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Biomedical subjects

G A Serwer

Publications and source records attributed to G A Serwer.

At least 19 recordsLinked to original sources
PubMed2001

The clinical course of multifocal atrial tachycardia in infants and children.

OBJECTIVES: This study outlines the clinical course, treatment and the late outcome of infants and children with multifocal atrial tachycardia (MAT). BACKGROUND: Multifocal atrial tachycardia is defined by three distinct P-waveforms, irregular P-P intervals, isoelectric baseline between P-waves and rapid rate on an electrocardiogram. Several smaller prior reports have described pediatric patients with MAT, but their long-term outcome has not been fully assessed. METHODS: The clinical records, echocardiograms and long-term follow-up of patients with MAT were reviewed and compared to previous reports of MAT. RESULTS: Fourteen boys and seven girls (median age 1.8 months) presented with MAT. At diagnosis, six patients had respiratory illness, of whom two were critical. Ten were asymptomatic. Seven patients had structural heart disease (SHD), one of whom died. Four of 15 patients (27%) with echocardiograms had diminished ventricular function. Ventricular rates were 111 to 253 beats/min (mean 181 beats/min). Median duration of the arrhythmia was 4.9 months (mean 6.7 months). Electrical cardioversion was attempted in 4 patients without success and 15 patients received antiarrhythmic medication. Seventeen patients were followed for a mean of 60 months. Four patients were lost to follow-up. There were no late arrhythmias. CONCLUSIONS: The majority of children with MAT are healthy infants under one year of age; a few may exhibit mild to life-threatening cardiorespiratory disease. Less often, MAT accompanies SHD. Mild ventricular dysfunction may be observed in the presence of MAT, but symptoms are few and resolution is generally complete. Response to antiarrhythmic agents is mixed, and cardioversion is of no avail. Finally, long-term cardiovascular and developmental outcome depends principally on underlying condition; for otherwise healthy children, it is excellent.

Child↗
PubMed2000

Use of a single coil transvenous electrode with an abdominally placed implantable cardioverter defibrillator in children.

While transvenous defibrillator electrode placement avoiding a thoracotomy is preferable, electrode size, a large intercoil spacing, and the need for subclavicular device placement preclude this approach in most children. We investigated a single RV coil to an abdominally placed active can ICD device. Five children ages 8-16 years (weight 21-50 kg, mean 35 kg) underwent ICD placement. Placement of a single coil Medtronic model 6932 or 6943 electrode was performed via the left subclavian vein approach and the electrode positioned in the RV apex with the coil lying along the RV diaphragmatic surface. The ICD (Medtronic Micro Jewel II model 7223 Cx) was implanted in a left abdominal pocket with the lead tunneled from the infraclavicular region to the pocket. Implant DFTs were < or = 15 J using a biphasic waveform. DFTs rechecked within 3-month postimplant were unchanged. Lead impedance at implant ranged from 38 to 56 omega, mean 51 omega. Follow-up was 3-21 months (total 82 months) with no electrode dislodgment, lead fractures, or inappropriate discharges. Two of the five patients have had successful appropriate ICD discharges. Transvenous ICD electrode placement can be performed in children as small as 20 kg with the device implanted in a cosmetically acceptable abdominal pocket that is well tolerated. Excellent DFTs can be achieved. This approach avoids a thoracotomy in all but the smallest child, does not require subclavicular placement of the device, and avoids use of a second intravascular coil.

Abdomen↗
PubMed1995

Peritoneal migration of an abdominally implanted epicardial pacemaker: a cause of intestinal obstruction.

We report the case of a 10-year-old child with an abdominally implanted epicardial pacemaker that eroded through the peritoneum and migrated to an intraperitoneal location, resulting in partial and then complete intestinal obstruction. This potentially life-threatening complication should be considered when a patient with an abdominally implanted pacemaker presents with abdominal pain.

Child↗
PubMed1993

Intraoperative mapping and radiofrequency ablation of the His bundle in a patient with complex congenital heart disease and intractable atrial arrhythmias following the Fontan operation.

Intraoperative mapping and radiofrequency ablation of the His bundle (with epicardial ventricular pacing) were performed in an 18-year-old woman with complex congenital heart disease and intractable chronic atrial arrhythmias following the Fontan operation. The presence of complex intracardiac anatomy as well as the exclusion of the atrioventricular conduction tissue from the systemic venous circulation strongly influenced the technical approach.

Adolescent↗
PubMed1992

Perceived exertion and exercise intensity in children with or without structural heart defects.

To assess the ability of children with cardiac disease to quantify their effort during exercise with the Borg perceived exertion scale, and to determine the validity of the scale for use with children by comparing the ratings with direct measurements of exercise intensity, we exercised 36 children with various cardiac defects and 15 normal children to exhaustion with the Bruce treadmill protocol. The subjects were able to quantify exercise intensity, so perceived exertion ratings can be used to predetermine the level of exercise intensity in an unmonitored setting and may be useful in defining appropriate exercise programs.

Adolescent↗
PubMed1991

Natural history of isolated atrial flutter in infancy.

To clarify the natural history of isolated (i.e., without associated congenital cardiac anomalies) atrial flutter in infancy, we reviewed the clinical course in nine patients who were seen with this arrhythmia in the first year of life (range 1 day to 4 months). Atrial flutter was identified by the typical sawtooth pattern in leads II, III, and aVF of the surface electrocardiogram or the pattern of atrial flutter on an atrial electrogram recorded through the esophagus. The mean cycle length of the atrial flutter was 151 msec (atrial rate 397 beats/min). Six of the nine patients had other perinatal problems, such as immune and nonimmune hydrops fetalis (two patients), pneumonia (one patient), anemia (five patients), or low birth weight (one patient). In all patients the rhythm reverted to normal, either spontaneously (two patients), with overdrive pacing (four patients), or after oral digoxin therapy (three patients). No consistent temporal relationship between digoxin administration and conversion was observed; conversion was instantaneous in the four patients who received atrial overdrive pacing. Four patients were discharged receiving digoxin therapy (6 months to 1 year). One patient had supraventricular tachycardia after discharge that was controlled with digoxin. No recurrence of atrial flutter was observed among the nine patients during a mean follow-up of 6.8 years (range 0.2 to 20 years). We conclude that isolated atrial flutter in infancy is rare, has a good prognosis, may be related to transient perinatal events, and often spontaneously converts to normal sinus rhythm; however, when it does not, it will respond to transesophageal pacing. Acute and chronic digoxin therapy is probably unnecessary.

Apgar Score↗
PubMed1991

Pediatric cardiovascular imaging.

Cardiovascular imaging in children has stressed acquisition of information with the least possible stress to the child. Improvements in noninvasive imaging have now largely supplanted the use of invasive techniques for diagnostic imaging. During the past year, major improvements in the diagnosis of complex cardiac malformations have occurred together with the extension of such techniques to the operating room. This review focuses on improvements in echocardiography, color flow imaging, and magnetic resonance in the imaging of complex cardiovascular defects, both intra- and extracardiac. Imaging of abnormalities of the atrioventricular region, intracardiac and coronary artery fistulae, homograft valved conduits, and pulmonary artery anatomy is discussed. The use of magnetic resonance imaging for the evaluation of pulmonary artery anatomy, ventricular septal defects, and aortic arch abnormalities is reviewed, as is the use of magnetic resonance imaging in small infants. Finally, the use of both epicardial and transesophageal echocardiography in the operating room for evaluation of the adequacy of surgical repair is reviewed. These studies demonstrate the ability of these techniques to provide information critical for the proper management of children undergoing cardiac surgery.

Child↗
PubMed1991

Use of radiofrequency current to ablate accessory connections in children.

BACKGROUND: Several investigators have recently ablated electrophysiologically mapped accessory connections in the adult human myocardium by using radiofrequency current. To examine the effectiveness and safety of radiofrequency current for ablation of accessory connections in children, 20 consecutive patients (age, 3-18 years) with preexcitation and/or supraventricular tachycardia were evaluated by electrophysiological study. METHODS AND RESULTS: Nineteen of the 20 patients were completely studied and demonstrated accessory connections. After identification of the earliest retrograde atrial activation site, a steerable 7F catheter (with a 4-mm-long electrode at the distal tip) was placed within the ventricular cavity ipsilateral to the accessory connection and positioned at the atrioventricular valve annulus directly opposite the earliest point of retrograde atrial activation. Radiofrequency current was delivered at 50-65 volts for 10-60 seconds at a frequency of 500 kHz. Radiofrequency pulses were delivered for two to 26 trials. Upon completion of radiofrequency trials, repeat electrophysiological testing was performed. Thirteen of 19 subjects (68%) experienced definite successful ablation of their accessory pathway; an additional patient had probable successful ablation, yielding an overall success rate of 74%. Eighty-seven percent of individuals with a left-sided pathway had permanent ablation and 100% with a manifest left-sided pathway experienced successful ablation. Only 29% of the first seven patients had a successful result; in contrast, 92% of the next 12 patients had successful interruption of their accessory pathways. After ablation, 4-day continuous electrocardiographic telemetry disclosed no significant arrhythmias. CPK enzyme rises peaked at 12-24 hours. The rise was excessive and associated with general anesthesia in five patients. The isoenzyme MB fraction rose mildly in five other patients and returned to normal within 72 hours. No clinical or electrocardiographic evidence of myocardial ischemia was detected. Follow-up for 4-12 months indicates no return of preexcitation or tachycardia in any patient whose accessory connection was successfully ablated. CONCLUSIONS: This experience indicates that radiofrequency current is an effective and safe technique for ablation of accessory connections in children.

Adolescent↗
PubMed1989

Usefulness of the Doppler mean gradient in evaluation of children with aortic valve stenosis and comparison to gradient at catheterization.

To assess the usefulness of the Doppler mean gradient as a noninvasive indicator of the need for intervention, 33 children (ages 3 months to 20 years) with valvular aortic stenosis (AS) underwent a 2-dimensional and Doppler echocardiographic examination a median of 1 day before cardiac catheterization. The clinical decision for intervention was based on finding a catheterization peak-to-peak pressure gradient of greater than 75 mm Hg or from 50 to 75 mm Hg in the presence of symptoms or an abnormal exercise treadmill test result. Of the 33 patients, 23 required intervention. The decision for intervention was compared to the Doppler mean gradient, and the Doppler peak and mean gradients were compared to the catheterization peak-to-peak gradient. All 12 patients with a Doppler mean gradient greater than 27 mm Hg had intervention and had a catheterization peak-to-peak gradient of greater than or equal to 75 mm Hg. All 3 patients with a Doppler mean gradient less than 17 mm Hg had no intervention and had a peak-to-peak gradient less than 50 mm Hg. The remaining 18 patients with Doppler mean gradients between 17 and 27 mm Hg comprised an intermediate group in whom the Doppler mean gradient alone did not predict the need for intervention. From a chi-square table, a Doppler mean gradient greater than 27 mm Hg predicted the need for intervention with 100% specificity (no false positives) and 52% sensitivity (11 false negatives).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Stenosis↗
PubMed1989

Doppler evaluation of homograft valved conduits in children.

To assess the flow characteristics of homograft valved conduits in the immediate postoperative period, 69 children with 71 homograft conduits underwent 2-dimensional and Doppler echocardiographic examination at 1 to 40 days (mean 8) after surgery. Of the 71 conduits studied, 19 were aortic and 52 were pulmonary homograft valved conduits. Two aortic homograft valved conduits were inserted in the aortic position, whereas all remaining homografts were placed in the pulmonary position. On the immediate postoperative echocardiogram, 25 (35%) of the conduit valves had no regurgitation and 44 (62%) had 1+ (mild) regurgitation. Two pulmonary valved conduits (3%) in the pulmonary position had 2+ (moderate) regurgitation and right ventricular dimensions greater than 95% for body surface area. The peak velocity across the homograft valve was normal (less than 1.3 m/s) in 58 valves (82%). In the remaining 13 valves, peak velocity ranged from 1.4 to 2.6 m/s. No homograft valve had a peak velocity greater than 2.6 m/s in the immediate postoperative period. To assess the fate of homograft valved conduits in the intermediate-term follow-up period, 38 children with 38 conduits had a repeat echocardiogram at 6 to 25 months (mean 15 +/- 6) after surgery. Of the 38 conduits examined, 10 (26%) had no regurgitation, 25 (66%) had 1+ regurgitation and 3 (8%) had 2+ regurgitation. Progression of the amount of regurgitation occurred in 11 (29%) patients. At the follow-up examination, peak velocity was less than or equal to 1.4 m/s across 34 conduit valves, between 1.4 and 2.6 m/s across 3 valves and greater than 2.6 m/s across 1 valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1989

Two-dimensional and Doppler echocardiographic evaluation after arterial switch repair in infancy for complete transposition of the great arteries.

The most recent postoperative echocardiographic examinations of all children who underwent arterial switch repair of transposition of the great arteries from August 1985 to December 1987 were reviewed. The patients included 35 children whose age at operation was 12 +/- 16 days and whose weight was 3.6 +/- 0.4 kg. Thirty-three patients are alive and well; 1 died intraoperatively and 1 died immediately postoperatively. The time of the follow-up echocardiographic examination ranged from 1 day to 2.5 years (mean 9.2 months) with 11 patients examined greater than 1 year after surgery. Complete examination of the repair site was possible in all patients. Echocardiographic visualization of distortion of the great arteries at the suture lines was seen in all patients; however, Doppler evidence of hemodynamically significant obstruction at the repair site was uncommon. On Doppler examination in the surviving 33 patients, 16 had no supravalvular pulmonary stenosis and 14 had mild to moderate supravalvular pulmonary stenosis with peak systolic pressure gradients ranging from 16 to 56 mm Hg (mean 31). Three patients had severe supravalvular pulmonary stenosis and peak systolic pressure gradients of 66, 74 and 77 mm Hg (2 have had reoperation, 1 is awaiting surgery). On Doppler examination, 4 patients had mild supravalvular aortic stenosis with peak systolic gradients ranging from 10 to 29 mm Hg. Doppler gradients were confirmed in 10 patients who had catheterization 12 +/- 3 months after surgery. Three patients had mild pulmonary regurgitation by Doppler examination, 5 had mild aortic regurgitation, 4 had mild tricuspid regurgitation and 2 had mild mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography↗
PubMed1989

Pulsed Doppler assessment of left ventricular diastolic filling in children with left ventricular outflow obstruction before and after balloon angioplasty.

To assess left ventricular (LV) diastolic filling in children with pressure overload hypertrophy, 12 patients with LV outflow obstruction (7 with aortic valve stenosis and 5 with aortic coarctation) and 12 healthy, age-matched control subjects were examined. Each child underwent M-mode echocardiography and pulsed Doppler examination of the LV inflow. The patients with LV outflow obstruction had cardiac catheterization and balloon angioplasty. Their echo/Doppler examinations were performed in the catheterization laboratory before and immediately after balloon angioplasty. From the M-mode echocardiogram, the LV cavity dimensions and wall thicknesses, LV mass and shortening fraction were measured. The following measurements were made from the Doppler recording: peak velocities at rapid ventricular filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, total area under the Doppler curve, percent of the total Doppler area occurring in the first one-third of diastole (0.33 area fraction), percent of the total area occurring under the E wave (E area fraction), percent of the total area occurring under the A wave (A area fraction) and the ratio of E area to A area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Failure of electrocardiographic monitoring to detect cardiac arrest in patients with pacemakers.

Two children with cardiac pacemakers are described who experienced cardiorespiratory arrest not detected by the electrocardiographic (ECG) monitor. The pacemaker stimuli were interpreted by the monitor as a QRS complex with inhibition of the heart rate alarm, demonstrating the need for reliable non-ECG monitoring in patients with pacemakers. A review of all deaths in children with pacemakers in the last ten years also shows the high association of respiratory failure in patients with congenital heart disease and a pacemaker, underscoring this need. Various non-ECG monitoring modalities are discussed. Finally, analysis of the ECG monitor characteristics contributing to inappropriate sensing of the pacemaker stimulus was performed, showing the direct relation between the pacemaker stimulus amplitude seen by the monitor and the monitor sensitivity with inappropriate sensing, and the inverse relation between the monitor bandwidth and inappropriate sensing. Recommendations for monitor adjustment when monitoring patients with pacemakers are provided.

Adolescent↗
PubMed1988

Epicardial ventricular pacemaker electrode longevity in children.

While epicardially implanted electrodes remain the most widely used in children for ventricular pacing, their expected longevity remains unknown. The longevity of 126 such electrodes implanted from January 1970 through December 1985 was evaluated in 81 children followed up for 1 to 192 months (median 63). Age at initial implant was 1 day to 18 years. Each child had from 1 to 5 electrodes implanted; 85 electrodes were of the sutureless helical type and 41 were of the suture-fixated type. Electrode failure, defined as loss of capture with a high pacing threshold found at operation or sensing failure, occurred in 38 electrodes from 1 to 157 months postimplant (median 37). Mode of failure was high threshold with high impedance (n = 15), low impedance (n = 6), complete inability to pace (n = 8), sensing failure (n = 2) or high threshold with no measure of impedance (n = 7). Actuarial life table analysis of electrode longevity showed a 88 +/- 3% (standard error of the estimate) survival rate at 6 months with no significant decrease until 53 months (75 +/- 5%, p less than 0.05). There was then a gradual steady decrease to 49 +/- 7% by 101 months. From 101 to 157 months no significant decrease occurred. Survival rate decrease was greatest within the first 6 month period postimplant (-12%). Electrodes surviving to 6 months are highly likely to survive until 53 months. Of those surviving to 53 months, 74% should survive to 120 months.

Adolescent↗
PubMed1988

Surgical management of children and young adults with the Wolff-Parkinson-White syndrome.

The Wolff-Parkinson-White syndrome, as originally described, includes palpitations, tachycardia, and an abnormal electrocardiogram (short PR interval and wide QRS complex). The clinical manifestations are dependent upon a reentrant tachycardia supported by an accessory connection bridging the atrioventricular junction and frequently appear during the first two decades of life. Palpitations are the usual symptoms; less frequently, severe symptoms, such as syncope and sudden death, may result from very rapid atrioventricular conduction across the accessory connection during atrial fibrillation. We report the surgical management of 30 young patients with this syndrome, including 6 with life-threatening tachycardia. Surgical interruption of the accessory connection(s) was curative in 90% (27/30) of the patients; life-threatening symptoms were eliminated in the other three. Based on the limited knowledge of the natural history of the Wolff-Parkinson-White syndrome, the individual patient symptoms, and the electrophysiologic properties of each patient's accessory pathway(s), an algorithm is presented outlining the treatment options. This experience strongly suggests that surgical treatment of the Wolff-Parkinson-White syndrome is safe, effective, and possibly the preferred treatment for this disorder in selected young symptomatic patients.

Adult↗
PubMed1988

Comparison of single and double balloon valvuloplasty in children with aortic stenosis.

To compare the effectiveness of the single and double balloon techniques, the short-term results of percutaneous balloon valvuloplasty were assessed in two consecutive groups of children with valvular aortic stenosis. In 16 children (aged 3 months to 17 years) the single balloon technique was utilized; the ratio of balloon diameter to valve anulus diameter was 0.96 +/- 0.03 (mean +/- SEM). In 11 children (aged 3 months to 21 years) the double balloon technique was utilized in which two balloons are positioned across the valve and inflated simultaneously; the ratio of the balloon diameter sum to valve anulus diameter was 1.32 +/- 0.05. The groups were similar in age, weight, cardiac output, prevalvuloplasty gradient and valve anulus diameter. Overall, valvuloplasty reduced the peak systolic gradient by 53% from 80 +/- 4 to 38 +/- 3 mm Hg (p less than 0.0001). In the single balloon group the gradient decreased from 82 +/- 6 to 46 +/- 4 mm Hg (p less than 0.0001), whereas in the double balloon group the gradient decreased from 76 +/- 5 to 26 +/- 4 mm Hg (p less than 0.0001). The peak systolic gradient after valvuloplasty was 43% lower in the double balloon group (p less than 0.01). Furthermore, the single balloon technique reduced the gradient by an average of 43% compared with a 67% reduction with the double balloon technique (p less than 0.001). The short-term complications of valvuloplasty were similar, with an increase in aortic insufficiency occurring in three children in each group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗