Temporary Epicardial Pacing after Open Heart Surgery: Complications and Prevention

Temporary wires are routinely sutured to atrial and/or ventricular epimyocardium after open heart surgery. Despite the common problems of poor sensing or capture, dislodgement or retention, no criteria exists for proper placement or removal. This report describes clinical complications due to: failure of ventricular sensing, failure of ventricular capture, bleeding from right ventricular laceration with tamponade, avulsion of a side branch from a saphenous vein coronary bypass graft, and perforation of the superior epigastric artery. Appropriate placement of temporary wires for optimum function requires 2-cm electrode separation, application into both atrium and ventricle with a gentle redundant loop to exit near the midline, avoiding both coronary arteries and coronary artery bypass grafts. Gentle traction for removal is recommended on the day prior to discharge, especially for patients on antiplatelet or anticoagulant therapy.     

Long-Term Antitachycardia Pacing Experience for Supraventricular Tachycardia

A pacemaker was used to control drug-resistant reentrant supraventricular tachycardia (SVT) in 40 patients. An antitachycardia pacemaker was implanted in 37 for SVT; in one for ventricular tachycardia that could also be used to terminate SVT; in one SVT could be terminated with an activity rate variable pacemaker; and in one a DDD pacemaker was used for prevention and termination of SVT. Twenty patients had AV nodal reentrant tachycardias, eight had tachycardias due to a concealed accessory pathway, eight had a Wolff-Parkinson-White syndrome, three had reentrant atrial tachycardias, and one had atrial flutter. Twenty-two patients were paced from the right atrium, five from the coronary sinus, ten from the right ventricle, and three had a DDD pacemaker. During a total follow-up period of 1,503 (mean 38) months an estimated 16,240 episodes of tachycardia were terminated promptly at home, 58 required several attempts, 57 episodes lasted longer than 30 minutes but did not require medical attention, and 11 required hospital admission. Hospital admission for SVT decreased from one per patient-month (in the 3 months before implantation) to 1 per 137 patient-months after implantation. Additional reentrant tachycardias occurred in 13 patients. Antiarrhythmic drug therapy in combination with a conservative antitachycardia pacing mode was required in four patients paced from the atrium to avoid pacing induced atrial fibrillation. Antiarrhythmic drug therapy was used in 42% of patients to help control SVT. Conclusions: (1) Drug-resistant SVTs can be safely and effectively managed on the long-term with antitachycardia pacemakers. (2) Rapid termination of SVT improved the quality-of-life significantly by avoiding prolonged episodes of tachycardia and repetitive hospital admissions.     

Better Predictors of Successful His-Bundle Ablation Analysis of First Shocks

IWA, T., ET AL.: Better Predictors of Successful His-Bundle Ablation Analysis of First Shocks. We have reported here that a longer HV interval in asssociation with a larger His amplitude yields a high rate of success when used to position the ablating catheter for His-bundle ablation. Additionally, we have shown that double discharge shocks are more effective than single discharge shocks, and that negative polarity is more effective than positive polarity. The use of bipolar or tripolar, and not quadripolar catheters, was also associated with a higher success rate. In our institution, using a bipolar catheter, we attempt to record an HV interval > 55 msec and a His amplitude > 0.35 mV. When both of these criteria are fulfilled, we use 3 to 4 joules per kg, and a single discharge shock. When one or the other of these criteria are not fulfilled, we use the double discharge shock method. Using these techniques, we have achieved successful His-bundle ablation with only one shock in all but one of the most recent 21 consecutive patients.     

Localization of the Accessory Pathway in the Wolff-Parkinson-White Syndrome from the Ventriculo-Atrial Conduction Time of Right Ventricular Apical Extrasystoles

In 18 consecutive patients with the Wolff-Parkinson-White syndrome undergoing electrophysiologic study, the ventriculo-atrial conduction time of right ventricular apical extrasystoles which advanced atrial activation during circus movement tachycardia was studied in relation to accessory pathway location. Accessory pathway location was determined by delta wave morphology during maximal pre-excitation, mapping of alrial activation during circus movement tachycardia and ventricular pacing, the effect of bundle branch block on ventriculo-atrial conduction time during circus movement tachycardia, and the effect of pacing from different sites in the atria on the stimulus-to-delta wave interval. In 7 patients with septal accessory pathways, ventriculo-atrial conduction time was similar during circus movement tachycardia and following right ventricular apical extrasystoles (mean difference 0 ± 6 ms, range -5 to + 10 ms). In contrast, in 11 patients with a left free wall accessory pathway, ventriculo-atrial conduction time increased by 46 ± 15 ms (range 15 to 65 ms) following right ventricular apical exlrasystoles. Therefore, measurement of the ventriculo-atrial conduction time of right ventricular extrasystoles during circus movement tachycardia provides an easy way to distinguish between septal and left free wall accessory pathways. This finding may be of particular use in determining the location of concealed bypass tracts.     

Early Benefit of Implantable Cardioverter Defibrillator Therapy in Patients Waiting for Cardiac Transplantation

The ICD can effectively recognize and treat ventricular arrhythmias that can lead to sudden death. Sudden death is a major problem in patients awaiting heart transplantation. We reviewed our experience with the ICD in patients with malignant ventricular arrhythmias waiting for cardiac transplantation. Nineteen patients were included. Seventeen were men, mean age was 54 ±11 years (range 17–66) and the left ventricular ejection fraction was 22%± 10% (range 9%–46%). After a mean follow–up of 6 ± 5 months (range 1–20 months), 17 patients reached heart transplantation. One patient died and the other is waiting for a transplant. Before transplantation 71 % of patients received an appropriate discharge. The mean time to the first appropriate discharge was 2 ± 2 months (range < 1–6 months), which was significantly shorter than the mean time to first discharge in the other patients (n = 182) receiving a defibrillator in our center (11 ±10 months; range 1–58 months) (P < 0.0004). In conclusion, cardiac transplantation candidates with life–threatening ventricular arrhythmias can effectively be protected against sudden arrhythmic death by ICD. These patients have a high incidence of appropriate shocks occurring very early after implantation.