +/- 2.0 vs 7.5 +/- 0.9 cm2, p < 0.01). The % increase in the annular area relative to the mean normal value was significantly greater in the tricuspid valve (44 +/- 18 vs 60 +/- 28%, p < 0.01). Moderate or severe MR was not observed and the incidence of moderate or severe valve regurgitation (% jet area >20%) was significantly higher in the tricuspid valve (0/31 vs 11/31, MR vs TR, p < 0.01) in patients with lone AF. The % TR jet area showed significant correlation with tricuspid annular area (r2 = 0.65, p < 0.001). Lone AF is associated with annular dilatation of both mitral and tricuspid valves, but the annular dilatation and valvular regurgitation are significantly greater in the tricuspid valve.

Transoesophageal echocardiography in patients without arterial and major cardiac sources of embolism: difference between stroke subtypes

We studied the records of 175 consecutive patients referred to our neurologic ward between January 1994 and February 2000 with a diagnosis of ischaemic cerebrovascular disease (ICVD) (stroke or transient ischaemic attack - TIA) who underwent transoesophageal echocardiography (TEE). We excluded patients with large vessel disease, high-risk embolic cardiopathies and other rare causes of stroke. According to clinical and neuroimaging findings, patients were divided into two groups. The lacunar (LAC) group (69/175 (39.4%)) and the nonlacunar (N-LAC) one (106/175 (60.6%)). The control population consisted of 78 consecutive patients, referred to the echocardiography laboratory for TEE without history of ICVD and known heart disorders. Patent foramen ovale (PFO) frequency was significantly higher in case patients than in control subjects (55/175 (31.4%) vs. 13/78 (16.6%); p = 0.02). Among case patients, PFO was more prevalent in the N-LAC group than in the LAC one (43/106 (40.6%) vs. 12/69 (17.4%); p = 0.0005). A large degree of shunt occurred in 53.5% of N-LAC patients and in 16.7% of LAC ones (p = 0.04). Atrial septal aneurysm (ASA) was detected in 12% of case patients and 1.3% of control subjects (p = 0.003) and was more frequent in the N-LAC group than in the LAC one (16 vs. 5.8%; p = 0.05). Mitral prolapse (MP) was present in 6/175 (3.4%) ICVD patients (vs. 1/78 among controls) in most cases associated with myxomatous valve redundancy. Aortic arch atheromas (AA) were detected in 12% of ICVD patients and in 10.2% of controls. The frequency was 9.4% in N-LAC and 15.9 in LAC. No complicated AA (plaque thickness >4 mm, ulcerated atheroma, superimposed thrombus) were detected. After multivariate analysis, PFO (OR = 3.8; 95% CI = 2.7-7.9) and ASA (OR = 8.01; 95% CI = 3.0-16.1) appeared to be independent predictors of ICVD. PFO (OR = 2.24; 95% CI = 1.24-4.92) was also independently associated with N-LAC stroke subtype and its importance was even higher in younger patients. Our study provides further evidence that TEE is a helpful diagnostic tool in stroke patients without arterial and major cardiac sources of embolism. However, its utility differs according to type and localization of the ischaemic lesion being more relevant in patient with N-LAC infarctions.

Natural history of asymptomatic mitral valve prolapse in the community

BACKGROUND

The outcome of mitral valve prolapse (MVP) is controversial, with marked discrepancies in reported complication rates.

METHODS AND RESULTS

We conducted a community study of all Olmsted County, Minn, residents first diagnosed with asymptomatic MVP between 1989 and 1998 (N=833). Diagnosis, motivated by auscultatory findings (n=557) or incidental (n=276), was always confirmed by echocardiography with the use of current criteria. End points analyzed during 4581 person-years of follow-up were mortality (n=96, 19+/-2% at 10 years), cardiovascular morbidity (n=171), and MVP-related events (n=109, 20+/-2% at 10 years). The most frequent primary risk factors for cardiovascular mortality were mitral regurgitation from moderate to severe (P=0.002, n=131) and, less frequently, ejection fraction <50% (P=0.003, n=31). Secondary risk factors independently predictive of cardiovascular morbidity were slight mitral regurgitation, left atrium > or =40 mm, flail leaflet, atrial fibrillation, and age > or =50 years (all P<0.01). Patients with only 0 or 1 secondary risk factor (n=430) had excellent outcome, with 10-year mortality of 5+/-2% (P=0.17 versus expected), cardiovascular morbidity of 0.5%/y, and MVP-related events of 0.2%/y. Patients with > or =2 secondary risk factors (n=250) had mortality similar to expected (P=0.20) but high cardiovascular morbidity (6.2%/y, P<0.01) and notable MVP-related events (1.7%/y, P<0.01). Patients with primary risk factors (n=153) showed excess 10-year mortality (45+/-9%, P=0.01 versus expected), high morbidity (18.5%/y, P<0.01), and high MVP-related events (15%/y, P<0.01).

CONCLUSIONS

Natural history of asymptomatic MVP in the community is widely heterogeneous and may be severe. Clinical and echocardiographic characteristics allow separation of the majority of patients with excellent prognosis from subsets of patients displaying, during follow-up, high morbidity or even excess mortality as direct a consequence of MVP.

Periodontal management of patients with cardiovascular diseases

Periodontists are often called upon to provide periodontal therapy for patients with a variety of cardiovascular diseases. Safe and effective periodontal treatment requires a general understanding of the underlying cardiovascular diseases, their medical management, and necessary modifications to dental/periodontal therapy that may be required. In this informational paper more common cardiovascular disorders will be discussed and dental management considerations briefly described. This paper is intended for the use of periodontists and members of the dental profession.

Cardiac risk factors and participation guidelines for youth sports

Accurate assessment of the cardiac system in pediatric and adolescent youth is important. The hemodynamic demands associated with exercise, training, and sport participation are usually positive and beneficial; however, when an underlying cardiac problem exists, it is imperative that such cardiac problems be identified. Safe sport-related cardiac participation guidelines should be provided for young athletes and their families and coaches. This chapter provides a physician perspective on the recognition and current cardiac management considerations for young athletes participating in both static and dynamic types of sports. The most recent guidelines for hypertension in youth are also provided.

Etiologic study of young ischemic stroke in Taiwan

BACKGROUND AND PURPOSE

The etiologic mechanisms of young ischemic stroke in Chinese are largely unknown. This work thus studied the etiologies of young ischemic stroke in Taiwan Chinese and made a comparison with previous reports.

METHODS

From January 1997 to October 2001, a total of 264 consecutive young ischemic stroke patients (18 to 45 years old) were admitted to the Department of Neurology in our hospital. The risk factors for stroke and the distribution of stroke subtype were studied. The vascular ultrasound and angiographic findings of these patients were also studied.

RESULTS

The sample contained 188 men and 76 women. Cerebral infarction was diagnosed in 241 patients and transient ischemic attack in 23 (8.7%). Regarding stroke subtype, stroke of small-vessel occlusion was diagnosed in 20.5% of cases, large-artery atherosclerosis in 7.2%, cardioembolism in 17.8%, other determined etiology in 22.3%, and undetermined etiology in 23.5%. The 4 most common risk factors were hyperlipidemia (53.1%), smoking (49.8%), hypertension (45.8%), and family history of stroke (29.3%). Twenty-three patients (9.6%) had significant stenosis (> or =50%) of the carotid (7.5%) and vertebral arteries (2.1%), the most common cause of which was dissection (60.9%). Forty-five patients (26.5%) had significant intracranial stenosis with 18.8% in the carotid and 10.6% in the vertebrobasilar system, and 5 (2.9%) had stenosis in both systems. Premature atherosclerosis (33.3%) was the most common cause of intracranial stenosis.

CONCLUSIONS

Our study found that strokes of other determined etiology and undetermined etiology were most common among the sample group, and a battery of extensive examinations is indicated to elucidate the etiology for further stroke prevention. Intracranial stenosis is more common than extracranial stenosis in both the carotid and vertebrobasilar systems.

The incidence of congenital heart disease

This study was designed to determine the reasons for the variability of the incidence of congenital heart disease (CHD), estimate its true value and provide data about the incidence of specific major forms of CHD. The incidence of CHD in different studies varies from about 4/1,000 to 50/1,000 live births. The relative frequency of different major forms of CHD also differs greatly from study to study. In addition, another 20/1,000 live births have bicuspid aortic valves, isolated anomalous lobar pulmonary veins or a silent patent ductus arteriosus. The incidences reported in 62 studies published after 1955 were examined. Attention was paid to the ways in which the studies were conducted, with special reference to the increased use of echocardiography in the neonatal nursery. The total incidence of CHD was related to the relative frequency of ventricular septal defects (VSDs), the most common type of CHD. The incidences of individual major forms of CHD were determined from 44 studies. The incidence of CHD depends primarily on the number of small VSDs included in the series, and this number in turn depends upon how early the diagnosis is made. If major forms of CHD are stratified into trivial, moderate and severe categories, the variation in incidence depends mainly on the number of trivial lesions included. The incidence of moderate and severe forms of CHD is about 6/1,000 live births (19/1,000 live births if the potentially serious bicuspid aortic valve is included), and of all forms increases to 75/1,000 live births if tiny muscular VSDs present at birth and other trivial lesions are included. Given the causes of variation, there is no evidence for differences in incidence in different countries or times.

Clinical, echocardiographic, and biomechanical differences in mitral valve prolapse affecting one or both leaflets

Mitral valve prolapse (MVP) is the most common cause of severe mitral regurgitation necessitating surgical correction. Unileaflet prolapse (ULP), usually involving the posterior leaflet, is more common than bileaflet prolapse (BLP), which is more difficult to repair. Little is known about clinical, echocardiographic, and biomechanical differences between ULP and BLP. In this study, biomechanical testing was performed on mitral valve leaflets and chordae obtained at operation for severe mitral regurgitation. Preoperative clinical characteristics and echocardiographic measurements were obtained on surgical patients (ULP = 88, BLP = 37). Men outnumbered women by a factor of 4:1 in ULP, and by 3:1 in BLP. Patients with BLP were younger (53.2 +/- 1.7 vs 59.5 +/- 1.1 years) than those with ULP, and this difference was greater in women (48.9 +/- 2.5 vs 62.9 +/- 2.2 years). BLP patients were less likely to be hypertensive, and more likely to undergo valve replacement rather than repair. Echocardiography showed that BLP leaflets were longer and thicker than ULP leaflets. The severity of mitral regurgitation was similar in both groups, although ULP patients had a much higher incidence of flail leaflets (45% vs 5% in BLP). Mechanical strength of chordae was greater in BLP than in ULP, although leaflet strength was similar. The increased chordal strength in BLP may be responsible for less flail. In patients with MVP and severe mitral regurgitation requiring surgery, ULP and BLP are distinct entities with substantial differences in the population affected, in echocardiographic manifestations including prevalence of flail, in chordal mechanics, and in the likelihood of surgical repair.