Mitral valve prolapse syndrome and arrhythmias

In patients with mitral valve prolapse syndrome various disturbances of cardiac rhythm can be observed such as atrial arrhythmias, ventricular tachycardias and conduction disturbances. Of timely interest are the questions of which etiology is at the basis of the arrhythmias, what is their relevance with respect to sudden cardiac death, what are the indications for treatment and which therapeutic results can be anticipated. Cardiac arrhythmias represent the most frequent complication of mitral valve prolapse. Holter ECG monitoring has assumed the central role in detection of all types of arrhythmias. As compared with normal persons, in patients with mitral valve prolapse, both ventricular and supraventricular arrhythmias can be found more frequently. Atrial arrhythmias: Supraventricular arrhythmias can be found less frequently than ventricular arrhythmias (Table 1). Premature atrial contractions can be observed in 35% of those with mitral valve prolapse but also in a similar number of normal individuals such that their presence is not of clinical relevance. There is only a tendency to more frequently incurred supraventricular couplets in mitral valve prolapse. Supraventricular tachycardias can be observed in 10.5 to 32% of which sinus tachycardia (heart rate greater than 120 beats per minute), paroxysmal atrial tachycardia and intermittent atrial fibrillation at about 5 to 6% each are not more common than in control subjects. Atrial fibrillation was seen more frequently in mitral valve prolapse with mitral regurgitation or, conversely, in mitral regurgitation due to mitral valve prolapse more frequently than in mitral regurgitation due to other causes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical ablation of arrhythmias.

The surgical approach was the earliest therapeutic ablation of hyperkinetic arrhythmias. Following the progressive improvements in electrophysiological mapping and operative techniques, new surgical approaches have been developed for the treatment of those arrhythmias related to ectopic phenomena or reentry mechanisms. These procedures have been proven to be highly effective but the associated morbidity and mortality were unacceptably high. More recent and advanced techniques of transcatheter ablation have revolutionized the treatment of these arrhythmias and now represent the treatment of choice in the majority of cases. However, the significant reduction in the operative risk and the improvement in patient outcome with respect to the past, thanks to a better patient selection and to advances in the surgical and myocardial protection techniques, make do that the surgical approach to some forms of arrhythmias is still valid, especially in those cases requiring associated surgery: atrial tachyarrhythmias in patients with congenital heart disease, post-ischemic ventricular tachycardias in patients who necessitate myocardial revascularization, and/or ventricular remodeling and chronic or paroxysmal atrial fibrillation in patients who require cardiac surgery. New techniques such as radiofrequency, microwaves and cryoablation guarantee the creation of linear and transmural lesions with minimum damage to the cardiac structures and appear very interesting as they are surgically simple and associated with shorter procedure times and less complications. The possibility of performing the ablative procedure completely on the epicardial surface may open the way for atrial fibrillation surgery on a totally beating heart and for procedures that are ever less invasive thus enabling treatment of patients without associated surgical indications.     

Treatment of ventricular arrhythmias

The term ventricular arrhythmia denotes various disorder in the cardiac rhythm--from isolated monomorphic ventricular extrasystoles to ventricular flutter and fibrillation. The choice of therapy of ventricular arrhythmias is primarily based on prognostic aspects. Ventricular tachycardias represent the main cause of sudden cardiac death, which is responsible for more than 60% of all deaths for cardial causes. In the industrially advanced countries the ventricular tachyarrhythmias represent more than 90% of cases based on coronary disease. The prevention of sudden death is directed particularly to prevention and therapy of ischaemic heart disease. The prognostic classification divides ventricular tachycardias into benign, potentially malignant and malignant ones, respectively. The benign arrhythmias do not require therapy. In the malignant (i.e. potentially lethal) ventricular tachyarrhythmias the implantation of cardioverter-defibrillator represents the most efficient treatment. In the largest group of patients with potentially malignant ventricular arrhythmias the present risk-oriented stratification enables a partial identification of persons with markedly increased risk of sudden death. They may be considered for preventive implantation of cardioverter-defibrillator. In some patients the therapeutic effect is reached by application of various therapeutic methods including a combination of pharmacological and non-pharmacological therapy, which also includes catheterization or surgical ablation of the arrhythmogenic substrate. A corresponding attention should be devoted to the basal cardial disease.     

Arrhythmias after surgery for congenital heart disease

The improvement of surgical techniques over the last few years have made postoperative chronotropic insufficiency either by sinus node dysfunction or iatrogenic atrioventricular block less common. However, reentrant tachycardia around lines of incision or a patch may be observed. Persistent dilatation of a cardiac chamber or ventricular dysfunction are predisposing factors. Flutter-like arrhythmias occur mainly after atrial surgery (closure of atrial septal defects, Mustard, Senning or Fontan procedures). Ventricular tachycardias are observed more often after correction of tetralogy of Fallot or in patients with severe ventricular dysfunction. In fact, any type of arrhythmia may arise, especially when the lesion is operated late in childhood or in adulthood with a partial haemodynamic result (residual gradient, valvular regurgitation or ventricular dysfunction...). In this context, regular ECG follow-up should be associated with repeated Holter monitoring and exercise stress testing. From the therapeutic point of view, amiodarone remains the best antiarrhythmic drug. Radiofrequency ablation techniques represent a recent but decisive advance in the management of atrial arrhythmias.     

Surgery for ventricular tachycardia associated with right ventricular dysplasia: disarticulation of right ventricle in 9 of 10 cases.

Ten patients (nine men, one woman; mean age 39 years) with arrhythmogenic right ventricular dysplasia underwent surgery to control life-threatening drug refractory ventricular arrhythmias. All had ventricular tachycardia causing syncope and six had a history of cardiac arrest. In all a minimum of three antiarrhythmic drugs (mean five) had been ineffective. At operation, the right ventricle was grossly diseased in all patients. Ventricular tachycardias were induced and mapped intraoperatively in all patients. The surgical plan was to ablate the arrhythmogenic focus if it was less than 4 cm2; one patient was so managed. Of the remaining nine, four underwent partial (approximately 40% of the right ventricular free wall) and five underwent total right ventricular disarticulation. All survived the operation and are alive at a mean follow-up interval of 24 months (range 5 to 67). Two patients developed new sustained ventricular tachycardias. These were well tolerated and, unlike the original arrhythmias, were easily controlled by drug treatment. All patients who underwent right ventricular disarticulation manifested signs of right heart failure in the early postoperative period, but these lessened progressively with the development of systolic septal movement into the right ventricular cavity. All 10 patients are in New York Heart Association class I or II at last review. In selected patients with arrhythmogenic right ventricular dysplasia, surgery offers a curative treatment for ventricular tachycardia and should be considered for patients whose arrhythmias are life-threatening and refractory to drug treatment.     

Residuae, sequelae, and complications of surgery for congenital heart disease

Definitive, if not curative surgery is available for the eight most common congenital cardiac defects—ductus arteriosus, ASD, VSD, coarctation, pulmonary valve stenosis, aortic valve stenosis, tetralogy of Fallot, and transposition.The results of surgery for uncomplicated cases of DA, ASD, VSD, and coarctation usually can be determined by clinical means (including chest radiogram and ECG). Postoperative heart catheterization is recommended for evaluation of the patient who has had surgery for pulmonary valve stenosis or aortic stenosis and is necessary after tetralogy of Fallot or transposition of the great arteries repair to identify the important postoperative residua and sequelae.The term “curative” surgery probably should be reserved for operation for division of ductus arteriosus unassociated with pulmonary hypertension and performed in childhood.After closure of ASD, patients should continue to be observed for late development of arrhythmias and persistent cardiac enlargement, although the incidence of these problems is low.After VSD closure the patient is still followed at intervals for possible ill effects of the ventriculotomy scar, manifest as arrhythmias, ventricular aneurysm or myocardial insufficiency.The patient with coarctation repair must be observed for a possible late complication from one of the several clinically silent cardiovascular or cerebrovascular anomalies as well as for the chance of restenosis or unrelieved hypertension.Patients who have had an effective relief of the pressure gradient from pulmonary valve stenosis have a good outlook but should be observed for signs of myocardial insufficiency or the possible effects of increased load on the right heart resulting from pulmonary insufficiency.The high incidence of some degree of aortic insufficiency after valvotomy for aortic valve stenosis as well as the slight chance of restenosis necessitates follow-up examinations for these patients.After tetralogy of Fallot repair partially unrelieved infundibular stenosis or pulmonary annular stenosis and/or persistent VSD may require some limitation of physical activities even though the patient feels much improved because of disappearance of the cyanosis. Whether there are residual defects or not, patients should continue to be re-examined annually for an indefinite period of time because of possible myocardial insufficiency or arrhythmias.The problems after transposition repair include arrhythmias, right ventricular myocardial insufficiency, tricuspid insufficiency, persistent communications around the atrial baffle, and vena caval and/or pulmonary vein stenosis. Despite the frequent residua and sequelae of surgery, most patients with transposition obtain remarkable relief of symptoms.The use of exercise stress testing should increase the reliability of clinic assessment of the operative result. In those patients at risk for arrhythmias after surgery, electrophysiological studies at the time of postop cath may contribute to the management of the patient. The addition of ultrasound in the pre and postoperative evaluation of patients will aid the identification of certain clinically silent associated defects and some of the postoperative sequelae.The risk of subacute bacterial endocarditis remains in most patients after intracardiac repair of defects and, with few exceptions, patients who have had definitive surgery require long-term follow-up despite relief of symptoms and the disappearance of clinical manifestations of cardiovascular dysfunction.It is reasonable to expect that with improvement in diagnostic and surgical technique, many of the currently acceptable residua and sequelae of surgery for congenital heart disease will, in the future, be designated as avoidable complications in these patients. With the current healthy interest in long-term postoperative results there is a good chance that more precise information will become available to guide in the selection for surgery of the patient with congenital heart disease.     

Supraventricular arrhythmia before and after surgical closure of atrial septal defects: spectrum, prognosis and management.

Supraventricular arrhythmias are often observed in patients before and after atrial septal defect repair. Although several papers report different incidences of sustained supraventricular arrhythmias, postoperative 'incisional' macroreentrant tachycardias have not been systematically investigated. METHODS: We reviewed 136 consecutive patients (79 female, 57 male, mean age 36.8+/-17.8 years) who underwent atrial septal defect repair at our institutions between January 1990 and January 1999. Coexisting valve disease requiring surgical intervention was noted in 13 patients (9.5%). The mean follow-up period was 78.8+/-30.1 months. RESULTS: Sustained supraventricular arrhythmias occurred in 12 patients (8.8%) before surgery (atrial fibrillation in 11 patients). Using multivariate analysis the occurrence of arrhythmia significantly correlated with the presence of coexisting heart disease (P< 0.001) and age at surgery (P=0.011) After surgery sustained supraventricular arrhythmias were recorded in 16 patients (11.7%). Eleven of them had atrial fibrillation, permanent in 8 cases, 4 'incisional' macroreentrant atrial tachycardia and 1 atrioventricular re-entry tachycardia. There was a significant correlation between pre and postoperative arrhythmia (P< 0.001). Two of the 4 patients with macroreentrant atrial tachycardia underwent successful radiofrequency catheter ablation, whereas the arrhythmia was controlled medically in the remaining 2 patients. CONCLUSIONS: Atrial fibrillation remains the most frequent form of arrhythmia before and after surgical closure of atrial septal defects in adulthood, and relates to age at the time of repair and coexisting heart disease. Incisional macroreentrant atrial tachycardia is an identifiable, albeit less common, form of tachycardia, which can be treated by transcatheter ablation.     

Electrophysiologic residua and sequelae of surgery for congenital heart defects

Postoperative arrhythmias may occur in any patient who undergoes intracardiac surgery for a congenital heart defect. The correction of certain intracardiac heart defects predisposes to a large incidence of cardiac arrhythmias. Ventricular arrhythmias and conduction disturbances are seen after correction of tetralogy of Fallot, ventricular septal defect and atrioventricular canal defect. Supraventricular arrhythmias and sinus nodal dysfunction may be seen after surgery for transposition of the great arteries or atrial septal defect. The identification, evaluation and treatment of these patients are discussed.     

Exercise testing in the assessment of ventricular arrhythmias (author's transl)

During exercise, ventricular arrhythmias may be observed in 50% of healthy subjects and up to 85% of patients with heart disease. For the quantitative as well as qualitative assessment of ventricular arrhythmias, continuous ECG (Holter) monitoring is superior to the Exercise ECG. Both methods together render a 10% increase in sensitivity over that achieved through the use of one method only. In patients with repeated ventricular tachycardias, assessment through electrical stimulation is more preferable than the use of the exercise ECG or continuous ECG monitoring. In patients with coronary artery disease, ventricular arrhythmias during exercise, depending on their incidence and complexity, may indicate a two to eight-fold increase in the likelihood of cardiac death. The reproducibility of ventricular arrhythmias during repeated exercise testing is reported between 30 and 77%. Thus, in the individual patient, the complete absence of an exercise-induced arrhythmia during treatment does not permit differentiation between therapeutic effect and spontaneous variability. Accordingly, the exercise ECG is generally not an adequate method for assessment of antiarrhythmic treatment.     

Late ventricular tachycardia after surgical correction of congenital cardiopathy. Impact, severity and predictive factors

A group of 6 patients operated for Fallot's tetralogy (4 cases) or a similar congenital cardiac malformation (2 cases) were studied to assess the prevalence, severity and predictive factors of late post-operative ventricular tachycardia. These 6 patients were compared with a control group of 44 patients undergoing complete correction of Fallot's tetralogy. The age at operation (6 +/- 2 years), the length of follow-up (8 +/- 2.5 years) and surgical technique were comparable in both groups. The clinical parameters and results of non-invasive investigations (resting ECG, Holter monitoring) were compared. The first attack of tachycardia occurred on average 3 years after surgery. A triggering factor was found in 3 cases (a blow on the chest--2 cases--, general anaesthesia--1 case). These postoperative tachycardias are characterised by poor clinical tolerance, a tendency to recur, resistance to therapy and reserved prognosis. They are significantly commoner in patients operated late and in those with a poor haemodynamic result: right ventricular systolic pressure greater than 60 mmHg and recurrence of the ventricular septal defect. The combination of ventricular tachycardia and a poor haemodynamic result is associated with a mortality rate of 33 p. 100. The functional status of the patient, conduction defects and the surgical technique used were not predictive of ventricular tachycardia. The detection of a ventricular arrhythmia on the resting ECG, and, particularly, on Holter monitoring, and the induction of ventricular tachycardia by ventricular stimulation should lead to treatment against malignant ventricular arrhythmias and sudden death. The choice of anti-arrhythmic agent may be guided by endocavitary stimulation techniques to assess its efficacy.     

Indications and prospects of cardiac fulguration

Fulguration is a new technique of palliative treatment (ablation or alteration of the atrioventricular junction) of refractory supraventricular tachycardias. It can be too a curative treatment of arrhythmias unresponsive to medial therapy and not suitable for surgery or implantable defibrillator (ventricular tachycardias - refractory arrhythmias of the Wolff-Parkinson-White Syndrome and permanent or incessant form of reciprocating tachycardia). An original indication of this method is the ablation of the retrograde pathway alone in refractory intranodal reciprocating tachycardias. The results of these indications are herein analysed.     

Stable ventricular tachycardia in arrhythmogenic dysplasia of the right ventricle in sportsmen

Right ventricular arrhythmogenic dysplasia (RVAD) is a typical asymptomatic arrhythmogenic cardiopathy in athletes, which is occasionally concurrent with normal ventricular function and life-threatening arrhythmias. A total of 32 athletes (28 males and 4 females, mean age, 23 years, mean follow-up, 6.7 years) were examined for severe cardiac arrhythmias with left bundle branch block. The conclusive diagnosis of RVAD was established from clinical, echocardio-, and angiographic evidence. The protocol of the examination involved Holter monitoring, loading tests, electrophysiological study, two-dimensional echocardiography, cardiac angiography of the right and left ventricles, coronary angiography. The most severe arrhythmias were observed in athletes whose mean age was 23.4 years, 20 patients had sustained ventricular tachycardia (it occurred only in 19 who were indulging in sports), 6 presented with transient ventricular tachycardia, and 1 had ventricular fibrillation. They all had been considered fit for sports. The disease proceeded severely in 16 of 32 athletes (in 13 of 16 while indulging in sports), the conditions close to syncope were seen in 9 patients (8 had sustained ventricular tachycardias and 1 had transient ventricular tachycardias), syncopes were observed in 5 patients (sustained ventricular tachycardias).     

Activation mapping in patients with coronary artery disease with multiple ventricular tachycardia configurations: occurrence and therapeutic implications of widely separate apparent sites of origin

Catheter or intraoperative activation mapping studies, or both, were performed in 17 patients with coronary artery disease with two to four distinct configurations of ventricular tachycardia, resistant to a mean of 12.1 +/- 6.0 antiarrhythmic drug trials per patient. Mapping studies were performed to guide anticipated surgical ablation of arrhythmias. Activation map data were adequate to determine sites of origin of 30 (64%) of 47 observed tachycardia configurations. These 30 ventricular tachycardias (26 observed clinically) were mapped to 22 separate endocardial sites of origin. Sites of origin of distinct tachycardias were identical or closely adjacent (within 3 cm) in six patients and widely separate (greater than or equal to 4 cm) in eight patients (47% of the group). Activation maps were not adequate to determine sites of origin of 17 (36%) of the 47 tachycardias, including all configurations in three patients. Fifteen patients underwent surgery for control of ventricular tachycardia: aggressive, map-guided endocardial resection (mean 26.5 +/- 14.2 cm2) in 12 patients with identified sites of tachycardia origin and extensive resection of visible endocardial scar (2 patients) or encircling endocardial ventriculotomy (1 patient) in those in whom the sites of origin of all clinical tachycardias remained undetermined. Two inoperable patients were treated with amiodarone. During postoperative electrophysiologic tests (11 of 13 surgical survivors), ventricular tachyarrhythmias were initially uninducible in only 4 of 11 patients. However, in two patients only nonclinical arrhythmias (ventricular flutter) were induced. Six (21%) of 29 clinical tachycardias whose sites of origin were either not determined or not resected (right septum or papillary muscle) remained inducible in five patients. Using previously ineffective antiarrhythmic drugs, initially inducible arrhythmias became uninducible (two patients), or harder to induce than preoperatively (five patients). As a result of surgical resections alone or in combination with previously ineffective drugs (and amiodarone in two inoperable patients), there were no recurrences of ventricular tachycardia in 14 (93%) of 15 patients discharged during 19.0 +/- 14.3 months of follow-up study. Thus, activation mapping may commonly reveal separate apparent sites of origin for clinically observed, morphologically distinct, highly drug-refractory ventricular tachycardias in patients with coronary artery disease with multiple tachycardia configurations. Extensive surgical resection of identified sites of origin may be required to ablate arrhythmias in these patients.(ABSTRACT TRUNCATED AT 400 WORDS)     

The adult with congenital heart disease: cardiac catheterization as a therapeutic intervention

The adult with congenital heart disease who undergoes cardiac catheterization at the present time is most likely to have complex heart disease and is left with clinically important sequelae or residual defects, ventricular dysfunction or arrhythmias. Residual defects such as paravalvular leaks, coronary fistulas and pulmonary artery narrowings may be corrected with transcatheter techniques. Patients with simple forms of congenital heart disease (for example, atrial septal defect, patent ductus arteriosus, aortic valve stenosis, pulmonary valve stenosis) will go to the catheterization laboratory for treatment, not diagnosis. Certain lesions previously considered benign (for example, patent foramen ovale) may require definitive interventional therapy to reduce the risk of stroke from paradoxic embolism.     

Ventricular arrhythmias late after aortic and/or mitral valve replacement

Since it is not yet known whether ventricular arrhythmias in patients with valve replacement are associated with an increased risk of sudden death, as in patients with coronary artery disease, a total of 46 patients who were long-term survivors of aortic and/or mitral valve replacement were examined with 24-hour ambulatory electrocardiographic monitoring, and the factors influencing the occurrence of ventricular arrhythmias were analyzed. The significance of ventricular arrhythmias in the prognosis of valve replacement is discussed. The occurrence of ventricular arrhythmias was significantly higher: 1) in patients with aortic stenosis than in those with aortic regurgitation, 2) in patients with multiple valve surgery than in those with single valve replacement and 3) in patients with larger heart size. Pre- and postoperative hemodynamics, including left ventricular function, were not significantly related to the incidence of ventricular arrhythmias. A review of the patients who died suddenly, late after valve replacement suggests that frequent ventricular arrhythmias and thromboembolism are the most important factors in the late mortality of these patients. The prognostic significance of postoperative ventricular arrhythmias in patients with valve replacement requires additional study.     

Atrial arrhythmia surgery in congenital heart disease

Atrial reentrant tachycardias are a common source of morbidity in children with significant structural heart disease, especially following cardiac surgery. Preexisting atrial geometry combined with the hemodynamic effect of a congenital cardiac defect and electrophysiological alterations caused by surgical lesions can create large anatomic-functional barriers to conduction, allowing reentrant wavefronts to flourish. Elucidation of the genesis of reentrant arrhythmias in children has led to catheterization and surgical therapies. The primary goals of these procedures are to restore synchronous atrioventricular conduction and eliminate hemodynamically significant residual physiologic lesions. Debilitating arrhythmias may be cured, and patients have an improvement in functional class.     

Technique of percutaneous laser-assisted valve dilatation for valvar atresia in congenital heart disease.

OBJECTIVE--To investigate the efficacy and safety of transcatheter laser-assisted valve dilatation for atretic valves in children with congenital heart disease. DESIGN--Prospective clinical study. SETTING--Supraregional paediatric cardiology centre. SUBJECTS--Eleven children (aged 1 day-11 years; weight 2.1-35.7 kg) with atresia of pulmonary (10) or tricuspid (one) valve underwent attempted laser-assisted valve dilatation as part of the staged treatment of their cyanotic heart disease. INTERVENTION--After delineating the atretic valve by angiography and/or echocardiography a 0.018 inch "hot tip" laser wire was used to perforate the atretic valve. Subsequently the valve was dilated with conventional balloon dilatation catheters up to the valve annulus diameter. RESULTS--Laser-assisted valve dilatation was successfully accomplished in nine children. In two neonates with pulmonary valve atresia, intact ventricular septum, and coexistent infundibular atresia the procedure resulted in cardiac tamponade: one died immediately and one later at surgery. During a follow up of 1-17 months (mean 11) two infants with pulmonary valve atresia and intact ventricular septum died (one with congestive cardiac failure). The remainder are either well palliated and do not require further procedures (three), or are awaiting further transcatheter or surgical procedures because of associated defects (four). CONCLUSIONS--Laser-assisted valve dilatation is a promising adjunct to surgery in this high risk group of patients. It may avoid surgery in some patients, and may reduce the number of surgical procedures in those requiring staged operations.     

Sustained ventricular tachycardia 7 years after complete correction of tetralogy of Fallot

The authors report a case of sustained ventricular tachycardia which occurred seven years after complete surgical correction of Fallot's tetralogy in a 13 year old girl. This arrhythmia was well tolerated haemodynamically, showed right-sided delay and was associated with mitral valve prolapse. After reviewing the literature, several physiopathological mechanisms are discussed: --the role of residual intraventricular conduction defects in sustaining the tachycardia; --the role of the ventriculotomy scar or of other associated lesions (mitral valve prolapse in this case) in the genesis of ventricular extrasystoles; --the postoperative haemodynamic status in the tolerance of the arrhythmias. This is a rare complication with an incidence of less than 2% of survivors followed-up over long periods. There is a risk of sudden death in 38% of these patients with ventricular arrhythmias which justifies Holter monitoring and ECG stress testing for their detection.     

Clinical features, problems in medical management and therapeutic planning in severe valvular heart disease

Clinical features and pathological findings were reviewed in 90 postmortem cases of valvular heart disease (VHD) to clarify the problems and limitations of medical management. The clinical features of severe mitral valve disease included congestive heart failure (CHF), with tricuspid regurgitation in many cases, atrial fibrillation, frequent ventricular premature beats, ventricular hypertrophy, cardiomegaly, increased pulmonary arterial pressure and abnormal hepatorenal function. The most common causes of aortic valve disease (AVD) were rheumatic fever and infective endocarditis, and the major causes of death were sudden death and intractable CHF. Autopsy in cases of AVD revealed marked left ventricular hypertrophy and dilatation, vegetations, thickening, adhesion and calcification in the aortic valve. Some patients died of cardiogenic shock due either to severely impaired cardiac function or to associated myocardial or pulmonary infarction. Abrupt onset of embolism was also related to death of the patients. The management of VHD must include the treatment of CHF and arrhythmias and the prevention of embolism. Appropriate timing for surgery and close follow-up by cardiologists is mandatory.