Reducing occupational distress in veterinary medicine personnel with acceptance and commitment training: a pilot study.

AIMS: To determine whether an educational programme targeting the reaction of veterinary personnel to difficult client interactions reduced burden transfer, stress and burnout in veterinary staff. METHODS: Employees of three small-animal veterinary hospitals in the south-western United States of America were recruited and randomised to intervention (educational programme; n = 16) or control (no intervention; n = 18) groups. Participants of this randomised, parallel arms trial completed pre-programme assessment including the Burden Transfer Inventory (BTI), Perceived Stress Scale, and Copenhagen Burnout Inventory. Assessment was followed by two, group-format educational sessions, based on acceptance and commitment training, tailored to reducing reactivity to difficult veterinary client interactions (intervention group only). After training was completed, both groups were assessed using the same measures and the intervention participants provided use and acceptability ratings. RESULTS: Intervention participants rated the programme as useful and appropriate, and reported that programme techniques were used a median of 43 (min 9, max 68) times during the 2 weeks prior to retesting. Relative to pre-programme scores, median post-programme scores for reaction (subscore of BTI) to difficult client interactions decreased in the intervention group (33 vs. 54; p = 0.047), but not in the control group (51 vs. 59; p = 0.210). Changes in median scores for stress and burnout from pre- to post-programme were non-significant for both groups. CONCLUSIONS: This pilot and feasibility trial showed high rates of acceptability and use by participants, as well as promising reductions in burden transfer. A larger scale clinical trial with follow-up at extended time points is needed to more fully examine the efficacy of this novel programme. CLINICAL RELEVANCE: Preliminary findings suggest this programme may be a useful approach to reducing occupational distress for individuals working in veterinary practice.

Relationships among owner consideration of euthanasia, caregiver burden, and treatment satisfaction in canine osteoarthritis.

Although diagnosis of osteoarthritis (OA) has been recently linked to euthanasia in dogs, no prior work has examined the roles of caregiver burden or treatment satisfaction in this relationship. We expected that there would be an indirect effect of caregiver burden on the association between consideration of euthanasia and clinical signs of OA, but that this effect would be influenced by owner satisfaction. Cross-sectional online evaluations were completed by 277 owners of dogs with OA recruited through social media. Canine OA-related pain and functional impairment, owner consideration of euthanasia, caregiver burden, and satisfaction were examined. Relationships among OA-related pain and functional impairment, owner consideration of euthanasia, caregiver burden, and satisfaction were statistically significant (P 0.01 for all). Cross-sectional mediation analysis demonstrated a statistically significant indirect effect of caregiver burden on the relationship between consideration of euthanasia and OA-related clinical signs (bias-corrected 95% confidence interval [BC 95% CI], 0.001-0.009), which was significantly moderated by owner satisfaction (BC 95% CI, -0.003 to -0.0002). Findings align with prior work connecting canine OA to euthanasia. The current study extends past research to demonstrate that caregiver burden in the owner may be partially responsible for this relationship. The moderating role of owner satisfaction suggests that optimizing owner impressions of treatment and the veterinary team could attenuate these relationships, potentially decreasing the likelihood of premature euthanasia for dogs with OA.

Predicting caregiver burden in general veterinary clients: Contribution of companion animal clinical signs and problem behaviors.

Caregiver burden, found in many clients with a chronically or terminally ill companion animal, has been linked to poorer psychosocial function in the client and greater utilization of non-billable veterinary services. To reduce client caregiver burden, its determinants must first be identified. This study examined if companion animal clinical signs and problem behaviors predict veterinary client burden within broader client- and patient-based risk factor models. Data were collected in two phases. Phase 1 included 238 companion animal owners, including those with a sick companion animal (n=119) and matched healthy controls (n=119) recruited online. Phase 2 was comprised of 602 small animal general veterinary hospital clients (n=95 with a sick dog or cat). Participants completed cross-sectional online assessments of caregiver burden, psychosocial resources (social support, active coping, self-mastery), and an item pool of companion animal clinical signs and problem behaviors. Several signs/behaviors correlated with burden, most prominently: weakness, appearing sad/depressed or anxious, appearing to have pain/discomfort, change in personality, frequent urination, and excessive sleeping/lethargy. Within patient-based risk factors, caregiver burden was predicted by frequency of the companion animal's signs/behaviors (P<.01). Within client-based factors, potentially modifiable factors of client reaction to the animal's signs/behaviors (P=.01), and client sense of control (P<.04) predicted burden. Understanding burden may enhance veterinarian-client communication, and is important due to potential downstream effects of client burden, such as higher workload for the veterinarian. Supporting the client's sense of control may help alleviate burden when amelioration of the companion animal's presentation is not feasible.

Importance of atrial flutter isthmus in postoperative intra-atrial reentrant tachycardia.

BACKGROUND: In survivors of congenital heart surgery, intra-atrial reentrant tachycardia (IART) often develops. Previous reports have emphasized the atriotomy scar as the central barrier around which a reentrant circuit may rotate but have not systematically evaluated the atrial flutter isthmus in such patients. We sought to determine the role of the atrial flutter isthmus in supporting IART in a group of postoperative patients with congenital heart disease. METHODS AND RESULTS: Nineteen postoperative patients with IART underwent electrophysiological studies with entrainment mapping of the atrial flutter isthmus for determining postpacing intervals. Radiofrequency ablation was performed at the identified isthmus in an effort to create a complete line of block. Twenty-one IARTs were identified in 19 patients, with a mean tachycardia cycle length of 293+/-73 ms. The atrial flutter isthmus was part of the circuit in 15 of 21 (71. 4%). In the remaining 6 of 21, the ablation target zone was at sites near atrial incisions or suture lines. Ablation was successful in 19 of 21 (90.4%) IARTs and in 14 of 15 (93.3%) cases at the atrial flutter isthmus. CONCLUSIONS: In most of our postoperative patients, the atrial flutter isthmus was part of the reentrant circuit. The fact that the atrial flutter isthmus is vulnerable to ablation suggests that whenever IART occurs late after repair of a congenital heart defect, the atrial flutter isthmus should be evaluated. These data support the theory that some form of conduction block between the vena cava is essential for the establishment of a stable substrate for the atrial flutter reentrant circuit.

Reflex control of sympathetic activity during simulated ventricular tachycardia in humans.

BACKGROUND: Ventricular tachyarrhythmias present a unique set of stimuli to arterial and cardiopulmonary baroreceptors by increasing cardiac filling pressures and decreasing arterial pressure. The net effect on the control of sympathetic nerve activity (SNA) in humans is unknown. The purpose of this study was to determine the relative roles of cardiopulmonary and arterial baroreceptors in controlling SNA and arterial pressure during ventricular pacing in humans. METHODS AND RESULTS: Two experiments were performed in which SNA and hemodynamic responses to ventricular pacing were compared with nitroprusside infusion (NTP) in 12 patients and studied with and without head-up tilt or phenylephrine to normalize the stimuli to either the arterial or cardiopulmonary baroreceptors in 9 patients. In experiment 1, the slope of the relation between SNA and mean arterial pressure was greater during NTP (-4.7+/-1.4 U/mm Hg) than during ventricular pacing (-3.4+/-1.1 U/mm Hg). Comparison of NTP doses and ventricular pacing rates that produced comparable hypotension showed that SNA increased more during NTP (P=0.03). In experiment 2, normalization of arterial pressure during pacing resulted in SNA decreasing below baseline (P<0.05), whereas normalization of cardiac filling pressure resulted in a greater increase in SNA than pacing alone (212+/-35% versus 189+/-37%, P=0. 04). Conclusions--These data demonstrate that in humans arterial baroreflex control predominates in mediating sympathoexcitation during ventricular tachyarrhythmias and that cardiopulmonary baroreceptors contribute significant inhibitory modulation.

Insights into the Electrophysiology Study Versus Electrocardiographic Monitoring Trial: its programmed stimulation protocol may introduce bias when assessing long-term antiarrhythmic drug therapy.

OBJECTIVES: We hypothesized that if the Electrophysiology Study Versus Electrocardiographic Monitoring (ESVEM) trial programmed stimulation protocol misclassified some drug trials as effective, then the misclassification rate would be proportionally greater for drugs other than sotalol. BACKGROUND: In the ESVEM trial, patients treated with sotalol had fewer arrhythmic recurrences than those treated with other antiarrhythmic drugs despite similar efficacy predictions during electrophysiologic testing. METHODS: We retrospectively compared the standard programmed stimulation protocol used at Case Western Reserve University, which used three extrastimuli during all follow-up studies, with the ESVEM protocol in 176 antiarrhythmic drug trials: sotalol (n = 54), procainamide (n = 73) and quinidine/mexiletine (n = 49). RESULTS: Predictions of efficacy were higher in the sotalol trials (14 of 54 standard, 20 of 54 ESVEM) than in procainamide trials (7 of 73 standard, 14 of 73 ESVEM) or quinidine/mexiletine trials (1 of 49 standard, 7 of 49 ESVEM). Thus, the two protocols classified 19 of 176 trials differently: not effective by the standard protocol but effective by the ESVEM trial. Discordant predictions of drug efficacy constituted a smaller proportion of ESVEM protocol efficacy predictions for sotalol (6 [30%] of 20) than for the other drugs (13 [62%] of 21, p < or = 0.05). CONCLUSIONS: In the present study, the ESVEM programmed stimulation protocol predicted efficacy more often than the standard protocol. Discordant predictions represented a smaller portion of efficacy predictions for sotalol than for the other drugs. Thus, in the ESVEM trial, the superior long-term follow-up observed in patients assigned to sotalol may have been an artifact of the stimulation protocol utilized by the ESVEM investigators.

Classification of death in antiarrhythmia trials.

OBJECTIVES: We sought to develop and apply a new scheme for the classification of death to be used in trials of antiarrhythmia treatments. BACKGROUND: Because presently accepted classifications of death do not fully describe or tabulate all significant aspects of terminal events, nor do they consider unique aspects of arrhythmia investigations, a new classification scheme that addresses these issues is desirable. METHODS: A classification scheme of deaths that occur in antiarrhythmia trials was developed using the following categories: 1) primary organ cause (cardiac [arrhythmic, nonarrhythmic or unknown], noncardiac or unknown); 2) temporal course (sudden, nonsudden or unknown); 3) documentation (witnessed, monitored [yes, no or unknown]); 4) operative relation (preoperative, perioperative or postoperative); and 5) system relation (procedure related, pulse generator related and lead related [yes, no or unknown]). RESULTS: The classification scheme was used in a clinical trial of a new implantable cardioverter-defibrillator (1,250 patients, of whom 79 died) and used in an application for device market approval. Application of the classification to data reported using an older classification scheme is demonstrated. CONCLUSIONS: We propose a descriptive classification scheme that 1) fully describes and tabulates all significant aspects of terminal events; 2) incorporates previously used categorizations of death and new categorizations that address unique aspects of arrhythmia investigations; and 3) tabulates sufficient data to allow comparison with other studies. Events in a clinical trial of implantable defibrillator therapy were classified using the new classification scheme.

Multiple monomorphic ventricular tachycardia configurations predict failure of antiarrhythmic drug therapy guided by electrophysiologic study.

OBJECTIVES: The purpose of this study was to determine whether the induction at electrophysiologic study of sustained monomorphic ventricular tachycardias with multiple QRS complex configurations predicted failure of subsequent serial electrophysiologic study guided antiarrhythmic drug testing. BACKGROUND: Ventricular tachycardias with multiple QRS complex configurations are associated with failure of surgical therapy for ventricular tachycardia. As such, the presence of multiple monomorphic QRS complex ventricular tachycardias during electrophysiologic testing may predict failure of subsequent medical therapy. METHODS: Fifty-one consecutive patients with coronary artery disease had reproducible induction of monomorphic ventricular tachycardia during a baseline electrophysiologic study. Each patient then underwent a mean of 1.5 antiarrhythmic drug trials. An antiarrhythmic drug regimen that suppressed induction of ventricular tachycardia was identified in 13 (26%) of the 51 patients. RESULTS: Patients with only one inducible monomorphic QRS complex ventricular tachycardia at baseline study were more likely to have an antiarrhythmic drug regimen identified that suppressed inducible ventricular tachycardia than were patients with multiple monomorphic QRS complex ventricular tachycardias (12[36%] of 33 patients vs. 1 [6%] of 18, p = 0.04). In seven patients with only one induced configuration of ventricular tachycardia, a second monomorphic ventricular tachycardia with a different QRS complex configuration occurred during attempts at pacing termination of the induced ventricular tachycardia. None of these seven patients then had successful drug suppression of inducible ventricular tachycardia. Thus, 12 (46%) of 26 patients with a single monomorphic QRS complex ventricular tachycardia observed at baseline study had successful serial drug testing compared with 1 (4%) of 25 patients with multiple QRS complex ventricular tachycardia configurations (p = 0.002). CONCLUSIONS: The induction or observation of multiple monomorphic QRS complex ventricular tachycardias at baseline electrophysiologic study predicted failure of subsequent serial electrophysiologic study--guided antiarrhythmic drug therapy.

Right ventricular outflow tract ventricular tachycardia: detection of previously unrecognized anatomic abnormalities using cine magnetic resonance imaging.

OBJECTIVES: This study attempted to determine whether cine magnetic resonance imaging (MRI), because of its unique ability to image the right ventricle, detects abnormalities in patients with right ventricular outflow tract ventricular tachycardia. BACKGROUND: Right ventricular outflow tract ventricular tachycardia occurs in the absence of apparent structural heart disease. METHODS: We compared cine MRI scans in 22 patients with right ventricular outflow tract ventricular tachycardia, 16 subjects without structural heart disease and 44 patients with other cardiovascular diseases. Echocardiography was performed in 21 patients with ventricular tachycardia. RESULTS: All 22 patients with ventricular tachycardia had normal left ventricular function and no evidence of coronary artery disease. Cine MRI revealed right ventricular structural and wall motion abnormalities more often in patients with ventricular tachycardia (21 [95%] of 22) than in normal subjects (2 [12.5%] of 16, p < 0.0001) or patients without arrhythmia (17 [39%] of 44, p < 0.0001). The abnormalities in patients with ventricular tachycardia (fixed focal wall thinning, excavation, decreased systolic thickening) were located in the right ventricular outflow tract, whereas those in patients without arrhythmia were confined to the free wall. Cine MRI demonstrated abnormalities in patients with ventricular tachycardia more often than did echocardiography (21 [95%] of 22 vs. 2 [9%] of 21, respectively, p < 0.0001). CONCLUSIONS: Right ventricular outflow tract ventricular tachycardia was associated with focal structural and wall motion abnormalities of the right ventricular outflow tract that were detected more often by cine MRI than by other imaging modalities and were not present in patients without arrhythmia or in normal subjects.

Programmed ventricular stimulation in patients with left ventricular dysfunction and ventricular tachycardia: effects of acute hemodynamic improvement due to nitroprusside.

To assess the electrophysiologic effects of acute hemodynamic improvement in patients with left ventricular systolic dysfunction, 12 patients with a left ventricular ejection fraction less than 0.40 and a history of sustained monomorphic ventricular tachycardia were studied. All patients had underlying coronary artery disease. Patients underwent programmed cardiac stimulation in random order during a baseline period and with nitroprusside infusion. Mean pulmonary capillary wedge pressure decreased from 20 +/- 8 mm Hg at baseline study to 8 +/- 3 mm Hg during nitroprusside infusion (p less than 0.0001). Pulmonary artery, right atrial and systemic arterial pressures also decreased with nitroprusside (p less than 0.01). Cardiac output did not change. Left ventricular dimensions, determined by two-dimensional echocardiography, decreased significantly during nitroprusside infusion. The right ventricular effective refractory period, measured during ventricular drive trains at cycle lengths of 400 and 600 ms, were similar during baseline and nitroprusside periods (271 +/- 30 versus 274 +/- 31 ms at 600 ms, and 249 +/- 25 versus 246 +/- 18 ms at 400 ms). In 2 patients no ventricular arrhythmias were induced during either study period; in the other 10, ventricular tachyarrhythmias were induced during both periods. The mean number of extrastimuli required to induce a ventricular tachyarrhythmia was similar during the baseline period (1.8 +/- 0.6) and during nitroprusside infusion (1.9 +/- 0.7). As well, the mean cycle length of ventricular tachycardia induced was similar during the baseline period (347 +/- 61 ms) and during nitroprusside infusion (342 +/- 70 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

Patients at lower risk of arrhythmia recurrence: a subgroup in whom implantable defibrillators may not offer benefit. Antiarrhythmics Versus Implantable Defibrillator (AVID) Trial Investigators.

OBJECTIVES: The goal of this study was to identify subgroups of arrhythmia patients who do not benefit from use of the implantable cardiac defibrillator (ICD). BACKGROUND: Treatment of serious ventricular arrhythmias has evolved toward more common use of the ICD. Since estimates of the cost per year of life saved by ICD therapy vary from $25,000 to perhaps $125,000, it is important to identify patient subgroups that do not benefit from the ICD. METHODS: Data for 491 ICD patients enrolled in the Antiarrhythmics Versus Implantable Defibrillators Study were used to create a hazards model relating baseline factors to time to first recurrent arrhythmia. The model was used to predict the hazard for recurrent arrhythmia among all trial patients. A priori cut points provided lower and higher recurrent arrhythmia risk strata. For each stratum the incremental years of life due to ICD versus antiarrhythmic drug therapy were calculated. RESULTS: Factors that predicted recurrent arrhythmia were: ventricular tachycardia as the index arrhythmia, history of cerebrovascular disease, lower left ventricular ejection fraction, a history of any tachyarrhythmia before the index event and the absence of revascularization after the index event. Survival times (over a follow-up of three years) were identical in each arm of the lowest risk sextile (survival advantage 0.03 +/- 0.12 [se] years), while the survival advantage for patients above the first sextile was 0.27 +/- 0.07 (se) years (two-sided p = 0.05). CONCLUSIONS: Patients presenting with an isolated episode of ventricular fibrillation in the absence of cerebrovascular disease or history of prior arrhythmia who have undergone revascularization or who have moderately preserved left ventricular function (left ventricular ejection fraction > 0.27) are not likely to benefit from ICD therapy compared with amiodarone therapy.

Life-threatening ventricular arrhythmias due to transient or correctable causes: high risk for death in follow-up.

OBJECTIVES: This study evaluated the prognosis of patients resuscitated from ventricular tachycardia (VT) or ventricular fibrillation (VF) with a transient or correctable cause suspected as the cause of the VT/VF. BACKGROUND: Patients resuscitated from VT/VF in whom a transient or correctable cause has been identified are thought to be at low risk for recurrence and often receive no primary treatment for their arrhythmias. METHODS: In the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, patients with a potentially transient or correctable cause of VT/VF were not eligible for randomization. The mortality of these patients was compared with the mortality of patients with a known high risk of recurrence of VT/VF in the AVID registry. RESULTS: Compared with patients having high risk VT/VF, those with a transient or correctable cause for their presenting VT/VF were younger and had a higher left ventricular ejection fraction. These patients were more often treated with revascularization as the primary therapy, more commonly received a beta-blocker, less often required therapy for congestive heart failure and less commonly received either an antiarrhythmic drug or an implantable cardioverter defibrillator. Nevertheless, subsequent mortality of patients with a transient or correctable cause of VT/VF was no different or perhaps even worse than that of the primary VT/VF population. CONCLUSIONS: Patients identified with a transient or correctable cause for their VT/VF remain at high risk for death. Further research is needed to define truly reversible causes of VT/VF. Meanwhile, these patients may require more aggressive evaluation, treatment and follow-up than is currently practiced.

Beta-blocker use and survival in patients with ventricular fibrillation or symptomatic ventricular tachycardia: the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial.

OBJECTIVES: To evaluate whether use of beta-adrenergic blocking agents, alone or in combination with specific antiarrhythmic therapy, is associated with improved survival in persons with ventricular fibrillation (VF) or symptomatic ventricular tachycardia (VT). BACKGROUND: The ability of beta-blockers to alter the mortality of patients with VF or VT receiving contemporary medical management is not well defined. METHODS: Survival of 1,016 randomized and 2,101 eligible, nonrandomized patients with VF or symptomatic VT followed in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial through December 31, 1996 was assessed using Cox proportional hazards analysis. RESULTS: The 817 (28%) patients discharged from hospital receiving beta-blockers had less ventricular dysfunction, fewer symptoms of heart failure and a different pattern of medication use compared with patients not receiving beta-blockers. Before adjustment for important prognostic variables, beta-blockade was not significantly associated with survival in randomized or in eligible, nonrandomized patients treated with specific antiarrhythmic therapy. After adjustment, beta-blockade remained unrelated to survival in randomized or in eligible, nonrandomized patients treated with amiodarone alone (n = 1142; adjusted relative risk [RR] = 0.96; 95% confidence interval [CI] 0.64-1.45; p = 0.85) or a defibrillator alone (n = 1347; adjusted RR = 0.88; 95% CI 0.55 to 1.40; p = 0.58). In contrast, beta-blockade was independently associated with improved survival in eligible, nonrandomized patients who were not treated with specific antiarrhythmic therapy (n = 412; adjusted RR = 0.47; 95% CI 0.25 to 0.88; p = 0.018). CONCLUSIONS: Beta-blocker use was independently associated with improved survival in patients with VF or symptomatic VT who were not treated with specific antiarrhythmic therapy, but a protective effect was not prominent in patients already receiving amiodarone or a defibrillator.

Impact of a guideline-based disease management team on outcomes of hospitalized patients with congestive heart failure.

BACKGROUND: Congestive heart failure is the most common reason for hospitalization in the United States, and guidelines to improve the quality of care for patients with congestive heart failure have been developed. However, adherence is typically low. We hypothesized that a guideline-based care management team would result in greater quality and efficiency of care than guidelines alone. METHODS: A faculty cardiologist and nurse care manager at an academic medical center reviewed each patient's data and made guideline-based recommendations. Hospital length of stay, total costs, and use of recommended guidelines were compared between 173 patients before team implementation but with available guidelines, 283 care-managed patients, and 126 concurrent non-care-managed patients. RESULTS: Care-managed patients achieved higher rates of use of angiotensin-converting enzyme inhibitor than baseline or non-care-managed patients (95%, 60%, and 75%, respectively; P<.001), as well as increased adherence to guidelines for daily weight monitoring and assessment of left ventricular function. Hospital length of stay was lower (median, 3, 4, and 5 days, respectively; P<.001) as were costs of hospitalization (median, $2934, $3209, and $4830, respectively; P<.01). These differences persisted after adjustment for severity of illness. CONCLUSIONS: When compared with dissemination of guidelines alone, an active care management approach was associated with significant improvements in quality and efficiency of care for hospitalized patients with congestive heart failure.

NMDA, AMPA, and benzodiazepine binding site changes in Alzheimer's disease visual cortex.

Quantitative receptor autoradiography was used to measure the laminar distribution of [3H]glycine and [3H]glutamate binding to the N-methyl-D-aspartate (NMDA) receptor complex, [3H]D,L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) binding to the AMPA receptor, and [3H]flunitrazepam binding to the benzodiazepine (BDZ) receptor in three areas of visual cortex in control and Alzheimer's disease (AD) postmortem human brains (primary or striate visual cortex, visual association cortex, and higher-order visual association cortex, corresponding to Brodmann Areas 17, 18, and 21, respectively). In Area 17, binding to the NMDA, AMPA, and BDZ receptors was not significantly altered in the AD brains (except in layer VI for [3H]glycine and layer III for [3H]AMPA, where binding was reduced in the AD brains). Ligand binding to the two EAA receptors in Area 18 was, however, significantly reduced in the AD brains (layers I through III for [3H]glycine and layers III through VI for [3H]AMPA). In Area 21, binding to both the NMDA and BDZ receptors but not to the AMPA receptor, was significantly reduced in almost all laminae of the AD brains (layers I through VI for [3H]glycine and layers I through V for [3H]flunitrazepam). This hierarchical pattern of laminar binding loss with increasing complexity of association visual cortices is consistent with the increasing numbers of neurofibrillary tangles found in those areas, implicating NMDA and BDZ receptor bearing cells in AD neuropathology. AMPA receptor losses do not parallel the pathology, suggesting that AMPA receptors are not directly correlated with the pathology.

Systolic blood pressure at rest, not the degree of beta blockade, predicts the result of follow-up tilt-table testing for vasovagal syncope.

Tilt-table testing after therapy with beta blockade is frequently used to predict clinical success. This study found that heart rate and blood pressure reductions after beta-blocker therapy did not predict the results of the follow-up tilt-table test, but low blood pressure at rest before the initial test predicts failure of this therapy.

Efficacy and safety of moricizine in the maintenance of sinus rhythm in patients with recurrent atrial fibrillation.

Maintenance of sinus rhythm is the primary goal of antiarrhythmic drug therapy for recurrent atrial fibrillation (AF). However, concern about proarrhythmic and negative inotropic effects has led to increasing reluctance to administer antiarrhythmic agents for this non-life-threatening arrhythmia. Moricizine is well tolerated in a wide variety of patients, and therefore, may be a safe and effective agent for treating AF. We retrospectively assessed the efficacy and safety of moricizine (mean dose 609 +/- 9 mg/day) in 85 consecutive patients with recurrent AF (2.6 +/- 0.5 years duration, 1.6 +/- 1 failed antiarrhythmic drugs). Structural heart disease was present in 69 (81%), but no recent myocardial infarct (< or =90 days) was present; mean left atrial size was 46 +/- 1 mm, and mean left ventricular ejection fraction was 0.51 +/- 0.01. Moricizine was discontinued because of unsuccessful direct-current cardioversion (n = 5) or clinically unacceptable side effects (n = 6); 6 patients developed transient side effects not requiring discontinuation. Of the 74 patients continuing therapy, 68% remained in sinus rhythm after 6 months, and 59% after 12 months. During a follow-up (21 +/- 2 months), there were neither deaths nor adverse effects requiring discontinuation of therapy. Thus, moricizine was effective, safe, and well tolerated in our patient cohort with AF.

A perspective on ventricular arrhythmias: patient assessment for therapy and outcome.

Clinical management of patients with ventricular arrhythmias continues to evolve. It is generally accepted that patients with sustained ventricular tachyarrhythmias (ventricular tachycardia [VT] or fibrillation) require treatment. It is also generally accepted that patients with frequent or complex ventricular ectopy or nonsustained VT, in the absence of underlying heart disease, do not require treatment unless relief of symptoms is warranted. Whether patients with frequent or complex ventricular ectopy or nonsustained VT require treatment in the presence of underlying organic heart disease remains uncertain. The concern is that these ventricular arrhythmias may be a precursor for sustained, potentially life-threatening ventricular tachyarrhythmias. Available data suggest that patients with underlying heart disease, particularly coronary artery disease and a previous myocardial infarction, who manifest frequent or complex ventricular ectopy or nonsustained VT are at increased risk for sudden cardiac death. However, no studies have shown that treatment of these arrhythmias will affect outcome. Data are accumulating to suggest that use of the principles of risk stratification permits identification of patients at very high risk for developing sustained ventricular tachyarrhythmias. Carefully designed clinical trials are required before one can provide firm guidelines for the management of these patients. Nevertheless, when several risk factors for sudden cardiac death (e.g., abnormal ejection fraction, a late potential on a signal-averaged electrocardiogram, and frequent or complex ventricular ectopy or nonsustained VT) are present in a patient, especially after a recent myocardial infarction, invasive electrophysiologic testing may help identify those who need treatment (sustained VT is inducible) and those who do not (no sustained VT is inducible).

Sensitivity of an automatic external defibrillator for ventricular tachyarrhythmias in patients undergoing electrophysiologic studies.

An automatic advisory external defibrillator (AED) was activated during all arrhythmias occurring at the time of 77 electrophysiologic studies in 45 patients. Sustained ventricular tachycardia (VT) occurred during 55 studies in 31 patients and nonsustained VT was induced during 10 studies in 9 patients. Ventricular fibrillation was induced 5 times in 5 patients and atrial arrhythmias with a rapid ventricular response occurred during 7 studies in 4 patients. The AED detection algorithm advised "shock" during 36 of 55 (65%) episodes of sustained VT and all 5 episodes of ventricular fibrillation. The device correctly advised "shock" for all 6 episodes of nonsustained VT that spontaneously terminated after analysis was complete. Thus, the sensitivity of the device for all ventricular arrhythmias analyzed was 47 of 66 (71%). The device recommended "shock" for all 31 episodes of rapid VT and 1 of 2 episodes of atrial fibrillation associated with systemic hypotension (32 of 33, 97%). The 19 episodes of VT for which "no shock" was advised were comparatively slow and were hemodynamically well tolerated. The device recommended "no shock" during all 21 episodes of normal sinus rhythm and all 20 episodes of rapid atrial pacing (cycle length 400 ms) analyzed. "No shock" was advised during 4 episodes of sustained narrow QRS complex supraventricular tachycardia and 4 brief episodes of nonsustained VT that terminated before analysis was complete. Thus, in this study the specificity of the AED for wide complex tachycardias was 100%.

Current-based transthoracic defibrillation.

This study examines in a prospective, multicenter trial the feasibility and advantage of current-based, transthoracic defibrillation. Current-based, damped, sinusoidal waveform shocks of 18, 25, 30, 35, or 40 amperes (A) were administered beginning with 25 A for polymorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) or 18 A for monomorphic VT; success rates were compared with those of energy-based shocks beginning at 200 J for VF/polymorphic VT and 100 J for VT. The current-based shocks were delivered from custom-modified defibrillators that determined impedance in advance of any shock using a "test-pulse" technique; the capacitor then charged to the exact energy necessary to deliver the operator-selected current against the impedance determined by the defibrillator. Three hundred sixty-two patients received > 1 shock for VF, polymorphic VT, or monomorphic VT: 569 current- based shocks and 420 energy-based shocks. Current-based shocks of 35/40 A achieved success rates of up to 74% for VF/polymorphic VT; 30 A shocks terminated 88% of monomorphic VT episodes. Energy-based shocks of 300 J terminated 72% of VF/polymorphic VT; 200-J shocks terminated 89% of monomorphic VT. We could not demonstrate a significant increase in the success rate of current-based shocks over energy-based shocks for patients with high transthoracic impedance; this may be due to inadequate sample size. Thus, current-based defibrillation is clinically feasible and effective. A larger study will be needed to test whether current-based defibrillation is superior to energy-based defibrillation.