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Biomedical subjects

A Zinner

Publications and source records attributed to A Zinner.

7 recordsLinked to original sources
PubMed1991

The effect of exercise on the atrial electrogram voltage in young patients.

Atrial electrogram sensing is an important function in active individuals with permanently implanted bipolar dual chamber pacing systems. We undertook to determine the effect of vigorous exercise on the atrial electrogram size in 11 children and young adults (average age 12 years). Using a telemetry signal through a handheld programming wand, nine tracings were completely and clearly recorded for analysis. Six patients had tined/passive fixation atrial leads and three patients had screw-in/active fixation lead systems. All leads were bipolar. The atrial electrogram size for each patient was measured at rest and at each minute of exercise. The atrial electrogram size decreased with exercise from a mean of 5.08 mV to 3.44 mV (range 0.9-4.25 mV) (P = 0.002). The 1.64 mV mean decrease represented a 33.8% reduction (range 19%-56%) (P less than 0.001). There was no difference in the change in atrial electrogram size between the two lead types. Treadmill exercise testing with telemetric data of atrial electrograms showed a decrease in atrial electrogram size produced by exercise and may be helpful in determining appropriate atrial sensitivity settings in selected individuals. Because of the documented decrease in atrial electrogram size produced by exercise, we recommend obtaining maximal atrial electrograms at the time of implant and use of pacing systems that allow maximal flexibility in atrial sensing especially in athletically active individuals.

Adolescent↗
PubMed1988

Decrease in canine endocardial and epicardial electrogram voltages with exercise: implications for pacemaker sensing.

Individuals with permanently implanted pacemakers who have normal sensing and pacing at rest may demonstrate abnormalities, particularly of atrial sensing, with exercise. Exercise is known to cause changes in the surface electrocardiographic voltages. The purpose of this study was to evaluate changes in endocardial and epicardial voltages during exercise in canines with permanently implanted pacing leads similar to those permanently implanted in humans with pacemakers. Six adult mongrel dogs were equipped with transvenous atrial and ventricular endocardial bipolar screw-in leads from a jugular venosection, and with atrial and ventricular bipolar stab-on leads from a left thoracotomy. Exercise was performed at one week following implantation and at weekly intervals for a total of 4 weeks. The animals were studied at rest and at a single workload of 3 miles per hour at a 30% elevation. Unfiltered electrograms were recorded with a VR-12 Electronics-for-Medicine photographic recorder. The mean decreases of electrograms with exercise from resting voltage were: 15% for atrial endocardial unipolar leads; 11% for atrial endocardial bipolar leads; 4% for atrial epicardial unipolar leads; 15% for atrial epicardial bipolar leads; 8% for ventricular endocardial unipolar leads; 18% for ventricular endocardial bipolar leads; 0.1% for ventricular epicardial unipolar leads and 5% for ventricular epicardial bipolar leads.

Animals↗
PubMed1987

Atrial tracking (synchronous) pacing in a pediatric and young adult population.

One hundred pediatric and young adult patients underwent implantation of an atrial tracking pacemaker. Seventy-four pacemakers paced in an atrioventricular (AV) sequential mode at the lower rate limit (DDD) while 26 paced in a ventricular demand mode at the lower rate limit (VDD). Five patients required reoperation during follow-up of 1 month to 2.5 years (mean 1.5 years). Six additional patients required programming to ventricular demand (3) or AV sequential (3) pacing, because of development of sinus bradycardia (2), atrial sensing problems (1) or pacemaker-mediated tachycardia (3). Pulse generators that could sense atrial signals less than 1.0 mV and had a programmable atrial refractory period did not require reprogramming out of the atrial tracking mode. No patient developed atrial flutter or fibrillation. Sensing problems during exercise occurred in 37% of the first 60 pacemakers but in none of the last 40, which had improved electronic components. Atrial tracking pacing is feasible in pediatric and young adult patients.

Adolescent↗
PubMed1985

Treatment of atrial automatic tachycardia by ablation procedures.

Sixteen cases of atrial focus tachycardia are described clinically, electrophysiologically and hemodynamically. In each case multiple attempts at drug treatment (average 2.5 drugs) had failed. After delineation of the electrophysiologic mechanism, the patients were treated by surgical removal or cryoablation or catheter electroablation of the focus. In two of four patients catheter ablation was successful and without complication. Surgical treatment was successful in 13 of 14 patients. Left ventricular function, which had been abnormal in 10 patients, normalized in all but 1 patient whose echocardiographic shortening fraction improved from 10 to 27%. There have been no recurrences in a follow-up period of 6 months to 5 years (mean 2.2 years). It is recommended that any atrial automatic focus tachycardia that produces hemodynamic compromise undergo definitive treatment. Patients with chronic tachycardia rates of more than 140 beats/min should be followed up closely.

Adolescent↗
PubMed1985

Transvenous catheter ablation of a right atrial automatic ectopic tachycardia.

A 10 year old patient with right atrial automatic ectopic tachycardia underwent successful transvenous catheter ablation after endocardial mapping. Tachycardia had been present for 7 years before ablation and associated with development of dilated cardiomyopathy. A single 50 J discharge at the point of earliest atrial activation was followed by the establishment of sinus rhythm that remains at 10 months' follow-up. This case represents the first reported successful catheter ablation of an atrial automatic ectopic tachycardia. Specific anatomic factors favoring successful ablation and improvement in technique are discussed.

Cardiac Catheterization↗