Mitral valve prolapse: a review of associated arrhythmias

Mitral Valve Prolapse, Ventricular Arrhythmias, and Sudden Death

Despite a 2% to 3% prevalence of echocardiographically defined mitral valve prolapse (MVP) in the general population, the actual burden, risk stratification, and treatment of the so-called arrhythmic MVP are unknown. The clinical profile is characterized by a patient, usually female, with mostly bileaflet myxomatous disease, mid-systolic click, repolarization abnormalities in the inferior leads, and complex ventricular arrhythmias with polymorphic/right bundle branch block morphology, without significant regurgitation. Among the various pathophysiologic mechanisms of electrical instability, left ventricular fibrosis in the papillary muscles and inferobasal wall, mitral annulus disjunction, and systolic curling have been recently described by pathological and cardiac magnetic resonance studies in sudden death victims and patients with arrhythmic MVP. In addition, premature ventricular beats arising from the Purkinje tissue as ventricular fibrillation triggers have been documented by electrophysiologic studies in MVP patients with aborted sudden death.

The genesis of malignant ventricular arrhythmias in MVP probably recognizes the combination of the substrate (regional myocardial hypertrophy and fibrosis, Purkinje fibers) and the trigger (mechanical stretch) eliciting premature ventricular beats because of a primary morphofunctional abnormality of the mitral valve annulus.

The main clinical challenge is how to identify patients with arrhythmic MVP (which imaging technique and in which patient) and how to treat them to prevent sudden death. Thus, there is a necessity for prospective multicenter studies focusing on the prognostic role of cardiac magnetic resonance and electrophysiologic studies and on the therapeutic efficacy of targeted catheter ablation and mitral valve surgery in reducing the risk of life-threatening arrhythmias, as well as the role of implantable cardioverter defibrillators for primary prevention.

Surgical correction of mitral valve prolapse : a cure for recurrent ventricular tachycardia in Marfan syndrome?

We describe the case of a 3-year-old child with neonatal Marfan syndrome complicated by mitral valve prolapse with regurgitation, marked aortic root dilatation, and ventricular tachycardia. The patient had resolution of ventricular tachycardia following surgical intervention consisting of a valve-sparing aortic root replacement and mitral valve annuloplasty.

Evaluation of QT Interval Prolongation in Dogs with Heart Failure

Comparison of the QT interval and corrected QT interval values that were calculated by the methods of Bazett (QTc1) and Fridericia (QTc2) were made between dogs with or without cardiac diseases to determine the influence of the QT interval on canine heart failure. Upon comparison of the measured values on ECG between the cardiac disease and non-cardiac disease groups, it was observed that the heart rate(HR) was significantly higher in the cardiac disease group than in the non-cardiac disease group, although the QT interval was similar in the two groups. The QTc1 and QTc2 were significantly longer in the cardiac disease group than in the non-cardiac disease group. With the progression of the New York Heart Association Class, the HR tended to increase. The QTc1 and QTc2 became significantly prolonged with the progression of heart failure. Nevertheless, because Bazett's correction formula is known to overcorrect when the HR is high, it was considered that the QTc1 was actually overcorrected by high HR with the progression of heart failure. The QTc2, on the other hand, was only slightly influenced by HR, suggesting that the prolongation was due to the progression of heart failure. These results suggest that the prolongation of QTc2 in cardiac disease reflects the substantial prolongation of the QT interval without the influence of HR. It is suggested that the QTc2 could be a useful parameter for assessing the degree of heart failure in dogs with cardiac disease.

Nonsustained ventricular tachycardia

The patient with nonsustained ventricular tachycardia represents a common management problem for the cardiologist. The challenges posed by this type of arrhythmia differs from those posed by other arrhythmias, because most instances of nonsustained ventricular tachycardia do not cause symptoms. This article reviews common situations in which nonsustained ventricular tachycardia occurs and their appropriate management.

Sudden death in mitral regurgitation due to flail leaflet

OBJECTIVES

We sought to assess the incidence and determinants of sudden death (SUD) in mitral regurgitation due to flail leaflet (MR-FL).

BACKGROUND

Sudden death is a catastrophic complication of MR-FL. Its incidence and predictability are undefined.

METHODS

The occurrence of SUD was analyzed in 348 patients (age 67 +/- 12 years) with MR-FL diagnosed echocardiographically from 1980 through 1994.

RESULTS

During a mean follow-up of 48 +/- 41 months, 99 deaths occurred under medical treatment. Sudden death occurred in 25 patients, three of whom were resuscitated. The sudden death rates at five and 10 years were 8.6 +/- 2% and 18.8 +/- 4%, respectively, and the linearized rate was 1.8% per year. By multivariate analysis, the independent baseline predictors of SUD were New York Heart Association (NYHA) functional class (p = 0.006), ejection fraction (p = 0.0001) and atrial fibrillation (p = 0.059). The yearly linearized rate of sudden death was 1% in patients in functional class I, 3.1% in class II and 7.8% in classes III and IV. However, of 25 patients who had SUD, at baseline, 10 (40%) were in functional class I, 9 (36%) were in class II and only 6 (24%) in class III or IV. In five patients (20%), no evidence of risk factors developed until SUD. In patients with an ejection fraction > or =60% and sinus rhythm, the linearized rate of SUD was not different in functional classes I and II (0.8% per year). Surgical correction of MR (n = 186) was independently associated with a reduced incidence of SUD (adjusted hazard ratio [95% confidence interval] 0.29 [0.11 to 0.72], p = 0.007).

CONCLUSIONS

Sudden death is relatively common in patients with MR-FL who are conservatively managed. Patients with severe symptoms, atrial fibrillation and reduced systolic function are at higher risk, but notable rates of SUD have been observed without these risk factors. Correction of MR appears to be associated with a reduced incidence of SUD, warranting early consideration of surgical repair.

Idiopathic ventricular tachycardia

Most ventricular tachycardias encountered in clinical practice occur in patients who have structural heart disease. Idiopathic ventricular tachycardia refers to those arrhythmias that occur in patients without structural heart disease, metabolic/electrolyte abnormalities, or the long QT syndrome. Three commonly recognized forms of idiopathic ventricular tachycardia include: (a) ventricular tachycardia associated with mitral valve prolapse, (b) ventricular tachycardia originating from the right ventricular outflow tract, and (c) ventricular tachycardia originating from the left ventricle. Recently, a fourth type of idiopathic ventricular tachycardia, termed the Brugada syndrome, has been identified as responsible for some cases of cardiac arrest in persons without apparent structural heart disease. Each form of ventricular tachycardia may be considered a discrete syndrome based on its electrocardiographic characteristics, mechanisms, responses to pharmacologic intervention, and prognosis (good in most cases). Ventricular tachycardias range from the common to the exotic, but all represent syndromes with which the internist and general cardiologist should be familiar.

Significance of QT dispersion on ventricular arrhythmias in mitral valve prolapse

The present study was designed to detect the arrhythmogenic effect of mitral valve prolapse, and the relationship between QT, QT dispersion and ventricular arrhythmias in subjects with mitral valve prolapse. Sixty-four mitral valve prolapse subjects (24 men and 40 women, mean age 27 +/- 6), and 80 healthy control subjects (32 men and 48 women, mean age 28 +/- 7) were studied. The frequency of ventricular arrhythmias by means of 24-h ambulatory electrocardiographic (ECG) monitoring was investigated. Grade > or = 3 ventricular arrhythmias according to modified Lown and Wolf classification were accepted as complex arrhythmias. The QT intervals were measured from the beginning of depolarization of the QRS complex to the end of the T wave. Using the Bazett formula, QT interval was corrected (QTc) for heart rate. QT dispersion was calculated as the difference between the maximum and minimum QT intervals on any of 12 leads. Premature ventricular complexes seemed to develop in 56 of 64 (87.5%) subjects with mitral valve prolapse. Thirty-eight of the mitral valve prolapse subjects had complex premature ventricular complexes during 24-h ECG and the prevalence of premature ventricular complexes was found to be higher than the control subjects (P < 0.001). We found QT and QTc intervals of 388 +/- 27 and 406 +/- 33 ms in mitral valve prolapse subjects, these values in control subjects were 382 +/- 18 and 402 +/- 11 ms respectively (P > 0.05). QT dispersion and QTc dispersion intervals were 71 +/- 17 and 78 +/- 19 ms in mitral valve prolapse subjects and these values were 43 +/- 16 and 52 +/- 22 ms in control subjects, respectively (P < 0.001). No correlation was found between complex premature ventricular complexes and QT, but there was a correlation between complex premature ventricular complexes and QT dispersion in the mitral valve prolapse subjects. It was concluded that QT dispersion might be a useful marker of cardiovascular morbidity and mortality due to complex ventricular arrhythmias.

Monomorphic right ventricular tachycardia in a patient with mitral valve prolapse

A patient with mitral valve prolapse and symptomatic ventricular ectopy underwent an electrophysiological study during which a sustained monomorphic ventricular tachycardia with a left bundle branch block/right axis deviation morphology was induced. This morphology was replicated by pace mapping at the right ventricular outflow tract. To the best of our knowledge, this finding has not been previously described and suggests that the association between ventricular arrhythmias and mitral valve prolapse may not necessarily be causal.

Circadian variation in the occurrence of paroxysmal supraventricular tachycardia in clinically healthy subjects

The purpose of this study was to assess prospectively the circadian distribution of spontaneous paroxysmal supraventricular tachycardia (PSVT) in drug-free subjects with no previous history or symptoms and signs of concomitant heart or lung disease. Of 112,424 presumably diurnally active patients admitted to the Emergency Department of a city hospital during a 2-year period (1990-1991), a total of 185 patients were screened with these characteristics. Time of symptom onset was exactly recordable in 177 (75 men and 102 women). Analysis of variance documented a higher incidence in the morning-afternoon hours. Cosinor analysis, although not a perfect method for the time series analysis, verified circadian rhythmicity with afternoon peak times. Our findings suggest that a circadian pattern in intrinsic electrical instability of the heart conduction system exists irrespective of the circadian fluctuations in the pathophysiologic mechanisms of the cardiovascular or lung diseases most frequently associated with PSVT itself.

Arrhythmias in mitral valve prolapse: relation to anterior mitral leaflet thickening, clinical variables, and color Doppler echocardiographic parameters

Atrial and ventricular arrhythmias have been reported with variable incidence in symptomatic patients with mitral valve prolapse (MVP). The role of clinical and echocardiographic parameters as predictors for arrhythmias still needs to be clarified. One hundred nineteen consecutive patients (56 women and 63 men, mean age 40 +/- 17 years) with echocardiographically diagnosed MVP were examined. A complete echocardiographic study (M-mode, two-dimensional, and Doppler) and 24-hour electrocardiographic monitoring were performed in all patients. Complex atrial arrhythmias (CAAs) included atrial couplets, atrial tachycardia, and paroxysmal or sustained atrial flutter or fibrillation. Complex ventricular arrhythmias (CVAs) included multiform ventricular premature contractions (VPCs), VPC couplets, and runs of three or more sequential VPCs (salvos of ventricular tachycardia). The relation between complex arrhythmias and clinical parameters (age and gender) and echocardiographic parameters (left atrial and left ventricular dimensions, anterior mitral leaflet thickness [AMLT], and presence and severity of mitral regurgitation) was evaluated by multiple logistic regression analysis. CAA were present in 14% of patients and CVA in 30%. According to multiple logistic modeling, CAA correlated separately in the univariate analysis with age, presence of MR, and left ventricular and left atrial diameters; age was the only independent predictor (p < 0.001). CVA, in the univariate analysis, correlated with age, female gender, left ventricular end-diastolic diameter, and AMLT; only female gender and AMLT were independent predictors in the multivariate analysis (p < 0.01). The incidence of mitral regurgitation (59%) was higher than expected in a general population of MVP patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic control of cardiovascular function: clinical evaluation in health and disease

The high- and low-pressure baroreceptor reflexes are integral to the control of blood pressure by the autonomic nervous system. Tests of the integrity of these baroreflexes make it possible to identify the site of autonomic dysfunction in patients with orthostatic hypotension. Clinical characteristics and typical results of autonomic testing in patients with autonomic failure, with carotid sinus hypersensitivity, and with hyperadrenergic autonomic dysfunction are described in this review.

Malignant ventricular arrhythmias in patients with mitral valve prolapse and mild mitral regurgitation

Mitral valve prolapse (MVP) is a common disorder that, in general, has a good prognosis. Rare occasions of sudden death have been reported in patients with MVP and it is presumed that the basis of sudden death is arrhythmic. We report seven patients with moderate to severe MVP and malignant ventricular arrhythmias. All patients had trivial to mild mitral regurgitation and normal left ventricular function. Three patients presented with syncope, two with out-of-hospital cardiac arrest, and three with recurrent palpitations and presyncope. In a mean follow-up period of 2.5 years (range 6 months to 5 years), two patients died suddenly despite successful control of their nonsustained ventricular tachycardia (VT) with sotalol as shown by ambulatory monitoring. Two patients, who had sustained VT despite antiarrhythmic drug therapy, had mitral valve surgery, however, monomorphic VT could be induced in both even after surgery. The arrhythmias in the remaining three patients are controlled on antiarrhythmic drugs. We conclude that a selected subset of patients with MVP, malignant ventricular arrhythmias, and mild mitral regurgitation are at risk of sudden death. Syncope, inferolateral repolarization changes, complex ventricular ectopy, and a markedly myxomatous valve may be pointers to higher risk of sudden death and mitral valve surgery may not provide control of ventricular arrhythmias.

Mitral valve billowing and prolapse--an overview

Three decades after it was demonstrated that nonejection systolic clicks and late systolic murmurs have a mitral valve origin and that a specific syndrome is associated with the primary degenerative mitral lesion, numerous questions remain unanswered. A principal cause of confusion is the use of the term 'prolapse', which essentially implies a pathological state, in many patients with minimal evidence of a mitral valve anomaly. It should be recognised that no specific feature, whether evaluated by high standard echocardiography or indeed by careful morphological and histological examination, can be defined which distinguishes a normal variant from a pathological valve. There is a gradation from the normal billowing during ventricular systole of mitral leaflet bodies to marked billowing. With advanced billowing or floppy leaflets, failure of leaflet edge apposition supervenes (true prolapse). This is functionally abnormal and allows mitral regurgitation. Prolapse in turn may progress to a flail leaflet and hence gross regurgitation. Relatively rare complications of this degenerative mitral valve anomaly include systemic emboli, infective endocarditis, arrhythmias and, arguably, autonomic nervous system abnormalities. An attempt is made to clarify the management of some symptoms and other aspects of mitral prolapse-including rheumatic anterior leaflet prolapse (without billowing) which remains prevalent in South Africa and Third World countries.

Haemodynamic and neurohormonal responsiveness to different stress tests in mitral valve prolapse

In this study the blood pressure, heart rate, plasma noradrenaline and plasma adrenaline responses to various forms of sympatho-neural stress were evaluated in patients with mitral valve prolapse (MVP). Sympathetic reactivity in different subgroups of MVP were related to the degree of ventricular arrhythmia. Thirty-eight patients with mitral valve prolapse and 17 healthy controls were studied. All underwent 24-h ECG recording, 2-D echocardiography, head-up tilt to 60 degrees, pressor tests (sustained handgrip, mental arithmetic, cold pressor) and psychological assessment. The blood pressure, noradrenaline and adrenaline response to stress in patients without premature ventricular contraction were similar to those of the controls. In patients with unifocal premature ventricular contraction (PVC) less than 300/h, responses were similar to normal but were associated with higher plasma noradrenaline levels in the basal state and a diminished response to isometric stress. In patients with more than 300/h unifocal premature ventricular contraction, pairs of premature ventricular contraction, or runs of ventricular tachycardia there were lower blood pressure values in the basal state with reduced blood pressure, heart rate and plasma noradrenaline and adrenaline responses to head-up tilt and sustained handgrip, but marked increases in blood pressure, heart rate and plasma noradrenaline levels during the cold pressor test. Our data suggest different degrees of autonomic involvement in mitral valve prolapse which may be related to the various degrees of arrhythmia which seem to contribute to their symptoms.

Mitral valve prolapse, panic disorder, and chest pain

Mitral valve prolapse is a common cardiac disorder that can readily be diagnosed by characteristic auscultatory and echocardiographic criteria. Although many diseases have been associated with mitral valve prolapse, most affected individuals have the primary form of the disorder. Mitral valve prolapse is an inherited condition commonly associated with myxomatous degeneration of the mitral valve and its support structures. Complications of mitral valve prolapse, including cardiac arrhythmias, sudden death, infective endocarditis, severe mitral regurgitation (with or without chordae tendineae rupture), and cerebral ischemic events, occur infrequently considering the wide prevalence of the disorder. Panic disorder is a specific type of anxiety disorder characterized by at least three panic attacks within a 3-week period or one panic attack followed by fear of subsequent panic attacks for at least 1 month. It too is a common condition with a prevalence and age and gender distribution similar to that of mitral valve prolapse. Panic disorder and mitral valve prolapse share many nonspecific symptoms, including chest pain or discomfort, palpitations, dyspnea, effort intolerance, and pre-syncope. Chest pain is the symptom in both conditions that most commonly brings the patient to medical attention. The clinical description of chest pain in patients with mitral valve prolapse is highly variable, possibly reflecting multiple etiologies. Chest pain in panic disorder is usually characterized as atypical angina pectoris and as such bears resemblance to the chest pain commonly described by patients with mitral valve prolapse. Multiple investigative attempts to elucidate the mechanism of chest pain in both conditions have failed to identify a unifying cause. Review of the literature leaves little doubt that mitral valve prolapse and panic disorder frequently co-occur. Given the similarities in their symptomatology, a high rate of co-occurrence is, in fact, entirely predictable. There is, however, no convincing evidence of a cause-effect relationship between the two disorders, nor has a single pathophysiologic or biochemical mechanism been identified that unites these two common conditions. Until specific biologic markers for these disorders are identified, it may be impossible to do so. The lack of a proven cause-and-effect relationship between mitral valve prolapse and panic disorder and the absence of a unifying mechanism do not diminish the clinical significance of the high rate of co-occurrence between the two conditions. Primary care physicians and cardiologists frequently encounter patients with mitral valve prolapse and nonspecific symptoms with no discernible objective cause who fail to respond to beta-blockade. Panic disorder should be considered as a possible explanation for symptoms in such patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Moricizine: a novel antiarrhythmic agent

Moricizine is a phenothiazine derivative with Vaughan Williams class 1 antiarrhythmic properties. It undergoes extensive first-pass metabolism, has a bioavailability of 34-38 percent, and is 95 percent bound to plasma proteins. Moricizine is extensively metabolized and may have pharmacologically active metabolites. A recent clinical study has shown that moricizine is slightly less effective than encainide or flecainide in suppressing ventricular premature depolarizations. Compared with disopyramide and quinidine, moricizine was equally or more effective in suppressing ventricular premature depolarizations, couplets, and nonsustained ventricular tachycardia. Further studies are needed comparing moricizine with other class 1 agents in the treatment of life-threatening arrhythmias; available data suggest that moricizine is comparable with these agents in the treatment of ventricular tachycardias and fibrillation. Moricizine appears to have a low incidence of serious adverse effects compared with other antiarrhythmics. This combination of apparently similar efficacy with a decreased incidence of adverse effects makes moricizine a worthwhile addition to currently available antiarrhythmic agents.

Propafenone in the prevention of non-ventricular arrhythmias associated with the Wolff-Parkinson-White syndrome

The antiarrhythmic effect of oral propafenone was evaluated in 10 patients with Wolff-Parkinson-White syndrome presenting with non-ventricular arrhythmias (paroxysmal supraventricular tachycardia n = 7, atrial fibrillation or flutter n = 3). The mean age was 38 +/- 13 years, the dose varied from 300 to 900 mg three times a day (mean 450 +/- 188) and the mean follow-up period was 7 +/- 3.5 months. All patients' drug responses were assessed on 12-lead electrocardiograms and 24-hour ambulatory Holter monitoring. Electrophysiologic studies were performed in cases of sustained tachycardia while echocardiography identified 2 cases with mitral valve prolapse. Four of 10 (40%) patients became asymptomatic on a starting propafenone dose of 300 mg, while 6 (60%) had recurrences necessitating an increase in dose for the complete control of the symptoms. We observed a slight slowing of the heart rate and an increase of the mean Q-T interval (P less than 0.001). Three patients reported minor side effects including nausea, dizziness and constipation that were tolerable and dosage dependent. It is concluded that propafenone is an effective and well tolerated drug for the treatment of non-ventricular arrhythmias associated with the Wolff-Parkinson-White syndrome.

Mitral valve prolapse: cardiac arrest with long-term survival

Cardiac arrest has been reported in patients with mitral valve prolapse; however, clinical characteristics and survival information are limited since most of the cases reported include autopsy data. Nine patients (2 male, 7 female) with mitral valve prolapse were identified who had cardiac arrest; ventricular fibrillation was documented in 8 patients; resuscitation was unsuccessful in 2. Eight had a history of palpitations (months to 15 years duration) and ventricular arrhythmias, 3 had a history (5-15 years) of recurrent syncope, and 1 was totally asymptomatic. Cardiac catheterization-angiographic studies in 8 patients demonstrated normal coronary artery anatomy and mitral valve prolapse. All 9 patients had auscultatory and echocardiographic evidence of mitral valve prolapse. Seven survivors (6 still alive) were followed from 3 to 14 years after cardiac arrest. A subset of patients with mitral valve prolapse and cardiac arrest is described in whom past medical history is compatible with cardiac arrhythmias or syncope, and whose long-term prognosis appears better than patients with other causes of cardiac arrest.

Quantitation and significance of systolic mitral leaflet displacement in mitral valve prolapse

Superior systolic displacement of the mitral leaflets is the echocardiographic finding generally used to diagnose mitral valve prolapse, but its clinical significance is not clearly established. This study was designed to determine if the presence of leaflet thickening, displacement in the multiple imaging planes or the quantitative degree of displacement could be used to identify clinically important valvular abnormality. To this end, these findings were prospectively assessed and correlated with the presence of mitral regurgitation and ventricular arrhythmia in 49 patients with displacement and in 49 age-matched control subjects with no identifiable displacement. Both ventricular arrhythmia and mitral regurgitation were found to occur with significantly greater frequency in patients with leaflet displacement than in control subjects. However, among the patients with leaflet displacement, both these complications occurred with greater frequency in subgroups characterized by the presence of leaflet thickening, quantitatively greater displacement and displacement evident in 2 orthogonal imaging planes. Logistic regression analysis demonstrated that the best echocardiographic predictor of either ventricular arrhythmia or mitral regurgitation was the quantitative degree of leaflet displacement. These results indicate that most patients with echocardiographic evidence of leaflet displacement had very low incidences of ventricular arrhythmia and mitral regurgitation. Subgroups, however, could be identified echocardiographically in which both complications occurred with significantly greater frequency.

Myxoid heart disease: a review with special emphasis on sudden cardiac death

Myxoid heart disease (MHD), more commonly known as mitral valve prolapse, is a very common cardiac abnormality affecting 5-10% of the general population. This article reviews the history, symptoms, physical findings, pathology, associated conditions and complications of this entity. Special emphasis is given to sudden cardiac death, which occurs as a result of acute heart failure or due to a fatal arrhythmia. Theories regarding the origin of the arrhythmias are discussed. Once the origin is known, those at risk for this devastating complication can be identified and perhaps a preventative therapeutic regimen developed.

Prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in apparently healthy subjects: a prospective study in the general population

The prevalence of left ventricular false tendons, premature ventricular complexes and their coexistence was evaluated prospectively in 187 healthy company workers aged 21 to 50 (mean 36) years. False tendons were demonstrated echocardiographically in 133 (71%). Eight subjects were withdrawn from the study because of silent mitral valve prolapse. In these 179 healthy subjects, false tendons were detected in 127 (71%) and premature ventricular complexes in 48 (27%). Their coexistence was observed in 40, which showed a significant correlation (p less than 0.05) of false tendons and premature ventricular complexes. In seven of the eight subjects without false tendons, premature ventricular complexes were uniform and infrequent (mean 3 beats/24 h). In the 40 subjects with false tendons, premature ventricular complexes were uniform in 29, multiform in 6 and repetitive in 5, and the mean frequency was 96 beats/24 h. Correlation of premature ventricular complexes with the type of false tendons showed that premature ventricular complexes were significantly associated with thick (greater than or equal to 2 mm) and longitudinal tendons (p less than 0.005). Although it is not certain that left ventricular false tendons are arrhythmogenic, the prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in the general population, and the special relation between the frequency and the form of premature ventricular complexes and the type of false tendons, suggests that false tendons may play an etiologic role in the genesis of premature ventricular complexes in apparently healthy subjects.

Cerebral ischemia and mitral valve prolapse: case-control study of associated factors

We evaluated 36 patients with cerebral ischemia and mitral valve prolapse and compared them with 36 age-matched controls with cerebral ischemia who had similar attributes but who did not have mitral valve prolapse. Stepwise logistic regression analysis revealed an inverse relation between cerebral ischemia in the presence of mitral valve prolapse and hypertension, diabetes mellitus, occlusive cerebrovascular disease, and completed stroke at p less than 0.01. We also found, by correlation analysis, a negative correlation between both hypertension and diabetes mellitus versus mitral valve prolapse at p less than 0.05. Overall, 10 study patients compared with two control patients had no risk factors for cerebrovascular disease detected (chi 2 = 4.9, p less than 0.05). These data indicate that the association of mitral valve prolapse and cerebral ischemia is of special importance in patients who do not have other detected risk factors for cerebrovascular disease.

Long-term follow-up of idiopathic mitral valve prolapse in 300 patients: a prospective study

A prospective long-term follow-up study was made of 300 patients with idiopathic mitral valve prolapse, diagnosed by clinical, cineangiographic and echocardiographic criteria. There were 136 male and 164 female patients, ranging in age from 10 to 87 years (mean 42.2). The study included all patients with primary mitral valve prolapse, irrespective of clinical condition at the onset, and excluded only those patients with "secondary" mitral valve prolapse attributable to an accompanying established disorder. The average follow-up period was 6.1 years (range 6 months to 20 years). Two patients died of a noncardiac cause. The clinical condition of 153 patients remained stable. In 27 patients a supraventricular tachycardia occurred that was readily controlled with medication and caused no serious clinical complications. In 20 patients signs of mitral regurgitation appeared, but the patients remained clinically asymptomatic. Serious complications developed in 100 patients. Sudden death, most likely due to ventricular fibrillation, occurred in three patients; documented ventricular fibrillation was seen in two. Ventricular tachycardia developed in 56 patients, but in all instances the rhythm disorder was managed effectively and durably with medication. Infective endocarditis occurred in 18 patients, 4 of whom died during treatment and 6 of whom needed mitral valve replacement. The remaining eight patients suffer from severe mitral regurgitation that will require surgery in the near future. Twenty-eight patients underwent mitral valve operation because of progressive regurgitation. Cerebrovascular accidents occurred in 11 patients, but lifelong treatment with coumarin derivatives or antiplatelet aggregation agents was not considered necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral valve prolapse

Mitral valve prolapse is a common mitral valve disorder manifested clinically as a midsystolic click and/or a late systolic murmur (the click-murmur syndrome) and pathologically as billowing or prolapsing mitral leaflets (the floppy valve syndrome). Not only is it one of the two most common congenital heart diseases and the most common valve disorder diagnosed in the United States, but it is also prevalent throughout the world. Mitral valve prolapse may be associated with a variety of other conditions or diseases. Diagnosis of mitral valve prolapse should be made on clinical grounds and, if necessary, supported by echocardiography. The majority of patients with mitral valve prolapse suffer no serious sequelae. However, major complications such as disabling angina-like chest pains, progressive mitral regurgitation, infective endocarditis, thromboembolism, serious arrhythmias, and sudden death may occur. Unless these serious complications occur, most of the patients with mitral valve prolapse need no treatment other than reassurance, including those with atypical chest pain or palpitation unconfirmed by objective data. Therapy with a beta-blocker for disabling chest pain and/or arrhythmias and antiplatelet therapy for cerebral embolic events may be indicated. In occasional patients with significant mitral regurgitation surgery may be necessary.

The QT and QS2 intervals in patients with mitral leaflet prolapse

The QT interval was plotted against the R-R interval in 92 patients with mitral prolapse and 92 age- and sex-matched control subjects. Ten patients (11%) lay above the upper 95% confidence limit for the control group, and analysis of variance confirmed a small group effect (p less than 0.05). Despite this, the mean QT intervals in the two groups differed by only 7 msec and a t test showed no significant difference between the groups. The prevalence of QT prolongation was exaggerated by Bazett's rate correction formula (62%) or historical control groups published by Simonson (58%) or Ashman (70%). Simultaneous QT and QS2 intervals were measured in 67 patients with mitral prolapse. Inversion of the normal QT:QS2 relationship occurred in nine patients (13%) and was more common in the presence of severe mitral regurgitation. It was not associated with an increased prevalence of absolute QT prolongation and was therefore thought to be caused by relative shortening of the QS2 interval. In conclusion, the prevalence of QT prolongation in mitral prolapse is low (11%). The QT:QS2 ratio is unlikely to be a reliable indicator of QT prolongation in these patients.

Cardiovascular disease of connective tissue origin

Inherited abnormalities of connective tissue elements often cause changes in the structure and function of the cardiovascular system. Well-known heritable disorders of connective tissue in which cardiovascular abnormalities are prominent include the Marfan syndrome and the Ehlers-Danlos syndrome. Connective tissue abnormalities also occur without the associated features of a recognized syndrome. These include isolated valvular prolapse and anuloaortic ectasia. In this review, the cardiovascular features of connective tissue abnormalities--both the recognized syndromes and the isolated abnormalities--are described, important concepts in the diagnosis and treatment of these disorders are reviewed, and the classification of inherited connective tissue abnormalities of the cardiovascular system is discussed.

Acute rupture of myxomatous mitral valve presenting as refractory cardiopulmonary arrest

A 59 year old white woman had an out of hospital sudden cardiac arrest. Resuscitation at the scene restored spontaneous pulse, blood pressure and respiration but cardiovascular collapse recurred within 30 minutes of hospital arrival. Medically refractory cardiogenic shock of unclear origin prompted the placement of an intraaortic balloon pump, and hemodynamic stabilization was achieved over several hours. Acute rupture of the chordae tendineae of myxomatous mitral valve was diagnosed as the cause of the cardiac arrest. Mitral valve replacement was performed and the patient made an uneventful recovery. This report describes the first known case of rupture of a myxomatous mitral valve presenting as sudden cardiac death. The differential diagnosis of sudden death in this disorder is reviewed, the role of mechanical circulatory assistance in refractory cardiac arrest is discussed and several interesting hemodynamic aspects of the case are considered.

Ventricular arrhythmia: management strategy

The management of ventricular arrhythmia continues to be one of the most difficult therapeutic problems in medicine today. Both invasive and noninvasive techniques have demonstrated success in management of patients at high risk for sudden cardiac death. High-risk subgroups include patients who have experienced sudden cardiac death and have been resuscitated successfully, patients with high-grade ventricular ectopy associated with left ventricular dysfunction, and patients who have had recent myocardial infarction. Traditional and experimental antiarrhythmic agents are available to the clinician, and in some patients combination therapy may prove more useful than application of a single agent alone. In individuals in whom pharmacologic intervention fails, map-guided surgical excision may be beneficial. The application of the automatic implantable defibrillator appears to have promise in truly refractory situations.

Normal sympathetic neural activity in patients with mitral valve prolapse

The hemodynamic and neurohumoral responses to head-up tilt and isometric exercise were studied in 14 mitral valve prolapse (MVP) patients with and 10 MVP patients without complaints and in 16 healthy control subjects. Plasma catecholamines at rest were not different between the three groups and neither were their changes during either test. The hemodynamic changes during head-up tilt were not different between the three groups. The symptomatic MVP patients showed a lower rise in diastolic blood pressure (14.3 +/- 6.4%) than the controls (22.9 +/- 9.6%) (p less than 0.05) during isometric exercise. In view of the fact that the neurohumoral responses to both tests were the same for all groups, we cannot support the suggestions from other studies that MVP patients have an impaired or enhanced sympathetic tone. Moreover, since there were no differences between symptomatic and asymptomatic MVP patients it is doubtful whether the complaints of symptomatic MVP patients are related to a high sympathetic neural activity.

Neurologic disorders associated with mitral valve prolapse

Mitral valve prolapse has been reported to be associated with a variety of neurologic disorders, including cerebral ischemia, transient global amnesia, migraine, autonomic dysfunction, and psychiatric disease. The evidence supporting these associations and possible pathogenetic mechanisms are discussed. Some neurologic disorders may be direct complications of mitral valve prolapse, while others may occur as part of an underlying genetic defect or common link.

Sudden death and the competitive athlete: perspectives on preparticipation screening studies

Sudden death in healthy athletes is uncommon but, when it occurs, the primary mechanism is cardiovascular. The major cause of sudden death in the young athlete is hypertrophic cardiomyopathy or related conditions characterized by left ventricular hypertrophy, aortic rupture due to cystic medial necrosis and congenital coronary artery abnormalities. In the middle-aged or older athlete, coronary artery disease is the most significant cause of sudden death. Noninvasive screening procedures are currently available that can detect most subjects at risk of sudden death. However, although some potentially lethal diseases can be excluded by a relatively simple screening program, other diseases require expensive procedures, such as echocardiography and exercise electrocardiographic stress testing. This means that the sensitivity of detecting diseases leading to sudden death increases in proportion to the financial resources that can be applied to the screening program. Thus, when a screening program designed to identify all cardiac diseases that have the potential to cause sudden death is planned by a community, school or nonprofessional athletic team, the costs will almost undoubtedly be considered prohibitive. The practicality of applying a community- or school-initiated screening program can be questioned because of the very low incidence of sudden unexpected death in young healthy individuals. It is therefore likely that comprehensive screening programs will be confined to individuals or organizations with adequate financial resources. Less expensive, limited screening can be undertaken by individuals or groups to identify some subjects at risk of sudden death during athletic competition.

The yield of programmed ventricular stimulation in mitral valve prolapse patients with ventricular arrhythmias

A high-risk subset of patients with mitral valve prolapse (MVP) and a predisposition to sudden cardiac death (SCD) has been proposed. We analyzed the results of programmed ventricular stimulation (PVS) in 20 patients with MVP and ventricular arrhythmias (ventricular premature depolarization in 6, ventricular couplets in 2, nonsustained ventricular tachycardia [VT] in 7, ventricular fibrillation [VF] in 5) and in 12 "normal" control subjects. With the use of an identical stimulation protocol from the right ventricular apex (twice diastolic threshold, three extrastimuli), 9 of 20 MVP patients and 1 of 12 normal subjects had inducible ventricular arrhythmias (p less than 0.05). When more aggressive attempts at ventricular stimulation were used, an additional five MVP patients had positive responses to PVS while no normal subjects did. In the MVP group, the following arrhythmias were induced: nonsustained polymorphic VT in 10, VF in three, and ventricular flutter in one. In all but two patients, triple ventricular extrastimuli were required to elicit this response. Two of the 10 MVP patients undergoing electropharmacologic testing had a successful antiarrhythmic regimen identified, while 13 patients were discharged on empiric antiarrhythmic therapy. At a follow-up of 19.8 +/- 13.1 months, all 19 MVP patients who could be contacted were alive. Five patients had symptomatic recurrences at follow-up including two SCD survivors (VT in one and VF in one). In conclusion, it was found that the majority of MVP patients with ventricular arrhythmias have inducible ventricular tachyarrhythmias during PVS and are more susceptible to this than patients without structural heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Wolff-Parkinson-White syndrome. Termination of paroxysmal supraventricular tachycardia with phenylephrine

A patient with Wolff-Parkinson-White syndrome, susceptible to tachydysrhythmias , presented for eye surgery under general anaesthesia. He developed a supraventricular tachycardia refractory to a variety of treatments. Phenylephrine consistently abolished the dysrhythmia, probably by acting directly to stimulate the arterial baroreceptors and hence vagal output. Vasopressor therapy should be considered in Wolff-Parkinson-White syndrome tachyarrhythmias, when circumstances permit.

Complex arrhythmias in mitral regurgitation with and without mitral valve prolapse: contrast to arrhythmias in mitral valve prolapse without mitral regurgitation

Atrial and ventricular arrhythmias were characterized by ambulatory electrocardiography in 31 patients with nonischemic mitral regurgitation (MR), 17 of whom had echocardiographic evidence of mitral valve prolapse (MVP) and 14 of whom had other causes of MR. Frequent and complex arrhythmias were common and equally prevalent in each MR subgroup, whether or not MVP was present. Multiform ventricular ectopy was found in 77% (24 of 31), ventricular couplets in 61% (19 of 31), and ventricular salvos or ventricular tachycardia in 35% (11 of 31) of patients with MR. Arrhythmias in patients with MR were significantly more prevalent than in 63 patients with MVP who had no evidence of MR. Among patients with MVP, excess arrhythmias associated with MR were most striking with respect to frequent ventricular premature complexes (41% with MR vs 3% without MR), multiform ventricular ectopic activity (88% vs 43%), ventricular couplets (65% vs 6%), and ventricular salvos or ventricular tachycardia (35% vs 5%) (p less than 0.005 for each comparison). These data demonstrate that complex arrhythmias are common in patients with nonischemic MR irrespective of etiology, and that these arrhythmias are more strongly associated with hemodynamically important MR than with MVP alone.

Mitral valve prolapse syndrome with coronary artery spasm: a possible cause of recurrent ventricular tachyarrhythmia

A 54-year-old man with mitral valve prolapse syndrome diagnosed by echocardiography complained of anginal pain associated with ventricular tachyarrhythmia. One day he suddenly lost consciousness, and ECG at that time revealed ventricular fibrillation. Thereafter, he developed ST elevation, sporadic premature ventricular contractions, and R on T phenomenon leading to ventricular fibrillation during the attack of anginal pain. His coronary arteriogram was normal. This case implies that coronary artery spasm may be one of the causes of chest pain and ventricular tachyarrhythmias in patients with mitral valve prolapse syndrome.

Surgical treatment of mitral systolic click syndrome: results in 37 patients

From 1974 to 1983, 37 symptomatic patients with mitral systolic click (Barlow's syndrome) underwent mitral valve repair. In 11 patients (30%), the click syndrome was associated with minor mitral regurgitation. Thirty-two patients (86%) had chest pain, 20 had arrhythmia (54%), and 20 had dyspnea as a major complaint. In 5 patients, the arrhythmia was serious, and in 2 of them, it was potentially life threatening. Mitral annuloplasty using a collar prosthesis was performed in 33 patients with posterior leaflet plication in 2, shortening of the chordae in 1, and commissural plication in 2. In 4 patients, commissural plication was performed. One of these patients also required cusp plication and shortening of the chordae, and another required repair of ruptured chordae. There were no operative or late cardiac-related deaths at a mean follow-up of 4.7 years (range, 1 to 10 years). Sixty-two percent of patients with prolapse alone and 91% of those with associated regurgitation were improved by at least one New York Heart Association Functional Class, with 60% of patients obtaining relief of one or more symptoms. In the presence of major symptoms, mitral annuloplasty offers symptomatic relief for some patients with mitral systolic click syndrome without valve incompetence, but it gives substantially better results in patients with mitral regurgitation.

Mitral valve prolapse requiring surgery. Clinical and pathologic study

The clinical, hemodynamic, surgical, and pathologic findings in 30 patients who required mitral valvular surgery and who had a preoperative diagnosis of mitral valve prolapse were reviewed. The mean age of the patients was 59.5 years; 28 patients were over 45 years of age and 10 were over 60 years. Surprisingly, 20 were males. A long history of systolic murmur was common, whereas symptoms of heart failure were of abrupt onset. At the time of surgery, a local holosystolic murmur typical of mitral regurgitation was present, although a mid- to late systolic click was not heard in any of the patients. Electrocardiographic abnormalities were present in all patients, with 13 patients demonstrating atrial fibrillation. Only four patients had a normal heart size radiographically. Echocardiography confirmed the radiographic findings, in that 27 patients demonstrated left atrial and ventricular enlargement. All 29 patients undergoing cardiac catheterization and angiography demonstrated a prolapsing mitral valve with severe regurgitation. Surgical and pathologic examination revealed findings characteristic of a myxomatous valve in all patients, with 19 also demonstrating ruptured chordae tendineae. This study demonstrates that heart failure requiring valvular surgery occurs in a subset of patients with mitral valve prolapse. In this subset, males predominate and most are over 50 years of age. These patients may be asymptomatic for many years, demonstrating mild to moderate mitral valvular regurgitation, before heart failure develops.