PubMed Health⌕ Search

Biomedical subjects

J Kasell

Publications and source records attributed to J Kasell.

28 records · Page 2Linked to original sources
PubMed1977

Cryosurgical ablation of the A-V node-His bundle: a new method for producing A-V block.

A cryosurgical instrument was used to ablate atrioventricular conduction. The procedure was carried out in 20 dogs and subsequently in three patients with drug resistant, life-threatening supraventricular tachycardias. In patients, the cryosurgical unit lowered the temperature of the His bundle area to 0 degrees C, effecting complete but reversible heart block. Rewarming resulted in resumption of normal atrioventricular conduction. The His bundle region then was cooled to -60 degrees C; complete heart block was produced with two or more 90-120 second freezes. Postoperative evaluations revealed persistent atrioventricular conduction block. The lesion showed no tendency to rupture, form aneurysm, or interfere with valvular function. In the clinical cases, postoperative studies demonstrated a stable pacemaker arising proximal to the branching portion of the His bundle. A potential application of the cryosurgical technique might be ablation of sites of dysrhythmia (i.e., ectopic foci, re-entry circuits, accessory pathways).

Adult↗
PubMed1977

Cryosurgical ablation of accessory atrioventricular connections: a method for correction of the pre-excitation syndrome.

Cryothermia, a new technique for definitive treatment of the pre-excitation syndrome, is described in two patients. The first patient presented with a normal P-R interval with a delta wave and reciprocating tachycardia. Preoperative electrophysiologic study suggested a free-wall atrioventricular connection on the left posterior atrioventricular (A-V) groove. At surgery, epicardial mapping confirmed the site of pre-excitation on the posterior left ventricular (LV) wall. An electrogram arising from the accessory pathway (AP) was recorded at the site of earliest ventricular activation. Interatrial delay combined with an apparently long accessory pathway to the ventricle caused the P-R interval to appear normal. Local pressure abolished pre-excitation. The site of early ventricular activation was cooled to -60 degrees C with a specially designed cryoprobe. All evidence of pre-excitation and arrhythmias disappeared. The second patient presented with a refractory reciprocating tachycardia and was found to have an AP in the septum capable of only retrograde conduction. Retrograde conduction was abolished by applying a temperature of 0 degrees C to the anulus at this site during tachycardia. Conduction over the AP and reciprocating tachycardia returned with rewarming. Ablation of the AP was obtained by applying a temperature of -60 degrees C for 90 seconds on two occasions to the same area. The His bundle was not injured.

Adult↗
PubMed1976

Multiple accessory pathways in patients with the pre-excitation syndrome.

We have studied 135 patients with the pre-excitation syndrome and have demonstrated evidence of multiple accessory pathways in 20 patients. Five patients had two distinct accessory atrioventricular (A-V) connections, associated with enhanced A-V node conduction in one patient. Twelve patients had a single accessory A-V connection associated with enhanced A-V conduction. In one of these there was an additional fasciculo-ventricular connection. One patient had an accessory A-V connection associated with a nodoventricular bundle. Two patients had fasciculo-ventricular connections combined with enhanced A-V conduction. The latter two patients had electrocardiograms suggestive of a complete accessory A-V connection. Patients with enhanced A-V conduction had shorter cycle lengths during reciprocating tachycardia, primarily because of a short A-H during the dysrhythmia, than those without such conduction. In addition, patients with enhanced A-V conduction demonstrated more rapid conduction from atrium to His bundle during induced atrial fibrillation and two developed life-threatening ventricular responses during atrial fibrillation. A nodo-ventricular pathway was documented to participate in reciprocating tachycardia in one patient. Surgery was undertaken in 13 patients. In 11, the intraoperative mapping studies confirmed the preoperative predictions. In two patients, the presence of a second accessory A-V connection was documented after ablation of one.

Adolescent↗
PubMed1975

Wolff-Parkinson-White syndrome. The problem, evaluation, and surgical correction.

Physiological studies of the type we have described, when performed in patients with the WPW syndrome, can yield diagnostic information regarding the mechanism of arrhythmia, demonstrate functional properties of therapeutic import, facilitate therapeutic decision-making about drug regimens and presumptively localize the site of pre-excitation as a basis for possible surgical intervention. Based on our experience, we feel that in selected patients, surgical correction of the WPW syndrome is entirely feasible, and can be accomplished in the majority of patients in whom free wall A-V connections are present. The continuing challenge of identification and correction of septal accessory pathways directs our present work with the WPW syndrome.

Adolescent↗
PubMed1975

Initial forces of ventricular depolarization in the Wolff-Parkinson-White Syndrome. Analysis based upon localization of the accessory pathway by epicardial mapping.

The epicardial activation sequence of 34 patients with the Wolff-Parkinson-White syndrome was determined. Epicardial pre-excitation occurred at a spectrum of sites over either the free wall of the left or right ventricle or in a paraseptal region, always adjacent to the atrioventricular rings. The site of pre-excitation was related to the spatial position of the 10 msec vector of the vectorcardiogram (VCG) in 15 patients and the 20 msec vector of the electrocardiogram (ECG) in 29 patients with a single accessory pathway. All patients whose 20 msec vector (ECG) was directed to the right had accessory pathways which caused epicardial breakthrough over the free wall of the left ventricle. When the 20 msec vector (ECG) was to the left and inferior, epicardial pre-excitation was over either the right ventricular free wall or in the region of the pulmonary outflow tract. Superior location of the initial forces, especially the 10 msec vector (VCG), strongly suggested the presence of a septal bypass tract. The polarity of the delta wave and maximum QRS forces in precordial lead V1 were discordant in a significant number of patients, pointing to probable shortcomings of a classification based upon the latter.

Adolescent↗
PubMedDate not supplied

The preexcitation syndromes.

Current methodology permits one to define the functional basis of the preexcitation syndromes with reasonable certainty and to develop a rationale for instituting trials of medical therapy. Future studies will hopefully result in a more exact definition of the anatomic substrates of preexcitation and their relationship to the pathophysiology of the associated syndromes. New antiarrhythmic agents must also be developed to add to the relatively small number of available drugs. Important questions still remain. Should asymptomatic patients with preexcitation be studied? If found to demonstrate potential for malignant arrhythmias, should they be treated prophylactically? The answers to these questions will require study and long-term follow-up of nonhospital referral patients. Surgery offers a feasible therapeutic alternative for patients with life-threatening or disabling arrhythmias but demands a team equipped to perform precise preoperative and intraoperative mapping studies to define the type and location of underlying anatomic substrates.

Arrhythmias, Cardiac↗