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PubMedDate not supplied

Amiodarone therapy for sustained ventricular tachycardia after myocardial infarction: long-term follow-up, risk assessment and predictive value of programmed ventricular stimulation.

We determine the value of the programmed ventricular stimulation (PVS) and of clinical, angiographic and electrophysiologic variables in assessing the long-term risk of arrhythmia recurrence in a group of coronary artery diseased patients presenting with a first episode of monomorphic sustained ventricular tachycardia (VT) treated with amiodarone. Mortality and arrhythmia recurrence rates were retrospectively assessed in 55 consecutive patients with previous myocardial infarction presenting with a first VT episode. Results of left heart catheterization, echocardiography and time-domain signal-averaging were collected. Patients underwent PVS after amiodarone oral loading and were classified according to inducibility before being all discharged on amiodarone (200 mg daily). The mean follow-up was 42+/-31 months. Total and cardiac mortality rates were 29% (16 patients) and 23% (13 patients) respectively. Sudden death (SD) occurred in nine patients (16%). VT recurred in 13 patients (23%). Sustained monomorphic VT was inducible in 40 patients (72%) after amiodarone loading. Neither total mortality (10/40 vs. 6/15) nor cardiac mortality (3/40 vs. 1/15) were significantly different between inducible and non-inducible patients. Recurrent VT rate was 27% (11/40 patients) for the inducible group and 13% (2/15 patients) for the non-inducible group (NS). SD occurred in 6/40 inducible patients (15%) and in 2/15 non-inducible patients (13%) (NS). Arrhythmic events occurred in 42% (17/40) inducible patients vs. 26% (4/15) non-inducible patients (P=0.07). Parameters correlated with outcome were ejection fraction (EF) (5 SD/11 patients with EF <0.3 vs. 4/44 with EF >0.3, P=0.003), mitral insufficiency (MI) (4 SD/10 patients with MI vs. 4/44 patients without MI, P=0.004) and age (65+/-9 years for patients with VT recurrence vs. 58+/-9, P=0.02). Although the risk stratification can be improved, reliable and safe long-term prediction of recurrence of malignant ventricular arrhythmia in individual patients cannot be made. Consequently, the systematic implantation of a cardioverter-defibrillator in case of a first episode of sustained VT occurring in coronary artery disease patients should be further debated.

Adult↗
PubMed2002

[Role of coronary artery revascularization and aneurysmectomy in ventricular arrhythmias in the chronic phase of myocardial infarction].

INTRODUCTION AND OBJECTIVES: The influence of coronary artery revascularization on the control of ventricular arrhythmias in patients with chronic myocardial infarction is uncertain. However, ablation of the arrhythmogenic circuit in these patients by aneurysm resection is useful for controlling ventricular arrhythmias. We made a prospective analysis of our clinical strategy in patients who were candidates for coronary artery revascularization and/or aneurysmectomy to determine its influence on the recurrence of ventricular arrhythmias. PATIENTS AND METHOD: Prospective study of 17 consecutive patients with chronic myocardial infarction and ventricular arrhythmias unrelated with an acute ischemic event, who had coronary artery disease and/or ventricular aneurysm susceptible to aggressive treatment. We evaluated our clinical strategy and the recurrence of ventricular arrhythmias during a mean follow-up period of 33.64 months. RESULTS: Two groups of patients were studied: patients with ventricular aneurysm (group I: 12 patients) and patients without ventricular aneurysm (group II: 5 patients). Seven patients of group I underwent endoaneurysmorrhaphy and endocardial resection (4 of these patients had associated revascularization procedures). Three patients were not candidates for aneurysmectomy or revascularization procedures. Two patients underwent only revascularization procedures. All the patients in group II were revascularized. The patients who underwent aneurysmectomy did not have recurrence of arrhythmias. In 5 of the 6 patients who underwent programmed electrophysiological stimulation after aneurysmectomy, no sustained arrhythmia could be induced. Patients who were only revascularized had a high rate of recurrence of ventricular arrhythmias (57%), which were inducible after revascularization. CONCLUSION: Aneurysmectomy and endocardial resection constituted, in our experience, an effective tool for controlling ventricular arrhythmias associated with left ventricular aneurysm. Coronary artery revascularization in patients with ventricular arrhythmias and chronic myocardial infarction probably does not prevent the recurrence of ventricular arrhythmias.

Adult↗
PubMed1997

Efficacy and safety of d,l-sotalol in patients with ventricular tachycardia and in survivors of cardiac arrest.

OBJECTIVE: The aim of this study was to assess the antiarrhythmic efficacy and safety of d,l-sotalol in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) and in survivors of cardiac arrest and to identify the factors that are associated with arrhythmia suppression and therefore might be helpful in predicting drug efficacy. BACKGROUND: Despite increasing use of the class III antiarrhythmic agent d,l-sotalol, data on its short- and long-term efficacy in a large patient cohort are lacking. Information on its long-term tolerability and safety is limited. METHODS: A total of 396 patients with inducible sustained VT or VF (VT/VF) underwent programmed stimulation before and after receiving oral d,l-sotalol (240 to 640 mg/day). Patients in whom VT/VF was rendered either noninducible or more difficult to induce (more extrastimuli or faster drive cycle length needed for VT/VF induction) were discharged on a regimen of oral d,l-sotalol. RESULTS: d,l-Sotalol suppressed VT/VF in 151 patients (38.1%) and rendered the arrhythmia more difficult to induce in 76 patients (19.2%). The extent of drug-induced prolongation of right ventricular refractoriness and a shorter VT cycle length at baseline were independent predictors of immediate drug efficacy. Torsade de pointes developed in seven patients (1.8%). Two hundred ten patients (53%) continued to receive d,l-sotalol and were followed up for 34 +/- 18 months (mean +/- SD). The actuarial rates for the absence of arrhythmic recurrence (either VT/VF or sudden death) at 1 and 3 years were 89% and 77%, respectively. Actuarial rates for overall survival at 1 and 3 years were 94% and 86%, respectively. VT/VF suppression by d,l-sotalol was an independent discriminant variable that separated patients with and without arrhythmia recurrence. However, noninducibility of VT/VF did not predict freedom from sudden death. CONCLUSION: Oral d,l-sotalol is effective and safe in patients with VT/VF. However, sudden cardiac death develops in a significant proportion of patients, and programmed stimulation seems to be of limited value for its prediction.

Administration, Oral↗
PubMed1997

Arrhythmogenic right ventricular dysplasia: clinical results with implantable cardioverter defibrillators.

Arrhythmogenic right ventricular dysplasia is a clinical entity characterized by fatty infiltration of the right ventricle and left bundle morphology ventricular tachycardia occurring in young patients. The most common cause of death is tachyarrhythmic. Pharmacological and nonpharmacological therapies, including implantable cardioverter defibrillators, have been used to treat the arrhythmias. However, right ventricular endocardial leads in this population may be associated with an increased risk of perforation and suboptimal sensing and defibrillation efficacy due to the diseased right ventricle. We report on 12 patients with arrhythmogenic right ventricular dysplasia who were treated with implantable cardioverter defibrillators. The mean age was 31 +/- 9 years (range 15-48). Patients presented with presyncope (5), syncope (4), or cardiac arrest (3). All patients had electrocardiographic abnormalities characteristic of the condition. During programmed electrical stimulation nine patients had sustained ventricular tachycardia, while three patients had no inducible arrhythmia. Transvenous leads were placed in nine patients. In these patients pacing thresholds were significantly higher, R-wave amplitudes were significantly lower and defibrillation thresholds were not significantly different than in a cohort of patients without right ventricular dysplasia. There were no acute or chronic complications of right ventricular lead placement. Follow-up averaged 22 +/- 13 months (range 1-45). There was one sudden death at 1 month of follow-up. Of the 12 patients, 8 have had appropriate therapy delivered by the implantable defibrillator. Six patients are currently on sotalol to reduce the frequency of implantable defibrillator discharges. In conclusion, implantable cardioverter defibrillators with nonthoracotomy leads are feasible and safe in patients with arrhythmogenic right ventricular dysplasia. The frequency of appropriate therapy is high, supporting the use of implantable cardioverter defibrillators in this population.

Adolescent↗
PubMed2006

Memory enhancement in healthy older adults using a brain plasticity-based training program: a randomized, controlled study.

Normal aging is associated with progressive functional losses in perception, cognition, and memory. Although the root causes of age-related cognitive decline are incompletely understood, psychophysical and neuropsychological evidence suggests that a significant contribution stems from poorer signal-to-noise conditions and down-regulated neuromodulatory system function in older brains. Because the brain retains a lifelong capacity for plasticity and adaptive reorganization, dimensions of negative reorganization should be at least partially reversible through the use of an appropriately designed training program. We report here results from such a training program targeting age-related cognitive decline. Data from a randomized, controlled trial using standardized measures of neuropsychological function as outcomes are presented. Significant improvements in assessments directly related to the training tasks and significant generalization of improvements to nonrelated standardized neuropsychological measures of memory (effect size of 0.25) were documented in the group using the training program. Memory enhancement appeared to be sustained after a 3-month no-contact follow-up period. Matched active control and no-contact control groups showed no significant change in memory function after training or at the 3-month follow-up. This study demonstrates that intensive, plasticity-engaging training can result in an enhancement of cognitive function in normal mature adults.

Adult↗
PubMed1999

The impact of multifocused interventions on sharps injury rates at an acute-care hospital.

OBJECTIVE: To determine the impact of a multifocused interventional program on sharps injury rates. DESIGN: Sharps injury data were collected prospectively over a 9-year period (1990-1998). Pre- and postinterventional rates were compared after the implementation of sharps injury prevention interventions, which consisted of administrative, work-practice, and engineering controls (ie, the introduction of an anti-needlestick intravenous catheter and a new sharps disposal system). SETTING: Sharps injury data were collected from healthcare workers employed by a mid-sized, acute-care community hospital. RESULTS: Preinterventional annual sharps injury incidence rates decreased significantly from 82 sharps injuries/1,000 worked full-time-equivalent employees (WFTE) to 24 sharps injuries/1,000 WFTE employees postintervention (P<.0001), representing a 70% decline in incidence rate overall. Over the course of the study, the incidence rate for sharps injuries related to intravenous lines declined by 93%, hollow-bore needlesticks decreased by 75%, and non-hollow-bore injuries decreased by 25%. CONCLUSION: The implementation of a multifocused interventional program led to a significant and sustained decrease in the overall rate of sharps injuries in hospital-based healthcare workers.

Emergency Medical Services↗
PubMed2006

Why healthcare workers don't wash their hands: a behavioral explanation.

OBJECTIVE: To elucidate behavioral determinants of handwashing among nurses. DESIGN: Statistical modeling using the Theory of Planned Behavior and relevant components to handwashing behavior by nurses that were derived from focus-group discussions and literature review. SETTING: The community and 3 tertiary care hospitals. PARTICIPANTS: Children aged 9-10 years, mothers, and nurses. RESULTS: Responses from 754 nurses were analyzed using backward linear regression for handwashing intention. We reasoned that handwashing results in 2 distinct behavioral practices--inherent handwashing and elective handwashing--with our model explaining 64% and 76%, respectively, of the variance in behavioral intention. Translation of community handwashing behavior to healthcare settings is the predominant driver of all handwashing, both inherent (weighted beta =2.92) and elective (weighted beta =4.1). Intended elective in-hospital handwashing behavior is further significantly predicted by nurses' beliefs in the benefits of the activity (weighted beta =3.12), peer pressure of senior physicians (weighted beta =3.0) and administrators (weighted beta =2.2), and role modeling (weighted beta =3.0) but only to a minimal extent by reduction in effort (weighted beta =1.13). Inherent community behavior (weighted beta =2.92), attitudes (weighted beta =0.84), and peer behavior (weighted beta =1.08) were strongly predictive of inherent handwashing intent. CONCLUSIONS: A small increase in handwashing adherence may be seen after implementing the use of alcoholic hand rubs, to decrease the effort required to wash hands. However, the facilitation of compliance is not simply related to effort but is highly dependent on altering behavioral perceptions. Thus, introduction of hand rub alone without an associated behavioral modification program is unlikely to induce a sustained increase in hand hygiene compliance.

Adult↗
PubMed2003

Nutrition guidance in Dutch family practice: behavioral determinants of reduction of fat consumption.

BACKGROUND: Studies have shown that the psychosocial determinants attitude, self-efficacy, subjective norm, and health threat are important in predicting intention to change fat consumption. However, the role of habit in relation to these determinants is still largely unknown. OBJECTIVE: We aimed to assess whether and how habit influences intention in relation to attitude, self-efficacy, subjective norm, and health threat. DESIGN: Cross-sectionally, we studied the self-reported psychosocial determinants and intention of 105 (52 intervention, 53 control) patients who participated in a family practice-based tailored nutrition counseling intervention study for lowering cardiovascular risk. Fat intake 15 mo before the assessment of psychosocial determinants was used as a measure of habit. We used logistic regression analyses to develop a model predicting intention to change fat consumption. RESULTS: Our regression model explained 43% of the variance in intention. Patients who perceived higher subjective norm or more social support had a higher intention. Habit was a significant predictor of intention in interaction with self-efficacy and health threat. Attitude, health threat, age, and group membership (ie, whether patients had been in the intervention group or the control group of the intervention study) were also included in the regression model. CONCLUSIONS: The results suggest that habit in addition to subjective norm and the other more frequently investigated psychosocial determinants are important in predicting intention to change fat consumption. To achieve sustainable health improvement through nutrition education programs, these programs should therefore start focusing more on subjective norm and habit.

Attitude to Health↗
PubMed1995

Long-term efficacy of d/l sotalol in patients with sustained ventricular tachycardia refractory to class I antiarrhythmic drugs.

The efficacy of d/l sotalol was investigated in 50 patients (43 men, seven women; 33 with coronary artery disease, 15 with dilated cardiomyopathy; ejection fraction 33 +/- 10%) with inducible sustained ventricular tachycardia. Before d/l sotalol a mean of 2 +/- 1 (1 to 4) class I antiarrhythmic drugs were ineffective. In 24 patients (48%) oral d/l sotalol (320 +/- 47 mg.day-1) prevented induction of the ventricular tachycardia; in 23 patients the ventricular tachycardia remained inducible (d/l sotalol 326 +/- 50 mg.day-1). The electrophysiological effects of d/l sotalol did not differ between patients in whom d/l sotalol prevented induction of ventricular tachycardia and those in whom the ventricular tachycardia remained inducible. In two patients, torsade des pointes developed after oral application of d/l sotalol; one patient suffered from severe hypotension even with 80 mg of sotalol per day. During long-term follow-up (27 +/- 12 months) 5/24 patients (21%) had a non-fatal recurrence of ventricular tachycardia (1 week to 21 months), one patient died suddenly and another from progressive heart failure. In patients in whom the ventricular tachycardia could be induced despite oral application of d/l sotalol, control of the ventricular tachyarrhythmia was attempted by the use of sotalol in combination with mexiletine (n = 2), amiodarone (n = 9), catheter ablation (n = 2), antitachycardia surgery (n = 1) or the implantation of an automatic cardioverter defibrillator (n = 12). Recurrence of ventricular tachycardia was observed in four patients without an implanted cardioverter defibrillator. Seven out of 12 patients with an implanted cardioverter defibrillator received appropriate shocks or successful antitachycardia pacing. Although no patient died suddenly, overall mortality was 17% in this group. It is concluded that d/l sotalol is highly effective in the suppression of sustained monomorphic ventricular tachycardia inducible by programmed electrical stimulation. However during a mean follow-up of 27 +/- 12 months a recurrence of ventricular tachycardia was seen in 21% of patients, and one patient died suddenly.

Administration, Oral↗
PubMed1990

A simplified technique for the production of heart failure in the dog by rapid ventricular pacing.

Prolonged rapid ventricular pacing (VP) in dogs produces low output heart failure (HF) characterized by cardiomegaly, ascites, and elevated plasma renin and norepinephrine levels. Commercially available pacemaker generators have a protective circuit that prevents pacing at rapid rates. Previously, investigators have had to use either external temporary pacemakers or customized generators to pace at rates greater than 130 beats per minute (bpm). The authors have developed a simple method to perform rapid VP by gluing magnets on Medtronic VVI generators, which allows programming in a temporary mode to sustain rates up to 400 bpm. Our results using 10 generators in 55 dogs demonstrates that HF is produced in all dogs when VP is maintained at 250 bpm for an average of 28 days. Technical difficulties during our early experience with this technique included magnets becoming unglued, loss of capture, and wound complications requiring generator removal. Thus, our method reuses commercially available generators to rapidly pace the ventricles and induce HF.

Animals↗
PubMed1990

Antiarrhythmic and electrophysiologic actions of CK-3579 and sematilide in a conscious canine model of sudden coronary death.

The antiarrhythmic and antifibrillatory actions of the CK-3579 and sematilide, two new class III antiarrhythmic drugs, administered in a multiple-dose regimen were evaluated in conscious dogs 3-5 days after anterior myocardial infarction. The study population consisted of three groups of 10 dogs each, in which all animals entered into the final protocol developed nonsustained or sustained ventricular tachycardia in response to programmed electrical stimulation using one, two or three premature stimuli. Each drug was administered intravenously in a dose of 3.0 mg/kg every 3 h for a total of six doses. Sematilide significantly suppressed the induction of ventricular tachyarrhythmia by programmed electrical stimulation in six of 10 postinfarcted dogs, whereas CK-3579 suppressed the induction of tachyarrhythmia in only two of 10 animals. Despite its ineffectiveness in preventing electrical induction of tachycardia, CK-3579 produced a significant increase in the cycle length of the induced ventricular rhythm. The administration of each drug was associated with an increase in the ventricular refractoriness and in the paced QT interval, suggesting that class III electrophysiologic properties contribute to the antiarrhythmic action of each drug. In addition, CK-3579 was shown to have beta 1-adrenoceptor blocking properties. The subsequent induction of an acute ischemic event in a region remote from the infarct-related artery was associated with a high incidence (80%, eight of 10 postinfarcted dogs) of ventricular fibrillation within the first hour after the onset of myocardial ischemia in the vehicle-treated control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed2001

Priorities for improving hospital-based trauma care in an African city.

BACKGROUND: This study sought to identify potential cost-effective methods to improve trauma care in hospitals in the developing world. METHODS: Injured patients admitted to an urban hospital in Ghana over a 1-year period were analyzed prospectively for mechanism of injury, mode of transport to the hospital, injury severity, region of principal injury, operations performed, and mortality. In addition, time from injury until arrival at the hospital and time from arrival at the hospital until emergency surgery were evaluated. RESULTS: Mortality was 9.4%. Most deaths (65%) occurred within 24 hours of admission. Sixty percent of emergency operations were performed over 6 hours after arrival. Tube thoracostomy was performed on only 13 patients (0.6%). Only 58% of patients received intravenous crystalloid and only 3.6% received 1 or more units of blood. CONCLUSION: We identified several specific interventions as potential low-cost measures to improve hospital-based trauma care in this setting, including shorter times to emergency surgery and improvements in initial resuscitation. In addition to addressing each of these aspects of trauma care individually, quality improvement programs may represent a feasible and sustainable method to improve trauma care in hospitals in the developing world.

Adolescent↗
PubMed2001

Program revision: a dynamic outcome of evaluation.

This critical review of program revision processes is guided by the program management model and considers issues germane to community-oriented health care programs, illustrated by examples from the literature. Options for program revision lie on a continuum from discontinuing a program, to various degrees of adjustments, to no change. Sustainability is the ultimate issue that must be addressed, and community and staff participation is critical for successful program revision.

Community Participation↗
PubMed2004

Toward the attainment of low-risk drinking goals: a 10-year progress report.

BACKGROUND: The Healthy People 2010 goals include reducing the proportion of U.S. adults whose alcohol consumption exceeds recommended daily and weekly limits, relative to baseline levels observed in 1991-1992. To date, there has been no assessment of initial progress toward attaining these goals. METHODS: Consumption data from the 1991-1992 National Longitudinal Alcohol Epidemiology Survey (n = 42,862) and the 2001-2003 National Epidemiologic Survey on Alcohol and Related Conditions (n = 43,093) were used to evaluate the trend in the proportion of U.S. adults adhering to and exceeding recommended drinking limits. These included weekly limits of no more than 14 standard drinks for men and no more than 7 standard drinks for women and daily limits of no more than 4 standard drinks for men and 3 standard drinks for women. The percentages exceeding the limits are compared for the two time periods, for the total adult population and sociodemographic subgroups, and the association between risk drinking and sociodemographic characteristics is disaggregated into a series of conditional odds ratios. RESULTS: The proportion of U.S. adults classified as regular drinkers whose intake exceeded recommended daily or weekly limits declined from 32.1% to 29.3% in the 10-year period. The reduction in risk drinking occurred solely among persons who exceeded the daily drinking limits less than once a week but did not exceed the weekly limits. There was a very small but significant increase in the proportion of adults exceeding the weekly limits, from 9.4% to 10.3%. Reduction of sociodemographic disparities in adherence to drinking limits was limited. CONCLUSIONS: Progress to date is limited and may reflect changes in population composition rather than changes in drinking habits. Attainment of Healthy People goals and reduction of disparities in risk drinking will require sustained effort and more targeted prevention programs.

Adolescent↗
PubMed1982

Procainamide in the induction and perpetuation of ventricular tachycardia in man.

The effects of a single intravenous infusion of 750 mg of procainamide was studied in 12 patients with symptomatic chronic recurrent ventricular tachycardia in whom arrhythmias could reproducibly be initiated and terminated by programmed electrical stimulation of the heart. Sustained ventricular tachycardia was induced in 6 patients and non-sustained tachycardia was induced in the remaining 6 patients during control studies. Following procainamide (plasma level 10.3 +/- 3.7 mcg/ml), ventricular tachycardia could be induced in 10/12 patients, sustained in 4 patients and non-sustained in the remaining 6 patients. In 8/12 patients (66%), induction of ventricular tachycardia was facilitated as demonstrated by: (1) tachycardia zone was widened in 4 patients and was unchanged in another 3 patients; (2) non-sustained ventricular tachycardia was sustained ventricular tachycardia in one patient. the ventricular tachycardia had a faster rate and a different QRS morphology; (3) in 4 patients tachycardia was inducible with a lesser number of extrastimuli and/or by spontaneously occurring ventricular premature depolarization and; (4) increase of the number of induced ventricular responses of non-sustained ventricular tachycardia. In 4/12 patients (33%), procainamide abolished or modified the induction of ventricular tachycardia as demonstrated by: (1) inability to induce ventricular tachycardia in 2 patients; (2) narrowing of the tachycardia zone and conversion from sustained into non-sustained ventricular tachycardia (one patient) and; (3) decrease in the number of induced ventricular responses in one patient. The response to procainamide could not be predicted from rates of spontaneous ventricular tachycardia, induced ventricular tachycardia during control studies, degree of slowing of ventricular tachycardia or from prolongation of the coupling interval after procainamide. These results suggest that instead of abolishing the arrhythmia, procainamide in frequently employed doses in patients with chronic recurrent ventricular tachycardia can facilitate its initiation sometimes at even faster rates. Patients not responsive to the usual doses of procainamide should undergo acute drug trials to determine the optimal dose/drug levels.

Aged↗
PubMed1988

Efficacy and safety of low doses of beta-blocker agents combined with amiodarone in refractory ventricular tachycardia.

Twenty patients aged 55 +/- 16 years with 40 chronic ventricular tachycardias (VT) refractory to 4.6 +/- 1.9 antiarrhythmic drugs, used alone or in combination, were managed by low doses of beta-blocker agents combined with oral amiodarone (Am), either after loading (1.2 g for 7 days, n: 5) or reloading (1.2 g for 4 days, n: 15) of Am. All patients proved refractory to Am alone. Seven VT were also refractory to endocardial catheter fulguration in six patients. Thirteen patients had coronary artery disease, three had arrhythmogenic right ventricular dysplasia, two had dilated cardiomyopathy, one had valvular disease, and one had no structural heart disease. Ten patients had an EF less than 30%. Ten patients were in NYHA functional class three. VT was permanent in three patients, daily in three, weekly in seven, paroxysmal in seven. In 11 patients, VT occurred both at day and night. In 11 patients, decrease of the sinus cycle preceeded VT. Oral administration of a daily low dose of a beta blocker agent (acebutolol 100 mg, betaxolol 5-10 mg, metoprolol 50 mg, nadolol 20-40 mg, pindolol 2.5 mg, propanolol 30 mg, sotalol 80-160 mg, terta-tolol 2.5 mg) combined with 400 mg/day of Am suppressed VT episodes in all patients. None presented heart failure or collapse. The mean reduction of the heart rate was 15% (65 to 55/min). At discharge, exercise ECG (n: 14) induced non sustained VT in two patients. At programmed electrical stimulation (PES) (n: 15), VT was no longer inducible in 4 patients, was slower, well-tolerated in nine patients, and remained inducible at the same rate in only two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1999

Can early timed internal atrial defibrillation shocks reduce the atrial defibrillation threshold?

The defibrillation threshold is markedly reduced very early following the initiation of ventricular fibrillation. The purpose of this study was to determine if the same finding holds true for atrial defibrillation. Sustained, reproducible AF was induced with programmed atrial pacing using acetyl-beta-methylcholine chloride (40-640 microL/min) in six adult sheep (heart weight 245-300 g). Seven timing intervals (125 ms, 200 ms, 1 s, 3 s, 10 s, 30 s, and 5 min after AF induction) and two lead configurations: (1) RA as cathode and CS as anode; and (2) RA as cathode and RV apex as anode were tested. Single capacitor biphasic waveforms (3/1 ms) were delivered and atrial defibrillation thresholds (ADFTs) were determined in random order. No significant differences in leading edge voltage and total energy were detected for the RA-CS configuration for the seven timing intervals. For the RA-RV configuration, a significant difference was detected comparing the voltage for 125 ms to the 5-minute timing interval. For all times except 125 ms, the RA-RV threshold was significantly higher than the RA-CS level. In contrast to ventricular defibrillation, the ADFT does not change significantly within the first 5 minutes after the initiation of AF for the RA-CS configuration. However, if the shock is given very early (125 ms after AF induction) with the RA-RV configuration, the ADFT is lowered almost to the RA-CS level.

Animals↗
PubMed1995

Parenteral antiarrhythmics for life-threatening ventricular arrhythmias.

The acute management of life-threatening ventricular tachyarrhythmias often includes the use of parenteral antiarrhythmics. There are a number of agents currently available for this purpose. They are used to suppress inducible monomorphic ventricular tachycardia during programmed electrical stimulation, they terminate spontaneous sustained ventricular tachycardia, and prevent ventricular fibrillation in the setting of an acute myocardial infarction. Serious adverse reactions include proarrhythmia, hypotension, severe bradyarrhythmias, and precipitation of congestive heart failure. A comparative evaluation of intravenous antiarrhythmics is difficult due to inherent differences in the choice of agents for study, protocol design, patient population, defined endpoint, and serum drug levels. Likewise, the reported adverse reaction rates vary from 0.4% to 75%. To understand the difficulties in clinical decision-making in this problem area, particularly drug selection, we present here a review of pertinent clinical trials evaluating parenteral drug efficacy and adverse effects.

Anti-Arrhythmia Agents↗