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Biomedical subjects

V L Vetter

Publications and source records attributed to V L Vetter.

At least 19 recordsLinked to original sources
PubMed1994

Use of the rate-corrected JT interval for prediction of repolarization abnormalities in children.

A prolonged rate-corrected QT interval (QTc) may be associated with an increased risk of developing ventricular arrhythmias and sudden death, particularly in patients with the hereditary long QT syndrome (LQTS), myocardial ischemia, or antiarrhythmic medication toxicity. It is known that there are some patients with LQTS who sometimes have a borderline or normal QTc (< or = 0.45 second). Although the QTc has been the standard measurement of ventricular repolarization, it includes both depolarization and repolarization and may not always be a sensitive indicator of the type of repolarization abnormalities seen in LQTS. Intraventricular conduction abnormalities complicate evaluation of the QTc interval. The rate-corrected JT interval (JTc) is a more accurate measurement of ventricular repolarization, and therefore may be a more sensitive means of assessing abnormalities. The QTc on a resting electrocardiogram was determined in 40 patients with LQTS and in 31 patients with right bundle branch block after tetralogy of Fallot repair. These were compared with 1,000 age-matched control subjects. The right bundle branch block group had normal JT and JTc measurements, despite having prolonged QT and QTc intervals compared with controls. The JTc identified 85% of patients affected with LQTS compared with only 58% identified using only the QTc as a marker for the syndrome. The JTc is a more specific measurement of ventricular repolarization than the QTc by eliminating QRS duration variability. It appears to be a more sensitive predictor of repolarization abnormalities, and may be helpful in identifying patients with LQTS who have borderline or normal QTc measurements on resting electrocardiograms.

Adolescent↗
PubMed1992

Electrocardiographic changes and arrhythmias after cancer therapy in children and young adults.

Transient electrocardiographic changes and arrhythmias are known to be acute manifestations of cardiotoxicity secondary to cancer therapy with anthracyclines or cardiac irradiation. However, despite the known risk of late cardiac dysfunction in survivors of childhood cancer therapy, the risk of clinically important electrocardiographic abnormalities and arrhythmias after treatment is unknown. Standard 12-lead and 24-hour ambulatory electrocardiograms were recorded in 73 patients who received anthracyclines alone, 24 who received cardiac irradiation alone, and 27 who received both anthracyclines and cardiac irradiation. The mean age of the patients was 15 years. Mean cumulative anthracycline dose was 282 mg/m2 in patients who received anthracyclines alone and 244 mg/m2 in patients who received both anthracyclines and cardiac irradiation. Analysis of the 12-lead and 24-hour electrocardiograms demonstrated increased frequency of QTc prolongation, supraventricular premature complexes, supraventricular tachycardia, ventricular premature complexes, couplets and ventricular tachycardia (all p less than 0.001) when compared with an age-matched healthy population. Most patients had abnormalities limited to single supraventricular or ventricular premature complexes; however, potentially serious ventricular ectopy, including ventricular pairs and ventricular tachycardia, were noted in patients with cumulative doses greater than 200 mg/m2. Electrocardiographic abnormalities and arrhythmias are not limited to the acute phase of treatment with anthracyclines and cardiac irradiation. Survivors of childhood malignancy who received anthracyclines or cardiac irradiation, or both, probably should undergo ambulatory electrocardiographic monitoring as part of their follow-up to detect potentially life-threatening arrhythmias.

Adolescent↗
PubMed1991

Electrophysiologic findings after Fontan repair of functional single ventricle.

Cardiac arrhythmias are well recognized sequelae of the Fontan operation for complex congenital anomalies. In this study the electrophysiologic effects of the Fontan procedure were evaluated in 30 patients who underwent cardiac catheterization with electrophysiologic study 1.9 +/- 1.3 years (mean +/- SD) after modified Fontan repair for functional single ventricle. Abnormalities of sinus node or ectopic pacemaker automaticity were detected in 50% (15 patients) by determination of a prolonged corrected sinus node or pacemaker recovery time. Total sinoatrial conduction time was prolonged in 50% of the patients with normal sinus rhythm. Sinus node or ectopic atrial pacemaker function was entirely normal in only 43% of patients. The predominant atrial rhythm was normal sinus in 70% and ectopic atrial or junctional in 30%. Abnormalities of atrial effective and functional refractory periods were noted in 43% of patients and were most pronounced at faster paced cycle lengths. Atrial endocardial catheter mapping revealed intraatrial conduction delays between adjacent sites in 76% of the patients tested and in eight of nine patients with inducible intraatrial reentry. Programmed atrial stimulation induced nonsustained supraventricular arrhythmias in 10% of the 30 patients and sustained arrhythmias in 27%. Intraatrial reentry was the most common inducible arrhythmia and was present in seven of the eight patients with sustained and two of the three patients with nonsustained atrial arrhythmias. Atrioventricular conduction abnormalities were noted in 10% (three patients). No patient had inducible ventricular arrhythmias with programmed ventricular stimulation. The electrophysiologic findings after Fontan repair include abnormal sinus node function, prolonged atrial refractoriness, delayed intraatrial conduction and inducible atrial arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1990

Evolving concepts in the management of congenital junctional ectopic tachycardia. A multicenter study.

We reviewed the records of 26 infants with congenital junctional ectopic tachycardia (JET) from seven institutions to examine the evolution in the management of this tachycardia that is difficult to treat. JET was defined electrocardiographically as an incessant tachycardia with normal QRS morphology and atrioventricular (AV) dissociation. The ventricular rate ranged from 140 to 370 beats/min (mean, 230 beats/min); 16 of 26 patients had cardiac failure. Treatment success was defined as a stable decrease in the rate of JET, below 150 beats/min; partial success was a significant decrease of JET rate with alleviation of symptoms. All patients received digoxin with no significant effect. Propranolol was given to 16 patients, with two successes and one partial success. Combinations of other conventional agents were used in 11 patients with two successes; 14 patients were treated with amiodarone, which resulted in eight successes and three partial successes; three patients died suddenly on medical treatment (amiodarone, one patient; propranolol, one patient; or amiodarone plus propranolol, one patient); sudden AV block was a possible cause and consequently, two later patients had pacemaker implantation as well as medical treatment. His catheter ablation was successfully performed twice but contributed to death in a newborn; three surgical His ablations were performed for intractable JET with two successes and one death. The overall mortality was 35%. Among survivors, treatment has been stopped without any complications in five patients ranging in age from 10 months to 8 years (mean, 3.5 years). It seems that amiodarone alone is the best drug for treatment of congenital JET; necessity for permanent pacing remains unsettled. His ablation should be reserved only for intractable JET.

Amiodarone↗
PubMed1990

Perioperative arrhythmias after Fontan repair.

Arrhythmias are well-recognized sequelae of the Fontan repair. A prospective analysis of perioperative arrhythmias after Fontan repair was performed. Thirty-three patients had 24-hour ambulatory monitoring on the day before surgery and for 24 hours immediately after surgery; the 27 surviving patients had an additional 24-hour study on the seventh postoperative day. The most common preoperative rhythm was normal sinus, which was present in 79%. Hemodynamically significant preoperative arrhythmias were present in only two patients-atrial flutter (n = 1) and complete heart block (n = 1). Other asymptomatic preoperative arrhythmias included ectopic atrial rhythm (n = 2), supraventricular tachycardia (n = 1), accelerated junctional rhythm (n = 1), and frequent ventricular premature beats (n = 1). On the first postoperative day, the most common rhythm was accelerated junctional rhythm, which was present in 48%. Hemodynamically significant arrhythmias were present in nine patients (27%) -rapid accelerated junctional rhythm (rate, greater than 190 beats/min) (n = 3), complete heart block (n = 2), atrial flutter (n = 2), supraventricular tachycardia (n = 1), and ventricular tachycardia (n = 1). Three of six deaths occurring between postoperative days 2 and 7 were in patients with rapid accelerated junctional rhythm and associated low cardiac output. On the seventh postoperative day, the most common rhythm was normal sinus, which was present in 41%. Nine of the 27 surviving patients had complete resolution of their arrhythmias between postoperative days 2 and 7. On postoperative day 7, hemodynamically significant arrhythmias were present in four patients-atrial flutter (n = 2) and complete heart block (n = 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1988

Inducible atrial flutter after the Mustard repair of complete transposition of the great arteries.

Atrial flutter is a common postoperative arrhythmia in patients with complete transposition of the great arteries (d-TGA) after the Mustard repair. Sixty patients with d-TGA who had the Mustard repair were evaluated by electrophysiologic studies. Thirty-three (55%) had inducible sustained atrial flutter; 17 of them developed spontaneous clinical episodes of atrial flutter (clinical atrial flutter group) and 16 did not (nonclinical atrial flutter group). In 6 of the 17 patients (35%) with clinical inducible atrial flutter, the condition was first documented in the electrophysiologic laboratory with subsequent development of spontaneous clinical episodes. Catheter endocardial mapping, used to determine atrial activation sequences and and conduction intervals, revealed intraatrial conduction delays with late activation of the low atrial sites in all patients. Abnormalities of atrial refractoriness were present, with a greater dispersion of atrial refractoriness found in the clinical atrial flutter group. Severe abnormalities of sinus nodal function appeared to a significantly greater degree among patients who had clinical episodes of atrial flutter. These electrophysiologic abnormalities and associated arrhythmias may predispose patients with d-TGA to sudden death.

Atrial Flutter↗
PubMed1988

Electrophysiologic consequences of the arterial switch repair of d-transposition of the great arteries.

Electrophysiologic studies were performed at 12.7 +/- 4 months postoperatively in 20 patients who had the arterial switch repair at 1 to 120 days (mean 13 +/- 26 [SD]) for d-transposition of the great arteries. Preoperative electrocardiograms (ECGs) at rest revealed an ectopic atrial rhythm in one patient. Postoperative rest ECGs revealed transient postoperative ectopic atrial or junctional rhythms in two patients, intermittent ectopic atrial rhythms in two and right bundle branch block in nine with a normal QRS axis. In addition, ambulatory monitor recordings revealed infrequent premature ventricular complexes in five patients. Catheter endocardial mapping revealed sinus rhythm in 18 patients and ectopic atrial rhythm in 1 patient. Atrial activation after the switch repair was comparable with normal atrial activation. Activation of all low atrial sites was significantly earlier after the switch repair than after the Mustard repair. Mild abnormalities of sinus node function were present and consisted of slight prolongation of corrected sinus node recovery time in six patients and slightly increased sinoatrial conduction time in four. The ratio of sinus node recovery time to sinus cycle length was normal in all 20 patients. Atrial effective and functional refractory periods were normal in all patients and no atrial arrhythmias could be induced by programmed stimulation. Atrioventricular (AV) node conduction was excellent with normal AV node effective and functional refractory periods. The only electrophysiologic abnormality of His-Purkinje function was distal right bundle branch block in nine patients. Programmed stimulation of the ventricle produced repetitive ventricular responses in four patients: bundle branch reentry in three and intraventricular reentry in one.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗
PubMed1987

Electrophysiologic consequences of the Mustard repair of d-transposition of the great arteries.

This study describes the electrophysiologic effects of the Mustard repair of d-transposition of the great arteries on the sinus node and on conduction and refractoriness in the atrium, atrioventricular (AV) node and ventricle. Seventy-two electrophysiologic studies were performed on 64 patients after the Mustard operation. Standard rest and 24 hour ambulatory electrocardiograms were evaluated. Catheter endocardial atrial mapping, available in 67 of the 72 studies, revealed that sinus rhythm was present in the atria in 33 patients, ectopic atrial rhythm in 26 and junctional rhythm in 8. Intraatrial conduction delays with very late activation of the low medial, low lateral or low right atrium at the AV junction were present in 53 of 59 patients with atrial or sinus rhythm. Sinus node function was normal in only nine patients. Prolonged refractory periods were found in the right atrial portion of the new right atrium when compared with the left atrial portion of the new right atrium. Forty-one percent of the patients had prolongation of atrial refractoriness with shortening of the paced cycle lengths. Fifty-one percent developed sustained intraatrial reentry with programmed atrial stimulation. Forty-eight percent of these patients with inducible atrial tachycardia have since developed clinical episodes of atrial flutter. In summary, electrophysiologic studies revealed significant abnormalities of sinus node function and atrial conduction and refractoriness. Alone or in combination, these abnormalities, which result in severe bradycardia or rapid atrial arrhythmias, may lead to sudden death. The Jatene or arterial switch procedure may provide an appropriate alternative operation in this group of patients.

Adolescent↗
PubMed1985

Sudden death in infants, children, and adolescents.

Sudden death in infants is rarely due to cardiac disease. Sudden death in children and adolescents is usually associated with cardiac disease. The major congenital lesions associated with sudden death are aortic stenosis, cardiomyopathies, idiopathic hypertrophic subaortic stenosis, Eisenmenger's syndrome, and cyanotic congenital defects with pulmonary stenosis or atresia. There is a high incidence of postoperative sudden death, especially associated with repair of tetralogy of Fallot and transposition of the great arteries. Cardiac arrhythmias, including the long Q-T syndrome, sick sinus syndrome, complete heart block, ventricular tachycardia, and pre-excitation are associated with sudden death. It is hoped that identification of high-risk patients along with appropriate intervention and treatment may significantly lower or prevent sudden death in children.

Adolescent↗
PubMed1982

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.

Arrhythmias, Cardiac↗