Patient discomfort following pectoral defibrillator implantation using conscious sedation.

BACKGROUND: The miniaturization of implantable cardioverter defibrillators (ICDs) has made pectoral implantation possible. However, postoperative pain following the procedure has not been systematically studied. The aim of the current study was to prospectively assess patient discomfort and identify factors influencing pain perception during follow-up. METHODS: Pain related to device implantation was quantified in 21 consecutive patients (age, 61 +/- 11 years; 17 men and 21 women; 16 of 21 had coronary artery disease; left ventricular ejection fraction, 32% +/- 15%) undergoing pectoral ICD implantation with conscious sedation (fentanyl 118 +/- 72 micrograms midazolam 14 +/- 9 mg). Patients completed the Visual Analogue Scale (VAS, 0-100) and the McGill Pain Questionnaire 24 hours and 1 month postoperatively. Regression analysis was used to define clinical and procedure related variables affecting patient discomfort and frequency of postoperative analgesic use. RESULTS: The mean VAS score was 34 +/- 20 24 hours postoperatively. A single (4.8%) patient described postoperative pain as severe. Pain was reported to be moderate by 10 (47.6%) patients and mild by 10 (47.6%) patients. Intraoperative fentanyl requirement was a predictor of postoperative pain (R = 0.51, P = 0.036), and procedural duration was a strong predictor of postoperative analgesic use (R = 0.75, P < 0.001). Pain at 1 month decreased to a VAS score of 19 +/- 18 (P = 0.002 vs 24 hours) and was rated to be severe, moderate, and mild by 1, 3, and 17 patients, respectively. Late pain was related to a VAS score at 24 hours (R = 0.67, P = 0.004). CONCLUSIONS: (1) Pectoral ICD implantation using conscious sedation is well tolerated. (2) Postoperative discomfort correlates with longer procedural times and larger intraoperative narcotic requirements.

Right ventricular outflow tract tachycardia as a result of blunt chest trauma.

Two patients presented with monomorphic ventricular tachycardia after blunt chest trauma. In both cases, the arrhythmia had a left bundle branch block, inferior axis morphology comparable to that seen with idiopathic ventricular tachycardia originating from the right ventricular outflow tract (RVOT). In one patient, the arrhythmia persisted and required catheter ablation. A history of cardiac trauma should be considered in patients presenting with RVOT tachycardia.

Frequency analysis of human atrial fibrillation using the surface electrocardiogram and its response to ibutilide.

This study assesses a technique for quantifying the frequency spectrum of atrial fibrillation (AF) using the surface electrocardiogram. Electrocardiograhic recordings were obtained in 61 patients during AF. After bandpass filtering, the QRST complexes were subtracted using a template-matching algorithm. The resulting fibrillatory baseline signal was subjected to Fourier transformation and displayed as a frequency power spectrum. These frequency spectra were compared to direct measurements from the right atrium and coronary sinus in 35 patients undergoing electrophysiologic study. The clinical use of this technique was explored by correlating fibrillatory frequency with the behavior of the arrhythmia in 26 patients referred for cardioversion. The electrocardiographic frequency spectrum during AF was characterized by a single peak that varied widely between patients (range 228 to 480 beats/min). There was a strong correlation between electrocardiographic peak frequency and that measured in the right atrium and coronary sinus (r = 0.79 to 0.98, p <0.0001). Episodes of AF that terminated in < 5 minutes had a lower frequency than those that persisted > 5 minutes (324 +/- 36 vs 402 +/- 78 beats/min, p = 0.001). Chronic AF (< 3 months in duration) had a lower frequency than chronic AF (present > 3 months) (336 +/- 48 vs 408 +/- 60 beats/ min, p = 0.012). Fibrillation frequency was an accurate predictor of conversion with ibutilide. Success rate was 100% in patients with peak frequency < 360 beats/min versus 29% in patients with frequencies > or = 360 beats/min (p = 0.003). Automatic analysis of the frequency content of the fibrillatory baseline on the surface electrocardiogram accurately reflects the average rate of AF. This measurement correlates with the clinical pattern of the arrhythmia and predicts the response to administration of ibutilide.

Anatomy of atrioventricular nodal reentry investigated by intracardiac echocardiography.

Intracardiac echocardiography was used to evaluate posteroseptal space anatomy in patients with atrioventricular nodal reentrant tachycardia compared with patients with other mechanisms of tachycardia. The posteroseptal space was found to be significantly wider in patients with atrioventricular nodal reentry, suggesting an anatomic basis for dual atrioventricular nodal physiology.

Incidence and implications of abrasion of implantable cardioverter-defibrillator leads.

Severe abrasion of implantable cardioverter-defibrillator leads is frequently found during abdominal generator replacement and occasionally results in lead system failure. Careful inspection of leads at the time of generator replacement will identify such abrasions, and, in some cases, lead repair or replacement may be indicated.

Comparison of three different automatic defibrillator implantation approaches: pectoral implantation using conscious sedation reduces procedure times and cost.

Recent technological advances in implantable defibrillator systems (ICD) have changed implantation approaches. The aim of this study was to investigate the influence of these improvements on procedure times, implant-related charges, patient recovery, and morbidity. Ninety-six consecutive patients undergoing implantation of a nonthoracotomy ICD were studied. Implantation was performed under general anesthesia with the generator placed abdominally in 22 patients (group I) and pectorally in 40 patients (group II). Thirty-four patients underwent pectoral implantation using conscious sedation (group III). Groups were comparable with respect to clinical variables. Implantation duration and total procedure duration were shorter in group III (67 +/- 21 minutes and 117 +/- 30 minutes) when compared with group I (100 +/- 25 minutes and 157 +/- 39 minutes) and group II (86 +/- 24 minutes and 153 +/- 34 minutes, P < 0.05). Patients in group III did not require admission to the Post-Anesthesia Care Unit. In contrast, patients in groups I and II spent 92 +/- 28 minutes and 91 +/- 31 minutes in the Post-Anesthesia Care Unit. Implantation-related charges were reduced in patients having pectoral implantation using conscious sedation ($1451 +/- 217 vs. $2354 +/- 550 and $2796 +/- 384, P < 0.05). Patients in group III had a lower frequency of postoperative oral analgesic use (3.2 +/- 2.7 doses, P < 0.05) and a shortened post-operative length of stay (1.9 +/- 1.6 days, P < 0.05) when compared with groups I (5.7 +/- 4.0 doses and 3.3 +/- 1.4 days) and II (5.2 +/- 3.5 doses and 2.6 +/- 1.1 days). The overall complication rate was low (6.3%), with no differences between groups. Advances in ICD technology have simplified implantation, leading to shorter, less painful, and less expensive procedures.

Effects of high energy shocks on pacing impedance during transvenous ICD implantation.

The purpose of the current study was to characterize the effects of transvenous ICD shocks on myocardial impedance. Rather than recording impedance during shocks, it was measured during continuous pacing in order to minimize confounding effects such as electrode polarization. Pacing impedance (reflecting the combined impedances of the electrode-tissue interface, myocardium, and blood pool) was measured every 5 seconds before and after 58 single shocks in 22 patients undergoing ICD implantation with a Transvene (n = 14) or Endotak (n = 8) lead. There was a progressive and long-lasting decrease in impedance after shocks. The magnitude of this change was similar for 0.6-J test shocks and shocks > or = 5 J (28 +/- 32 omega vs 23 +/- 16 omega; P = 0.8). However, the drop in impedance was more abrupt after high energy shocks. Because impedance continued to decline throughout the 5-minute interval between shocks, successive shocks had a cumulative effect, with a decrease of 46 +/- 42 omega after four discharges. In conclusion, a progressive decline in pacing impedance is a characteristic response to transvenous ICD discharges.

Estimation of temperature during radiofrequency catheter ablation using impedance measurements.

Temperature monitoring during radiofrequency catheter ablation is useful but requires specialized equipment that is not generally available. Previous studies have shown that impedance characteristically decreases as the result of heating at the electrode-tissue interface. The purpose of the current study was to determine if impedance changes during radiofrequency current application could be used to estimate endocardial temperature in patients undergoing catheter ablation. Data from 43 patients treated with a thermistor ablation catheter were retrospectively analyzed. The slope of the initial 2 seconds of the impedance curve and subsequent changes in impedance were incorporated into an equation for estimation of temperature in real-time. The accuracy of this equation was assessed by prospectively comparing the calculated and measured temperatures in 19 patients. Of the 88% of energy applications that were suitable for analysis, the average difference between calculated and measured temperatures was 5.2 +/- 5.6 degrees C. The average error was < 10 degrees C in 89% of applications. The results of this study suggest that impedance measurements can be used to quantify tissue temperature in real-time during radiofrequency catheter ablation. This method is sufficiently accurate to allow titration of power output to produce temperatures in the useful range (50-80 degrees C) while avoiding excessive heating (> 90 degrees C).

Wide complex tachycardia due to automaticity in an accessory pathway.

Patients with the Wolff-Parkinson-White (WPW) syndrome have preexcited tachycardia as the result of atrial arrhythmias or antidromic reentry. This article describes a patient with persistent wide complex tachycardia due to abnormal automaticity in the accessory pathway. Radiofrequency catheter ablation resulted in simultaneous elimination of accessory pathway conduction and automaticity. Accessory pathway automaticity may be an infrequent cause of preexcited tachycardia in patients with the WPW syndrome.

Treatment of ventricular tachycardia induced cardiogenic shock by percoronary chemical ablation.

Incessant ventricular arrhythmias pose an especially challenging therapeutic dilemma. We describe the successful treatment and follow-up of a patient with refractory ventricular tachycardia-induced cardiogenic shock with percoronary chemical ablation. After endocardial mapping was used to identify the "tachycardia-related" coronary artery, temporary termination of the arrhythmia with balloon occlusion and subselective intracoronary installation of iced saline as previously advocated was unsuccessful. This was probably due to a dual arterial blood supply to the arrhythmogenic focus. However, infusion of 2 cc ethanol (99%) permanently terminated the arrhythmia. Contrary to previous experience, ethanol-induced arrhythmia termination did not result in arterial occlusion, further supporting a direct toxic effect on the myocardium as its mode of action. Use of standard angioplasty balloon inflation prevents "backwash" of distally infused ethanol and more generalized cell death. The only complication of this procedure was temporary third-degree AV block, requiring permanent pacemaker implantation.

Operating room scheduling data base analysis for scheduling.

A methodology to determine and maintain the schedule times used in a computer-based OR Scheduling System is presented. State-of-the-art equations to be used for different scheduling situations are presented and discussed with the attendant data base reduction methodology to provide the scheduling parameters. An example is given of the data reduction methodology as well as suggestions for maintenance of the data base.

Intermittent mitral regurgitation: an indicator of severe Beall valve dysfunction.

The Teflon disc of Beall valves is subject to extraordinary wear and tear. Clinical evidence of valvular dysfunction is critical in following patients who have implanted Beall valves. We describe 4 patients with the interesting auscultatory finding of intermittent mitral regurgitation. Each of these patients demonstrated severe wear of the Teflon disc with abnormal intermittent disc tilting noted at cardiac catheterization. Intermittent mitral regurgitation in patients with Beall valves in the mitral position heralds severe valvular dysfunction and should prompt urgent cardiac catheterization and valve replacement.

Reduce hospital costs with admissions and operating room scheduling systems.

This paper is the authors' attempt to summarize major aspects of an admissions and OR scheduling systems. The admissions scheduling system can help achieve a stabilization of elective OR procedures and potential increase in utilization of ORs; however, a computer-aided-OR scheduling system is needed to meet the special needs of the OR scheduling process. Thus, combined use of an admissions and OR scheduling system appears to provide the best opportunity for reducing hospital costs as well as providing superior service.

Influence of left ventricular function on signal averaged late potentials in patients with coronary artery disease with and without ventricular tachycardia.

Left ventricular dysfunction has been suggested as a cause of late potentials on the signal averaged ECG of patients with coronary artery disease. We compared the averaged surface ECG with angiographic findings in 57 patients with coronary artery disease and left ventricular dysfunction. Sixteen patients had sustained ventricular tachycardia and 41 had no documented arrhythmia. These two patient groups were comparable with respect to age, mean ejection fraction, and wall motion score. Late potentials, defined as voltage less than 25 microV in the last 40 msec of the filtered QRS complex, were found in 10 of 16 patients with ventricular tachycardia and in 6 of 41 patients without arrhythmia (p less than 0.005). However, late potentials were independent of ejection fraction, wall motion score, or presence of dyskinesis in both groups. There was no correlation between the total filtered QRS duration and ejection fraction or wall motion score in either patient group. In patients with coronary artery disease, late potentials are associated with ventricular tachycardia but are independent of global or regional left ventricular function. This finding has important implications for studies of the prognostic value of late potentials following myocardial infarction.

Rapid ventricular tachycardia due to His-Purkinje reentry.

Two patients developed rapid His-Purkinje reentrant tachycardia during programmed ventricular stimulation for evaluation of recurrent ventricular tachycardia. In Patient 1, His-Purkinje reentry induced a morphologically distinct ventricular tachycardia which may have been a reentrant circuit operating independently for several cardiac cycles. His-Purkinje reentry was not inducible in Patient 2 until lidocaine was given. Following lidocaine administration, sustained His-Purkinje reentrant tachycardia was initiated by 2 premature ventricular stimuli. The tachycardia was rapid (240 beats per minute) and required cardioversion.