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D Wilber

Publications and source records attributed to D Wilber.

27 records · Page 2Linked to original sources
PubMed1992

Ventricular tachycardia rate and morphology determine energy and current requirements for transthoracic cardioversion.

BACKGROUND: The electrical current and energy required to terminate ventricular tachyarrhythmias are known to vary by arrhythmia: Ventricular tachycardia (VT) is generally considered to require less energy than ventricular fibrillation (VF). The hypothesis of our study was that current requirements for transthoracic termination of VT are further determined by VT rate and QRS complex morphology. METHODS AND RESULTS: We prospectively studied 203 patients who received a total of 569 shocks for VT or VF by following a current-based protocol. This protocol recommended shocks for VT beginning at 18 A (70 +/- 22 J) and shocks for VF beginning at 25 or 30 A (137 +/- 52 J or 221 +/- 70 J). The ventricular tachyarrhythmias were subclassified as monomorphic VT (MVT): uniform QRS complex morphology on surface electrocardiogram and heart rate greater than 100 beats per minute; polymorphic VT (PVT): nonuniform QRS complex morphology and heart rate less than or equal to 300 beats per minute; or VF: nonuniform QRS complex morphology and heart rate greater than 300 beats per minute. We found that shocks of 18 A and 25 A for terminating MVT had success rates of 69% and 82%, respectively, whereas such low-current shocks were less successful for PVT (33% at 18 A) and for VF (19% at 18 A, 53% at 25 A). High-current shocks of 35 A and 40 A were equally successful for the three ventricular tachyarrhythmias. Subdividing MVT revealed that slower MVT (heart rate less than 200 beats per minute) had a significantly better success rate with low-current shocks of 18 A and 25 A than did faster MVT (greater than 200 beats per minute) (89% versus 72% success, p less than 0.01). Bundle branch block morphology, QRS axis, and duration of ventricular tachyarrhythmia did not alter current requirements. CONCLUSIONS: Heart rate and electrocardiographic degree of organization of ventricular tachycardia are important determinants of transthoracic energy and current requirements for cardioversion and defibrillation. Transthoracic termination of MVT requires relatively low current or energy, but PVT behaves more like VF and requires higher electrical current or energy.

Electric Countershock↗
PubMed1991

The effects of global normothermic hypoperfusion on the processed electroencephalogram in patients.

This study examined the effects of global normothermic hypoperfusion on the compressed spectral array (CSA) processed electroencephalogram (EEG) during high-dose narcotic anesthesia. Fifteen patients undergoing cardiac electrophysiologic surgery were studied. The patients were anesthetized with a standard high-dose narcotic technique and then connected to a Nicolet Pathfinder I CSA EEG analysis system using seven subdermal electrodes in a modified International 10-20 configuration. There were 167 intervals of profound hypotension ranging from 8 to 96 seconds. During these periods the cerebral perfusion pressure was almost zero. Despite 38 intervals up to 32 seconds long, 6 of the 15 patients had no EEG changes. Overall, there were 36 (21.6%) ischemic EEG recordings. None of the patients developed neurological complications. The incidence of EEG changes was much lower than expected from other studies. Either the processed EEG was inherently insensitive, the high-dose narcotic masked the processed EEG effects of hypoperfusion, or the narcotic provided a previously unknown protective effect.

Anesthesia, General↗
PubMed1990

Surgical ablation for idiopathic ventricular tachycardia.

A 33-year-old man with a right-bundle branch, left-axis deviation ventricular tachycardia was medically treated unsuccessfully. Surgical mapping and ablation was performed with a successful surgical result. A discussion of surgical results for this problem is provided.

Adult↗
PubMed1990

Surgical ablation of ventricular tachycardia in the normothermic heart.

Nineteen patients with ventricular tachycardia were subjected to surgery using a normothermic map-guided approach. Surgical ablation was performed by endocardial resection and cryoablation. Eleven patients had multiple distinct morphologies, and eight patients needed concomitant coronary artery bypass surgery. Seventeen patients survived the perioperative period, and all but one patient had a successful surgical ablation of all documented morphologies. Ventricular tachycardia surgery can be accomplished with the sequential map-guided approach on the normothermic beating heart, and in this era of the implantable defibrillator should remain a mainstay of the surgical treatment for ventricular tachycardia.

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PubMed1989

Median sternotomy for implantable cardioverter/defibrillator.

The automatic implantable cardioverter/defibrillator is an accepted mode of therapy for medically refractory sustained ventricular tachycardia or fibrillation. At the Loyola University Medical Center, Maywood, Ill, 39 implantations were performed in a 14-month period. The method of implantation was the median sternotomy. Our population included 9 patients in whom sternotomies had to be redone and 17 patients with concomitant revascularization. Two patients died due to pump failure, and one major complication (infection) occurred that was directly related to the automatic implantable cardioverter/defibrillator. The median sternotomy, because of good results, continues to be our method of choice for insertion of the automatic implantable cardioverter/defibrillator.

Electric Countershock↗
PubMed1986

Antiarrhythmic vs. antifibrillatory activity of the basic diphenylhydantoin derivative 3-[3-(4-phenyl-1-piperidyl)propyl]-5-(4-methoxyphenyl)-5-phenylhydantoin hydrochloride.

The effects of 3-[3-(4-phenyl-1-piperidyl)propyl]-5-(4-methoxyphenyl)-5-phenylhydantoin hydrochloride (TR 2985), a basic diphenylhydantoin derivative, were studied in four canine models of experimental cardiac dysrhythmias. In conscious dogs, 48 h after myocardial infarction, TR 2985 significantly reduced the frequency of spontaneous ventricular arrhythmias. However, in anesthetized dogs, TR 2985 produced only a slight and insignificant increase in the ventricular fibrillation threshold. In conscious dogs, 4 to 7 days after myocardial infarction, TR 2985 failed to prevent the electrical induction of reentrant ventricular tachycardia, and failed to protect against the development of ventricular fibrillation in response to ischemia at a site distant from the previous infarction. These results indicate that TR 2985 may be effective in preventing arrhythmias of a non-reentrant nature, but may be relatively ineffective in preventing reentrant ventricular tachycardia or ventricular fibrillation.

Anesthesia, General↗
PubMed1984

Effects of reperfusion on complete heart block complicating anterior myocardial infarction.

Two patients with complete heart block complicating extensive anterior myocardial infarction underwent late (greater than 40 hours) coronary reperfusion with angioplasty. One to one atrioventricular conduction was restored within minutes of reperfusion despite a lack of measurable ventricular muscle salvage as demonstrated by ventriculography 1 week later. The evidence favors reversible ischemia rather than extensive necrosis of the proximal conduction system as the mechanism of heart block in this subgroup of patients.

Adult↗
PubMedDate not supplied

Prognostic significance of sustained ventricular tachyarrhythmia occurring during dobutamine infusion.

The prognostic significance of a de novo sustained ventricular tachyarrhythmia occurring during a dobutamine infusion is unknown. This study was performed to determine (1) the risk of recurrent ventricular arrhythmia, (2) the safety of future dobutamine infusions, and (3) the role of electrophysiologic testing. The study population consisted of 15 patients, six with coronary artery disease, and nine with idiopathic dilated cardiomyopathy. Mean ejection fraction was 17% +/- 4.1%. The arrhythmia during the infusion was ventricular tachycardia in 13 patients and ventricular fibrillation in two patients and was not associated with preceding hemodynamic instability, electrolyte abnormality, digoxin toxicity, or antiarrhythmic drug therapy. During electrophysiologic testing, 7 of 15 patients had inducible ventricular tachycardia. All patients with inducible ventricular tachycardia were treated with either antiarrhythmic drugs, defibrillators, or ablation. Over a 12.3 +/- 5.2 month follow-up period, all 15 patients received further dobutamine treatment. Seven of 15 (47%) had a recurrent sustained ventricular tachyarrhythmia. Although three of seven recurrences occurred during a dobutamine infusion, all three of these patients had hemodynamically unstable conditions and were receiving high-dose (> 10 micrograms/kg/min) therapy at the time of recurrence. The other four recurrent arrhythmias were not associated with clear precipitating factors. Ejection fraction, origin of left ventricular dysfunction, and inducibility at baseline electrophysiologic testing did not predict arrhythmia recurrence. The de novo occurrence of a sustained ventricular tachyarrhythmia during dobutamine infusion is associated with a significant risk of arrhythmia recurrence (47%), which can occur in the presence or absence of dobutamine therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗