Jay G. Selle

Surgical treatment of arrhythmias

Surgical treatment of arrhythmias is often more expeditious and more cost-effective in the long run than pharmacologic therapy. In the past, surgical treatment of arrhythmias has been reserved for patients with disabling paroxysmal or incessant tachycardia refractory to medical management, severe life-threatening arrhythmia or aborted episodes of sudden death. However, tachyarrhythmias that are refractory to pharmacologic therapy because of drug inefficacy, noncompliance or limiting side effects are not uncommon. Although nonpharmacologic treatment of arrhythmias carries with it a one-time period of higher risk (i.e., when the patient undergoes surgery), it is curative and often preferable to the uncertainty and possibly higher cumulative risk associated with medical management.

Successful Clinical Laser Ablation of Ventricular Tachycardia: A Promising New Therapeutic Method

This preliminary report describes 5 consecutive patients operated on for drug-resistant ventricular tachycardia (VT). All were successfully treated with laser photocoagulation ablation alone. The continuous-wave neodymium:yttrium-aluminum garnet (Nd:YAG) laser (wavelength, 1.06 micron) was chosen because of its capability for controlled deep tissue penetration, which can be adjusted by manipulating the power and exposure time of the beam. All patients had severe coronary artery disease. Preoperative left ventricular ejection fractions were low (0.18 to 0.29). Risk factors associated with increased failure rates by conventional surgical approaches were frequent: absence of discrete left ventricular aneurysm (5 patients) and multiple VT morphologies with disparate sites of origin (4 patients). All patients recovered fully. VT was not inducible prior to discharge, and no patient was placed on a regimen of antiarrhythmic drugs. Current direct surgical approaches to drug-resistant VT have markedly improved operative results compared with indirect procedures. However, failures and mortality remain high. Laser photocoagulation obviates some of the problems associated with conventional methods. It is similar to cryotherapy in that the structural integrity of affected tissues is maintained. In contrast to cryosurgery, however, laser photocoagulation is achieved more rapidly and with more precise myocardial destruction. One of the most promising features of laser coagulation is that it is administered to the perfused normothermic heart. Consequently, each morphological form of induced VT is observed to disappear as its area of origin is systematically located by mapping and then ablated.

Laser photoablation of ventricular tachycardia: Correlation of diastolic activation times and photoablation effects on cycle length and termination-observations supporting a macroreentrant mechanism

Neodymium:yttrium-aluminum-garnet (YAG) photocoagulation during ventricular tachycardia allows the electrophysiologic effects of the temporal and spatial sequence of energy delivery to be correlated with local activation times. A retrospective analysis was performed of the termination of 19 episodes of ventricular tachycardia for which the local diastolic activation time was known for all successful ablation sites and for 95% of all ablation sites. The mode of termination was compared with that of 26 episodes of spontaneously terminating ventricular tachycardias. Spontaneous terminations occurred without a change in cycle length (54%) or with a 7 +/- 15% change in cycle length over one to three terminal beats (46%). In contrast, laser ablation-induced terminations resulted in a 39 +/- 55% increase in cycle length over nine or more cycles. The effect of attempted laser ablation was compared with the local presystolic activation time and the local activation time expressed as a percent of the diastolic interval (end of QRS complex = 0%, onset of next QRS complex = 100%). With one exception, no tachycardia terminated at ablation sites activating less than -50 ms before the QRS complex. All 8 successful first ablation attempts and 13 of all 19 successful ablations occurred in the 35% to 50% interval of diastolic activation. All successful ablations at sites activating at greater than 50% of the diastolic interval required multiple ablation attempts. Successful ablation was performed from the epicardium in 6 and from the endocardium in 13 episodes of ventricular tachycardia. These results are most consistent with a macroreentrant mechanism with a region of high vulnerability represented by the 35% to 50% interval of diastolic activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracoabdominal aortic aneurysms. A review and current status.

Surgical management of the thoracoabdominal aortic aneurysm is a formidable undertaking. Presently two fairly distinct operative methods are available. The conventional technique, pioneered by Etheredge, involves replacement of the aneurysm with a synthetic graft and then, step by step, revascularization of the abdominal organs with prosthetic side limbs taken from the primary graft. Individual organ ischemic time is limited to that time required for the performance of each distal side limb anastomosis. The second operative method, first described by Crawford, consists of proximal and distal control of the aneurysm, followed by its incision to simultaneously expose the origin of all four major intra-abdominal arteries. Replacement is then rapidly performed with a tubular Dacron® graft including anastomosis of these major intra-abdominal arteries to four elliptical graft incisions, from within the aneurysm. Total operating time is reduced at the expense of prolonged organ ischemia. The conventional method allows for step-by-step intraoperative planning and action, and this technique is accordingly recommended to most surgeons, who have had little experience with this unusual lesion. Our recent successful experience with two cases of extensive thoracoabdominal aortic aneurysms is described as well as a discussion of additional measures which may become useful in certain cases to favor a successful outcome. Finally the problem of potential resultant paraplegia is discussed.

Technical Considerations in the Surgical Approach to Multiple Accessory Pathways in the Wolff-Parkinson-White Syndrome

Surgical techniques for the approach to and division of atrioventricular accessory pathways have been designed and perfected during the past 18 years. The standard method of exposure of a single left free wall accessory pathway is by a left atriotomy. All other single accessory pathways are exposed through a right atriotomy. Up to twenty percent of patients with Wolff-Parkinson-White (WPW) syndrome harbor multiple atrioventricular accessory pathways. In this subgroup, classic operative techniques, especially the methods of approach, must be combined or modified depending on the specific locations of the accessory pathways encountered. Eighteen of 90 patients operated on for WPW syndrome at Charlotte Memorial Hospital from August, 1983, through September, 1986, had multiple accessory pathways. Thirty-eight of thirty-nine pathways were successfully divided. One posterior septal accessory pathway reappeared 2 months postoperatively and was catheter ablated. The most frequent combination of atrioventricular accessory pathways included a right free wall and a posterior septal accessory pathway (10 patients). This combination is approached by a right atriotomy. The posterior septal space dissection is extended onto the right free wall area. Technically the most difficult combination includes a left free wall and a posterior septal accessory pathway (3 patients in the present series). Our preferred approach is begun with a right atriotomy for the posterior septal space dissection, followed by an atrial septotomy to expose the left free wall area. There are other methods, however, that may be advantageous depending on the exact locations of the accessory pathways encountered.

High grade entrance and exit block in an area of healed myocardial infarction associated with ventricular tachycardia with successful laser photoablation of the anatomic substrate

Abstract Delayed potentials recorded during sinus rhythm are believed to be a marker for ventricular tachycardia (VT) in humans. 1,2 This study demonstrates a variety of local activation phenomena not reported before and discusses their relevance to the site of VT origin.

Laser Modification of the Myocardium for the Treatment of Cardiac Arrhythmias: Background, Current Results, and Future Possibilities

The impetus for the development of new treatment techniques, pharmacological or nonpharmacological, derives from an inner dissatisfaction with less than perfect results. This is a goal that we strive for, but that may never be achieved. Nevertheless, it is important to explore the possibilities inherent in new technologies in pursuit of this goal. The history of medicine is replete with numerous examples of new pharmacological agents supplanting existing ones, new technologies replacing the old, and new operative procedures expanding the horizon of potential cures for human disease. This chapter deals with the possibilities and limitations inherent in laser technology for the ablation of cardiac arrhythmias.

Indium 111-labeled platelet deposition in woven and knitted Dacron bifurcated aortic grafts with the same patient as a clinical model.

A study was designed to compare platelet deposition between knitted and woven Dacron grafts in the same patient. Twenty patients received aortoiliac or aortofemoral bifurcated Dacron grafts, each composed of one woven and one double-velour knitted limb. External nuclear graft imaging was carried out after injection of autologous platelets labeled with indium 111. The patients were studied postoperatively in time periods ranging from 6 days to 42 months. Platelet accumulation was almost identical in knitted and woven limbs in all patients. This study appears to indicate that there is no difference in thrombogenicity between knitted and woven bifurcated Dacron grafts in the aortoiliac or aortofemoral positions measured by platelet accumulation.

Patency Rate of Bifurcated Aortic Grafts: Comparative Analysis of Woven versus Knitted Prostheses in the Same Patient

To investigate the difference in patency rate between woven and knitted aortofemoral or aortoiliac prosthetic grafts, a special vascular prosthesis was manufactured with one limb of the graft knitted and the other, woven. The prosthesis was implanted in 143 consecutive patients with occlusive aortoiliac arteriosclerotic disease or aneurysms. Detailed statistical analysis failed to reveal any difference in the patency rate between the woven and knitted limbs of the grafts during an observation period ranging from one month to two years.

Technical Options in Repairing the Diseased Ascending Aorta with Aortic Valve Involvement

Operative repair of the diseased ascending aorta with aortic valve involvement consists of replacement of the ascending aorta and the aortic valve plus reconstitution of coronary arterial flow. Two basic techniques are presently available. The conventional technique involves separate replacement of the aorta and valve above and below a small segment of retained aorta including the coronary orifices. The second method consists of replacement of the entire ascending aorta and aortic valve with reconstitution of coronary flow by approximation of the coronary orifices to the Dacron conduit or with saphenous vein bypasses. Each method has its merits depending on the exact pathological anatomy encountered near the coronary orifices. Other pathological variables exist that demand additional intraoperative choices in technique. The present report details the operative repair of this lesion and outlines the technical options available for solution of the various problems encountered.