Usefulness of early versus late programmed ventricular stimulation in acute myocardial infarction

To determine the influence of timing on the prognostic value of programmed ventricular stimulation after acute myocardial infarction (AMI), 32 patients were studied on day 19 (early study) and again on day 36 (late study) after AMI using up to 3 extrastimuli. At the early study, sustained monomorphic ventricular tachycardia (VT) was induced in 12 patients (38%), sustained polymorphic VT in 8 (25%), nonsustained monomorphic VT in 1 (3%), nonsustained polymorphic VT in 1 (3%) and no inducible arrhythmia in 10 (31%). At the late study, sustained monomorphic VT, nonsustained monomorphic VT and nonsustained polymorphic VT were induced in 8 patients (25%) each, and no inducible arrhythmia in 8 (25%). Of the 12 patients who had inducible sustained monomorphic VT at the early study, 7 had noninducibility of sustained monomorphic VT at the late study. Of the 20 patients who had noninducibility of sustained monomorphic VT at the early study, 3 had inducible sustained monomorphic VT at the late study. During the follow-up period (mean +/- standard deviation 21 +/- 8 months), there were 2 sudden cardiac deaths and 3 occurrences of sustained VT. Univariate analysis revealed both inducibilities of sustained monomorphic VT at the early study (p = 0.045) and at the late study (p less than 0.001) to be predictive of sudden cardiac death or clinical occurrence of sustained VT. However, inducibility of sustained monomorphic VT at the late study had a higher sensitivity (100%), specificity (89%), positive predictive value (63%) and negative predictive value (100%) than at the early study (80, 70, 33 and 95%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

DDD versus VVIR versus VVI mode in patients with indication to dual-chamber stimulation: a prospective, randomized, controlled, single-blind study.

BACKGROUND: The aim of this study was to compare VVI, VVIR and DDD modes in patients with indication to dual-chamber stimulation, depending on left ventricular function. METHODS: Two groups of patients were implanted with a DDD pacemaker: Group I with ejection fraction > 40% and Group II with ejection fraction < 40%. Patients with a history of atrial arrhythmia or retrograde conduction were excluded. At follow-up (1 month each) quality of life (QoL), patient preference and echo parameters were collected. At hospital discharge all patients were programmed in DDD for 1 month and then randomized to VVI or VVIR mode. At the end of the period in VVI or VVIR mode each patient underwent a control period in DDD and then was programmed in VVIR or VVI mode. RESULTS: Seventeen patients out of 23 preferred DDD mode and 6 did not perceive any subjective difference among DDD, VVI and VVIR modes (4/9 in Group I and 2/14 in Group II, p = 0.0017). QoL was significantly different between the two groups and at each follow-up showed the best values in DDD. The correlation between QoL and Tei index was 0.62 in Group I (p < 0.001) and 0.35 in Group II (p = 0.001). Neither ejection fraction nor fractional shortening showed any significant difference during the three phases of the study. CONCLUSIONS: Most patients preferred the DDD mode. The Tei index showed a good correlation with QoL and both QoL and Tei index significantly improved with DDD mode as compared to VVI and VVIR.     

Current-based versus energy-based ventricular defibrillation: a prospective study

Defibrillation is thought to be mediated by a depolarizing current; however, the present method of defibrillation is based on delivering an empiric dose of energy to all patients. The hypothesis of this study was that for equivalent efficacy rates, a current-based defibrillation method would result in delivering less energy and peak current than would the standard energy-based method. In a group of 86 consecutive patients with ventricular fibrillation, every other patient was prospectively assigned to receive shocks according to method 1 or method 2. Method 1 was current based and delivered successive shocks of 25, 25 and a maximum of 40 A; method 2 was energy based and delivered shocks of 200, 200 and 360 joules. Patients in both groups were similar with respect to age, gender, weight, cardiac diagnosis, ejection fraction, antiarrhythmic therapy, chest circumference, chest depth and transthoracic impedance. Each method had statistically equivalent first shock (79% current-based versus 81% energy-based) and cumulative shock success rates. The mean first shock energy was 120 +/- 30 joules for patients receiving the current-based method and 200 joules for patients receiving energy-based shocks (p = 0.0001). The mean peak current was 24 +/- 2.3 and 33 +/- 5.0 A, respectively (p = 0.0001). Therefore, for equivalent first shock success rates, the energy-based method delivered 67% more energy and 38% more current than the current-based method. High transthoracic impedance (greater than or equal to 90 omega) predicted first shock failure only in patients undergoing defibrillation by the energy-based method (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the results of programmed ventricular stimulation from the right ventricular apex and outflow tract: a randomized, prospective study

Objective: The aim of this prospective study was to analysethe yield of programmed ventricular stimulation at the rightventricular apex compared with the outflow tract. Methods: A stepwise randomized cross-over protocol of programmedventricular stimulation with alternating stimulation at bothsites was used in 66 patients who were studied because of sustainedventricular tachycardia (n = 30), ventricular fibrillation (n= 7), or non-sustained ventricular tachycardia and/or syncope(n = 29). Results: There were no significant differences between the resultsof stimulation from either right ventricular site with regardto the presence or absence of structural heart disease, spontaneousarrhythmia, ejection fraction or effective refractory periods.Overall, monomorphic ventricular tachycardia was inducible in33 patients (50%); in 25 patients (75.8%), this arrhythmia wasinduced from both sites. However, in only 17 of these 25 patients(68%) did the induced monomorphic ventricular tachycardias havethe same morphologies and similar (± 50 ms) cycle lengths.Ventricular fibrillation was inducible in 11 patients (17%),mostly by three extrastimuli (n=8; 73%). Conclusions: (1) stimulation from at least two right ventricularsites is desirable because of their independent contributionto the induction of ventricular tachyarrythmias, (2) the non-inducibilityor inducibility at one ventricular site does not predict theeffect at another stimulation site, (3) the effective refractoryperiod at the right ventricular apex and outflow tract do notdiffer, (4) the inducibility of multiple ventricular tachycardiamorphologies emphasizes the importance of documenting the causeof spontaneous arrhythmias with multiple electrocardiographicleads to ensure the correct interpretation of arrhythmias inducedby programmed stimulation, (5) clinical or haemodynamic featurescannot predict whether one or more stimulation sites will berequired for induction of ventricular tachycardia. These resultsare important for the diagnostic evaluation and assessment ofpharmacological or non-pharmacological interventions.     

Pacing of the interventricular septum versus the right ventricular apex: A prospective, randomized study

BackgroundLeft ventricular (LV) function may be impaired by right ventricular (RV) apical pacing. The interventricular septum is an alternative pacing site, but randomized data are limited. Our aim was to compare ejection fraction (EF) resulting from pacing the interventricular septum versus the RV apex.MethodsRV lead implantation was randomized to the apex or the mid-septum. LVEF and RVEF were determined at baseline and after 1 and 4 years by radionuclide angiography.ResultsWe enrolled 59 patients, of whom 28 were randomized to the apical group and 31 to the septal group, with follow-up available in 47 patients at 1 year and 33 patients at 4 years. LVEF in the apical and in the septal groups was 55 ± 8% vs. 46 ± 15% (p = 0.021) at 1 year and 53 ± 12% vs. 47 ± 15% (p = 0.20) at 4 years. Echocardiography confirmed a mid-septal lead position in only 54% of patients in the septal group, with an anterior position in the remaining patients. In the septal group, LVEF decreased significantly in patients with an anterior RV lead (? 10.0 ± 7.7%, p = 0.003 at 1 year and ? 8.0 ± 9.5%, p = 0.035 at 4 years), but not in patients who had a mid-septal lead. Left intraventricular dyssynchrony was significantly increased in case of an anterior RV lead. RVEF was not significantly impaired by RV pacing, regardless of RV lead position.ConclusionsPacing at the RV septum confers no advantage in terms of ventricular function compared to the apex. Furthermore, inadvertent placement of the RV lead in an anterior position instead of the mid-septum results in reduced LV function.     

Radiofrequency versus conventional diathermy Milligan-Morgan hemorrhoidectomy: a prospective, randomized study

Background  

In the past decade, several new surgical tools have revived the hope for an improved technique to treat radically hemorrhoids with less postoperative pain. Among these radiofrequency (RF), excisional surgery seems to be safe, fast, and accompanied by less postoperative pain. The aim of this study was to evaluate and compare RF (ligasure TM) to conventional diathermy Milligan-Morgan hemorrhoidectomy (MMH).     

Cefotaxime versus penicillin in the late stage of lyme disease — prospective,randomized therapeutic study

Summary The low responsiveness of Lyme arthritis to high dose intravenous penicillin G therapy has evoked the demand for new drugs for the treatment of late stage borreliosis. As can be deduced fromin vitro susceptibility data, third generation cephalosporins are far more effective onBorrelia burgdorferi spirochetes than penicillin G. The study presented here was designed to compare cefotaxime at a dosage of 2 × 3 g/day with penicillin G at a dosage of 2 × 10 megaunits/day, for ten days in a prospective randomized trial. A total of 135 patients were included in the study. They were diagnosed to suffer from late stage Lyme borreliosis on the basis of defined clinical symptoms compatible with stage three borreliosis manifestations of at least six months' duration and positive antibody titers againstB. burgdorferi. Final outcomes were recorded after a 24 month post-treatment observation period with re-examination at three-month-intervals. Cefortaxime proved to be significantly superior to penicillin G with 87.9% versus 61.3% of treatments resulting in full or incomplete remission of symptoms (p=0.002). Clinical remission was accompanied by declining antibody titers. Herxheimer-like reactions were observed in 20% of the patients of the penicillin group and in 40.5% of the patients of the cefotaxime group and may be interpreted as an indication of a response to therapy.

---

Cefotaxim im Vergleich zu Penicillin zur Therapie der Lyme-Borreliose im Spätstadium. Prospektive, randomisierte Studie

Zusammenfassung Die geringe Ansprechrate der Lyme-Arthritis auch bei intravenöser und hochdosierter Gabe von Penicillin G hat das Interesse an neueren Antibiotika zur Behandlung der Lyme-Borreliose im Spätstadium erhöht. Wie schon auf Grund vorliegender In-vitro-Daten zur Empfindlichkeit vonBorrelia burgdorferi erwartet werden konnte, sind Cephalosporine der dritten Generation sehr viel effektiver als Penicillin G. In der hier vorgestellten randomisierten prospektiven Untersuchung wurde deshalb Cefotaxim in einer Dosierung von 2 × 3 g täglich mit Penicillin G in einer Dosierung von 2 × 10 Mega-Einheiten verglichen. 135 Patienten, bei denen eine definierte klinische Symptomatik im Sinne einer Stadium-3-Borreliose für mindestens sechs Monate bestanden hatte und bei denen Antikörper gegenB. burgdorferi nachweisbar waren, wurden in die Studie aufgenommen. Die Patienten wurden 24 Monate nachbeobachtet und im Abstand von drei Monaten reevaluiert. Die mit Cefotaxim behandelten Patienten zeigten ein signifikant besseres Therapieergebnis. Während in der Penicillin-Gruppe nur 61,3% der Patienten eine Voll- oder Teilremission ihrer Beschwerden zeigten, konnte dies bei der Cefotaxim-Gruppe bei 87,9% der Patienten erreicht werden (p=0,002). Parallel zum klinischen Effekt war ein Absinken der Antikörpertiter im Immunfluoreszenztest zu beobachten. Herxheimer-artige Reaktionen waren bei 20% der Patienten der Penicillin-Gruppe und bei 40,5% der Patienten der Cefotaxim-Gruppe zu beobachten. Diese Reaktion kann als Hinweis auf ein Ansprechen der Therapie gewertet werden.

     

Effects of early reperfusion in acute myocardial infarction on arrhythmias induced by programmed stimulation: a prospective, randomized study

This study compares inducibility of ventricular tachyarrhythmias by programmed electrical stimulation of the heart in patients with myocardial infarction with and without reperfusion after streptokinase therapy. Sixty-two consecutive patients admitted with an acute myocardial infarction were randomized to either combined intravenous and intracoronary streptokinase (streptokinase group) or to standard coronary care unit treatment (control group). Thirty-six of the 62 patients (21 patients from the streptokinase and 15 from the control group) with a first myocardial infarction were studied by programmed ventricular stimulation after a mean of 26 +/- 14 days. No patient had a history of antiarrhythmic drug use or documentation of a ventricular arrhythmia before the initial admission. A sustained ventricular arrhythmia was induced in 10 (48%) of the 21 patients randomized to streptokinase therapy and in all 15 (100%) control patients (p less than 0.001). Sustained monomorphic ventricular tachycardia was induced in 6 (29%) and 10 (67%) patients, respectively (p less than 0.05). To terminate an induced arrhythmia, direct current countershock was required in 33% of patients in the streptokinase group and 73% of patients in the control group (p less than 0.02). Seventeen of the 21 patients treated with streptokinase and no control patient had evidence of early reperfusion 200 +/- 70 minutes after the onset of pain. In comparison with patients without early reperfusion, patients in the reperfused group had a lower maximal serum creatine kinase value (p less than 0.01), a shorter time to peak creatine kinase value (p less than 0.001) and a higher angiographic left ventricular ejection fraction (62 versus 45%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Thermal welding versus cold knife tonsillectomy: a prospective randomized study

This is a prospective randomized study conducted in a group of children who underwent two methods of tonsillectomy: thermal welding or cold knife tonsillectomy. Parameters, such as postoperative pain scores, intraoperative blood loss, operation time, and postoperative bleeding rates, were analyzed to find out which technique is better. Ninety-one children (aged between 2 years and 13 years) with recurrent tonsillitis, obstructive sleep apnea syndrome, or both were included in the study. According to the type of tonsillectomy procedure, the patients were divided into two groups: cold knife and thermal welding procedure. The two groups were compared on the basis of postoperative pain scores, intraoperative blood loss, operation time, and postoperative bleeding. Fifty-seven patients underwent thermal welding tonsillectomy and 34 had cold knife tonsillectomy. The mean pain score in thermal welding group was significantly lower (p<0.001). There was no remarkable blood loss intraoperatively in the thermal welding procedure. The operation time was not significantly different between two groups. No postoperative bleeding was encountered in the thermal welding group. Compared with the cold knife technique, thermal welding was found to be a relatively new and safe technique for tonsillectomy as it results in significantly less postoperative pain and no remarkable blood loss.     

KaPPa 700 DDD与DDDR模式起搏治疗病态窦房结综合征的研究

目的评价Kappa700DDD与DDDR模式起搏治疗病态窦房结综合征对心脏结构和功能及房性心律失常的远期影响。方法选择病态窦房结综合征患者28例,随机分为A组和B组,用超声心动图测量术前、术后6个月、术后1年心脏重量指数(LVMI)、左房内径(LA)、左室舒张功能,用HOLTER了解术前、术后6个月、术后1年房性心律失常情况。结果术后半年,A、B两组在阵发性房颤(AF)发作的次数和持续时间较术前减少(P<0.05),且B组较A组显著(P<0.05);B组LA、LVMI及左室舒张功能术后与术前比较差异有统计学意义(P<0.05)。起搏模式交叉半年后,A组AF发作的次数和持续的时间较B组减少(P<0.05);A组LA、LVMI较起搏模式交叉前减小(P<0.05),B组LA、LVMI较起搏模式交叉前增大(P<0.05);A组左室舒张功能继续好转,而B组左室舒张功能较术后半年有所减退,两组比较差异有统计学意义(P<0.05)。结论Kappa700DDDR与DDD模式比较,DDDR模式更加利于改善心脏重构,改善舒张功能和减少AF的发生。     

Induction of ventricular arrhythmias by programmed ventricular stimulation: a prospective study on the effects of stimulation current on arrhythmia induction.

A protocol for programmed ventricular stimulation is described in which the effect of increasing stimulation current on ventricular refractoriness and arrhythmia induction was specifically examined. The protocol was evaluated prospectively in 70 patients undergoing electrophysiological study for documented or suspected ventricular arrhythmias. Programmed electrical stimulation was performed at the right ventricular apex and outflow tract using single and double extrastimuli and burst pacing. Stimulation currents of 2, 5, 10, and 20 mA were used in ascending order. The initial (lowest) current was never less than twice diastolic threshold and was maintained during each stimulation run until refractoriness was reached. The current was then increased to the next level to facilitate premature capture until refractoriness was encountered at 20 mA or a sustained arrhythmia occurred. Ventricular arrhythmias were induced in 34 patients, 31 of whom had presented with a sustained ventricular arrhythmia. The incidence of induced arrhythmias was low in those patients who had presented with symptoms alone, a non-sustained arrhythmia, or a sustained arrhythmia in association with a predisposing clinical event. Only one patient with a negative result had further ventricular arrhythmias during the mean follow up period of 15 months. Although each increase in stimulation current caused a decrease in measured ventricular refractoriness, this resulted in only four arrhythmias. Only one arrhythmia was induced above 5 mA. These results suggest that this simple protocol using two extrastimuli and a single stimulation current of 5 mA will reliably identify most patients who have symptomatic ventricular arrhythmias.     

Right versus left ventricular stimulation: influence on induction of ventricular tachyarrhythmias in dogs

The contribution of left (versus right) ventricular stimulation to the induction of ventricular tachyarrhythmias was studied in 37 dogs with chronic experimental myocardial infarction, and 17 dogs with normal hearts. Programmed stimulation of the endocardium at both ventricular apices employed an aggressive protocol of up to 7 extrastimuli. The right ventricle was the most successful site for induction of ventricular tachycardia after myocardial infarction (74% of dogs with ventricular tachycardia). Ten of 11 animals with slow ventricular tachycardia (greater than or equal to 140 msec) were inducible from the right ventricle. In contrast, left ventricular stimulation was required to induce rapid ventricular tachycardia (cycle length less than 140 msec) in 5 of 10 dogs (P less than 0.05). No animal required more than five extrastimuli from any site for induction of ventricular tachycardia. In the normal heart, ventricular fibrillation was induced most often from the right ventricle (77% of dogs) when compared with the left ventricle (47%, P less than 0.05). Ventricular tachycardia was never induced in normal animals. These results show that the right ventricular apex is the most successful site for induction of "slow" ventricular tachycardia in this canine model when using five extrastimuli. Rapid ventricular tachycardia is frequently induced from the infarcted left ventricle, but this arrhythmia may not be clinically significant. The normal right ventricle is significantly more susceptible to ventricular fibrillation than is the left ventricle, but this does not interfere with induction of ventricular tachycardia in the infarcted heart.     

Regular-dose versus high-dose omeprazole in peptic ulcer bleeding: a prospective randomized double-blind study.

BACKGROUND: It has been suggested that profound acid inhibition along with endoscopic therapy might prevent rebleeding and reduce mortality in patients with peptic ulcer bleeding. The aim of the study was to test the possible equivalence of a high dose and the regular dose of omeprazole in peptic ulcer bleeding. METHODS: We performed a prospective randomized double-blind study involving 142 patients with acute peptic ulcer bleeding (Forrest classification I-II: spurting or oozing bleeding, non-bleeding visible vessel, clot and black base). One-hundred-and-two (71.8%) patients received endoscopic treatment (adrenaline injection and/or heater probe) in pre-entry. Patients were randomly assigned to receive the regular dose of omeprazole intravenously (20 mg once a day for 3 days, i.e. 60 mg/72 h) or a high dose of omeprazole (80 mg bolus + 8 mg/h for 3 days, i.e. 652 mg/72 h). Rebleeding, surgery and death were the outcome measures. RESULTS: Six (8.2%) of the 73 patients receiving the regular dose of omeprazole and 8 (11.6%) of the 69 patients receiving the high dose of omeprazole rebled (P = 0.002 for equivalence, equivalence limit 0.15). Three (4.1%) of the former patients and 5 (7.2%) of the latter group underwent surgery. Four (5.5%) patients in the regular-dose and 2 (2.9%) in the high-dose group died within 30 days. CONCLUSION: Under the defined tolerance limits, the regular dose of omeprazole is as successful as a high dose in preventing peptic ulcer rebleeding.     

Rate-control versus conversion strategy in postoperative atrial fibrillation: a prospective, randomized pilot study

BACKGROUND: Atrial fibrillation remains a frequent complication after heart surgery. The optimal strategy to treat the condition has not been established. Several retrospective studies have suggested that a primary rate-control strategy may be equivalent to a strategy that restores sinus rhythm. METHODS: Fifty patients with atrial fibrillation after heart surgery were randomly assigned to a strategy of antiarrhythmic therapy with or without electrical cardioversion or ventricular rate control. Both arms received anticoagulation with heparin overlapped with warfarin. The primary end point was time to conversion to sinus rhythm analyzed by the Kaplan-Meier method. Atrial fibrillation relapse after the initial conversion was monitored in the hospital over a 2-month period. RESULTS: There was no significant difference between an antiarrhythmic conversion strategy (n = 27) and a rate-control strategy (n = 23) in time to conversion to sinus rhythm (11.2 +/- 3. 2 vs 11.8 +/- 3.9 hours; P =.8). With the use of Cox multivariate analysis to control for the effects of age, sex, beta-blocker usage, and type of surgery, the antiarrhythmic strategy showed a trend toward reducing the time from treatment to restoration of sinus rhythm (P =.08). The length of hospital stay was reduced in the antiarrhythmic arm compared with the rate-control strategy (9.0 +/- 0.7 vs 13.2 +/- 2.0 days; P =.05). In-hospital relapse rates in the antiarrhythmic arm were 30% compared with 57% in the rate-control strategy (P =.24). There were no significant difference in relapse rates at 1 week (24% vs 28%), 4 weeks (6% vs 12%), and 6 to 8 weeks (4% vs 9%). At the end of the study, 91% of the patients in the rate-control arm were in sinus rhythm compared with 96% in the antiarrhythmic arm (P =.6). CONCLUSIONS: This pilot study shows little difference between a rate-control strategy and a strategy to restore sinus rhythm. Regardless of strategy, most patients will be in sinus rhythm after 2 months. A larger randomized, controlled study is needed to assess the impact of restoration of sinus rhythm on length of stay.     

Disposable-sheath, flexible gastroscope system versus standard gastroscopes: a prospective, randomized trial.

BACKGROUND: Endoscopically transmitted infections due to inadequate disinfection are rare but well-recognized complications. A new prototype of a flexible, fiberoptic endoscope has been developed that uses a disposable sheath to cover and protect all working surfaces of the endoscope from contamination. The present study investigated the function, reprocessing, and hygienic status of this endoscope system in comparison with standard systems. METHODS: In a prospective, randomized trial, 100 upper endoscopic procedures (50 standard, 50 sheathed) were performed. Analog rating scales were used to evaluate endoscopic performance and reprocessing. Reprocessing time, procedure duration, insertion depth, total instrument downtime, and problems occurring during the procedure were recorded. Microbiologic swabs were obtained from each endoscope. RESULTS: Mean procedure duration was slightly longer with the sheathed system than with standard endoscope (9.9 vs. 8.4 min). Set up and reprocessing times, however, were significantly shorter with the Endosheath (8.9 vs. 48.4 min with the standard endoscope). The disposable-sheath endoscope system permits the rate of performance of procedures to be increased by a factor of up to 3.0. Both endoscopists and reprocessing personnel preferred the standard endoscope. No post-procedure sheath leakage or rupture was seen. CONCLUSION: Our results suggest that the "disposable endoscope" may have important advantages in terms of decreased instrument turn-around time and potentially improved safety.     

Single- versus triple-lumen central catheter-related sepsis: a prospective randomized study in a critically ill population.

PURPOSE: A prospective randomized study was conducted over a 23-month period in an adult medical-surgical intensive care unit to determine whether triple-lumen catheters reduce the need for peripheral vascular access and whether they are associated with a higher rate of infection than single-lumen catheters. PATIENTS AND METHODS: After the insertion route, internal jugular or subclavian, was selected by the physician, patients were randomized either to single-lumen or triple-lumen catheter groups. Complementary peripheral vascular access was allowed in both groups. Catheters were removed according to preestablished defined reasons: suspicion of catheter-related sepsis, uselessness of central venous access, duration of catheterization of more than 21 days, discharge from the intensive care unit, or death. RESULTS: Data on 129 central venous catheters were collected from 91 consecutive patients. Twenty-five of 68 patients from the single-lumen group and 1 of 61 patients from the triple-lumen group needed peripheral vascular access (p less than 0.001). Catheter-related sepsis rates, defined either by clinical signs and positive qualitative tip cultures (8.9% versus 11.5%) or by quantitative tip cultures (16.2% versus 11.5%), were identical in the single-lumen and triple-lumen groups (type II error: 8%). CONCLUSION: In intensive care units, the use of triple-lumen catheters is associated with a dramatic decrease in the need for peripheral vascular access. The incidence of central venous catheter-related sepsis appears identical for single- and triple-lumen catheters.     

Induction of ventricular arrhythmias by programmed ventricular stimulation: a prospective study on the effects of stimulation current on arrhythmia induction

A protocol for programmed ventricular stimulation is described in which the effect of increasing stimulation current on ventricular refractoriness and arrhythmia induction was specifically examined. The protocol was evaluated prospectively in 70 patients undergoing electrophysiological study for documented or suspected ventricular arrhythmias. Programmed electrical stimulation was performed at the right ventricular apex and outflow tract using single and double extrastimuli and burst pacing. Stimulation currents of 2, 5, 10, and 20 mA were used in ascending order. The initial (lowest) current was never less than twice diastolic threshold and was maintained during each stimulation run until refractoriness was reached. The current was then increased to the next level to facilitate premature capture until refractoriness was encountered at 20 mA or a sustained arrhythmia occurred. Ventricular arrhythmias were induced in 34 patients, 31 of whom had presented with a sustained ventricular arrhythmia. The incidence of induced arrhythmias was low in those patients who had presented with symptoms alone, a non-sustained arrhythmia, or a sustained arrhythmia in association with a predisposing clinical event. Only one patient with a negative result had further ventricular arrhythmias during the mean follow up period of 15 months. Although each increase in stimulation current caused a decrease in measured ventricular refractoriness, this resulted in only four arrhythmias. Only one arrhythmia was induced above 5 mA. These results suggest that this simple protocol using two extrastimuli and a single stimulation current of 5 mA will reliably identify most patients who have symptomatic ventricular arrhythmias.     

Electroanatomic versus fluoroscopic mapping for catheter ablation procedures: a prospective randomized study

INTRODUCTION: The aim of this prospective randomized study was to compare the routine use of electroanatomic imaging (CARTO) with that of conventional fluoroscopically guided activation mapping (conventional) in an unselected population referred for catheter ablation. We sought to compare the two approaches with respect to procedure outcome and duration, radiation exposure, and cost. Methods AND RESULTS: All patients undergoing catheter ablation (with the exception of complete AV nodal ablation) were prospectively randomized to either a CARTO or conventional procedure for mapping and ablation. One hundred two patients were randomized. Acute procedural success was similar with either strategy (CARTO vs conventional 43/47 vs 51/55, P > 0.5), as was procedure duration (144 [58] vs 125 [48] min, P = 0.07 (mean [SD]). CARTO was associated with a substantial reduction in fluoroscopy time (9.3 [7.6] vs 28.8 [19.5] min, P < 0.001) and radiation dose (6.2 [6.1] vs 20.8 [32.7] Gray, P = 0.003). CARTO cases used fewer catheters (2.5 [0.7] vs 4.4 [1.1], P < 0.001), but catheter costs were higher (13.8 vs 9.3 units, P < 0.001, where one unit is equivalent to the cost of a nonsteerable quadripolar catheter). CONCLUSION: For all catheter ablation procedures, even when a center's "learning curve" for CARTO is included, procedure duration and outcome are similar for CARTO and conventional procedures. CARTO is associated with drastically reduced fluoroscopy time and radiation dose. Although fewer catheters are used with CARTO, catheter costs remain higher.