The economic impact of transvenous defibrillation lead systems

Effects of Radix dichroae extract supplementation on growth performance, oocysts output and gut microbiota in growing lambs with coccidiosis

Coccidiosis is an intestinal protozoan disease of sheep, that causes substantial economic losses in the industry due to its intestinal protozoan origins. Many anti-protozoan drugs including ionophores, triazines, and sulfonamides have been widely used to treat sheep coccidiosis. Still, anticoccidial resistance and drug residues in edible tissues have prompted an urgent search for alternatives. In this study, the anti-coccidial effectiveness of the Radix dichroae extract was compared to that of the conventional anti-coccidial drug diclazuril. Here, eighteen 45-day-old lambs naturally-infected with Eimeria spp. were randomly allocated in three groups: control group, Radix dichroae extract group and diclazuril group. The results showed that the body weight gain (BWG) during the treatment and withdrawal periods was considerably improved in the coccidiosis-infected sheep treated with Radix dichroae extract and diclazuril compared to the control group, respectively. Additionally, the Radix dichroae extract and diclazuril had fewer oocysts per gram (OPG) than the control group, showing similar anti-coccidial effects on days 14, 21, 28, 35 and 78, respectively. Furthermore, Radix dichroae extract and diclazuril treatment altered the structure and composition of gut microbiota, promoting the relative abundance of Actinobacteriota, Firmicutes, Alistipes, and Bifidobacterium, while decreasing the abundance of Bacteroidota, Marinilaceae, Helicobacteraceae, and Prevotella. Moreover, Spearman's correlation analysis further revealed a correlation between the OPG and BWG and gut microorganisms. Collectively, the results indicated that Radix dichroae extract had similar anti-coccidial effects as diclazuril, and could regulate gut microbiota balance in growing lambs.

Safety and potential cost savings of same-setting electrophysiologic testing and placement of transvenous implantable cardioverter-defibrillators

BACKGROUND

Separately, electrophysiologic study (EPS) and placement of a transvenous implantable cardioverter-defibrillator (ICD) can be performed safely in the majority of patients. The safety and potential cost savings of same-setting procedures have not been evaluated.

HYPOTHESIS

Electrophysiologic study and placement of transvenous ICDs can be performed safely in the same setting at reduced cost.

METHODS

In all. 160 (mean age 65 +/- 10 years, 75% men) and 41 (mean age 66 +/- 11 years, 73% men) consecutive patients who underwent same- versus separate-setting procedures, respectively, were prospectively evaluated.

RESULTS

The two groups had similar clinical characteristics and indications for EPS and ICD therapy. Complications occurred in eight patients (5.0%, 95% confidence interval [CI] 2.3-10.3) who had same-setting procedures (one hypotension during ICD testing, one pocket hematoma, two lead dislodgments, two pneumothoraces, one stroke, and one infection) and in two (4.9%, CI 0.60-16.5) who had separate-setting procedures (one pocket hematoma and one infection). There were no procedure-related deaths or long-term ICD-related complications in either group. The mean time from ICD implantation to hospital discharge was similar in the two groups (2.5 +/- 2.4 vs. 2.7 +/- 2.2 days, p = NS). The combined procedure cost was higher in patients who had separate-setting procedures ($12,403 +/- 1,386 vs. $10,242 +/- 2.256, p = < 0.001). who incurred an additional hospital cost of $2,121 +/- $2,125 for the waiting period (1.7 +/- 1.6 days) between EPS and ICD implantation.

CONCLUSIONS

In patients deemed candidates for ICD therapy based on EPS results, placement of transvenous defibrillators in the same setting as EPS is as safe as separate-setting procedures and, if adopted, could further reduce the cost of providing ICD therapy.

ICD therapy in the new millennium

Remarkable progress has been made in the 15 years since ICD therapy was approved for human use. The early "shock boxes" had almost no diagnostic capabilities and required thoracotomy for epicardial patch implantation with typical duration of hospitalization of about a week. Pulse-generator longevity was less than 2 years. Modern devices provide detailed information about the morphology and rate of electrocardiographic signals before, during, and after arrhythmia therapy. The down-sizing of pulse generators and improvements in lead design and shock waveforms allow the simplicity of defibrillator implantation to approach that of pacemakers, with defibrillation thresholds comparable with those initially observed with epicardial patches. Despite the marked reduction in size and increase in diagnostic capabilities, device longevity is now longer than 6 years. Routine outpatient ICD implantation is presently feasible and will increase in frequency if ongoing primary prevention trials prove beneficial. Further advances in lead technology and arrhythmia discrimination should increase the efficacy and reliability of therapy. Finally, devices have the capabilities to treat multiple problems in addition to life-threatening ventricular arrhythmias including atrial arrhythmias and congestive heart failure.

Replacing abdominally implanted defibrillators: effect of procedure setting on cost

Although most ICDs are currently placed using a pectoral approach, there exists a large population of patients with abdominally implanted ICDs who will require device replacement due to a depleted battery. The purpose of this study was to compare the cost, convalescence, and complication rate of replacing abdominally implanted ICDs in the OR versus the EP laboratory. Between August 1993 and September 1994, we prospectively enlisted nine consecutive patients who presented for their second ICD generator replacement and who had a prior generator replacement in the OR 3-4 years earlier. The mean age of the patients was 63 +/- 17 years and their mean ejection fraction was 37% +/- 15%. ICD replacement was performed in the EP laboratory and consisted of explanting the old device, electronic interrogation of the lead system, and confirmation of defibrillation thresholds prior to implanting a new device. Local anesthesia was provided by lidocaine infiltration and sedation was achieved with intravenous (i.v.) midazolam and fentanyl. Following the procedure, the patients were returned to an outpatient monitored setting for 4 hours and were then discharged. Comparisons of the health care charges for the same procedure performed in the two different settings revealed a significant reduction in physician fees (from $3,621 +/- $556 to $2,179 +/- $577, P < 0.05), in hospital charges (from $5,811 +/- $1,102 to $2,306 +/- 696, P < 0.05), and in total charges (from $9,431 +/- $1,375 to $4,541 +/- $1,010, P < 0.05), exclusive of ICD cost, when the procedure was performed on an outpatient basis in the EP laboratory. Inpatient days averaged 3.0 +/- 0.3 when the procedure was performed in the OR. On long-term follow-up there were no complications following abdominal ICD generator replacement in the OR (mean follow-up, 39 +/- 2 months) or in the EP laboratory (mean follow-up, 42 +/- 4 months). Thus, ICD replacements in the EP laboratory cost less than in the OR due to significantly lower physician fees, hospital charges, and a shorter postprocedural convalescence.

A comparison of pectoral and abdominal transvenous defibrillator implantation: analysis of costs and outcomes

Traditionally cardioverter-defibrillator implantation was performed by surgeons under general anesthesia. However, with advances in lead and pulse generator technology, the surgical implantation technique has been simplified and routine pectoral pulse generator placement without general anesthesia is now possible. To assess the economic benefit of pectoral implantation, we analyzed 43 consecutive initial transvenous defibrillator implantations. The patients were grouped according to whether the implant was abdominal by a surgeon in the operating room (n = 23) or pectoral by an electrophysiologist in a laboratory (n = 20). The duration of hospitalization was significantly longer in the operating room than in the laboratory group (8.1 +/- 3.4 vs 5.8 +/- 2.4 days, p = 0.01), which was due primarily to the postoperative stay which averaged 1.9 days longer. Total costs were $40,274 +/- 6,861 for the operating room cohort and $32,546 +/- 3,634 for the lab group (p < 0.001). This reduction was due to a 32% lowering of professional costs and an 18% lowering of facility costs. We conclude that pectoral defibrillator implantation is cost effective and results in significant reductions of hospital stay.

Biphasic waveforms for ventricular defibrillation: optimization of total pulse and second phase durations

Waveform parameters may affect the efficacy of ventricular defibrillation. Certain biphasic pulse waveforms are more effective for ventricular defibrillation than monophasic waveforms, but the optimal biphasic waveform parameters have not been identified. The purpose of this study was to investigate the effects of total pulse duration and the duration of the second (negative) phase on voltage and energy defibrillation requirements using biphasic waveforms. Defibrillation efficacy was evaluated in an isolated rabbit heart model using the Langendorff technique. The biphasic waveform was a truncated exponential with the initial voltage of the second phase equal to 50% of the final voltage of the first phase. An up/down protocol was used to determine the 50% probability-of-success levels (E50) for delivered energy and initial voltage. First, using pulse waveforms with equal positive and negative phase durations, test waveforms with total durations of 4 ms (2 ms positive + 2 ms negative), 6 ms (3 + 3 ms), and 16 ms (8 + 8 ms) were compared to the control waveform of 8 ms (4 + 4 ms) in 30 experiments. Defibrillation voltage requirements with 4 ms (174 +/- 56 V) were higher (P = 0.001) compared to 8 ms (127 +/- 49 V). Defibrillation voltage requirements for the 6-ms and 16-ms waveforms were similar to the 8-ms control waveform. Delivered energies tended to be higher with the 4-ms waveform. A second series of 40 experiments were performed to compare monophasic (4 + 0 ms) and three asymmetric biphasic waveforms (4 + 2 ms, 4 + 8 ms, and 4 + 16 ms) to the symmetric control waveform (4 + 4 ms). The monophasic (2.15 +/- 1.21 J) and the 4 + 16 ms waveform (1.86 +/- 1.09 J) required higher energies (P < or = 0.05) than the control waveform (1.24 +/- 0.41 J and 0.87 +/- 0.7 J, respectively). The monophasic waveform also resulted in greater voltage requirements (223 +/- 64 V) compared to the control waveform (160 +/- 26 V) (P = 0.02). Energy and voltage requirements were similar for the 4 + 2 ms and 4 + 8 ms waveforms compared to the control. Defibrillation requirements with biphasic waveforms were affected by total and second phase duration. For waveforms with equal phase durations, total durations between 6-16 ms resulted in the lowest values for defibrillation. For waveforms with variable second (negative) phase durations, durations ranging from 50%-200% of the first phase did not affect defibrillation efficacy.

Long-term follow-up of cardioverter-defibrillator implanted under conscious sedation in prepectoral subfascial position

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) with intravenous electrode systems and downsized generators can be implanted by use of operative techniques similar to those employed for the insertion of permanent pacemakers. However, the safety, efficacy, and long-term follow-up of simplified implantation procedures remain to be evaluated. This report is a prospective long-term evaluation of nonselected patients receiving ICDs in the prepectoral subfascial position under conscious sedation.

METHODS AND RESULTS

Clinical characteristics of the 231 consecutive patients included a mean age of 63 years, a male-to-female ratio of 6.4, a left ventricular ejection fraction of 0.34, a mild-to-moderate heart failure in 91%, coronary artery disease in 84%, and a history of aborted sudden cardiac death or refractory ventricular tachyarrhythmias. Insertion of transvenous leads and prepectoral subfascial ICD implantation were performed in electrophysiology laboratories under local anesthesia and conscious sedation with intravenous midazolam and propofol. Successful implantation in all patients (operation time, 80 +/- 32 minutes, mean +/- SD) irrespective of body size and skin thickness was free of major complications, including need for emergency intubation. After surgery, 1 pocket hematoma, 1 seroma, and 1 pneumothorax required treatment. There was no operative or first-month mortality. During long-term follow-up averaging 453 +/- 296 days, six leads required repositioning, but pocket erosions or infections did not occur. First-year total survival was 97%.

CONCLUSIONS

Implantation under conscious sedation of ICDs in the prepectoral subfascial position is a safe and effective procedure with low operative and postoperative morbidity and favorable long-term outcome.

Undertreatment and overtreatment of patients with infected antiarrhythmic implantable devices

BACKGROUND

Infection of implantable defibrillators or pacemakers is a serious complication, reported with increasing frequency probably because of an increase in the total number of devices implanted due to a change in trends in the treatment of arrhythmias. This review is aimed to provide guidelines on how to deal with these infections and which method is most likely to be successful.

METHODS

This is a review of 38 patients with infected antiarrhythmic implantable devices under three different plans of therapy. There were 17 implantable cardioverter defibrillators and 21 pacemakers. In 27, infection occurred after primary implantation (15 pacers, 12 implantable cardioverter defibrillators), and in 11 after replacement (six pacers, five implantable cardioverter defibrillators). Three therapeutic plans were identified. Group I (n = 12) received intravenous antibiotics without removal of the antiarrhythmic implantable device, but with relocation to a different area or plane, and with or without the use of a topical irrigating-suction system. Group II (n = 19) had complete removal of the system, 2 weeks of intravenous antibiotics, and implantation of a new unit followed by 10 more days of antibiotics. Group III (n = 7) underwent complete removal, 6 weeks of antibiotics, implantation of a new unit, and another 6 or more weeks of antibiotic therapy.

RESULTS

Failure occurred in 100% of cases in group I. Groups II and III had complete clearing of infection and successful reimplantation of new systems with no recurring infections. Follow-up was 8 months to 5 years. Two deaths occurred, both in group I. Hospitalization for groups I and III was 104 days and 65 days, respectively, versus 22 days for group II. No deaths occurred in group II or III.

CONCLUSIONS

With an infected antiarrhythmic implantable device, immediate removal of the entire unit is recommended, followed by 2 weeks of intravenous antibiotics, implantation of a new system, and 10 more days of postoperative antibiotics. This regimen is sufficient to cure the problem. No attempts should be made to save an infected system from removal because it endangers the patient's life, prolongs hospitalization, increases costs, and most likely will fail.

Implanted cardioverter-defibrillators are preferable to drugs as primary therapy in sustained ventricular tachyarrhythmias

The choice of initial therapy for patients with malignant ventricular tachyarrhythmias is examined based on clinical efficacy, patient safety, and cost. Antiarrhythmic drug therapy can be administered using a guided or empiric approach. Guided type-1 antiarrhythmic drug therapy has been associated with high arrhythmia recurrence rates (> 40% at 1 year) and moderate sudden death rates (10% at 1 year). Sotalol is associated with lower arrhythmia recurrence rates (20% at 1 year) that increase to 50% at 4 years. Beta-blocking agents have a limited role as stand-alone therapy in this condition. Empiric amiodarone therapy has sudden death-free survival rates of 82% at 2 years but has significantly poorer results in patients with ejection fractions < or = 40%. In contrast, implantable cardioverter-defibrillator (ICD) therapy has reported sudden death recurrence rates of 1% to 2% per year, with a cumulative index of 10% at 5 years. Total survival rate of ICD recipients ranges from 85% to 92% at 2 years. In patients with good left ventricular function, it approaches 90% at 5 years, whereas it is between 50% to 60% in patients with severe left ventricular dysfunction. Data from device memory indicate an absolute reduction in mortality rates with ICD intervention. Comparison of drug and device therapy has been performed in retrospective and prospective studies. Improved survival with device therapy is noted, particularly in patients with ejection fractions < or = 35% to 40% in retrospective studies. The results of two small prospective randomized trials also show significant survival advantage as compared with those for type-1C drugs and a mixed group of antiarrhythmic drugs. An initial strategy of ICD therapy was shown to be superior in the Netherlands Cooperative Study. The 30-day perioperative mortality rate of ICD therapy of 0.8% contrasts favorably with a 13% mortality rate in the ESVEM trial with antiarrhythmic drugs and a 3.5% mortality rate in the CASCADE study. Economic analyses show that drug therapy and device therapy are both within the range of other current cardiovascular therapies. An improving economic profile for device therapy has been observed with nonthoracotomy and pectoral implantation and direct use of ICD therapy because primary therapy shortens hospital stay and reduces costs. Based on available data, ICD therapy is preferable as initial therapy in patients with malignant ventricular tachyarrhythmias.

The additional hospital costs generated in the management of complications of pacemaker and defibrillator implantations

The rapid approach of capitated reimbursement mandates that providers examine their practice patterns associated with all surgical procedures. Documentation of (1) the complications associated with these procedures and (2) the additional hospital costs associated with the management of these complications is critical for comprehensive fiscal accountability. This study analyzed (1) the feasibility of obtaining accurate hospital cost data specific for complications and (2) the outcome in terms of fully loaded hospital costs generated in the management of the most common surgical complications associated with pacemaker and nonthoracotomy implantable defibrillator therapies. Between July 1989 and September 1994, a total of 1031 pacemaker and 105 implantable defibrillator procedures were performed by a cardiac surgeon in a tertiary-level teaching hospital setting. The additional fully loaded hospital costs were determined by (1) correlating clinical data from the complete medical record with complete hospital charge data for the admission(s) related to the complication, (2) carving out complication-related charges based on the clinical data, (3) converting complication-related charges to fully loaded costs based on conversion factors in effect at the time of service, and (4) correlating cost with hospital net reimbursement and payor source. The feasibility study determined that accurate and reliable cost data specific to complications can be obtained, although the process was cumbersome and difficult. The outcomes study determined that mean fully loaded complication costs were $4345 +/- $1540 for pacemaker lead revision and $4879 +/- $3167 for implantable defibrillator lead dislodgement, $24,459 +/- $14,585 for pacemaker infection, and $13,736 +/- $12,505 for defibrillator generator system malfunction. The one infected defibrillator cost $57,213 to treat. Costs exceeded reimbursement for almost all Medicare patients with complications in this study, suggesting that similar shortfalls would occur under a capitation scheme. This information is critical to a complete understanding of the financial impact of interventional procedures in a capitated reimbursement environment.

The role of catheter ablation in atrial tachycardia, flutter, and fibrillation

The first experiences of nonpharmacological treatment of ectopic atrial tachycardia (EAT), common atrial flutter (AFl), and atrial fibrillation (AF) were performed by surgical techniques. Many studies reported a very high success rate on the use of catheter ablation with radiofrequency current for the treatment of supraventricular arrhythmias; and recently, various preliminary reports are dedicated to the treatment of EAT, AFl, and AF with that source of energy. To our knowledge 108 cases of EAT treated by catheter ablation of the ectopic focus are reported in the literature with a success rate superior to 90%. On the basis of our personal experience regarding 11 cases (4 of right atrium EAT and 7 of left) we discuss here the essential role of unipolar leads derived from the mapping catheter to select the target for radiofrequency applications. Two hundred and one cases of AFl tested by catheter ablation were previously reported. The majority of them (> 80%) were successfully treated with radiofrequency. Some working groups performed the procedure as the basis of electrophysiological findings, while others preferred an anatomical approach applying radiofrequency energy at the isthmus lying between the coronary sinus ostium and the tricuspid ring, near the vena cava orifice. On the basis of these assumptions, we obtained 83% of final success in 12 cases of AFl treated by radiofrequency. Finally, we discuss the problem related to the modulation of atrioventricular (AV) nodal conduction during AF. In our laboratory, five cases with chronic AF and very fast ventricular response were treated with radiofrequency with a posterior septal approach. In all patients, we obtained very encouraging results with a constant decrease of ventricular rate (from 137 +/- 33 to 69 +/- 14 beats per minute). All cases treated by modulation of AV nodal conduction demonstrated an appropriate chronotropic response to the variations of the functional state that persists during the follow-up. More experience with longer follow-up and accurate pre- and postprocedure evaluations are needed to finalize the most appropriate technique of radiofrequency applications in these cases.

Neurally mediated syncope and serotonin reuptake inhibitors

Serotonin (5-hydroxytryptamine or 5HT) is a neurotransmitter which appears to play a prominent role in central regulation of heart rate and blood pressure. Recent evidence suggests that the activation of cerebral serotonin receptors results in a depressor effect principally through sympatho-inhibition. Several common clinical disorders resulting in hypotension leading to syncope are neurally mediated syncope, carotid sinus hypersensitivity and orthostatic hypotension, each of which may involve a serotonergic component. This brief review provides a summary of serotonergic blood pressure regulation, as well as the initial experience with the clinical effects of the serotonin reuptake inhibitors in the therapy of the aforementioned disorders.

Comparison of implantation of nonthoracotomy defibrillators in the operating room versus the electrophysiology laboratory

Implantable cardioverter-defibrillators (ICDs) with nonthoracotomy lead systems are widely available, and are implanted either in the electrophysiology laboratory or the operating room. The purpose of this study was to prospectively evaluate the safety and efficacy of nonthoracotomy ICD implantation in an electrophysiology laboratory versus an operating room. During a 7-month period, 62 consecutive ICDs with nonthoracotomy lead systems were implanted in patients in an electrophysiology laboratory. During the next 10 months, 110 consecutive ICDs were implanted in patients in a surgical operating room. All ICD implantations were performed under general anesthesia by electrophysiologists. There were no differences in age (58 +/- 14 vs 62 +/- 12 years, p = 0.06), gender distribution (p = 0.3), frequency of structural heart disease (97% vs 97%, p = 0.9), ejection fraction (0.31 +/- 0.15 vs 0.29 +/- 0.13, p = 0.3), or presentation with cardiac arrest (65% vs 53%, p = 0.2) between patients undergoing ICD implantation in the electrophysiology laboratory and operating room, respectively. The rate of successful implantation and of complications for systems implanted in the electrophysiology laboratory (95% and 13%, respectively) and in the operating room (98% and 14%, respectively) were similar (p = 0.4 and p = 0.8, respectively). Specifically, the rate of infection (0% vs 4%, p = 0.3) and hematoma formation (2% vs 4%, p = 0.8) were not statistically significantly different. Three patients who had undergone ICD implantation in an operating room died within 30 days. ICDs with nonthoracotomy lead systems can be implanted with a similarly high rate of success and acceptable complication rate in the electrophysiology laboratory and in the operating room.