Operative results after unsuccessful radiofrequency ablation for Wolff-Parkinson-White syndrome.
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Adult↗
Biomedical subjects
W L Holman
Publications and source records attributed to W L Holman.
Electrical instability during reperfusion.
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Heart Arrest, Induced↗
Variation in cryolesion penetration due to probe size and tissue thermal conductivity.
The purpose of this study is to present data comparing the penetration of cryolesions created by various sizes and shapes of cryoprobes in human cadaveric myocardium, fat, and tissue of the central fibrous body. Ten cryolesions were made for each combination of tissue and cryoprobe studied. All cryolesions enlarged most rapidly during the first minute of cryothermia (p less than 0.01). Maximal cryothermic penetration into nontrabeculated myocardium was 8.5 +/- 0.5 mm (15-mm flat probe) and 6.1 +/- 1.0 mm (5-mm small probe). Maximal cryothermic penetration into trabeculated myocardium was 9.4 +/- 1.0 mm (10-mm cone-tipped probe) and 7.4 +/- 0.5 mm (10-mm flat probe). Maximal cryothermic penetration into fat was 4.7 +/- 0.7 mm (15-mm flat probe) and 3.9 +/- 0.7 mm (5-mm flat probe). The deeper penetration of cryothermia into myocardium as compared with fat (p less than 0.05) is related to the lower thermal conductivity of fat. Maximal cryothermic penetration of the central fibrous body was similar to that of the myocardium with transmural freezing of the central fibrous body after 4.4 +/- 0.3 minutes of cryothermia. These data can be used when determining the optimal cryothermic exposure for ablation of arrhythmogenic tissue.
Arrhythmias, Cardiac↗
Quantitation of mapping uncertainty in Wolff-Parkinson-White syndrome. Implications for anatomic characterization and surgical division of accessory atrioventricular connections.
The purpose of this study was to quantitate the uncertainty inherent in the electrophysiologic mapping of ventricular preexcitation as seen in Wolff-Parkinson-White syndrome. An ink-coated needle electrode was constructed to serve as a point source of unipolar stimulation along the atrioventricular junction. Activation times for 11 ventricular mapping sites at the atrioventricular junction were measured for each stimulation point. Maps were successfully completed for 18 right free wall and 14 posterior septal stimulation points. The activation time at the mapping site closest to the stimulation point was termed the index activation time. Activation times identical to the index activation time were noted at 1.3 +/- 0.5 mapping sites for each free wall stimulation point and 1.9 +/- 0.9 mapping sites for each septal stimulation point (p < 0.05, septal versus free wall stimulation points). Activation times falling within 5 msec of the index activation time were noted at 2.4 +/- 1.0 mapping sites for each free wall stimulation point and at 3.9 +/- 1.4 mapping sites for each septal stimulation point (p < 0.05, septal versus free wall stimulation points). The uncertainty of electrophysiologic mapping can be quantitated, and this error should be considered when making inferences regarding the anatomy of accessory pathways based on electrophysiologic data. A knowledge of the uncertainty inherent in the localization of accessory atrioventricular connections by electrophysiologic mapping can be used to plan borders of surgical dissection that will account for this uncertainty at a 95% confidence level.
Animals↗
Rejection after cardiac transplantation. A time-related risk factor analysis.
BACKGROUND: The determinants of early and repeated episodes of acute rejection after cardiac transplantation remain elusive. METHODS AND RESULTS: To gain insight into this phenomenon, a multivariate analysis for repeated events was applied to 229 patients receiving 249 transplanted hearts between 1981 and July 1, 1991 (595 rejection episodes). The mean frequency of rejection per patient after initial cardiac transplantation was 1.2 at 3 months, 1.8 at 1 year, and 2.8 at 5 years. The pattern of rejection was characterized by an early period of higher risk (greatest during the first month) followed by a low constant risk that continued throughout the period of follow-up (maximum, 9.5 years). By multivariate analysis, risk factors were identified for the likelihood of subsequent rejection after a previous rejection episode (or time of transplantation). Triple-drug immunosuppression plus induction therapy yielded a higher risk of early subsequent rejection compared with other baseline immunotherapy protocols, but it also provided the greatest freedom (95%) from rejection-related death during the first year. Risk factors in the constant phase of hazard included younger age at transplant, female donor and/or recipient, longer donor ischemic time, greater HLA donor-recipient mismatch, and an increased number of previous rejection episodes. CONCLUSIONS: Immunologic and other patient-specific characteristics as well as rejection history predict the likelihood of future rejection events. The value of any antirejection protocol must be evaluated both in terms of rejection episodes and rejection-related deaths. Future analyses may identify specific high- and low-risk patient subsets for rejection, which may provide a more rational basis for altering the amount of chronic immunosuppressive therapy.
Adult↗
Oxyhemoglobin dissociation during hypothermic blood cardioplegia arrest.
BACKGROUND: Coronary sinus effluent contains desaturated blood during the first few seconds of hypothermic cardioplegia infusion in humans. This occurs despite the high affinity of hemoglobin for oxygen at a low temperature and alkaline pH. The present study quantitates oxyhemoglobin dissociation during hypothermic cardioplegic arrest. METHODS AND RESULTS: Three infusions of a 4 degrees C alkalotic blood cardioplegia solution were given into the cross-clamped aortic root during 1 hour of cardioplegic arrest. Paired aortic root and coronary sinus blood samples were obtained before and shortly after initiating cardiopulmonary bypass and at t = 5 seconds and 30 seconds during each cardioplegia infusion. Throughout the study, the hemoglobin saturation in the aortic root samples was 100%. The mean coronary sinus hemoglobin saturation at t = 5 seconds during hypothermic cardioplegia infusion ranged from 63.0% to 66.5% (p < 0.05 coronary sinus compared with aortic root samples). The coronary sinus hemoglobin saturation approximated the aortic root hemoglobin saturation at t = 30 seconds during hypothermic cardioplegia infusion. The mean PO2 of the aortic root samples ranged from 214 to 307 mm Hg during hypothermic cardioplegia infusion. The mean PO2 of the t = 5 seconds coronary sinus samples ranged from 31 to 39 mm Hg, whereas the mean PO2 of the t = 30 seconds coronary sinus samples ranged from 85 to 119 mm Hg during cardioplegia infusion (p < 0.05 coronary sinus compared with aortic root samples). CONCLUSIONS: Oxygen dissociates from hemoglobin contained in a hypothermic, alkalotic blood cardioplegia solution during the nonperfused phase of cardioplegic arrest. However, the only oxygen delivered to the myocardium during the infusion of a hypothermic alkalotic blood cardioplegia solution is oxygen physically dissolved in the solution.
Animals↗
Wolff-Parkinson-White syndrome. A quantitative morphometric analysis of surgical anatomy.
Previous descriptions of the four anatomic regions of dissection in Wolff-Parkinson-White syndrome have been largely qualitative. In this study quantitative data describing this anatomy are presented, together with statistical analysis of selected anatomic relationships. Fourteen human hearts were dissected. The borders of the posteroseptal dissection along the mitral anulus, tricuspid anulus, and epicardium were measured. A positive correlation between the mitral and tricuspid annular dimensions was found (r = 0.55; p = 0.04); however, the length of epicardial dissection was more variable. The dimensions of the anteroseptal space and the position of the right coronary artery within this space were measured. These measurements emphasize the proximity of the aortic sinuses of Valsalva to the right atrial endocardium near the posteromedial extent of the dissection. The dimensions of the right and left free walls and the position of the coronary arteries within these spaces were measured. A positive correlation was found between the width of the atrioventricular groove and the length of the dissection necessary to separate the atrioventricular groove fat from the ventricular surface (r = 0.89; p = 0.0001, right free wall; r = 0.87; p = 0.0001, left free wall). The quantitative data presented in this article are intended to enhance the surgeon's appreciation of the anatomy relevant to the treatment of Wolff-Parkinson-White syndrome. The knowledge gained from this quantitative analysis may improve accuracy in the electrophysiologic localization and surgical disruption of accessory atrioventricular connections.
Autopsy↗
Removal of massive right atrial thrombus guided by transesophageal echocardiography.
Formation of massive right atrial thrombi around a peritoneovenous shunt is a known complication of these devices. Removal of an obstructive right atrial thrombus requires cardiopulmonary bypass and has been associated with a high morbidity and mortality. Transesophageal echocardiography was used in this case to diagnose and guide the surgical removal of a massive right atrial thrombus.
Adult↗
Intermediate septal accessory pathways: electrocardiographic characteristics, electrophysiologic observations and their surgical implications.
Intermediate septal accessory pathways are located in close proximity to the atrioventricular (AV) node and His bundle, have unique features that distinguish them from typical anterior and posterior accessory pathways and have been associated with a high risk for unsuccessful pathway division and the production of complete AV block after surgery. Between July 1986 and May 1990, 4 of 70 patients (3 men and 1 woman; mean age 33 +/- 13 years) undergoing surgery for accessory pathway division were found to have an intermediate septal accessory pathway. The presenting arrhythmia was atrial fibrillation with rapid anterograde conduction over the accessory pathway in two patients and recurrent orthodromic reciprocating tachycardia in two patients. In all patients, the delta wave on the electrocardiogram (ECG) was inverted in lead V1, but two patterns of delta wave configuration were observed. In three patients (type 1 intermediate septal accessory pathway), the delta wave was upright in lead II, inverted in lead III and isoelectric in lead a VF; the transition from a negative to an upright delta wave occurred in lead V2. The fourth patient exhibited a different delta wave pattern (type 2 intermediate septal accessory pathway). The delta wave was upright in each of leads II, III and aVF; the transition from a negative to an upright delta wave occurred at lead V3. Intraoperative electrophysiologic study localized the atrial insertion of type 1 pathways to the midpoint of Koch's triangle close to the AV node.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Usefulness of transesophageal echocardiography in assessment of aortic dissection.
BACKGROUND: The value of transesophageal echocardiography in the assessment of patients with aortic dissection was studied. METHODS AND RESULTS: Group 1 (34 patients) represented all patients studied at our institution with this technique in whom aortic dissection was proven by aortography, surgery, or autopsy. Group 2 (27 patients) represented all patients studied with this technique at our institution in whom aortic dissection was excluded by aortography. Transesophageal echocardiography made a correct diagnosis of aortic dissection in 33 of 34 patients (sensitivity, 97%; specificity, 100%). It also correctly demonstrated the type of dissection in all 29 patients with aortographic or surgical proof. On the other hand, computed tomography scanning, performed in 24 of 34 patients in group 1, made a correct diagnosis in only 67% of patients and misclassified the type of dissection in 33%. Transesophageal echocardiography correctly identified involvement of the coronary arteries by aortic dissection in six of seven patients as well as absence of both left and right coronary artery involvement in 10 patients with aortic dissection. This technique was also useful in detecting communications between the true and false lumens, presence of thrombi in the false lumen, and, in two patients, localized dissection rupture with formation of a false aneurysm. In both groups 1 and 2, transesophageal echocardiography correctly identified patients with moderate to severe aortic regurgitation. CONCLUSIONS: Transesophageal echocardiography is very useful in the assessment of aortic dissection.
Aortic Dissection↗
Case report: circulatory support for seventy days with resolution of acute heart failure.
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Acute Disease↗
Agglutination of blood cardioplegia by cold-reacting autoantibodies.
Cold-reacting autoantibodies occasionally occur in patients requiring cardiac operations. This report describes the clinical course of 1 patient with cold-reacting autoantibodies and intracoronary agglutination of the blood cardioplegia solution. Observations made in vivo and in vitro are considered in discussing recommendations for the management of extracorporeal circulation and cardioplegic arrest in patients with clinically silent cold-reacting autoantibodies.
Aged↗
Combined use of transesophageal echocardiography and endocardial mapping to localize the site of origin of ectopic atrial tachycardia.
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Adult↗
Coronary artery bypass grafting with unanticipated fibrosing mediastinitis.
Coronary artery bypass grafting in the setting of superior vena caval obstruction due to unanticipated fibrosing mediastinitis is described. Intraoperative decisions regarding the management of this unusual patient are discussed.
Constriction, Pathologic↗
The Blalock-Taussig shunt: an analysis of trends and techniques in the fourth decade.
The original description of the Blalock-Taussig shunt was published in 1945 and represented the first direct surgical procedure for the treatment of cyanotic congenital heart disease. The present study analyzes the results of Blalock-Taussig shunts performed at Duke University Medical Center during the fourth decade since the original description of the procedure. From 1975 to 1984, 53 classic and 24 modified Blalock-Taussig shunts were performed with a hospital mortality of 8%. These deaths occurred in critically ill patients with either pulmonary atresia or complex congenital cardiac lesions. The results of the early group (1975-1979) were compared to the late group (1980-1984) of patients. There was a greater proportion of infants less than 1 week of age in the late group, and the actuarial event-free shunt survival following operation was significantly better in the late group. This improvement in the late group was apparent both in patients receiving classic and modified Blalock-Taussig shunts and probably represents the effects of advances in microsurgical technique as well as improvement in the support of critically ill infants at the time of surgery by pediatric anesthesiologists and neonatologists. The data in the present study indicate that the mortality associated with Blalock-Taussig shunting is related to the condition of the patient at the time of surgery and the underlying cardiac pathology rather than the age of the patient at the time of shunting. The efforts to further reduce morbidity and mortality associated with Blalock-Taussig shunting should therefore be directed primarily to the support of infants during the preoperative and intraoperative phases of care.
Actuarial Analysis↗
Cryosurgical ablation of atrioventricular nodal reentry: histologic localization of the proximal common pathway.
A method using cryosurgery has been previously described to selectively ablate atrioventricular nodal reentry tachycardia while preserving intact atrioventricular conduction. The purpose of the present study was to define the histologic features of the cryolesions in relationship to the specialized conduction system. In 12 adult dogs a series of nine discrete cryolesions was placed along the perimeter of the triangle of Koch while continuously monitoring the His bundle electrogram. All animals survived the operation and maintained intact atrioventricular conduction. At 14 weeks after surgery the hearts were sectioned and examined. In all 12 animals there was a confluent mass of dense fibrous tissue present in the lower atrial septum that was in immediate proximity to but did not involve the atrioventricular node-His bundle. The ablation of perinodal tissue with preservation of the specialized conduction system with the use of this cryosurgical technique was confirmed. It is likely that the cryoablated perinodal tissue represents the proximal common pathway of the circuit for atrioventricular nodal reentry tachycardia.
Animals↗
Cryosurgical treatment of atrioventricular node reentrant tachycardia.
Paroxysmal supraventricular tachycardia most commonly arises from reentry within the atrioventricular (AV) node. Although ablation of the His bundle has gained popularity for treating patients with AV node reentrant tachycardia refractory to medical therapy, undesirable sequelae include complete heart block and the necessity for a permanent pacemaker. To obviate this limitation, we have developed a discrete cryosurgical procedure that interrupts the reentrant circuit responsible for AV node reentrant tachycardia without blocking AV conduction. After first characterizing the salutary effects of this approach in experimental animals, we performed this procedure in eight patients with AV node reentrant tachycardia. Preoperative, intraoperative, and postoperative electrophysiologic studies were performed in each patient. Under conditions of normothermic cardiopulmonary bypass and during atrial pacing at a constant rate with continuous monitoring of AV conduction, nine separate 3 mm cryolesions (-60 degrees C for 2 min) were placed at predetermined sites around the triangle of Koch in the lower right atrial septum. Postoperatively, each patient had a single AV node conduction curve. No patient had AV node reentrant tachycardia induced or has experienced AV node reentrant tachycardia clinically during a follow-up of up to 5 years. The cryosurgical procedure had no detrimental effects on the AH or HV interval or on the paced cycle length at which AV node Wenckebach occurred. Based on these results, this curative operation offers promise for patients with AV node reentrant tachycardia that is refractory to medical treatment.
Adolescent↗
Cryosurgical modification of retrograde atrioventricular conduction. Implications for the surgical treatment of atrioventricular nodal reentry tachycardia.
Paroxysmal supraventricular tachycardia resulting from atrioventricular nodal reentry is a common arrhythmia that usually responds to medical therapy. When atrioventricular nodal reentry tachycardia is refractory to medical therapy, cryoablation or endocardial catheter ablation of the His bundle has been employed to protect the ventricles from the tachycardia. However, these techniques necessitate implantation of a permanent ventricular pacemaker. A cryosurgical procedure that ablates the anatomic-electrophysiologic substrate for atrioventricular nodal reentry tachycardia while preserving antegrade atrioventricular conduction has been described. The purpose of the present study was to determine the effects of this procedure on retrograde atrioventricular conduction and on the ventricular echo phenomenon in particular. Thirty adult mongrel dogs underwent either the cryosurgical procedure (n = 20) or a sham operation (n = 10). The animals were studied either immediately postoperatively (acute cryosurgery group and control group, n = 10 for each group) or 14 weeks postoperatively (chronic cryosurgery group, n = 10). Decremental ventricular pacing and programmed premature ventricular pacing protocols were used to determine the retrograde atrioventricular nodal conduction time, Wenckebach point, atrioventricular nodal refractory periods, and ventricular echo reflection time. No electrophysiologic alterations were noted in the sham-operated group. In the acute cryosurgery group, the retrograde Wenckebach point, atrioventricular nodal conduction time, functional refractory period of the atrioventricular node, effective refractory period of the atrioventricular node, and ventricular echo reflection time were all significantly prolonged. In the chronic cryosurgery group, no significant change in ventriculoatrial conduction was noted, but the ventricular echo phenomenon was eliminated in all but one animal. These data further document that this cryosurgical procedure is capable of ablating the anatomic-electrophysiologic substrate necessary for atrioventricular nodal reentry tachycardia while preserving atrioventricular conduction.
Animals↗