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F Coltorti

Publications and source records attributed to F Coltorti.

33 records · Page 2Linked to original sources
PubMed1986

Double tachycardia following surgery for recurrent ventricular arrhythmias.

Simultaneous accelerated "junctional" rhythm and atrial flutter were observed postoperatively in a patient who had undergone electrophysiologic surgery for recurrent ventricular fibrillation. Digitalis toxicity was excluded, based on the low serum level of the drug and on the recurrence of the tachycardia after withdrawal of digitalis. While atrial flutter probably represented a postoperative recurrence of a clinically occurring arrhythmia, the accelerated "junctional" rhythm at unusually fast rates most likely developed as a consequence of a cryolesion applied to the ventricular septum as part of the surgical treatment. Phenytoin proved effective in suppressing this "junctional" tachycardia.

Aged↗
PubMed1985

Effect of damped sine-wave shocks on catheter dielectric strength.

This study evaluated the ability of 24 new standard tripolar and quadripolar U.S. Catheter Instruments catheters to withstand a single damped sinusoidal shock delivered by a standard defibrillator. The schema for energy delivery was meant to simulate possible clinical practices. Delivered peak voltage and current were measured during each shock. Each electrode was examined for pitting and changes in line resistance as a consequence of the shock. Electrode pitting occurred on all selected anodal poles. However, it also was found on "unsolicited" electrodes from 7 catheters, indicating that current had followed unanticipated routes. Electrode line resistance was unmeasurable in 6 of these 7 inappropriately pitted electrodes. Delivered peak voltage and postshock catheter dielectric strength depended on the manner of energy delivery. To simulate a posterior septal accessory pathway ablation procedure, a shock was delivered to 2 proximal (anodal) poles in 16 quadripolar catheters (8 received 200 J and 8 received 360 J). Delivered peak voltage was 3,125 +/- 362 V for the 200-J shock and 4,100 +/- 160 V for the 360-J shock. Postshock catheter dielectric strength for the 200- and 360-J shock was 1,425 +/- 826 V and 601 +/- 707 V, respectively. This was significantly lower than peak delivered voltage (p less than 0.001 for either energy). To simulate His bundle or ventricular tachycardia focus ablation, 8 tripolar catheters each received a single 200-J shock to the tip electrode. This resulted in a delivered peak voltage of 2,900 +/- 351 V, compared with a postshock dielectric strength of 1,325 +/- 1,320 V (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
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-mediated electrical ablation of the posterior septum via the coronary sinus: electrophysiologic and histologic observations in dogs.

In a series of 12 dogs, the electrophysiologic and histologic effects of a single damped sine-wave shock delivered via standard electrocatheters to the region of the coronary sinus orifice were investigated. Six dogs received 200 J and six received 360 J of stored energy. The shock was delivered to two consecutive proximal poles of a standard quadripolar catheter positioned at the coronary sinus orifice and connected to the positive output (anode) of a defibrillator. A disc electrode positioned on the anterior chest wall served as the cathode (negative pole). During the shock, voltage and current were recorded. Electrophysiologic testing was done before and 4 weeks after the shock. At 4 weeks, animals were killed and serial sections of the atrioventricular groove and conduction system were performed. No significant long-term change in atrioventricular conduction, spontaneous or induced atrial or ventricular arrhythmias was observed. However, transient atrioventricular block was seen in five and idioventricular rhythms in six animals in the short term. No persistent electrocardiographic changes were observed, and no sudden deaths occurred. Microscopically, transmural injury at the anulus proper or basilar ventricular epicardium was inconstant and infrequent. However, transmural atrial injury at the level of the coronary sinus was produced over a 10 +/- 5 mm length with the 200 J shock and a 21 +/- 6 mm length with the 360 J shock. Neither coronary artery injury nor damage to the conduction system was seen and cardiac tamponade did not occur. However, localized intramural atrial rupture of the coronary sinus wall (on the endocardial aspect only) was observed in each dog, consistent with barotrauma. With the present technique, atrial injury potentially capable of blocking the effects of accessory pathway conduction could be produced without other electrophysiologic alterations or complications. Injury to the anulus proper (and therefore to any accessory pathway per se) is probably unlikely. Barotrauma may play a significant role in the type of injury observed in this study.

Animals↗
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↗
PubMed1983

Antegrade slow bypass conduction after closed-chest ablation of the His bundle in permanent junctional reciprocating tachycardia.

A case of permanent junctional reciprocating tachycardia in a 36-year-old woman successfully treated with closed-chest interruption of the His bundle is reported. Tachycardia had lasted for 14 years and showed a retrograde P wave (P') and RP' longer than PR' interval. The tachycardia used an anomalous pathway with a long conduction time in the retrograde direction. The atrial end of the anomalous pathway was located near the coronary sinus orifice. His ablation was accomplished by delivering a direct-current shock from a cardioversion unit to the nodal-His zone by means of a conventional electrode catheter percutaneously introduced via the femoral vein. Two shocks were necessary to obtain the desired results. After the procedure, complete atrioventricular block below the His bundle was induced, while antegrade conduction was assured through the anomalous pathway that showed decremental properties. During 7 months of follow-up, stable sinus rhythm with a long PR interval has been observed; the patient has remained free from tachycardia. Furthermore, she is not pacemaker-dependent and requires no cardioactive medication. This case demonstrates the therapeutic value of closed-chest ablation of the His bundle in a patient with permanent junctional reciprocating tachycardia, as well as demonstrating for the first time that the underlying accessory pathway is capable, in some instances, of antegrade conduction.

Adult↗
PubMed1982

[Closed chest interruption of A-V conduction in the treatment of refractory supraventricular tachyarrhythmias. A clinical contribution].

The AA. describe a technique for interrupting the A-V conduction using a direct-current shock delivered from a cardioversion unit to the A-V junctional tissue by means of a conventional electrode-catheter. The method was used in 2 patients with refractory supraventricular tachycardias. After the procedure both patients received a programmable A-V sequential pacemaker. The first patient, with cardiomyopathy and intermittent W-P-W syndrome, had a 2-year history of iterative reciprocating tachycardia and occasional episodes of atrial flutter-fibrillation. The second patient, with coronary heart disease, had recurrent episodes of atrial flutter for at least 2 years. In patient 1 the shock caused a suprahisian first-degree block. Atrial pacing at 580 ms cycle length provoked a 2:1 block and ventricular pacing showed no retrograde conduction. The patient, who is not pacemaker-dependent, is now free from reciprocating tachycardia and, during atrial flutter-fibrillation episodes, the ventricular rate varies from 62 to 75 bpm. In patient 2 the shock caused a persistent complete A-V block and neither antegrade nor retrograde conduction was observed during atrial and ventricular pacing. During a long episode of atrial flutter, there was a complete A-V block with a ventricular rate between 40 and 48 bpm. The follow-up is 9 months in both patients. We conclude that the technique used, which does not require open heart surgery, can be effectively used in patients with disabling supraventricular tachyarrhythmias resistant to drug treatment.

Amiodarone↗