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Biomedical subjects

J A Abbott

Publications and source records attributed to J A Abbott.

At least 37 records · Page 2Linked to original sources
PubMed1986

Catheter atrioventricular junctional ablation in patients with accessory pathways.

Seven patients with accessory pathway and symptomatic atrioventricular reciprocating tachycardia underwent catheter ablation of the atrioventricular junction (AVJ). Four patients had the Wolff-Parkinson-White syndrome, two had concealed left free-wall accessory pathways, and one patient had a nodoventricular connection. All patients failed multiple antiarrhythmic drugs and one failed attempted surgical ablation of a posteroseptal accessory pathway. Chronic interruption of atrioventricular node-His conduction was achieved in all patients. Over a mean follow-up period of 21 +/- 14 months, four patients remained asymptomatic without antiarrhythmic therapy. One patient developed atrial fibrillation after magnet application to her VVI pacemaker, another developed atrial flutter, and a third had nonparoxysmal sinus or atrial tachycardia. Two patients required chronic quinidine therapy. Two patients with concealed accessory pathways had pacemaker-mediated tachycardia which was controlled by pacemaker reprogramming. Atrioventricular junctional ablation in patients with accessory pathways proved effective in that all are currently controlled without need for surgical intervention. On follow-up, a relatively high incidence of atrial arrhythmias requiring antiarrhythmic therapy was found.

Adult↗
PubMed1986

Clinical and electrophysiologic characterization of automatic junctional tachycardia in adults.

Junctional ectopic tachycardia has been described in infants but not in adults. Five adults with rapid symptomatic paroxysmal junctional tachycardia, distinct from the more common slower nonparoxysmal junctional tachycardia, were recently evaluated. The tachycardia was irregular (rate 120 to 250) and accompanied by periods of atrioventricular dissociation and narrow QRS complexes. A junctional origin was documented during electrophysiologic study in four of the five patients. Analysis of Holter recordings; the response to exercise, isoproterenol, and propranolol; and the effects of atrial and ventricular stimulation appeared to implicate abnormal automaticity of a high junctional focus that was catecholamine sensitive or dependent as the tachycardia mechanism. All patients responded somewhat to beta-blockers, although a combination of procainamide and propranolol proved to be the most effective therapy in one patient and another chose electrode catheter ablation of the atrioventricular junction rather than continued drug therapy. Thus, junctional ectopic tachycardia may occur in adults and its mechanism appears to be related to abnormal automaticity that is catecholamine sensitive or dependent. Initial therapy should include beta-blockers but selected patients may require more aggressive management.

Adult↗
PubMed1985

Efficacy and safety of transcatheter ablation of posteroseptal accessory pathways.

Eight patients with a posteroseptal accessory pathway and symptomatic atrial fibrillation and/or orthodromic reciprocating tachycardia underwent attempted transcatheter ablation of the accessory pathway. A quadripolar electrode catheter was positioned within the coronary sinus such that the proximal pair of electrodes straddled the os. This proximal pair of electrodes was made electrically common and connected to the cathodal output of a defibrillator. A patch electrode placed over the midthoracic spine was connected to the anodal sink of the defibrillator. Two to three transcatheter shocks were delivered, with a cumulative energy of 600 to 900 J. Immediately after the shocks were delivered, retrograde accessory pathway conduction was absent in each patient. Anterograde conduction through the posteroseptal accessory pathway was absent in six patients. In one patient, retrograde accessory pathway conduction was absent and anterograde conduction was present but was slower than at baseline. In this patient, orthodromic tachycardia was no longer inducible and the ventricular rate during induced atrial fibrillation was 150 beats/min, compared with 220 beats/min before the attempted ablation. He has remained asymptomatic without antiarrhythmic drug therapy for 18 months. In one patient, the transcatheter shocks had no long-term effect on accessory pathway conduction. The shocks delivered at the os of the coronary sinus were well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Hospital use in a fee-for-service system.

The population of Olmsted County, Minnesota, receives care virtually exclusively from two fee-for-service group practices: the Mayo Clinic and the Olmsted Medical and Surgical Group. Study of the use of acute-care hospital services by this population in 1976 reveals that the hospital discharge rate per 1,000 population, adjusted for age and sex, was 30% less than the national rate; the age-sex-adjusted rate of hospital days per 1,000 population was 38% less than the national rate. Analysis by length of stay, type of hospital service, frequency of selected diagnoses and surgical procedures, and certain demographic and economic characteristics did not explain the differences from national use rates. These rates are comparable, after age and sex adjustment, with those in larger prepaid group practices. The analysis suggests that the organization of medical care may have an important influence on hospital use.

Catchment Area, Health↗
PubMed1982

Value of the H-Q interval in patients with bundle branch block and the role of prophylactic permanent pacing.

His bundle electrograms were obtained in 313 patients with chronic bundle branch block who were followed for a mean period of almost 3 years. The infranodal conduction time (H-Q interval) was less than 55 ms in 97 patients (Group I), 55 to 69 ms in 99 patients (Group II), and greater than or equal to 70 ms in 117 patients (Group III). There was a higher incidence of organic heart disease in patients in Group III, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but patients in Group III had a greater incidence of progression to high degree atrioventricular block (HDB) than did those in Groups I and II (14 of 117 [12%] versus 4 of 97 [4%] and 2 of 99 [2%], p less than 0.01, respectively). High degree block was found in 4 of 17 (24%) patients with an H-Q interval (H-Q) greater than or equal to 100 ms. Sixty-two patients underwent permanent prophylactic pacemaker insertion at the discretion of the referring physician and were compared with 231 patients who did not. Paced patients had a higher incidence of transient neurologic symptoms and prolonged H-Q, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but symptom relief was significantly more common among patients with pacemakers. In conclusion, in our population (1) H-Q greater than or equal to 70 ms was an independent risk factor for progression to HDB, (2) H-Q greater than or equal to 100 ms identified a subgroup at particularly high risk, and (3) prophylactic pacemakers relieved neurologic symptoms but did not prolong life.

Aged↗
PubMed1982

Electrophysiologic effects of disopyramide in patients with atrioventricular nodal dysfunction.

Seventeen patients with first-degree or Mobitz I atrioventricular (AV) block and narrow QRS complexes underwent electrophysiologic drug testing before and after i.v. administration of disopyramide. Disopyramide did not significantly change the mean sinus cycle length (895 +/- 131 vs 877 +/- 119 msec), mean maximal sinus node recovery time (1134 +/- 160 vs 1133 +/- 13 msec), mean atrial effective refractory period (314 +/- 72 vs 307 +/- 54 msec), mean AV nodal conduction time (187 +/- 79 vs 180 +/- 73 msec) or the mean paced cycle length at which AV nodal Wenckebach conduction occurred (545 +/- 144 vs 497 +/- 130 msec) after disopyramide. The mean AV nodal effective refractory period decreased significantly (from 535 +/- 137 to 521 +/- 122 msec), and both infranodal conduction time and the paced ventricular cycle length producing ventriculoatrial block increased significantly (from 56 +/- 12 to 63 +/- 13 msec and from 625 +/- 158 to 655 +/- 157 msec, respectively). We conclude that i.v. disopyramide administered in a dose resulting in therapeutic blood levels showed no adverse effects on AV nodal conduction in patients with AV nodal dysfunction. In contrast, i.v. disopyramide depressed retrograde AV conduction.

Aged↗
PubMed1982

Intravenous antiarrhythmic drugs: newer aspects of therapy.

The use of the intravenous form of antiarrhythmic drugs from the perspective of prophylaxis, urgency of therapy, and rapid assessment of effectiveness is reviewed. Examples of clinical relevance for each of these 3 variables are used to illustrate the relevance of these approaches. 1) In the human model of acute myocardial infarction, prophylaxis with lidocaine is proved and is safe, with toxicity minimized when accurate determinations of blood levels of drug are readily available. 2) When reversion is unsuccessful and ventricular response cannot be controlled with conventional therapy, rapid supraventricular tachyarrhythmias will often normalize in response to intravenous verapamil therapy, a calcium-blocking agent soon available for clinical use. 3) A long-term outpatient antiarrhythmic drug program guided by target blood levels can be defined rapidly by intravenous administration of drug; this approach enhances safety and simplifies the definition of an ongoing antiarrhythmic program. Disopyramide responsiveness can be defined using this technique.

Anti-Arrhythmia Agents↗
PubMed1980

Effects of antiarrhythmic drugs on atrioventricular conduction in patients with acute myocardial infarction.

Three hundred fifty-eight of 429 (83%) consecutive patients with acute myocardial infarction (MI) and a normal PR interval received various antiarrhythmic drugs (AD), including lidocaine and/or procainamide, quinidine, digoxin, propranolol or disopyramide. There was no significant difference in the incidence of progression to any degree of atrioventricular (AV) block or to higher degrees of AV block (Mobitz II or third-degree AV block) between those treated and not treated with AD: 38 of 358 (11%) and six of 358 (1.7%) with AD vs 11 of 71 (15%) and two of 71 (2.8%) in the untreated group, respectively. Similarly, there was no significant difference in progression between treated and untreated patients with anterior MI, 14 of 144 (10%) vs five of 32 (16%); inferior MI, 21 of 111 (19%) vs five of 26 (19%), or subendocardial MI, three of 103 (3%) vs one of 12 (8%). Bundle branch block (BBB) (without AV block) was initially present in 89 of 249 (21%). The incidence of AV block (seven of 24, 30%) was higher in treated patients with newly acquired BBB (27 patients) than in the untreated patients (none of three, p less than 0.05). The commonly used ADs did not adversely affect AV conduction in patients with acute MI with narrow QRS and either normal, first-degree, or Mobitz I AV block. Moreover, no subset of patients grouped by infarct location, specific AD used, or BBB (except perhaps for those with newly acquired BBB) appeared to be at risk of development of AV block during AD therapy.

Aged↗
PubMed1978

Cardiovascular trauma from angiographic jets--validation of a theoretic concept in dogs.

The relationship of angiographic injections to cardiovascular trauma was determined. The aorta of dogs was studied by a mathematic model that (a) defines the kinetic energy of contrast-media jets emanating from the exit holes of catheters and (b) enables precise correlation of energy levels to potential trauma. A universal curve independent of the Reynolds number of the jet readily determines how far the jet penetrates intravascular blood. A traumatic histopathologic spectrum was found for those injections predicted by the model to be traumatic. The curve enables the angiographer to calculate the safe operating range of any catheter.

Angiography↗
PubMed1978

Cardiac trauma from angiographic injections. A quantitative study.

To relate angiographic injections to potential cardiac trauma, we verified a mathematic theory that allows quantitative definition of the kinetic energy content of contrast jets emanating from the exit holes of angiographic catheters. Cineangiographic recordings of a range of jets of known energy content were obtained in 18 cardiac canine experiments and energy content and dissipation were quantified precisely from center line to jet edge. All contrast jets produced in clinical angiographic practice were turbulent, even those from hand injections into the coronary arteries. Energy content was related to an estimated cardiac wall damage threshold. At energy levels and damage thresholds predicted by the theory and computations, a traumatic spectrum was found by cineradiology and microscopic examination. A unique curve independent of jet Reynolds number was discovered relating the penetration of the contrast jet into the intravascular blood to the potential for cardiac trauma. This curve allowed ready calculation of hydraulic energy dissipation for any clinically used angiographic catheter and the definition of safe operational injection flow rates. Thus potential cardiac trauma can be anticipated and prevented.

Angiography↗
PubMed1978

Late sequelae of penetrating cardiac wounds.

Physiological and psychological parameters of 20 survivors of penetrating wounds of the heart were examined 7 to 52 months after recovery. All survivors had cardiac complaints. The psychological parameters for hypochondriasis, compulsiveness, and internalization were much greater in the patients than in control subjects but were similar to those in victims of violent major abdominal trauma. Physiological abnormalities were present in 19, although no particular pattern or abnormality could be related with certainty to the type of wound, operative procedure, or postoperative course. One recovered and re-employed victim required late surgical repair of a traumatic ventricular septal defect and ventricular diverticulum. Although functional work capacity measured by stress testing was normal in 90 percent, only eight survivors resumed employment. Complete rehabilitation was impaired by a residual traumatic neurosis. Management goals for patients with penetrating cardiac wounds should be broadened to include prevention of psychological disabilities.

Adult↗