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Biomedical subjects

G Critelli

Publications and source records attributed to G Critelli.

At least 55 records · Page 3Linked to original sources
PubMed1988

The automatic implantable cardioverter/defibrillator: transesophageal atrial pacing discloses the potential for erroneous discharges.

We report the occurrence of erroneous discharge from an implanted automatic cardioverter/defibrillator during transesophageal atrial pacing. Transesophageal pacing was performed as part of a study protocol on the inducibility of ventricular tachycardia from the atrium in patients with ischemic heart disease. At an induced heart rate of 166 beats per minute (a value just above the cut-off rate of the device), the cardioverter/defibrillator was triggered. This observation suggests that transesophageal atrial pacing could be utilized to disclose the potential for spurious discharges in the event of fast atrial rhythms in patients with the automatic implantable cardioverter/defibrillator.

Cardiac Pacing, Artificial↗
PubMed1986

Transvenous catheter ablation of the His bundle in ventricular tachycardia.

The usefulness of transvenous catheter ablation of the His bundle in three patients with recurrent ventricular tachycardia (VT), in which the initiating mechanism was recognized during a rapid atrial rhythm, is reported. Tachycardia was refractory to conventional treatment and required transthoracic direct-current shocks in all patients. In patient No. 1 double tachycardia (atrial flutter and VT) was documented and VT was easily induced by rapid atrial pacing. In patients Nos. 2 and 3 initiation of VT during junctional reciprocating and atrial tachycardia, respectively, was observed. Interruption of the His bundle was performed by means of fulguration. Stable atrioventricular (AV) block was observed in patient No. 1 after the ablative procedure; patient No. 2 showed anterograde conduction over a posterior septal accessory pathway with no evidence of conduction over the normal conduction system in both the anterograde and retrograde directions. In patient No. 3, transient AV block was observed; AV conduction resumed 2 days later and the cardiac rhythm showed persistent ectopic atrial tachycardia with second-degree AV block. Patients Nos. 1 and 2 underwent pacemaker implantation, but patient No. 2 was not pacemaker dependent. After the procedure, VT no longer occurred in any of the patients (follow-up: 2 years, 5 months, and 6 months).

Aged↗
PubMed1985

Electrophysiologic and histopathologic correlations in a case of permanent form of reciprocating tachycardia.

A case of permanent junctional reciprocating tachycardia with post-mortem documentation of an accessory atrioventricular pathway as the substrate of the arrhythmia is reported. Tachycardia had lasted for 15 years and showed a retrograde P wave (P') and R-P' longer than P'-R interval. The tachycardia circuit utilized a concealed posterior septal accessory pathway as the retrograde limb. Because the arrhythmia was disabling and unresponsive to pharmacological treatment, the patient underwent closed chest ablation of the His bundle. After the procedure, no anterograde or retrograde conduction over the normal conduction system was observed; anterograde conduction over the anomalous pathway showed decremental properties. Because of previous myocardial infarction, the patient developed a ventricular aneurysm and died suddenly 5 months after His bundle ablation. Histological examination of the heart revealed a group of tiny fibromuscular bundles joining the lower rim of the coronary sinus outlet to the summit of the interventricular septums; the anomalous atrioventricular connection pursued a sinuous, tortuous path. The geometrical disposition of the accessory pathway may have been responsible for the decremental properties of conduction observed during life.

Atrioventricular Node↗
PubMed1985

Catheter ablation of accessory pathway in the permanent form of junctional reciprocating tachycardia.

Successful transvenous catheter ablation of accessory pathway (AP) in a patient (pt) with the permanent form of junctional reciprocating tachycardia is reported. A concealed AP with long conduction time comprised the retrograde limb of tachycardia circuit. The atrial end of the AP was near the coronary sinus (CS) orifice. Catheter ablative technique was performed after assessment of its feasibility and safety by using a canine model. During an electrophysiologic study CS mapping was obtained; the earliest retrograde activity was recorded 1-2 cm inside the orifice of the CS. Two unipolar shocks of 120 J were delivered on the sites exhibiting the earliest retrograde atrial activity. After the procedure, the AP was no longer conducting in both anterograde and retrograde direction. During a follow-up period of 13 months, the pt remained free of tachycardia on no antiarrhythmic medication.

Adult↗
PubMed1984

Histologic observations after closed chest ablation of the atrioventricular conduction system.

Postmortem examination of the heart was done in a case with disabling supraventricular tachyarrhythmia successfully treated by closed-chest ablation of the His bundle. A ventricular aneurysm developed as a result of a previous myocardial infarction, and death occurred suddenly five months after the procedure. Histologic studies of the atrioventricular (AV) junctional tissue demonstrated severe damage to the nearby AV node and penetrating His bundle. No damage to the branching His bundle or either bundle branch was observed.

Atrioventricular Node↗
PubMed1984

Evaluation of noninvasive tests for identifying patients with preexcitation syndrome at risk of rapid ventricular response.

Intermittent preexcitation, block in the accessory pathway after intravenous injection of ajmaline or procainamide, and block in the accessory pathway during exercise usually exclude a short antegrade refractory period of an accessory pathway in patients with the Wolff-Parkinson-White syndrome. This report describes three patients with these findings suggestive of a relatively long antegrade effective refractory period of the accessory pathway in whom life-threatening ventricular response occurred during atrial fibrillation. In the first patient with a pattern of intermittent preexcitation, rapid ventricular response with wide QRS was present during atrial fibrillation. In the second patient in whom preexcitation disappeared after intravenous injection of ajmaline or procainamide as well as during exercise testing, atrial pacing showed 1:1 conduction over the accessory pathway at a cycle length of 220 msec and the shortest R-R interval during induced atrial fibrillation was 190 msec. The third patient, with no evidence of preexcitation during sinus rhythm, presented antidromic reciprocating tachycardia and atrial fibrillation with life-threatening ventricular response, the minimal R-R interval being 220 msec. Noninvasive tests in the preexcitation syndrome lack sufficient prognostic sensitivity. The evaluation of ventricular response during induced atrial fibrillation represents the most reliable means of identifying such patients at risk.

Adult↗
PubMed1984

Anatomic and electrophysiologic substrate of the permanent form of junctional reciprocating tachycardia.

Data are reported on three patients with the permanent form of junctional reciprocating tachycardia, in whom conduction over a slow accessory pathway was observed after His bundle ablation. Tachycardia was almost incessant and showed a retrograde P wave (P') and RP' interval longer than P'R interval in all patients; during sinus rhythm, the PR interval was normal and there was no evidence of a delta wave. An accessory pathway with a long conduction time located in the posterior pyramidal space provided the retrograde limb of the reentry circuit. After His bundle ablation, the accessory pathway was capable of conducting in both anterograde and retrograde directions with decremental properties in all patients. Postmortem documentation of the accessory pathway was achieved in one patient. Serial sections revealed an accessory atrioventricular connection composed of ordinary myocardium joining the lower rim of the coronary sinus outlet to the uppermost ventricular muscle. This anomalous atrioventricular connection pursued a sinuous, tortuous path. As a result of changing cross-sectional area, such an accessory pathway might exhibit slow conduction, thus explaining its decremental characteristics.

Adolescent↗
PubMed1984

[Closed-chest interruption of abnormal bundles of His. Its use in a case of "incessant" tachycardia guided by an experimental model].

The usefulness and safety of intracardiac discharge of a synchronized DC shock through a catheter-electrode to ablate the His bundle has led the Authors to evaluate the use of this technique to interrupt bypass tracts located near the coronary sinus. Acute experiments were performed in 10 open chest dogs. A tripolar 6F catheter-electrode was placed in the coronary sinus and 2 or 3 unipolar shocks of 80-120 joules were delivered to each electrode. After the procedure the coronary sulcus was inspected and a lesion 2-3 cm wide and 2-4 mm deep with edema and haemorrhage was found in all cases. On the basis of the data obtained in dogs, the technique was successfully used in a woman with "incessant" supraventricular tachycardia due to reentry through a concealed anomalous pathway located in the posterior septum. A careful mapping of the coronary sinus allowed the localization of the earliest retrograde atrial activation. Two shocks of 120 joules were delivered in the coronary sinus at the site suggested by the electrophysiologic mapping. The patient has remained free from tachycardia since the time of the discharge (follow-up: three weeks).

Adult↗
PubMed1983

Transesophageal pacing for prognostic evaluation of preexcitation syndrome and assessment of protective therapy.

An esophageal lead was used to perform decremental atrial pacing and elective induction of atrial fibrillation (AF) in 5 patients with the Wolff-Parkinson-White (W-P-W) syndrome before and after amiodarone therapy. In the control state, 1:1 atrioventricular (AV) conduction over the accessory pathway ranged from 220 to 260 ms (mean 232). The shortest R-R interval during AF ranged from 190 to 210 ms (mean 198). The ventricular rate ranged from 175 to 212 beats/min (mean 196). After amiodarone therapy, the shortest cycle length with 1:1 AV conduction increased in all patients, ranging from 290 to 540 ms (mean 370); during AF, no preexcited beat was present in 2 patients, whereas the minimal preexcited R-R interval in the remaining 3 was 290, 240, and 370 ms, respectively. The ventricular response during AF decreased in all patients. Thus, esophageal pacing is a useful method for identifying patients at risk with the W-P-W syndrome and for assessing appropriate management in individual patients. Amiodarone provides protection against life-threatening arrhythmias in these patients.

Adolescent↗