By R. Jerek. Southern Illinois University Medical School at Springsfield.
If recurrent shocks due to bundle branch reentry occur purchase haldol with paypal, ablation is a reasonable approach discount generic haldol canada. As stated in Chapter 11 purchase haldol 10mg with mastercard, I have only seen one such patient who has had this as the sole arrhythmia generic 1.5 mg haldol visa. In that patient, ablation of the right bundle branch cured the tachycardia (see Chapter 11). Another tachycardia that uses the His–Purkinje conduction system is intrafascicular reentry. This disorder almost always occurs in patients with prior myocardial infarction and bifascicular block. Occasionally, it may occur in patients without infarction who have bifascicular block. In this instance the right bundle branch is permanently blocked in both directions. This tachycardia is characterized by an H-V interval significantly shorter than that in sinus (usually 40 to 80 msec shorter). Activation of the conducting system goes from left bundle branch to the His bundle and then to the proximal right bundle branch. The reason for the shortened H- V is the fact that the H-V interval is determined by antegrade conduction from the turnaround site in the fascicle minus the retrograde conduction to the His bundle. Ablation of such tachycardias is not only difficult, but is virtually never curative since these patients typically have large infarctions and multiple arrhythmias. A: On top, the mapping catheter demonstrates a diastolic potential as well as a Purkinje potential from its tip. Rapid pacing increases at times between the diastolic potential and the Purkinje potential. Significance of late diastolic potential preceding Purkinje potential in Verapamil-sensitive idiopathic left ventricular tachycardia. This usually takes the form of a macroreentrant circuit around the ventriculotomy incision at the outflow tract. Mapping of this tachycardia usually shows a complete reentrant circuit around the ventriculotomy scar in either a clockwise or counterclockwise direction (Fig. In the past, this tachycardia was approached easily with cardiac surgery in which completion of the ventriculotomy scar to the pulmonary valve cured the tachycardia. One must make sure, however, that the tachycardia does not arise at a different site. Occasionally tachycardias arise in the region of the ventricular septal defect repair in which case an isthmus is present between the circling wavefront and the tricuspid annulus. Detailed mapping and entrainment techniques are obviously necessary to discern the critical sites for ablation. A diastolic potential is observed at a site that demonstrates neither a Purkinje potential nor the earliest ventricular activation. Antegrade conduction goes from high septum toward the inferior septum (A, B, C) over a decrementally conducting, verapamil-sensitive pathway. The retrograde limb which is not well characterized is attached to the distal Purkinje system (septal or posterior fascicle) which acts as a bystander. Panels A, B, and C below are recordings from the corresponding points in the schema. Another congenital anomaly that is associated with ventricular tachyarrhythmias is Ebstein anomaly of the tricuspid valve. In this disorder the tricuspid valve displaced into the ventricle creating an atrialized portion of the ventricle. We have recently encountered a patient in whom an automatic ventricular tachycardia arose from the atrialized ventricle just distal to the His bundle recording site. The location is schematically shown in the electroanatomical map in Figure 13-187, panel A. Ventricular tachyarrhythmias can occur in a variety of disorders, and if they are recurrent and stable the mapping technique described in prior sections can be used to ablate them. A recent report by Nademanee describes epicardial catheter ablation in the Brugada syndrome for the treatment of recurrent ventricular fibrillation. Intraoperative Mapping and Surgical Ablation of Ventricular Tachycardias With the development and wide spread utilization of implantable defibrillator therapy, the practice of surgical ablation of ventricular arrhythmias has diminished considerably. The development of curative surgery for ventricular arrhythmias in healed infarction provided so much insight P. Panel A: Epicardial activation in ventricular tachycardia following repair of tetralogy of Fallot. Prevention of ventricular fibrillation episodes in Brugada syndrome by catheter ablation over the anterior right ventricular outflow tract epicardium. In particular, in the setting of coronary artery disease, surgery offers a single procedure in which coronary revascularization, aneurysmectomy with ventricular remodeling, and cure of ventricular tachyarrhythmias can take place. Thus, particularly in coronary artery disease in which revascularization is necessary, antiarrhythmic surgery can play an important role. The marked decline in its use is not logical from a medical standpoint, but has been driven by the economics. Catheter mapping is an integral part of any surgical approach to ventricular tachycardia since it offers a greater opportunity to localize all potential tachycardia circuits in an individual patient, something that may not be possible in the operating room under general anesthesia. The role of the electrophysiologist is to select those patients who might benefit from a surgical procedure and localize the tachycardias accurately enough so that the surgeon can ablate the arrhythmogenic area without unnecessarily destroying tissue unrelated to the tachycardia. Obviously, the selection of patients in whom surgery is indicated depends not only on the presence of a drug-resistant tachycardia and the need for revascularization, but on the presence of a team of electrophysiologists and surgeons. The variability of results of surgery, as well as selection of operative candidates, is most dependent on the team of electrophysiologists and surgeons. While the majority of centers refuse to operate on patients with ejection fractions less than 25%, nearly 50% of our arrhythmia surgical patients had ejection fractions lower than 25%. However, this approach does not address the marked ventricular dysfunction that is associated with aneurysms. The substrate provides a rational basis for undertaking surgery, even in the absence of mapping, although this is less desirable. In such patients arrhythmia surgery may be directed at the electrophysiologic substrate either by direct visualization of the substrate (e. It is important to recognize that in the presence of such a substrate, tachycardias are almost always inducible and, if tolerated, are mappable in the electrophysiology laboratory and are certainly mappable in the operating room regardless of the hemodynamic status. In patients with an inducible sustained monomorphic tachycardia who presented with a cardiac arrest, revascularization alone is insufficient to prevent the arrhythmia. The ability to induce this arrhythmia implies the presence of a fixed substrate, and either percutaneous or operative revascularization has not been shown to alter this substrate. Revascularization should only be considered a primary therapy for cardiac arrest in patients with no inducible arrhythmias and multivessel disease, with a positive thallium test and ejection fractions greater than 40% without significant scar. Once in the operating room, map-guided surgery provides the best results for sustained uniform tachycardias because (a) 15% of tachycardias arise outside regions of visible scar or abnormal electrograms; (b) in the setting of recent myocardial infarction, visible landmarks of the entire arrhythmogenic substrate are not distinct and well defined; (c) tachycardias may arise in deeper areas of the myocardium that would not normally be addressed by routine, nonmap-guided procedures. These involve resection, incision, cryoablation, laser photoablation/coagulation, or combinations of the above, of the arrhythmogenic tissue. All of these procedures may be map-guided, or either visually directed or electrogram- directed (sinus rhythm mapping) to remove or isolate the pathophysiologic substrate. Of the nonmap-guided procedures, extended subendocardial resection, encircling subendocardial ventriculotomy or cryoablation, an extended laser photocoagulation/vaporization, have been employed. This technique obviously requires a stable monomorphic tachycardia for all designated mapping sites to be acquired. Simultaneous multisite data acquisition systems using either preformed plaques, epicardial sock electrodes, or endocavitary balloon electrodes are also available. Most of these multisite data acquisition systems are computerized and allow acquisition of 64 to 256 simultaneous sites of activation. Many of these are commercially available, although several institutions have developed their own in-house systems. Regardless of the ability to record multiple sites, several limitations still exist. These include (a) an unknown relevance of nonsustained or polymorphic arrhythmias to the spontaneous sustained arrhythmias that a patient has exhibited; (b) the inability for the computer to accurately analyze low-amplitude multicomponent signals, for which no good software program exists; (c) the inability of the computer to deal with intermittent signals; (d) the length of time it takes for the investigator to completely check and validate the computer-designated activation times. Moreover, while these tools offer exceptional power to further understand the arrhythmogenic mechanisms, reentrant pathways, and the physiology of initiation and termination of arrhythmias, it is uncertain whether they have added to the success of surgery. Although more data can be acquired in a shorter period of time, there is at present no good evidence that the surgical results have improved as a result of enhanced data acquisition. In part this may result because it takes too long to validate the computer-generated data (hours to days).
The adhesions are taken down discount haldol 5mg otc, and dissection continues directly on the tube until the band itself is found 10 mg haldol with visa. This usually involves opening a hole inside the stomach where the erosion occurred purchase haldol 5 mg otc. The hole in the stomach is closed with 2–0 prolene suture and an omental patch (Fig order haldol 1.5 mg on-line. A gastrographin swallow is done on postoperative day 4–5, and if normal, the patient will be started on diet. Occasionally, if most of the band is inside the stomach, the procedure can be done endoscopically. Next, the band is cut inside the stomach using endoscopic scissors and removed via the mouth. Since there is no opening of the tract intraoperatively, there is no need for drainage or closure of the defect. The tract around the tube works like a tract around a t-tube and will close over time. Good exposure of the stomach, by ensuring Gastrectomy the stomach is stretched, is crucial for the dissection of the greater curvature. The har- monic shear is used to take down all the branches of the left gastroepiploic vessels. The greater curvature dissection continues approximately two centimeters to the pylorus, then a distance of fve to six centimeters proximal to the pylorus is identifed to start the frst fring (Fig. The second fring is then performed, making sure that there is no occlusion of the gastric lumen. A 32–34, French bougie is then inserted and advanced along the lesser curvature into the duodenum to allow the calibration of the sleeve (Fig. It is important to leave some gastric tissue at the upper edge near the angle of His to avoid injuring the gastro-esophagal junction. The gastric specimen is then removed through the umbilical port in a specimen bag (Fig. An alternative technique is to divide the stomach before dividing the high gastroepiploic vessels and the short gastric vessels, thus allowing the stomach to remain attached and naturally retracted (Fig. It is also possible to imbricate the areas of intersecting staple lines with interrupted stiches as an additional safety measure (Fig. C camera port; A left hand of surgeon; B right hand of sur- geon; D grasper for assistant; E liver retractor Laparoscopic Sleeve Gastrectomy 251 5-6 cm. Note that there is a sliver of stomach left at the angle of His to reduce the risk of postoperative leaks at this area Laparoscopic Sleeve Gastrectomy 253 Fig. Mobilization of the greater curve and fundus following the division of the stomach, thus allowing for a natural retraction of the stomach during stapling 254 Chapter 14 Bariatric Surgery Fig. Arch Surg 135(9):1029–33 Katkhouda N, Moazzez A, Gondek S, Lam B (2008) A new and standardized technique for trocar placement in laparoscopic Gastric Bypass. The umbilicus is usually used for basic procedures such as laparoscopic cholecystectomy, Basic appendectomy, and hernias. The incision can circumscribe the umbilicus or go through Transumbilical the umbilicus, as depicted in Fig. In the latter technique, the umbilicus is carefully Procedures cleaned, and two kocher clamps invert the umbilicus to expose the skin. An eleven blade is used to cut the skin, and then the skin incision is enlarged with a Kelly. Two S-retractors are inserted to retract the edges of the skin incision, and a fne scissor is used to create a pocket, developing a fascial plane slightly larger than the skin incision. It is then impor- tant to identify the natural defect in the linea alba, which is then enlarged by inserting a Kelly and spreading it open. Carefully, a blunt 5-mm trocar, preferably without any protu- berant plastic edges, is inserted and the abdomen is then insuffated. At this point, a spe- cial long 40 cm, 5 mm, 30° bronchoscope (Karl Storz, Tuttlingen, Germany) is inserted between and hooked to the camera, and the exploration of the abdomen is performed. This fgure also clearly shows the relationship of the different trocars and the long 5 mm scope. Ideally, they should be short and stealthy to avoid the “knitting needle” effect of the trocars. We prefer insertion of the 5 mm camera site at about 7 o’clock for a laparoscopic cholecystectomy, with one 5 mm trocar at 11 and one at 3 o’clock (Fig. One can also use disposable perforated rubber like devices offered by several companies that would require one slightly larger facial incision (around 2 cm). Again our solution is to avoid unnatural movements of the hands and keep them on top of each other thus allowing for more lateral freedom (Fig. The procedure is performed in the same fashion as the standard cholecystec- tomy, with one exception - the retracting grasper for the fundus would be inserted below the 5 mm trocar with a scope; ideally, the insertion occurs at about 6 o’clock. We have found with others that the insertion of a long ratcheted 36 cm needle-nosed grasper without a trocar is most benefcial, as it doesn’t interfere with the other 5 mm trocar. It is imperative, though, to be careful when inserting this instrument, as it is done without direct visualization; we recommend the exploration of this area with a 10-mm scope at the end of the procedure. Another technique is to retract the fundus using a Keith needle inserted through the skin just under the right costal margin. Minimal cautery is used as to avoid any burn injury to the adjacent structures (e. Once the junction of the cystic duct and the gallbladder is identifed, and the junction between the cystic and hepatic ducts is also seen, a 5-mm clip applier is inserted and clips are placed in the usual fashion. The cystic artery is also dissected and divided, and the gallbladder is removed in the gallbladder fossa. At this point, two 5 mm trocars are enlarged to allow the insertion of a 10-mm tro- car and a bag in which the gallbladder is removed. The 10 mm trocar allows the insertion of a 10-mm scope in order to explore the area of insertion of the trocars for recognition of any possible bowel injury, and all the trocars are then removed. The fascia that allowed the insertion of the 10 mm trocar is then closed using the usual vicryl sutures, and cos- metic closure of the umbilicus fnishes the procedure. Laparoscopic Appendectomy The same concepts and patient positioning are used as with traditional laparoscopy; the difference here is the use of the harmonic shear to coagulate the meso-appendix, and the ligation of the appendix itself is performed using two endoloops at the base and one endoloop more distally. The appendix is then divided and removed in a 10-mm bag inserted through the enlarged 10 mm incision inside the umbilicus. These devices are made of rubber or silicone gel, are perforated to allow the Using insertion of small trocars. Disposable The big difference with our basic technique is the need for one incision only on the Devices fascia to insert the disposable rubber seal. The advantage is the possibility of slight rotation of the device and the attached ports allowing to compensate for the lack of horizontal freedom of the hands and enabling the hands to position themselves better in our favorite position (left hand above right one). Arch Surg 144(8):734–738 Reading Dunning K, Kohli H (2009) Transumbilical laparoscopic cholecystectomy: a novel tech- nique. Arch Surg 144(6):593–594 Marescaux J, Dallemagne B, Perretta S, Wattiez A, Mutter D, Coumaros D (2007) Surgery without scars: report of transluminal cholecystectomy in a human being. Arch Surg 142(9):823–826 Advanced Laparoscopic 16 Suturing Techniques L aparoscopic suturing is a fundamental skill in advanced laparoscopic surgery. The mastery of this skill will enable the surgeon to perform many complex laparoscopic procedures and to laparoscopically repair complications should they occur. The monitor should be comfortably located at the level of Height, Monitor surgeon’s eyes, facing the surgeon on the side of the lesion. For example, during a chole- Placement) cystectomy the monitor should be positioned on the patient’s right side in direct line of vision of the surgeon. While during a laparoscopic Nissen the surgeon stands between the legs of the patient in the French position with the monitor placed at the head of the patient facing the surgeon. To fx a height discrepancy between the surgeon and the table, one should either readjust the table or use steps. If the problem is not fxed with adjustment of the table, the ports are placed too high and need to be repositioned to a lower location.
During atrial pacing (S1-S1) at a cycle length of 500 msec an atrial extrastimulus (S2) was delivered purchase haldol with a visa, which depolarizes both components of the split electrogram mimicking block between the accessory pathway and the ventricle purchase haldol with mastercard. Assessment of pacing maneuvers used to validate anterograde accessory pathway potentials buy haldol uk. Assessment of pacing maneuvers used to validate anterograde accessory pathway potentials order haldol discount. The observations 32 38 102 103 104 111 indicating the presence of a bypass tract are well-described , , , , , and include: 1. The amount of A-V delay allows the bypass tract to recover and an atrial echo (Ae) results from retrograde conduction over the bypass tract. That impulse conducts slowly through the A-V node (A-H 300 msec) but blocks below the recorded His bundle deflection. Thus, during rapid tachycardias, a single right ventricular stimulus might not reach a left lateral bypass tract in time to preexcite the atrium. This is shown in Figure 10-84, in which the first of two ventricular extrastimuli fails to affect retrograde atrial activation while the second can terminate the tachycardia. This early activation of the atrium then resets the tachycardia with a longer A-H and a delay in the return cycle. The ability to preexcite the atria when the His bundle is refractory with the same atrial activation sequence as seen during the orthodromic tachycardia confirms the presence of functioning posteroseptal bypass tract. The tachycardia terminates by retrograde block in the bypass tract when the His is refractory. This confirms the necessary participation of the bypass tract in the tachycardia circuit. Only conditions 2, 3, 5, 6, and 7 absolutely demonstrate participation of the bypass tract in the reentrant circuit, because they demonstrate requirement of the ventricle in the tachycardia circuit. Atrial preexcitation alone is compatible with the presence of a bypass tract if the atrial activation sequence of the preexcited atrial activation is identical to that of the atrial activation sequence seen during tachycardia. Although this supports the involvement of a bypass tract in the reentrant circuit, atrial tachycardia or intra-atrial reentry conceivably could occur at the site of the atrial insertion of the bypass tract. Then, retrograde atrial activation during ventricular preexcitation would look identical to that of the atrial tachycardia. However, if atrial tachycardia were present, there would be a V-A-A-V return cycle. The V-A-V return cycle with a constant V-A excludes atrial tachycardia and makes the diagnosis of orthodromic tachycardia. Condition 1 is compatible with the presence of a bypass tract but does not demonstrate its requirement to maintain the tachycardia, because it is theoretically possible, although highly unlikely, that retrograde atrial activation over a bypass tract may be an unrelated epiphenomenon to another tachycardia mechanism. For example, we have seen ventricular tachycardia with retrograde atrial activation over a bypass tract. In this instance, ventricular tachycardia certainly does not require the bypass tract for its persistence. These are theoretical possibilities; however, in the vast majority of cases, all the conditions mentioned are useful in diagnosing the presence of a bypass tract. The first ventricular extrastimulus fails to affect the tachycardia with the antegrade His and retrograde atrial activation over the bypass tract being unaltered. The second extrastimulus, which is introduced earlier in the cardiac cycle, conducts over the bypass tract retrogradely. The inability of a right ventricular extrastimulus to affect circus movement tachycardia demonstrates the lack of requirement of the right ventricle in tachycardias using a left-sided bypass tract. As noted earlier, the most common rhythm associated with a regular preexcited tachycardia is atrial flutter or atrial 40 tachycardia. Whether or not conduction proceeds over the bypass tract is obvious by the appearance of a typical preexcited complex. Usually, there are runs of total preexcitation and/or runs of normal ventricular activation (Fig. Obviously, in these instances, the bypass tract is used only passively during anterograde conduction during fibrillation or flutter. Retrograde activation of the atrium over the bypass tract during normal anterograde conduction has been observed and may contribute to perpetuation of atrial fibrillation as well as anterograde 113 conduction over the normal conduction system. Atrial tachycardia is more difficult to distinguish from preexcited circus movement tachycardias. Resetting the tachycardia by an atrial extrastimulus with an A-V-A with an identical V-A interval or termination of the tachycardia by ventricular stimulation in the absence of an A excludes an atrial tachycardia. Demonstration of resetting a preexcited tachycardia with atrial fusion by atrial stimulation, excludes a focal tachycardia. The latter phenomenon, particularly when stimulation is performed from the atrium opposite that demonstrating earliest atrial activation, suggests the presence of a macro-reentrant circuit associated with antegrade conduction over one bypass tract and retrograde conduction over another bypass tract, one of the more common mechanisms of preexcited circus movement tachycardias (Fig. A ventricular extrastimulus delivered from the right ventricle after the His bundle has been depolarized antegradely can preexcite the atrium using the right anterior paraseptal bypass tract. During atrial flutter, antegrade conduction usually occurs over the bypass tract, resulting in marked preexcitation (first six complexes). When conduction proceeds over the normal pathway (last three complexes), the ventricular response is usually slower because of a higher degree of concealment without block in the A-V node than in the bypass tract, which tends to function in an all-or-nothing fashion. Factors associated with atrial–fibrillation-induced ventricular fibrillation include male gender, septal location of the bypass tract, short refractory period of the bypass tract (shortest R-R <220 msec), and heightened adrenergic state. Conversely, we are probably better able to predict those patients who are at low risk for lethal ventricular responses during atrial flutter and fibrillation by demonstrating a long effective refractory period of the bypass tract. A preexcited tachycardia using a left lateral bypass tract antegradely and a right free wall bypass tract retrogradely is shown. This S2 produces an exact capture of the ventricles with antegrade conduction over the bypass tract and retrograde atrial activation equal to the exact capture of the ventricle. This excludes an atrial tachycardia and confirms the diagnosis of preexcited circus movement tachycardia using two bypass tracts. Intermittent Preexcitation Intermittent preexcitation is a term used differently by different investigators. Although some have included 58 59 38 patients who manifest preexcitation on one day and none on another day, , we and others require that intermittent preexcitation be observed on the same rhythm strip and always be associated with a prolongation of the P-R interval. Changes in autonomic tone on different days can influence conduction over the A-V node and can decrease the manifestations of preexcitation daily. Loss of preexcitation should reflect properties of the bypass tract, and therefore, factors producing enhancement of conduction over the normal pathway must be excluded. Despite the differences of definition, intermittency of preexcitation, however defined, is correlated with a long effective refractory period, long cycle lengths maintaining 1:1 conduction over the pathway antegradely, and prolonged preexcited R-R intervals during atrial fibrillation. This would therefore suggest a low risk for the spontaneous occurrence of rapid rates during atrial fibrillation. However, occasional patients with intermittent preexcitation have been noted to have atrial fibrillation, with the shortest preexcited R-R interval being less than P. In all patients, the response to atrial fibrillation is governed by the degree of shortening of the refractory period of the bypass tract by the high rate of impulses in depolarizing the bypass tract, the degree of antegrade decremental conduction and concealed conduction in the bypass tract, and the effects of accompanying sympathetic tone on shortening the refractory period of both the bypass tract and the A-V node. Even in the presence of exercise, life-threatening responses in these patients remain a rare event. These patients also commonly exhibit block in the bypass tract during exercise (see following discussion). The patients with alleged intermittent preexcitation who have been reported to develop a rapid ventricular response during atrial fibrillation usually showed marked catecholamine enhancement of conduction over both the bypass tract and the A-V node, but they rarely demonstrated 58 59 120 intermittent preexcitation on the same electrocardiogram. However, if one compares a group of patients with intermittent preexcitation on the same tracing with those showing persistent preexcitation or inapparent preexcitation, the ventricular response during induced atrial fibrillation, even during isoproterenol administration, is slower in patients with intermittent preexcitation. Thus, our experience parallels that of Wellens 38 and Brugada intermittent preexcitation (sudden loss of delta wave with prolongation of the P-R interval) is an indication of prolonged refractoriness over the bypass tract and relative low risk for the development of life- threatening ventricular responses during atrial fibrillation. The last two complexes manifest preexcitation with delta waves occurring simultaneous with the His bundle deflection. These patients may, in fact, develop life-threatening responses, and the inappropriate inclusion of these patients in a series of patients with alleged intermittent preexcitation has probably been responsible for the imperfect correlation between “intermittent preexcitation” and slow ventricular responses during atrial fibrillation. Caution should be used if adenosine is administered since it can cause atrial fibrillation.