bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospective Randomized Comparison of Two Defibrillation Safety Margins in Unipolar, Active Pectoral Defibrillator Therapy
Authors: CARLSSON JOERG , SCHULTE BRITTA , ERDOGAN ALI , SPERZEL JOHANNES , GÜTTLER NORBERT , SCHWARZ TORSTEN , PITSCHNER HEINZ‐F. , NEUZNER JOERG
Published: December 2004

CARLSSON, J., et al.: Prospective Randomized Comparison of Two Defibrillation Safety Margins in Unipolar, Active Pectoral Defibrillator Therapy.
Various techniques are used to establish defibrillation efficacy and to evaluate defibrillation safety margins in patients with an ICD. In daily practice a safety margin of 10 J is generally accepted. However, this is based on old clinical data and there are no data on safety margins using current ICD technology with unipolar, active pectoral defibrillators. Therefore, a randomized study was performed to test if the likelihood of successful defibrillation at defibrillation energy requirement (DER) +5 J and +10 J is equivalent. Ninety‐six patients (86 men; age

61.0 ± 10.3

years; ejection fraction

0.341 ± 0.132
; coronary artery disease [n = 65],dilated cardiomyopathy [n = 18], other [n = 13]) underwent implantation of an active pectoral ICD system with unidirectional current pathway and a truncated, fixed tilt biphasic shock waveform. The defibrillation energy requirement (DER) was determined with the use of a step‐down protocol (delivered energy 15, 10, 8, 6, 4, 3, 2 J). The patients were then randomized to three inductions of ventricular fibrillation at implantation and three at predischarge testing with shock strengths programmed to DER + 5 J at implantation and + 10 J at predischarge testing or vice versa. The mean DER in the total study population was7.88 ± 2.96 J. The number of defibrillation attempts was 288 for +5 J and 288 for +10 J. The rate of successful defibrillation was 94.1% (DER + 5 J) and 98.9% (DER + 10 J;P < 0.01for equivalence). Charge times for DER + 5 J were significantly shorter than for DER + 10 J (3.65 ± 1.14vs5.45 ± 1.47 s; P < 0.001). A defibrillation safety margin of DER + 5 J is associated with a defibrillation probability equal to the standard DER + 10 J. In patients in whom short charge times are critical for avoidance of syncope, a safety margin of DER + 5 J seems clinically safe for programming of the first shock energy. (PACE 2003; 26[Pt. I]:613–618)
Quality‐of‐Life in Patients with Paroxysmal Atrial Fibrillation After Catheter Ablation:
Authors: ERDOGAN ALI , CARLSSON JOERG , NEUMANN THOMAS , BERKOWITSCH ALEXANDER , NEUZNER JOERG , HAMM CHRISTIAN W. , PITSCHNER HEINZ F.
Published: December 2004

ERDOGAN, A., et al.: Quality‐of‐Life in Patients with Paroxysmal Atrial Fibrillation After Catheter Ablation: Results of Long‐Term Follow‐Up.
Paroxysmal atrial fibrillation (PAF) significantly impairs patients' quality‐of‐life (QOL). The effect on QOL of recently developed ablation techniques with curative intention has not been studied. Thirty patients (21 men, age

54.1 ± 9.5

years) with PAF (duration

5.6 ± 5.2

years) who failed antiarrhythmic

(3.8 ± 1.2 trials)

drug therapy underwent catheter ablation. The follow‐up time was

33.9 ± 11

months. QOL was assessed preablation, 3, 6, 9, 12, 24, and 36 months after catheter ablation. The Medical Outcomes Survey Short‐Form (SF‐36), scored on a 0–100 scale for each of eight domains: bodily pain, general health, mental health, physical functioning, role‐emotional, role‐physical, social functioning, and vitality, was used. Simultaneously, patients filled out a symptom‐specific checklist (SSC) with seven clinical items scored 1–4 (1 best): dyspnea, nausea, palpitations, anxiety, syncope, presyncope, and NYHA classification. Patients with successful catheter ablation had a significant benefit in seven of eight subscales while patients with recurrence had an impact on QOL in two of eight subscales. Using SSC, a successful ablation influenced scores in all seven items while patients with recurrence had a significant change of clinical symptoms in only one item, anxiety. The subscales of the study group compared to a healthy population show higher scores after 24 months of follow‐up. Patients with PAF experience a significant improvement in QOL after a successful catheter ablation. In contrast, in patients with recurrence of PAF the QOL showed improvement to a lesser extent and patients experienced ongoing symptoms. (PACE 2003; 26:678–684)
Neurohumoral Activation and Ventricular Arrhythmias in Patients with Decompensated Congestive Heart Failure:
Authors: ARONSON DORON , BURGER ANDREW J.
Published: December 2004

ARONSON, D., et al.: Neurohumoral Activation and Ventricular Arrhythmias in Patients with Decompensated Congestive Heart Failure: Role of Endothelin.
Patients with congestive heart failure (CHF) have a high incidence of ventricular arrhythmias and sudden arrhythmic death. CHF entails profound and complex abnormalities in humoral responses that are thought to promote arrhythmic events. However, it is unknown which of the many endogenous mediators that accumulate as part of neurohormonal activation is important in arrhythmogenesis in the setting of CHF. The study included 83 patients admitted to the hospital for treatment of decompensated CHF. Neurohormonal and cytokine activation was assessed by measuring plasma renin activity, aldosterone, norepinephrine, endothelin‐1, tumor necrosis factor‐α, and interleukin‐6 levels. Atrial and ventricular arrhythmic events were assessed by 24‐hour Holter monitoring. In a univariate analysis, a highly significant, positive relationship was found between plasma endothelin‐1 levels and the average hourly total premature ventricular beats

(P = 0.003)

, the frequency of ventricular pairs

(P = 0.0003)

, and the frequency of ventricular tachycardia episodes

(P = 0.001)
. After inclusion of clinical variables, drug therapies, neurohormones, and cytokine levels in a multivariate analysis, the positive relationship between plasma endothelin‐1 level and the average hourly total premature ventricular beats(P = 0.008), the frequency of ventricular pairs(P = 0.007), and ventricular tachycardia episodes(P = 0.009)remained independent. No association between other neurohormones or cytokines and arrhythmic events was demonstrated. The results of the present study suggest that increased endothelin‐1 concentrations may be involved in promoting the occurrence of ventricular ectopy in patients with decompensated CHF. Proarrhythmic effects may account, in part, for the poor outcome associated with increased endothelin‐1 levels in patients with decompensated CHF. (PACE 2003; 26:703–710)
Open‐Chest Epicardial “Surgical” Defibrillation:
Authors: ZHANG YI , DAVIES LOYD R. , CODDINGTON WILLIAM J. , ZIMMERMAN M. BRIDGET , WUTHRICH SCOTT , JONES JANICE L. , KERBER RICHARD E.
Published: December 2004

ZHANG, Y., et al.: Open‐Chest Epicardial “Surgical” Defibrillation: Biphasic Versus Monophasic Waveform Shocks.
The aim of the study was to compare biphasic versus monophasic shocks for open‐chest epicardial defibrillation. Transthoracic biphasic waveform shocks require less energy to terminate ventricular fibrillation compared to monophasic waveform shocks. However, if biphasic shocks are effective for open‐chest epicardial (“surgical”) defibrillation has not been established. Twenty‐eight anesthetized adult swine (15–25 kg) underwent a midline sternotomy. Ventricular fibrillation was electrically induced. After 15 seconds of ventricular fibrillation, each pig in group 1

(n = 16)

randomly received damped sinusoidal monophasic epicardial shocks and truncated exponential biphasic epicardial shocks from large

(44.2 cm2)

paddle electrodes at eight energy levels

(2–50 J)
. Pigs in group 2(n = 12)received monophasic and truncated exponential biphasic shocks from small(15.9 cm2)paddle electrodes. In group 1 (large paddle electrodes), the overall percent shock success rose from15 ± 9%at 2 J to97 ± 3%at 50 J. In this group there was no significant difference in percent of shock success between damped sinusoidal monophasic and biphasic waveform shocks. In group 2 (small paddle electrodes), biphasic shocks yielded a significantly higher percent of shock success than monophasic shocks at mid‐energy levels from 7 to 20 J (allP < 0.01). With small surgical paddle electrodes, biphasic waveform shocks demonstrated a significantly higher percent of shock success rate compared to monophasic waveform shocks. With large paddle electrodes, the two waveforms were equally effective. (PACE 2003; 26:711–718)
Elevations in Ventricular Pacing Threshold with the Use of the Y Adaptor:
Authors: RHO ROBERT W. , PATEL VICKAS V. , GERSTENFELD EDWARD P. , DIXIT SANJAY , POKU JOSEPH W. , ROSS HEATHER M. , CALLANS DAVID , KOCOVIC DUSAN Z.
Published: December 2004

RHO, R.W., et al.: Elevations in Ventricular Pacing Threshold with the Use of the Y Adaptor: Implications for Biventricular Pacing.
Cardiac resynchronization therapy (CRT) is a new and promising therapeutic option for patients with severe heart failure and intraventricular conduction delay. Patients who are candidates for CRT and have a previously implanted device may utilize a “Y” IS 1 connector to accommodate the coronary sinus lead. This modification has the potential to alter biventricular pacing thresholds. During an 18 month period, successful biventricular pacemaker implantation was performed in 72 patients (age:

67 ± 11

years, left ventricular ejection fraction:

20.5 ± 5.6%

). All of these patients had severe symptomatic congestive heart failure (NYHA Class III and IV). In 20 patients a special “Y” adaptor that bifurcates the ventricular IS 1 bipolar output to two bipolar outputs or one unipolar and one bipolar output was utilized. During initial implantation, LV thresholds obtained in a unipolar configuration prior to connecting to the “Y” adaptor were significantly lower than thresholds obtained after connecting to the “Y” adaptor (

1.7 ± 1.11 V

at 0.5 ms pulse width versus

2.8 ± 1.5 V

at 0.5 ms pulse width

[P = 0.01]

). Two patients (10%) required left ventricular lead revisions due to unacceptably high left ventricular thresholds during device follow‐up. The difference in measured left ventricular thresholds between the two configurations is best explained by a resistive element that is added to the circuit when performing threshold measurement of the LV lead through the “Y” adaptor (combined tip to RV ring configuration) versus measurement of the LV lead in a unipolar configuration. This resistive element represents multiple factors including anode surface area, resistive polarization at the tissue‐electrode interface, and transmyocardial resistance. LV thresholds should be measured in an LV tip to RV ring configuration or ideally in a combined tip (LV and RV) to shared ring configuration in order to accurately assess LV thresholds. This observation has significant clinical implications as loss of capture may occur as a result of improper measurement of left ventricular thresholds at the time of implantation. (PACE 2003; 26:747–751)
Pharmacological Prevention of Atrial Tachycardia Induced Atrial Remodeling as a Potential Therapeutic Strategy
Authors: SHINAGAWA KAORI , DERAKHCHAN KATAYOUN , NATTEL STANLEY
Published: December 2004

SHINAGAWA, K., et al.: Pharmacological Prevention of Atrial Tachycardia Induced Atrial Remodeling as a Potential Therapeutic Strategy.
Atrial fibrillation (AF) is the most common cardiac arrhythmia requiring medical therapy, and present treatment modalities are inadequate. Over the past few years, we have learned a great deal about the phenomenon of electrical remodeling, by which rapid atrial activation leads to changes in atrial electrical properties that promote AF initiation and maintenance. This knowledge opens up the possibility that electrical remodeling may itself be a novel therapeutic target in AF. The present paper reviews what is known about the basic mechanisms of atrial electrical remodeling and then discusses the experimental and clinical evidence that remodeling can be prevented by drug therapy. Despite great potential value, the development of pharmacological interventions to prevent atrial electrical remodeling is still in its infancy. (PACE 2003; 26:752–764)
Three‐Dimensional Reconstruction of Pulmonary Veins in Patients with Atrial Fibrillation and Controls:
Authors: PEREZ‐LUGONES ALEJANDRO , SCHVARTZMAN PAULO R. , SCHWEIKERT ROBERT , TCHOU PATRICK J. , SALIBA WALID , MARROUCHE NASSIR F. , CASTLE LON W. , WHITE RICHARD D. , NATALE ANDREA
Published: December 2004

PEREZ‐LUGONES, A., et al.: Three‐dimensional Reconstruction of Pulmonary Veins in Patients with Atrial Fibrillation and Controls: Morphological Characteristics of Different Veins.
Multidetector computed tomography can be used to evaluate the anatomy of pulmonary veins (PVs) in patients with AF. The study evaluated two groups. Group 1 included 61 patients assessed following PV ablation with ultrasound or RF energy. Group 2 included 15 patients undergoing ablation for AF and 14 control subjects without a history of AF matched for age and sex. The anatomy of the PVs was analyzed in this group prior to the ablation and compared to controls. Computed tomography was used to measure the ostium of the left superior, left inferior, right superior, right inferior PVs, and the left atrial appendage size. In group 1, PV stenosis was seen in 14 (30%) of 46 patients undergoing ablation with RF energy and in none of the 15 patients receiving ablation with ultrasound energy. In group 2, the ostium size was not different between patients with AF and controls. Similarly, the ostium of the PV that appeared to trigger AF was not larger than the ostium of the remaining veins. A “clustering pattern” of PV branches near the right inferior PV ostium was seen in almost every patient, independent of the presence of the arrhythmia. Computed tomography frequently detects PV stenosis following RF ablation. Ultrasound ablation does not appear to result in PV narrowing. Overall, patients with AF do not have larger sizes of PV ostia. Multiple ramifications from the right inferior PV ostium is a common pattern and may represent a protective anatomic variant. (PACE 2003;26[Pt. I]:8–15)
Gender Differences in Ventricular Repolarization:
Authors: NAKAGAWA MIKIKO , TAKAHASHI NAOHIKO , WATANABE MAKI , ICHINOSE MASASHI , NOBE SEIKI , YONEMOCHI HIDETOSHI , ITO MORIO , SAIKAWA TETSUNORI
Published: December 2004

NAKAGAWA, M.,

et al.

: Gender Difference in Ventricular Repolarization: Terminal T Wave Interval was Shorter in Woman than in Men. The incidence of sudden death is lower in women than in men, although women have a longer QT interval and are more prone to develop torsades de points than men. It has been recently proposed that the time interval between the apex and end of the T wave (Ta‐e) represents the transmural dispersion of ventricular repolarization. Gender and age differences in Ta‐e interval have not been fully assessed previously. Standard surface 12‐lead ECGs recorded in 760 healthy subjects (382 women, 0–88 years of age) were studied. The intervals from j‐point to the apex of the T wave (JaT) and to the end of the T wave (JeT) were measured in lead V5 in each ECG and corrected by preceding RR intervals using the formula of Bazett (JaTc and JeTc). The Ta‐e and Ta‐e/JeT ratio were also evaluated. Both JaTc and JeTc intervals were significantly longer in women aged > 20 years than in men of the same age(P < 0.0001). The difference was due to shortening of these intervals after puberty in men. However, the Ta‐e interval was significantly shorter in women than in men(P < 0.05)and subsequently the Ta‐e/JeT ratio was significantly smaller in women than in men (P < 0.0001). The results showed gender differences in the Ta‐e interval and JaTc and JeTc intervals in healthy adults, and suggest that the small transmural dispersion of repolarization in women, in spite of the long JaTc and JeTc intervals, might be a beneficial antiarrhythmic property. (PACE 2003; 26[Pt. I]:59–64)
Ventricular Oversensing:
Authors: WERETKA SLAWOMIR , MICHAELSEN JOCHEN , BECKER RUEDIGER , KARLE CHRISTOPH A. , VOSS FREDERIK , HILBEL THOMAS , OSSWALD BRIGITTE R. , BAHNER MALTE L. , SENGES JULIA C. , KUEBLER WOLFGANG , SCHOELS WOLFGANG
Published: December 2004

WERETKA, S.,

et al.

: Ventricular Oversensing: A Study of 101 Patients Implanted with Dual Chamber Defibrillators and Two Different Lead Systems. Modern dual chamber ICD systems are able to overcome various sensing problems. However, improvement of their performance is still required. The aim of this study was to assess the sensing function in 101 consecutive patients (84 men, 17 women; mean age 63 ± 12 years; mean follow‐up 24 ± 4 months) implanted with dual chamber defibrillators and integrated (IB) or dedicated bipolar (DB) lead systems. Follow‐up data were analyzed for the presence of ventricular oversensing. Oversensing occurred in 25 (25%) patients, significantly more frequent in patients implanted with IB compared to DB lead systems (21/52 vs 4/49, P = 0.0002). Patients with cardiomyopathies (CMs) were more prone to sensing malfunctions than patients with no CM (12/30 vs 13/71, P = 0.04). T wave oversensing (n = 14), respirophasic ventricular oversensing (n = 4), and P wave oversensing (n = 6) were the most common pitfalls of ventricular sensing. P wave oversensing was unique to the IB lead system. CT scans performed in these patients disclosed the position of the RV coil to be proximal to the tricuspid area. Four patients received inappropriate ICD shocks due to oversensing. In all but two patients who received lead revision, oversensing was resolved by noninvasive means. In conclusion: (1) ventricular oversensing is a common problem occurring in up to 25% of patients with dual chamber ICDs; (2) P wave oversensing is a ventricular sensing problem affecting function of 11% of dual chamber devices with IB lead systems; (3) IB leads are significantly more susceptible to T wave and P wave oversensing than DB leads; and (4) patients with cardiomyopathies are more prone to oversensing than patients with other heart diseases. (PACE 2003; 26[Pt. I]:65–70)
Successful Treatment of Severe Orthostatic Hypotension with Erythropoietin
Authors: KAWAKAMI KAZUNOBU , ABE HARUHIKO , HARAYAMA NOBUYA , NAKASHIMA YASUHIDE
Published: December 2004

KAWAKAMI, K., et al.: Successful Treatment of Severe Orthostatic Hypotension with Erythropoietin.
A 71‐year‐old man, who was diagnosed with familial amyloidosis type I, was admitted for treatment of severe orthostatic hypotension associated with recurrent syncopal attacks. Head‐up tilt testing demonstrated severe orthostatic hypotension (114/72 mmHg in the supine position and 62/34 mmHg in the upright position) with syncope or presyncope. Oral midodorine and fludrocortisone therapies failed to prevent his symptoms. After administration of subcutaneous erythropoietin, his blood pressure drop in the upright position was decreased and symptoms disappeared unassociated with improvement of anemia. Although previous reports have shown that the mechanism by which erythropoietin improves orthostatic hypotension is related to improvement in anemia, other mechanisms may also play a role. (PACE 2003; 26[Pt. I]:105–107)
Moricizine Induced Increase in Pacing Threshold
Authors: GIROD JOHN P. , MARROUCHE NASSIR , CHEN MICHAEL S. , NATALE ANDREA
Published: December 2004

GIROD, J.P., et al.: Moricizine Induced Increase in Pacing Threshold.
A 72‐year‐old woman who was experiencing incessant ventricular tachycardia and recurrent automatic implantable cardioverter defibrillator (AICD) firing despite amiodarone therapy was referred to the Cleveland Clinic Foundation. Myocardial ischemia and infarction were ruled out by standard means. Several antiarrhythmic medications were tried previously without success. Moricizine, 200 mg three times daily, was initiated and controlled the ventricular tachycardia. However, after the dose of moricizine was titrated upward, the patient became symptomatically bradycardic and the ECG exhibited 2:1 block of her paced rhythm and an increased ventricular pacing threshold. (PACE 2003; 26[Pt. I]:110–111)
Haemodynamic changes during low‐pressure carbon dioxide pneumoperitoneum in young children
Authors: De Waal E.E.C. , Kalkman C.J.
Published: December 2004

Background: Both mechanical and pharmacological effects may contribute to the haemodynamic consequences of carbon dioxide (CO2) pneumoperitoneum. The aim of the present study was to evaluate the haemodynamic effects of low‐pressure pneumoperitoneum [intra‐abdominal pressure (IAP) 5 mmHg] in young children (< 3 years).

Methods: Thirteen children, aged 6–36 months, ASA physical status I–III, who were scheduled for laparoscopic fundoplication for gastro‐oesophageal reflux were investigated in the head‐up position (10°). Noninvasive thoracic electrical bioimpedance cardiac index (CI), stroke volume index (SVI), heart rate (HR), mean arterial pressure (MAP) and peak inspiratory pressure (PIP) were recorded, together with PetCO2 and PaCO2 at five time points: before insufflation, 20, 35 and 70 min after start of CO2 insufflation and 12 min after desufflation. During insufflation, minute ventilation was not adjusted and the IAP was maintained at 5 mmHg.

Results: During insufflation, PetCO2 increased from 29 ± 4 to 37 ± 5 mmHg (P < 0.001) and PaCO2 increased from 31 ± 4 to 39 ± 5 mmHg (P < 0.01). CI increased from 2.39 ± 0.86 to 2.92 ± 0.94 l·min−1·m2 (P < 0.01), HR increased from 108 ± 10 to 126 ± 22 b·min−1 (P < 0.01), MAP increased from 52 ± 10 to 63 ± 9 (P < 0.05) and PIP increased from 16 ± 3 to 18 ± 3 cm H2O (P < 0.001). There were no changes in SVI and arterial oxygen saturation.

Conclusions: We conclude that low‐pressure CO2 pneumoperitoneum (with IAPs not exceeding 5 mmHg) for laparoscopic fundoplication in infants and children does not decrease their cardiac index.
Combining low inspired oxygen and carbon dioxide during mechanical ventilation for the Norwood procedure
Authors: Keidan Ilan , Mishaly David , Berkenstadt Haim , Perel Azriel
Published: December 2004

Background: Staged reconstruction has become the preferred approach for treating neonates with hypoplastic left heart syndrome (HLHS). The haemodynamic instability of a single ventricle providing blood flow in parallel to the systemic and the pulmonary circulation, combined with the effects of cardiopulmonary bypass (CPB), results in precarious perioperative conditions. The two ventilatory manoeuvres commonly used for increasing pulmonary vascular resistance are (i) decreasing the fraction of inspired oxygen to < 0.21 and (ii) adding carbon dioxide (CO2) to the ventilatory circuit. Whether molecular nitrogen (N2) or CO2 is used in these situations is a matter of physician and institutional preference. The effect of the two modalities in combination has not been studied in depth.

Methods: This prospective observational study was designed to look at the effects of adding inhaled CO2 to children with HLHS who were already on a hypoxic mixture during the immediate perioperative period.

Results: Twelve suitable neonates were enrolled in the study. Combining the two ventilatory modalities had an additive effect. The effect was more significant in the prebypass (83% of patients) compared with the postbypass period (25% of patients).

Conclusions: Low inspired oxygen and CO2 have an additive vasoconstrictive effect on the pulmonary vessels. The use of both of these ventilatory manoeuveres is less effective postoperatively compared with the prebypass period.
Anaesthetic management in a case of a type IV laryngotracheo‐oesophageal cleft
Authors: Fernández A. , Jerez A. , Falcone N.
Published: December 2004

Summary We report the case of a newborn baby with a type IV laryngotracheo‐oesophageal cleft and the anaesthetic management during the rigid bronchoscopy that was performed at 5 days of age. After anaesthetic induction with sevoflurane and atropine, the child was maintained with sevoflurane 2–2.5% and remifentanil at an infusion rate of 0.5 μg·kg−1·min−1. Ventilation was managed through the lateral port of the bronchoscope. The patient breathed sevoflurane and oxygen/N2O spontaneously via a Jackson‐Rees circuit. To prevent the stomach from filling up with anaesthetic gases, a Foley catheter was placed orally into the stomach. The Foley balloon was inflated and retracted until it sealed the gastro‐oesophageal junction. Tracheal intubation was performed after bronchoscopy to allow suture of the stomach into two chambers. Oxygenation was adequate with no air leakage, with spontaneous ventilation. The Foley catheter was removed afterwards and the patient awakened. We review the literature on different ways of managing the airway in these cases and protecting it from gastric aspiration during ventilation.
Dolasetron for the prevention of postoperative vomiting in children undergoing strabismus surgery
Authors: Wagner Deborah , Pandit Uma , Voepel‐Lewis Terri , Weber Monica
Published: December 2004

Background: Children undergoing strabismus surgery have a high incidence of postoperative vomiting (POV). The purpose of this study was to assess the efficacy and safety of dolasetron for the prevention of emesis comparing a single 0.35 mg·kg−1 or 12.5 mg dose with placebo.

Methods: Children aged 2–12 years with an ASA status of 1 or 2 undergoing strabismus surgery were randomized in a double‐blind manner to one of three treatment groups. Patients were excluded with a history of previous postoperative vomiting or motion sickness, allergy to serotonin receptor antagonists or previous antiemetic administration within 24 h prior to enrollment.

General anaesthesia was induced with sevoflurane and N2O/O2 and maintained with isoflurane and N2O/O2. The study medication was administered 15 min prior to the end of surgery. Patients experiencing two or more episodes of vomiting were rescued in the postanaesthesia care unit (PACU) with metoclopramide 0.15 mg·kg−1. A total of 118 patients were enrolled with documentation of the number and severity of vomiting episodes, time to awakening, PACU length of stay and postoperative agitation.

Results: Patients with an acute complete response (ACR), defined as no emetic episodes and no rescue medication within 24 h of study drug administration were 62% (weight dose), 64% (fixed dose) and 33% (placebo, P < 0.05).

Conclusions: There was no statistical difference between the 0.35 mg·kg−1 dose and the fixed 12.5 mg dose of dolasetron with both reducing the incidence of POV.
Death after re‐exposure to propofol in a 3‐year‐old child: a case report
Authors: Holzki Josef , Aring Christoph , Gillor Alex
Published: December 2004

This case report discusses the cause of death in a 3‐year‐old child who survived a high dose (20 mg·kg−1·h−1) of propofol, infused over a period of 15 h, following which the patient developed a combined respiratory and metabolic acidosis, the oxygenation remaining normal. Bronchospasm was assumed to be the cause of hypercapnia. At this time the doctors in charge did not think of a possible side‐effect of propofol. The administration of propofol was interrupted, the patient recovered within 13 h from the acidosis, woke up and required further sedation. A supposedly entirely safe infusion of 4 mg·kg−1·h−1 propofol, as recommended in the literature for up to 48 h, was administered. After only 8 h intractable bradycardic dysrhythmias occurred. Although pharmacokinetic studies have pointed to a possible accumulation of propofol during continuous infusions, an interruption of an infusion for several hours has been considered sufficient for practically total clearance of the drug from the body. In this case re‐exposure with a recommended dose of propofol was accompanied by bradycardia and dysrythmias that proved to be resistant to therapy and led to fatal cardiac insufficiency with a functioning artificial pacemaker in place. This case raises concerns about the safety of long‐term infusions of propofol for sedation in children and possibly also in adults.
Thoracentesis in pericardial and pleural effusion caused by central venous catheterization: a less invasive neonatal approach
Authors: Pignotti Maria Serenella , Messeri Andrea , Donzelli Gianpaolo
Published: December 2004

An 840 g infant developed a rapid onset of shock‐like symptoms. Pericardial and pleural effusions from an indwelling central catheter were diagnosed via echocardiography. A thoracentesis was promptly performed with immediate clinical improvement. The fluid withdrawn from the pleural space was analysed as hyperalimentation. The infant survived because of early diagnosis and aggressive therapeutic intervention. A pericardial effusion should be drained if there is cardiovascular compromise and because pericardiocentesis represents a high risk technique, attempts should be made to rectify the extravasation via thoracentesis.
The cardiac analgesic assessment scale (CAAS): a pain assessment tool for intubated and ventilated children after cardiac surgery
Authors: Suominen Pertti , Caffin Chelsea , Linton Sophie , McKinley Dianne , Ragg Philip , Davie Gabrielle , Eyres Robert
Published: December 2004

Background : This study evaluated the reliability and validity of the Cardiac Analgesic Assessment Scale (CAAS) as a postoperative pain instrument for children after cardiac surgery.

Methods : Two prospective studies included 69 children (aged 0–16 years) admitted to the intensive care following cardiac surgery with a sternotomy incision. Four concurrent observers performed paired observations with the CAAS or a visual analogue scale (VAS) for 32 patients. After a stimulus to the patient, two nursing observers independently scored the patient with the CAAS, and another two independent nursing observers simultaneously scored the patient using a VAS. In the second part of this study the CAAS was evaluated with respect to its ability to detect changes in pain status and responses to analgesia over time in 37 patients.

Results : Interrater reliability, represented by Lin's concordance correlation coefficient proved to be almost perfect for the CAAS score 0.97 (95% CI: 0.95, 0.99). About 91% of patients received the same total CAAS score from the two raters. The dichotomized CAAS scores of the two nurses indicated that in 97% of cases the nurses agreed upon whether there was an indication for treatment of pain. The CAAS was shown to significantly reflect changes in pain status over time. The average Spearman's rank correlation between VAS and CAAS was low (0.27), indicating that CAAS did not correlate well with VAS.

Conclusion : This study provides evidence that postoperative pain in sedated and intubated children after cardiac surgery can be assessed reliably using a formal pain tool.
Clinical Evaluation of Peak Endocardial Acceleration as a Sensor for Rate Responsive Pacing
Authors: GRECO ENRICO MARIA , FERRARIO MARCO , ROMANO SALVATORE
Published: December 2004

GRECO, E.M., et al.: Clinical Evaluation of Peak Endocardial Acceleration as a Sensor for Rate Responsive Pacing.
An innovative control parameter for rate responsive (RR) pacing that uses a sensor to measure mechanical vibrations generated by the myocardium during the isovolumetric contraction phase (peak endocardial acceleration [PEA]), has been devised by SORIN Biomedica (BEST Living System). To assess the physiological sensitivity of the pacemaker sensor along with reliability of the algorithm to supply appropriate pacing rates three different relationships were examined (linear regression analysis): (1) recorded ΔPEA exercise steps against the calculated energy cost of exercise (MET), (2) exercise pacing rates against predicted values, and (3) ΔPEA against exercise pacing rates. Fifteen patients (mean

age 68 ± 12 years

) in NYHA Class I‐II, implanted with the BEST Living System (Living 1 DDDR pacemaker) for advanced AVB and/or SSS, underwent one of the following maximal exercise stress protocols: bicycle (25 W, 2‐minute steps) or Bruce or Chronotropic Assessment Exercise Protocol (CAEP). Pacing rates for each step were matched against those predicted by a reliable and tested custom software called Pacing Rate Profile Software (PRPS). The PRPS is based on the oxygen pulse reserve (OPR) method (OPR = VO2 reserve divided by heart rate reserve), American College of Sports Medicine (ACSM) formulas for calculating workload/metabolic requirements, and data derived from the Weber functional classes. On the basis of certain patient data the PRPS then supplies appropriate metabolic pacing rate profiles. In all 15 patients linear regression analysis ofΔPEA against MET, as evaluated during the exercise protocol steps, showed a high correlation

(r = 0.97)

. Likewise, a high correlation was also obtained between PRPS predicted heart rates and exercise pacing rates

(r = 0.96)

and PEA against exercise pacing rates

(r = 0.96)

. The results of this study show that, through PEA dynamic monitoring, the SORIN Best Living System produces physiological pacing rates that are significantly related to metabolic needs. (PACE 2003; 26[Pt. I]:812–818)
Beat‐to‐Beat Assessment of QT/RR Interval Ratio in Severe Heart Failure and Overt Myocardial Ischemia:
Authors: FABER THOMAS S. , GROM ANDREAS , SCHÖPFLIN MARKUS , BRUNNER MICHAEL , BODE CHRISTOPH , ZEHENDER MANFRED
Published: December 2004

FABER, T.S., et al.: Beat‐to‐Beat Assessment of QT/RR Interval Ratio in Severe Heart Failure and Overt Myocardial Ischemia: A Measure of Electrical Integrity in Diseased Hearts.
The study was designed to assess the beat‐to‐beat variation of ventricular repolarization in patients with myocardial ischemia, heart failure, and in normal subjects. Autonomic tone may alter the dynamic QT/RR interval relation and thus may be involved in ventricular arrhythmia development, especially in the diseased heart. The study included 145 patients (age 16–86 years) with CHF (LVEF ≤ 0.30) or unstable angina pectoris

(LVEF > 0.60)

. The control group consisted of healthy volunteers giving physiological baseline measures for the evaluated parameters: cycle length, QT interval, and QT/RR interval ratio during three time periods. In patients with myocardial ischemia

(LVEF > 0.60)

and healthy subjects the QT/RR interval ratio did not reveal significant differences between both groups (QT/RRCAD= 0.36 ± 0.77 vs QT/RRcontrols= 0.28 ± 0.83; NS). In sharp contrast, in patients with severe heart failure, RR dependent instantaneous variation of the QT interval was almost missing and regression line analysis disclosed a QT/RR interval slope substantially enhanced by 196% (compared to normal subjects) and 131% (compared to CAD patients; P < 0.05) with a complete loss of circadian modulation (QT/RRCHF= 0.83 ± 0.71 vs QT/RRCAD= 0.36 ± 0.77 vs QT/RRcontrols= 0.28 ± 0.83; P < 0.05). Beat‐to‐beat QT interval assessment provides a dynamic parameter of physiological and altered repolarization in defined study groups. Compared to other groups (preserved LVEF), patients with left ventricular impairment exhibited a significantly increased sensitivity of repolarization to cycle length (enhanced QT/RR interval ratio) and a blunted circadian modulation of the QT interval. This is consistent with concept that increased repolarization disparity may be deleterious being a potential pathophysiological basis for enhanced arrhythmic risk. (PACE 2003; 26[Pt. I]:836–842)
Video‐Assisted Thoracoscopic Sympathectomy for Congenital Long QT Syndromes
Authors: LI JIANFENG , WANG LEXIN , WANG JUN
Published: December 2004

LI, J., et al.: Video‐Assisted Thoracoscopic Sympathectomy for Congenital Long QT Syndromes.
The feasibility, safety, and effectiveness of video‐assisted thoracoscopic sympathectomy (VATS) for congenital long QT syndrome were assessed in four patients who had frequent syncopal events before the surgeries. Under general anaesthesia, the pleural cavity was entered via two small incisions in the left third and fifth intercostal spaces at the mid‐axillary line. The left thoracic sympathetic chain was identified and resected from T2‐T5. The lower one third of the left stellate ganglion was also resected. VATS resulted in a significant shortening in corrected QT intervals (QTc) in three patients, the average QTc of the four patients immediately before and after VATS was

538 ± 76

and

512 ± 57 ms

, respectively

(P = 0.047)

. The heart rate remained unchanged after the VATS (

67 ± 4

vs

69 ± 4 beats/min, P > 0.05

). There were no major perioperative complications apart from mild ptosis of the left upper eyelid in one patient who recovered in the following days. There was no recurrence in syncopal events after a 3‐month follow‐up. VATS is a safe and effective technique for left cardiac sympathectomy in patients with congenital long QT syndromes. (PACE 2003; 26[Pt. I]:870–873)
Radiofrequency Catheter Ablation:
Authors: DORWARTH UWE , FIEK MICHAEL , REMP THOMAS , REITHMANN CRISTOPHER , DUGAS MARTIN , STEINBECK GERHARD , HOFFMANN ELLEN
Published: December 2004

The success and safety of standard catheter radiofrequency ablation may be limited for ablation of atrial fibrillation and ventricular tachycardia. The aim of this study was to characterize and compare different cooled and noncooled catheter systems in terms of their specific lesion geometry, incidence of impedance rise, and crater and coagulum formation to facilitate appropriate catheter selection for special indications. The study investigated myocardial lesion generation of three cooled catheter systems (7 Fr, 4‐mm tip): two saline irrigation catheters with a showerhead‐type electrode tip (sprinkler) and a porous metal tip and an internally cooled catheter. Noncooled catheters (7 Fr) had a large tip electrode (8 mm) and a standard tip electrode (4 mm). RF energy was delivered on isolated porcine myocardium superfused with heparinized pig blood (37°C) at power settings of 10–40 W. Both irrigated systems were characterized by a large lesion depth (

8.1 ± 1.6 mm

) and a large lesion diameter (

13.8 ± 1.6 mm

). In comparison, internally cooled lesions showed a similar lesion depth (

8.0 ± 1.0 mm

), but a significantly smaller lesion diameter (

12.3 ± 1.2 mm

,

P = 0.04

). Large tip lesions had a similar lesion diameter (

14.5 ± 1.6 mm

), but a significantly smaller lesion depth (

6.3 ± 1.0 mm

,

P = 0.002

) compared to irrigated lesions. However, lesion volume was not significantly different between the three cooled and the large tip catheter. To induce maximum lesion size, power requirements were three times higher for the irrigation systems and two times higher for the internally cooled and the large tip catheter compared to the standard catheter. Impedance rise was rarest with irrigated and large tip ablation. In case of impedance rise crater formation was a frequent observation (61–93%). Irrigated catheters prevented coagulum formation most effectively. Irrigated rather than internally cooled ablation appears to be most adequate for the induction of deep and long lesions at a low rate of impedance rise and thrombus formation. Large tip ablation may be feasible for the creation of long linear lesions, however, with an increased risk of thrombus formation. (PACE 2003; 26[Pt. I]:1438–1445)
Chronic Performance of Steroid‐Eluting Epicardial Leads in a Growing Pediatric Population:
Authors: HORENSTEIN M. SILVANA , HAKIMI MEHDI , WALTERS HENRY , KARPAWICH PETER P.
Published: December 2004

Patient size and congenital heart defects complicate pacemaker therapy in children favoring an initial epicardial approach. Steroid‐eluting (SE) epicardial (EPI) leads maintain stable, low pacing thresholds in the short‐term when compared to the nonsteroid (NSE) epicardial (EPI) leads. The purpose of this study was to evaluate chronic, 10‐year performance of SE leads in growing children compared with NSE EPI leads implanted during the same time interval. From 1990 to 2000, 35 patients (age 1 month to 18 year, median 3 years), 28 with and 7 without congenital heart disease (CHD) received 51 SE leads: 27 ventricular and 24 atrial. NSE leads were implanted in 27 patients (age 1–28 years, median 8 years), 24 with and 3 without CHD: 27 ventricular and 1 atrial. Pacing lead threshold, impedance, and energy were measured at implant and during a 10‐year follow‐up. Unpaired t‐test showed that impedance remained stable for all leads with lower mean values for the SE

(376 ± 55 vs 443 ± 109 Ω) (P = NS)

. The mean energy requirement for SE leads at 10 years

(1.2 ± 0.9 μJ)

was significantly lower than for NSE

(4.4 ± 5.5 μJ) (P < 0.05)

. At 2.5‐V output, chronic thresholds for SE leads did not significantly differ from implant values for atrial (0.08 vs 0.09 ms) or ventricular (0.08 vs 0.08 ms) sites. There were no differences in SE lead performances among patients with or without CHD. Fracture or dislodgement occurred in two SE (4%) and four NSE (14%) leads. SE outperform NSE EPI leads and show stable, chronic low thresholds over time in all growing children. (PACE 2003; 26[Pt. I]:1467–1471)
A Technical Approach to Optimized Atrial Recognition in the ICD:
Authors: GROM ANDREAS , BARON THOMAS W. , BRUNNER MICHAEL , GIESLER ULRICH , FABER THOMAS S. , BODE CHRISTOPH , ZEHENDER MANFRED
Published: December 2004

Present‐day ICD systems offer the possibility to reconstruct an intrathoracic 6‐lead ECG (IT‐ECG), using the defibrillator coils in the right ventricle and superior vena cava and the left‐laterally positioned ICD as electrodes according to Einthoven and Goldberger. The aim of this study was to assess the feasibility of (1) automated P wave recognition in the IT‐ECG without an additional atrial electrode as the basis of AV synchronous ventricular pacing (VDD) and for improved differentiation between supraventricular tachyarrhythmias and, (2) the automated detection of pacing evoked atrial potentials (EAP) in dual chamber ICDs as the basis for atrial “autocapture”pacing systems. In 27 patients during ICD implanation intraoperatively, the IT‐ECG was digitally recorded. A recently established algorithm for automatic P wave and EAP detection correctly identified 1,663/1,672 (99.5%) P waves (oversensing rate 0.6%) and 543/554 (98.0%) EAP (no oversensing). During subthreshold atrial stimulation, 405/412 (98.3%) P waves were correctly identified (oversensing due to pacemaker spikes,n = 421, without subsequent EAP, 1.9%,n = 8). During stimulated ventricular tachycardia in 26/27 patients retrograde P wave or AV dissociation were identified. The 6‐lead IT‐ECG, easily implementable in ICD systems, is a diagnostic tool providing reliable information about atrial activation, serving as a basis for VDD pacing in single chamber ICD systems, allowing reliable EAP recognition that enables atrial “autocapture”pacing in dual chamber ICDs, and improves the differentiation between supraventricular and ventricular tachycardia. (PACE 2003; 26[Pt. I]:1472–1478)
Cardiac Sarcoidosis Masquerading as Right Ventricular Dysplasia
Authors: OTT PETER , MARCUS FRANK I. , SOBONYA RICHARD E. , MORADY FRED , KNIGHT BRADLEY P. , FUENZALIDA CHARLES E.
Published: December 2004

Patients with cardiac sarcoidosis may present with clinical and morphological features similar to arrhythmogenic right ventricular dysplasia (ARVD) or cardiomyopathy (ARVC). Three cases of cardiac sarcoidosis are presented that clinically mimicked ARVD or ARVC until a pathology diagnosis of sarcoidosis was made at biopsy or autopsy. A diagnostic distinction, while often difficult to make, is important since treatment with corticosteroids may benefit those with sarcoidosis but is not expected to be useful in cases with ARVD or ARVC. (PACE 2003; 26[Pt. I]:1498–1503)
Rate Response of a Closed‐Loop Stimulation Pacing System to Changing Preload and Afterload Conditions
Authors: CRON THOMAS A. , HILTI PATRICK , SCHÄCHINGER HARTMUT , POUSKOULAS CHRISTOS D. , KELLER DAGMAR I. , ZAUGG CHRISTIAN E. , BUSER PETER T. , PFISTERER MATTHIAS E. , OSSWALD STEFAN
Published: December 2004

Closed‐loop stimulation (CLS) is a new sensor concept for rate adaptive pacing measuring changes in the unipolar right ventricular impedance, which correlates to changes of the right ventricular contractility and reflects the autonomic nervous innervation of the heart. Some patients do not tolerate the CLS mode because of inappropriate tachycardia, mainly related to postural changes. This study tested if the rate response of the CLS sensor is influenced not only by myocardial contractility but also by rapid changes in right ventricular filling. In 12 patients (10 men, median age 77 years) with a Biotronik Inos2‐CLS DDDR pacemaker and 14 controls (13 men, median age 59 years) head‐up tilt and handgrip testing was performed to provoke rapid changes in pre‐ and afterload. Tilting the pacemaker patients resulted in a nonphysiological steep increase of the sensor rate (increase >20 beats/min, peak after 1 minute, return to baseline within 2–3 minutes), which was significantly different from the control group, showing only a slight rise in intrinsic heart rate immediately after tilting. Simultaneously to the rapid increase in sensor rate, the pacemaker patients showed a marked orthostatic decline of systolic blood pressure. During handgripping, heart rate and blood pressure curves were similar in both groups. In patients with this CLS pacemaker, rapid preload reduction during head‐up tilting caused an overshooting sensor rate increase, reproducing the authors' clinical observation of postural pacemaker tachycardia in some patients. Consequently, they concluded that the rate response of the CLS pacing system can be inappropriately influenced by rapid shifts of blood volume, affecting right ventricular filling. (PACE 2003; 26[Pt. I]:1504–1510)
Inter‐Relationships Between Atrial Flutter and Atrial Fibrillation
Authors: WALDO ALBERT L.
Published: December 2004

It has been appreciated for a long time that atrial flutter and atrial fibrillation have a clinical relationship. Now, with the technological advances that permit more sophisticated electrophysiological studies, especially mapping studies, we have significantly advanced our understanding of this interrelationship. Regarding the relationship at atrial fibrillation to atrial flutter: Atrial fibrillation of variable duration (very brief to prolonged episodes) precedes the onset of atrial flutter in most instances. It seems that during the period of atrial fibrillation, the functional components of the atrial flutter reentrant circuit are formed. This is principally a line of block between the venae cavae. If this line of block does not form, classical atrial flutter does not form. And if this line of block shortens or disappears, classical atrial flutter disappear as well. In fact, it might be said that the major difference in whether classical atrial flutter or atrial fibrillation develops is whether a line of block forms between the venae cavae. Regarding the relationship of atrial flutter to atrial fibrillation: Studies have demonstrated that a driver (a single focus or reentrant circuit of very short cycle length) can be responsible for causing atrial fibrillation by producing fibrillatory conduction to the rest of the atria. In experimental models and now beginning to be demonstrated in patients, this driver may be a stable reentrant circuit of very short cycle length, i.e., a fast form of atrial flutter, if you will. In fact, there is probably a spectrum of these short cycle lengths that depend, in part, on where the reentrant circuit (i.e., “atrial flutter”) exists. When the stable reentrant circuit is of sufficiently short cycle length, it will only activate small portions of the atria in a 1 : 1 manner. The rest of the atria will be activated irregularly, resulting in atrial fibrillation. Unstable reentrant circuits can also do the same thing. In short, it appears that there are several mechanisms of atrial fibrillation, one of which is due to a form of very rapid atrial flutter. (PACE 2003; 26[Pt. II]:1583–1596)