bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial Clinical Experience with a New Self‐Retaining Left Ventricular Lead for Permanent Left Ventricular Pacing
Authors: TSE HUNG‐FAT , YU CANNAS , LEE KATHY LF , YU CHEUK‐MAN , TSANG VELLA , LEUNG SUM‐KIN , LAU CHU‐PAK
Published: October 2013

This study evaluated the performance of a new lead for permanent left ventricular (LV) pacing via the coronary sinus (CS) in four men and nine women (mean age = 71 ± 13 years) with sick sinus syndrome. It consists of a 75‐cm‐long, 4.8‐Fr, unipolar ventricular lead with a distal portion preshaped in an S curve to provide steerability and stability within the CS. Its efficacy and stability for permanent LV pacing were tested at implant, predischarge, and at 1, 3 and 6 months of follow‐up. The lead was successfully implanted in 11/13 patients (85%) within a mean fluoroscopy time of 35 ± 22 minutes. The final positions of the electrodes at the tip of the lead within venous tributaries of the CS were: (1) anterior (n = 2, 18%); (2) posterolateral (n = 5, 45%); and (3) the lateral (n = 4, 36%). Unsuccessful implants were due to unstable lead position (n = 1), or high pacing threshold (n = 1). There was no postprocedural lead dislodgment or significant changes in the R wave amplitude, LV pacing threshold and lead impedance up to 6 months of follow‐up. In summary, this initial experience suggests that this new lead offers safe and reliable permanent LV pacing via the CS in the majority of patients and may be used in isolation or in conjunction with right ventricular pacing for biventricular synchronization.
Effects of Different Atrioventricular Intervals During Dual‐Site Right Atrial Pacing on Left Atrial Mechanical Function
Authors: HO PUI‐CHING , TSE HUNG‐FAT , LAU CHU‐PAK , HETTRICK DOUGLES A. , MEHRA RAHUL
Published: October 2013

Recent studies have suggested that dual‐site right atrial (RA) pacing via the high RA and coronary sinus ostium (CSos) prevents atrial fibrillation (AF). However, the programming of the atrioventricular (AV) interval associated with optimal left atrial (LA) mechanical function during high RA and dual‐site RA pacing has not been defined. LA mechanical function was studied by measuring transmitral pulsed Doppler echocardiographic peak A wave velocity and percent A wave filling, in six women and three men, 67 ± 8 years of age, who had received dual‐site RA pacemakers in a randomized study. Serial echocardiographic measurements were performed during high RA or dual‐site RA pacing at 80 beats/min with AV intervals of 50, 100, 150, or 200 ms tested in random order. High RA and dual‐site RA pacing at an AV interval of 50 ms were associated with significantly lower peak A wave velocity and percent A wave filling, compared to the other A V intervals (all P < 0.05). Compared with high RA pacing, dual‐site RA pacing was associated with significantly higher peak A wave velocity (85 ± 12 vs 72 ± 17 cm/s, P = 0.04) and percent A wave filling (24 ± 3 vs 20 ± 4 %, P = 0.02) at an AV interval of 100 ms, but a lower peak A wave velocity at an AV interval of 200 ms (77 ± 10 vs 84 ± 8 cm/s, P = 0.004). In conclusion, variations in the AV interval during atrial pacing have significant effects on LA function. As a consequence of altered atrial activation, the AV interval associated with optimal LA mechanical function during dual‐site RA pacing was significantly shorter than that during RA pacing. This observation has important implications with respect to the programming of dual‐site RA pacemakers implanted to prevent AF for hemodynamic purpose.
The Influence of Right Atrial Septal Pacing on the Interatrial Contraction Sequence
Authors: KINDERMANN MICHAEL , SCHWAAB BERNHARD , BERG MONIKA , FRÖHLIG GERD
Published: October 2013

Right atrial septal pacing yields shorter interatrial conduction delays than conventional right atrial pacing at the free wall or the right atrial appendage. However, the hemodynamic effects of right atrial septal pacing are less well known. This study measured the delay between right and left atrial contractions during right atrial septal pacing (n = 21), conventional right atrial pacing (n = 32) and atrial multisite pacing (n = 6) by pulse Doppler echocardiography of transtricuspidal and transmitral blood flow. The effects of right atrial septal pacing (n = 14) versus conventional right atrial pacing (n = 22) on the optimal AV delay during dual chamber pacing was examined in patients with high degree atrioventricular (AV) block. Compared to sinus rhythm, conventional right atrial pacing increased P wave duration from 119 ± 21 ms to 137 ± 24 ms (P < 0.001), whereas both right atrial septal pacing (119 ± 10 ms before, 106 ± 13 ms during pacing, P = 0.002) and atrial multisite pacing (123 ± 20 ms before, 112 ± 11 ms during pacing, P = 0.5) shortened P wave duration. Atrial pacing caused a significant (P < 0.002) prolongation of atrial conduction delays from 24 ± 21 ms to 41 ± 26 ms during conventional right atrial pacing, and reversed the right‐to‐left into a left‐to‐right contraction sequence in 20 of 21 patients during right atrial septal pacing (atrial conduction delay during sinus rhythm: 34 ± 23 ms vs 37 ± 26 ms during atrial pacing, P < 0.0001). Atrial multisite pacing caused a nonsignificant shortening of the usual right‐to‐left contraction delay from 22 ± 34 ms to 11 ± 18 ms. The optimal left heart AV delay during AV sequential pacing was significantly (P = 0.002) shorter during right atrial septal pacing (108 ± 38 ms) than during conventional right atrial pacing (152 ± 33 ms). During conventional right atrial pacing the optimal right heart AV delay was significantly (P = 0.029) shorter than the optimal left heart AV delay. The opposite relation was observed for right atrial septal pacing (P = 0.033). Conclusions: Interatrial septal pacing does not synchronize right and left atrial contractions. It reverses the atrial mechanical timing from a right‐to‐left to a left‐to‐right contraction sequence, and requires the setting of shorter AV delays during dual chamber pacing if based on the optimization of left heart timing. Interatrial septal pacing is a technique which allows pacing of the left atrium from a right atrial site, rather than a single site approach to biatrial pacing.
Comparison of Metabolic Expenditure During CAEP Versus a Test Adapted to Aerobic Capacity (Harbor Test) in Elderly Healthy Individuals
Authors: PAGE ERIC , BONNET JEAN‐LUC , DURAND CATHERINE
Published: October 2013

Cardiopulmonary exercise tests are frequently used to test rate responsive pacemakers. The chronotropic assessment exercise protocol (CAEP) has been specifically proposed for the evaluation of rate responsive pacing systems. A mathematical method, based on CAEP measurements, was developed with a view of normalizing the exercise induced metabolic response. CAEP was compared to a tailored protocol (Harbor), adapted to the metabolic capacity of each patient. Harbor was set to keep the exercise duration within 10 minutes and achieve a workload as linear as possible. Metabolic parameters were continuously recorded by a cardiopulmonary system. Those data were used in the construction of slopes by the normalization method. The results of the tests performed in 16 elderly healthy patients showed no differences in metabolic or functional parameters. Slopes of the mathematical model were comparable (1.09 ± 0.16 for CAEP vs 1.07 ± 0.17 for Harbor), though both were higher than the value of 1, defined as normal. In both cases, linearity was confirmed by the coefficient of correlation (0.98 ± 0.02 for CAEP and Harbor). In conclusion, no significant differences were found in the outcomes of the two protocols. Higher values of the slopes with the normalization method can be explained by the definition of the maximal predicted heart rate as 220 — age, which is probably not appropriate for elderly, healthy, active subjects.
The Impact of Automatic Threshold Tracking on Pulse Generator Longevity in Patients with Different Chronic Stimulation Thresholds
Authors: SIMEON LUCAS , DURU FIRAT , FLURI MARTIN , JENZER HANS R. , RAHN MARIETTE , CANDINAS RETO
Published: October 2013

Automatic adjustment of the stimulation output of pacemakers to changing stimulation thresholds using the Autocapture feature increases patient safety and decreases energy consumption. This study examined the impact of Autocapture on pulse generator longevity in patients with different chronic stimulation thresholds. Eighty patients (mean age 79 ± 9 years; 37 men, 43 women) with Pacesetter Regency SR + pacemakers were included in the study. Data were collected before discharge of the patients from the hospital, 6–12 weeks postimplant, and then every 6–12 months. Pulse generator longevity was calculated theoretically, assuming 100% stimulation with a stable threshold, at a pacing rate of 65 ± 6 beats/min and 1% backup pulses. Theoretical pulse generator longevity was calculated for low (< 1 V), intermediate (≥ 1 V and < 2 V), and high (≥ 2 V) stimulation thresholds. Pulse generator longevity was compared among three groups: (A) Autocapture programmed On, (B) Autocapture programmed Off, (C) theoretical calculations using thresholds of patients in group A with the stimulation voltage programmed at twice pacing threshold, or at a minimum of 2.4 V. The mean follow‐up time since implantation was 19 ± 8 months. The calculated longevity benefits for patients in group A were 36%, 59%, and 30% compared to group B, and 19%, 32%, and 49% compared to group C in patients with low, intermediate, and high chronic stimulation thresholds, respectively. Theoretical calculations based on chronic stimulation thresholds in our patient population with Regency SR+ pacemakers suggest that Autocapture may markedly prolong pulse generator longevity in patients with a broad range of long‐term pacing thresholds.
Evolution of an Active Fixation Atrial Pacing Lead
Authors: SCHWAAB BERNHARD , KINDERMANN MICHAEL , FROHLIG GERD , KUSCH OLIVER , SCHIEFFER HERMANN
Published: October 2013

Three bipolar atrial pacing leads from one manufacturer differing in a single electrode design characteristic were compared. Each lead had nonretractable screw and a microporous electrode tip made of activated carbon. Model S84F had a tip surface area of 8 mm2. In model S44F, the tip surface area was reduced to 4 mm2 by insulation of the screw, and in model BS45D, steroid elution was added to the 4 mm2 tip. Ten patients in each group received identical pulse generators. During implantation, atrial potentials (5.4 ± 2.0, 4.2 ± 2.0, 4.6 ± 2.1 mV), pacing thresholds at 0.5 ms (0.47 ± 0.14, 0.41 ± 0.15, 0.55 ± 0.33 V) and lead impedance at 2.5 V/0.5 ms (515 ± 80, 575 ± 152, 546 ± 131 Ω) were comparable among groups. The early postoperative threshold peak was significantly lower with the BS45D than with the S84F and S44F lead models. One year after implantation, charge threshold was significantly lower with the BS45D lead than with the S84F and the S44F model (0.34 ±0.11 vs. 0.68 ± 0.20 and 0.56 ± 0.21 μC; P < 0.05). Lead impedance at 2.5 V/0.5 ms (557 ± 90, 549 ± 36, 524 ± 72 Ω) and atrial sensing (4.3 ± 2.1, 4.7 ± 1.9, 4.7 ± 0.9 mV) were not significantly different. One year postimplant, current drain of the pacing system was measured by pacemaker telemetry at chronic output settings in AAI mode/70 beats/min. Battery current measured among the three atrial lead models did not differ significantly (S84F: 11.9 ± 0.90, S44F: 12.2 ± 1.8, BS45D: 11.5 ± 0.26 μA). In conclusion: reduction of the tip surface area by insulation of the screw did not improve pacing performance. Addition of steroid elution to the 4 mm2 tip significantly lowered the early threshold peak and the long‐term pacing threshold. Lowering of the pacing threshold, however, did not lower the current drain of the pacing system.
Uncoupling of ATP‐Sensitive Potassium Current from Cell Metabolism Due to Antisense Oligonucleotides Against Sulfonylurea Receptor in Guinea‐Pig Atrial Myocytes
Authors: BRANDTS BODO , BENDER KIRSTEN , WEISMÜLLER PETER , POTT LUTZ , TRAPPE HANS‐JOACHIM
Published: October 2013

ATP‐sensitive K+ current [Ik(atp)] plays an important role in the regulation of cardiac electrical activity. In the myocardium, Ik(atp) is regulated by the sulfonylurea receptor (SURIIA) which mediates the inhibition of Ik(atp) due to glibenclamide (Gli). The role played by SURIIA in the sensitivity of Ik(atp) to metabolic inhibition is unclear. We studied the effect of SURIIA antisense oligonucleotides (ODNs) on the properties of Ik(atp) in cultured guinea‐pig atrial myocytes. Ik(atp) was measured by the whole‐cell voltage clamp method and was activated with cromakalim (Cro; 200 μm) and dinitrophenole (DNP; 100 μm). Mean Ik(atp) density activated by DNP and Cro in nonincubated cells was 117 ± 12 pA/pF [n =17] and 17 ± 9 pA/pF [n =16] respectively. No significant difference was observed after incubation with nODN [DNP: 121 ± 13 pA/pF (n = 20); Cro:19 ± 4 pA/pF (n = 8)]. Cells incubated with ODNs showed a significant reduction of Ik(atp) due to DNP (19 ± 13 pA/pF; P < 0.05, n = 6), whereas Cro‐induced Ik(atp) was unaffected (16 ± 8 pA/pF, n = 8). The effectiveness of DNP‐induced metabolic inhibition was apparent in a concomitant reduction of the nucleotide‐phosphate dependent muscarinic K+ current (inhibition of IK(ACh) in ODN incubated myocytes without activation of IK(ATP)]. The ATP sensitivity of IK(ATP) appears mediated by SURIIA. Activation of this current by Cro seems to be SURIIA‐independent. ODN‐induced metabolic uncoupling of Ik(atp) may be a useful experimental tool. A reduced sensitivity of Ik(atp) to intracellular ATP concentrations may be of clinical interest.
Pulmonary Veins‐Left Atrial Junction: Anatomic and Histological Study
Authors: MOUBARAK JEAN B. , ROZWADOWSKI JACK V. , STRZALKA CHRISTOPHER T. , BUCK WALTER R. , TAN WILFREDO S. , KISH GEORGE F. , KISIEL THERESA , FRONC HENRY C. , MALONEY JAMES D.
Published: October 2013

Pulmonary veins (PVs) are the target of ablation procedures to cure paroxysmal atrial fibrillation (PAF). There are few anatomic and histological studies of PVs. Sixteen human hearts were obtained from autopsies performed at our hospital and cadavers from a local medical school. The anatomic relationship between the PVs and the left atrium (LA) was categorized according to the spatial orientation of the veins within horizontal and vertical planes viewed from the dorsal aspect of the LA. The PVs were sectioned longitudinally, and the sections were stained with hematoxylin and eosin. In addition, selected sections were stained with antismooth muscle antibodies (vessel wall), antipankeratin, and antimyoglobin antibodies (myocardium). The PV‐LA junction has variable orientations. Confluent superior and inferior veins, observed in 25% of the hearts, were more common on the left side. A myocardial sleeve extended from the LA onto the adventitial surface of the PV. The sleeve was distinct from the smooth muscle in the PV media, from which it was separated by loose fibrous strands. There was no microscopical boundary between the PV and the LA endocardium. The PV join the LA at variable angles. Each PV is surrounded by a myocardial sleeve extending from the LA.
Linear Lesion Formation by ND:YAG Laser Versus Radiofrequency Energy in Porcine Atria
Authors: MENZ VOLKER , SCHOLZ STEFFEN , BAUMGÄRTL DIRK , HOFFMANN JÜRGEN , GRIMM WOLFRAM , MOOSDORF RAINER , MAISCH BERNHARD
Published: October 2013

The efficacy of RF energy versus the neodymium:yittrium aluminum‐garnet laser to create linear lesions was compared in fresh ex vivo swine hearts. A total of 598 lesions were created in four locations: ostium of the pulmonary veins, trabeculated lateral left atrium, smooth posterior part of the right atrium, and the isthmus between the inferior vena cava and tricuspid valve. A 400‐μm bare quartz fiber with CO2 cooling (distance to the tissue 5, 10, and 15 mm) and an RF ablation catheter (4‐mm tip) were mechanically dragged over the tissue at speeds 0.5, 1.0, and 1.5 mm/s. A continuous and transmural ablation line was recorded as successful. A 100% success rate was achieved at the pulmonary veins and the isthmus at some settings of energy delivery by the laser and RF. In the thick posterior right atrium, RF resulted in transmural lesions only when associated with carbonization, while the laser produced successful ablation lines in 100% of the attempts. In the left atrium, because of the presence of prominent trabeculations, RF was unsuccessful at all settings of energy delivery. In contrast, deep photocoagulation by laser resulted in successful ablations in the left atrium in 100% of attempts. Lesion formation was faster by laser ablation and mean lesion width was at least 25% smaller with the laser than with RF. In conclusion, the formation of linear lesions at the isthmus and at the pulmonary veins was successful with the laser and RF. In the trabeculated left atrium and the thick posterior right atrium, only laser ablation was successful.
Coagulum Index Predicts Coagulum Formation in Right Atrial Radiofrequency Energy Delivery to Ablate Atrial Fibrillation
Authors: CHAN ERIC K.Y. , ABATI ALLAN L. , VEPA KUSHAL
Published: October 2013

An ongoing multicenter U.S. clinical study evaluates the safety and effectiveness of creating linear lesions with radiofrequency (RF) energy using a 3.7 Fr microcatheter used with a 9 Fr steerable guiding catheter in the right atrium (RA) to treat paroxysmal atrial fibrillation (PAF). Study entry criteria were symptomatic, drug refractory PAF. RF energy was delivered in 60‐second episodes at 30 W or 50 W power settings. Electrode tissue contact was ascertained by sharp electrograms of high amplitude. Coagulum Index (C.I.), a new calculation to predict the probability of coagulum development, was derived analytically from measurements of RF power, RF current, and time to reach maximum temperature in each ablation episode. The RF data from 398 separate ablation episodes in 15 patients were used to calculate C.I. Coagulum presence was determined by postablation visual inspection of the microcatheter electrodes. A logistic model was used to estimate the probability of coagulum occurrence, with C.I. as the predictive variable. When C.I. ≥ 12, the probability of coagulum formation increased significantly in this model (P < 0.0001). Prolonging the power delivery rise time and limiting maximum RF power setting to 30 W effectively lowers C.I. and minimizes coagulum formation. These results should also apply to left atrium ablation, where minimizing coagulum formation may decrease the risk of stroke or mortality.
P Wave Dispersion in Hypertensive Patients with Paroxysmal Atrial Fibrillation
Authors: ÖZER NECLA , AYTEMIR KUDRET , ATALAR ENVER , SADE ELIF , AKSÖYEK SERDAR , ÖVÜNç KENAN , AçÝL TAYFUN , NAZLÝ NASÝH , ÖZMEN FERHAN , OTO ALI , KES SÝRRÝ
Published: October 2013

It is important to assess the risk of developing paroxysmal atrial fibrillation (PAF) in hypertensive patients since hypertension is a common disorder predisposing to PAF. We sought to determine if patients with hypertension at risk of PAF can be identified while in sinus rhythm by measurements of P wave dispersion. Twelve‐lead surface electrocardiograms were recorded in 44 hypertensive patients with history of PAF (group I, mean age = 60) and in 50 hypertensive patients without history of AF (group II, mean age = 57). The maximum P wave duration, the minimum P wave duration, and P wave dispersion (Pd = Pmax ‐Pmin) were calculated from 12‐lead surface ECGs. Left atrial dimension (LAD) and left ventricular ejection fraction (LVEF) were measured by echocardiography. P wave dispersion was significantly greater in group I than group II (50 ± 12 vs 38 ± 8 ms, P = 0.001). P minimum (75 ± 13 vs 87 ± 11 ms, P = 0.001) and LVEF (0.63 ± 0.05 vs 0.67 ± 0.04, P = 0.03) were significantly lower in group I than group II. However P maximum and LAD were not significantly different in group I than group II (P > 0.05). In univariate analysis, P minimum, P wave dispersion, and LVEF were significant predictors of PAF, whereas only P wave dispersion remained a significant independent predictor of PAF in a multivariate analysis. Measurement of P wave dispersion in sinus rhythm may be a useful noninvasive clinical tool to identify patients with hypertension at risk of developing atrial electrical instability and atrial fibrillation.
An Increase in Plasma Atrial Natriuretic Peptide Concentration During Exercise Predicts a Successful Cardioversion and Maintenance of Sinus Rhythm in Patients with Chronic Atrial Fibrillation
Authors: WOZAKOWSKA‐KAPLON BEATA , OPOLSKI GRZEGORZ , KOSIOR DARIUSZ , JANION MARIANNA
Published: October 2013

The aim of this study was to determine the value of an increase in plasma atrial natriuretic peptide (ANP) concentrations during submaximal exercise as a predictor of return of sinus rhythm (SR), and of its maintenance over a period of 6 months after cardioversion (CV) of chronic atrial fibrillation (AF). The study group included 42 patients with AF (mean duration 7 ± 7 months) and a controlled ventricular rate. They underwent submaximal exercise testing 24 hours before CV. Blood samples were collected at rest and at peak of exercise for measurement of plasma ANP concentrations. Thirty‐five of 42 patients were successfully cardioverted to SR. At 6 months, 23 patients remained in SR, while 12 had recurrence of AF. The plasma ANP concentrations before CV increased insignificantly during exercise in patients with unsuccessful CV or with recurrence of AF (60.8 ± 17.3 pg/mL to 64 ± 13.5 pg/mL, NS). The mean increase in plasma ANP concentration during exercise was significantly greater in the 23 patients who remained in SR than in the 19 patients unsuccessfully cardioverted or with recurrence of AF (17.5 ± 7.6 pg/mL vs 5.8 ± 4.5 pg/mL, P < 0.01). In multivariate logistic regression analysis, an increase in ANP plasma concentration was independently associated with successful CV and maintenance of SR up to 6 months of observation. In patients with chronic AF an exercise‐induced increase in ANP concentration predicts successful CV and maintenance of SR.
Single Oral Administration of Pilsicainide Versus Infusion of Disopyramide for Termination of Paroxysmal Atrial Fibrillation: A Multicenter Trial
Authors: KUMAGAI KOICHIRO , ABE HARUHIKO , HIRAKI TATSURO , NAKASHIMA HIDEKO , OGINOSAWA YASUSHI , IKEDA HISAO , NAKASHIMA YASUHIDE , IMAIZUMI TSUTOMU , SAKU KEIJIRO
Published: October 2013

A single oral dose of pilsicainide (PLS) is effective in terminating acute‐onset atrial fibrillation (AF). However, the effectiveness of this single oral treatment has not been compared with the infusion of other antiarrhythmic drugs. The effects of a single oral dose of PLS on the termination of AF were compared with an infusion of disopyramide (DISO) in a multicenter trial. Seventy‐two patients with electrocardiographically confirmed, symptomatic, paroxysmal AF (< 48‐hour duration) were randomized to receive either a single 100‐ to 150‐mg dose of PLS versus a 2 mg/kg (maximum dose = 100 mg) infusion of DISO. Successful defibrillation was defined as termination of AF within 2 hours of drug administration. Conversion of AF to sinus rhythm was achieved within 2 hours in 29 of 40 patients (73%) treated with PLS, and in 18 of 32 patients (56%) treated with DISO (NS). The mean time to return of sinus rhythm was 60 ± 30 minutes in the PLS group versus 23 ± 18 minutes in the DISO group (P < 0.001). DISO was particularly effective in terminating nocturnal AF, whereas PLS had a stable circadian effect. PLS was significantly more effective than DISO between 6 am and 12 pm (64% vs 17%, P < 0.05). No adverse effect was observed in either group. In conclusion, a single oral dose of PLS was as effective as an infusion of DISO to restore sinus rhythm in patients with recent‐onset AF. PLS consistently terminated AF regardless of its time of onset.
Clinical Significance of Residual Slow Cavotricuspid Isthmus Conduction After Ablation of Typical Atrial Flutter
Authors: TAKAHASHI RYOKO , IESAKA YOSHITO , TAKAHASHI ATSUSHI , HIROE MICHIAKI , MARUMO FUMIAKI
Published: October 2013

The purpose of this study was to evaluate the clinical significance of residual slow cavotricuspid isthmus (IT) conduction on the ablation line after typical atrial flutter (AF) ablation, undetected by analysis of right atrial (RA) activation. Seventy patients with AF underwent IT ablation. In the first 35 patients (group I), IT block was verified only by the RA activation sequence. In the subsequent 35 patients (group II), IT block was verified by the presence of parallel double potentials with an isoelectric interval through the entire ablation line (in addition to RA activation sequence criteria) during pacing from the low lateral RA and the coronary sinus ostium. In group I patients, residual IT conduction was retrospectively analyzed at the ablation site immediately after the last radiofrequency (RF) application. Six of 33 group I patients (18%) with IT block had residual IT conduction represented by fractionated or multicomponent potentials immediately after the final RF application. Four of these 6 patients (67%) had recurrences of AF, 3 ± 1.4 months after ablation. Four (12%) of 33 group II patients with IT block had residual IT conduction in the ablation line after creation of IT block confirmed by RA activation sequence. This conduction was eliminated by 1.6 ± 0.9 further RF applications in all 4 patients. No AF recurrence was observed in group II patients. Up to 18% of patients with apparent IT ablation had residual slow IT conduction on the ablation line. This conduction was associated with AF recurrences and must be eliminated to achieve complete cure of AF.
Nonlinear Ablation Targeting an Isthmus of Critically Slow Conduction Detected by High‐Density Electro anatomical Mapping for Atypical Atrial Flutter
Authors: IESAKA YOSHITO , TAKAHASHI ATSUSHI , GOYA MASAHIKO , FUJIWARA HIDEOMI , NITTA JUNICHI , NOGAMI AKIHIKO , AONUMA KAZUTAKA , HIROE MICHIAKI , MARUMO FUMIAKI , HIRAOKA MASAYASU
Published: October 2013

Focused high‐density atrial endocardial mapping was performed with a three‐dimensional electroanatomical mapping system or a multi‐electrode basket catheter in six men and two women (mean age = 54 years) with atypical atrial flutter (AFL) to characterize its reentry circuit and identify its isthmus of critically slow conduction (ICSC). Activation mapping revealed figure‐8 reentry with ICSC between a surgical atrial scars in three atypical AFLs following atriotomy, and between the crista terminalis (CT) and the inferior (IVC) or superior (SVC) vena cavae in atypical right atrial (RA) AFL in absence of prior atriotomy. Figure‐8 double loop reentry was documented in one RA atypical AFL. ICSC was characterized by concealed entrainment with a post‐pacing interval identical to the AFL cycle length, and a mid‐diastolic fractionated electrogram, 129 ± 23 ms in duration, spanning the isoelectric line between double potentials on adjacent area of conduction block. All AFLs were successfully ablated with 4.9 ± 4.3 RF pulses applied at ICSC. A possible mechanism of atypical AFL consists of figure‐8 reentry with ICSC between surgical scars in postoperative AFL, and between the CT and the IVC/SVC in RA AFL not preceded by cardiac surgery. Late and partial regeneration of conduction across the atriotomy scar can create an ICSC. Nonlinear ablation targeting ICSC can cure atypical AFL, whether it follows surgery or not.
Orcadian Variation and Onset Mechanisms of Ventricular Tachyarrhythmias in Patients with Coronary Disease Versus Idiopathic Dilated Cardiomyopathy
Authors: GRIMM WOLFRAM , WALTER MELANIE , MENZ VOLKER , HOFFMANN JÜRGEN , MAISCH BERNHARD
Published: October 2013

To determine the circadian variations and the onset mechanisms of ventricular tachyarrhythmias (VT) in patients with implantable cardioverter defibrillators, stored electrograms of 364 VT episodes occurring in 40 patients with coronary artery disease (CAD) and in 29 patients with idiopathic dilated cardiomyopathy (DCM) were analyzed. A similar circadian distribution of VT episodes was observed in both groups, with a morning peak and less pronounced evening peak. After exclusion of patients with atrial fibrillation, VT onset was classified as (1) sudden if preceded by ≥ 8 regular cycles without ventricular premature beats, (2) onset with a short‐long‐short interval, and (3) a more complex onset with variable patterns of ventricular premature beats before initiation of VT. Sudden onset was found in 26% and 21 % of VTs in CAD and DCM respectively. A short‐long‐short interval preceded 29% of VTs in CAD compared to 14% of VTs in DCM (P < 0.05). A more complex onset was observed in the remaining 45% of VTs in CAD and 65% of VTs in DCM (P < 0.05). In conclusion, patients with DCM and CAD had similar circadian distributions of VT episodes. The majority of episodes were preceded by complex occurrence of ventricular premature beats rather than by the classic short‐long‐short sequence. These findings have important implications for the development of preventive pacing methods.
Factors Determining Long‐Term Outcomes and Survival in Patients with Coronary Artery Disease and Ventricular Tachyarrhythmias: A Single Center Experience
Authors: DE SUTTER JOHAN , KAZMIERCZAK JAREK , FONTEYNE WINOC , TAVERNIER RENE , JORDAENS LUC J.
Published: October 2013

A Single‐Center Experience. The influence, after ICD implantation, of concomitant CABG, angioplasty, and other antiischemic therapeutic interventions, like treatment with β‐blockers, on outcome and mortality of patients with VT or VF due to CAD remains uncertain. The univariate and multivariate risks of recurrence of ventricular arrhythmias requiring ICD interventions or death associated with baseline clinical and functional variables were studied in 160 consecutive patients with CAD of whom 30 underwent CABG or angioplasty at ≤ 2 weeks before ICD implantation. ICD interventions occurred in 98 (61%) patients over a mean follow‐up of 1,065 days. In univariate and multivariate analysis, VT as the presenting arrhythmia was the only clinical factor predictive of recurrences. Treatment with β‐blockers at hospital discharge reduced the probability of recurrences. Kaplan‐Meier analysis confirmed the effect of β‐blockers (P < 0.005) and of VT as the presenting arrhythmia (P < 0.01). Overall mortality was 61 % (29/160). In multivariate analysis a low ejection fraction (≤ 0.20) and omission of angiotensin‐converting enzyme inhibitors at discharge were associated with excess mortality. In Kaplan‐Meier analysis, a low ejection fraction (borderline between 0.30 and 0.21, significant < 0.21) was the single predictor of mortality. Revascularization by CABG or angioplasty had no influence on ventricular arrhythmia recurrences or survival. During long‐term follow‐up, VT as the presenting arrhythmia and the omission of β‐blocker therapy were associated with excess recurrences of ventricular arrhythmias after ICD implantation. In contrast, survival depended primarily on left ventricular function at discharge. Revascularization did not prevent recurrences of arrhythmias and had no significant effect on survival in the small group of patients who underwent CABG or angioplasty.
Can the Assessment of Dynamic QT Dispersion on Exercise Electrocardiogram Predict Sudden Cardiac Death in Hypertrophic Cardiomyopathy?
Authors: YI GANG , POLONIECKI JAN , DICKIE SHAUGHAN , ELLIOTT PERRY M. , MALIK MAREK , MCKENNA WILLIAM J.
Published: October 2013

Premature sudden cardiac death (SD) is a critical event in the natural history of hypertrophic cardiomyopathy (HCM), and occurs during or just after physical exertion in approximately 60% of instances. Abnormalities in ventricular repolarization may not be present at rest in some patients but may become apparent under certain conditions. This study was performed to examine whether dynamic QT dispersion during exercise is associated with SD in HCM. Twenty‐four HCM patients with catastrophic events (group I; 18 SD, 6 ventricular fibrillation) and 24 event‐free survivors (group II) were studied. The two groups were pair‐matched for age, gender, and maximum left ventricular wall thickness. QT intervals were manually measured from 12‐lead exercise electrocardiogram (ECG) with a digitizing board. A custom‐developed program was used to calculate QT and JT dispersion. The QT/RR relationship was evaluated by the slope of linear regression analysis. Before exercise, significant differences in heart rate and JT dispersion were found between group I and II. During exercise, heart rate increased and QT decreased significantly in both groups. QT and JT dispersion decreased in both groups, though the magnitude of reduction was greater in group I than in group II. No significant differences in QTc interval and QT or JT dispersion were found between the groups at any stages. At 3 minutes of recovery, heart rate had decreased but remained higher than before exercise, and all measurements of QT components remained shorter compared with those made before exercise in both groups. There was a strong correlation between QT and RR interval during exercise in all study patients (r = 0.95). No difference in the slope of QT against RR intervals was found between the groups (0.317 vs 0.319). In conclusion, exercise reduced QT dispersion in patients with HCM. The dynamic changes in QT dispersion examined by this method on exercise ECG did not make additional contributions in their risk stratification.
The Terminal Portion of the T Wave: A New Electrocardiographic Marker of Risk of Ventricular Arrhythmias
Authors: LUBINSKI A. , KORNACEWICZ‐JACH Z. , WNUK‐WOJNAR A.M. , ADAMUS J. , KEMPA M. , KRÓLAK T. , LEWICKA‐NOWAK E. , RADOMSKI M. , SWIATECKA G.
Published: October 2013

Experimental studies have shown that transmural dispersion of repolarization (DoR), defined as the difference in action potential duration between mid‐myocardial M‐cells, epicardial, and endocardial cells is reflected in the duration of the terminal portion of the T wave (TpTe) on the surface ECG. Since DoR is an important factor associated with the propensity for reentrant arrhythmias, this study examined if TpTe may serve as a marker of risk of ventricular arrhythmias. Data from 18 patients with coronary artery disease and inducible sustained ventricular tachycardia (VT group) were compared with those of 16 survivors of myocardial infarction without inducible VT (control group). TpTe was automatically measured in each beat of 24‐hour ECG recordings, and programmed ventricular stimulation was performed in the antiarrhythmic drug‐free state. TpTe was expressed as the absolute interval in milliseconds, and relative to the duration of QTe (TpTe/QTe × 100%). TpTe duration was 74 ± 14 ms in the VT group versus 63 ± 16 ms in the control group (P < 0.004). The TpTe interval expressed as a percent of the QT interval was 21 ± 4% in the VT group versus 17 ± 3% in the control group (P = 0.02). In patients with coronary artery disease, TpTe was longer in patients with, versus without, inducible VT. The results of this study support the hypothesis that TpTe reflects transmural dispersion of repolarization.
Relation Between Microvolt Level T Wave Alternans and Other Potential Noninvasive Predictors of Arrhythmic Risk in the Marburg Cardiomyopathy Study
Authors: GRIMM WOLFRAM , HOFFMANN JÜRGEN , MENZ VOLKER , MAISCH BERNHARD
Published: October 2013

The relation between microvolt level T wave alternans (TWA) and other noninvasive arrhythmia risk predictors was analyzed in 221 consecutive patients with idiopathic dilated cardiomyopathy (IDC) and sinus rhythm enrolled in the Marburg Cardiomyopathy Study between March 1996 and May 2000. TWA analysis was also performed in 110 healthy controls of similar age and sex. TWA during symptom‐limited exercise was positive, negative and indeterminate in, respectively, 108 (49%), 65 (29%) and 48 (22%) patients with IDC versus, respectively, 5 (5%), 98 (89%) and 7 (6%) healthy controls (P < 0.05). Patients with IDC and positive TWA had a lower left ventricular (LV) ejection fraction (29 ± 9% vs 34 ± 10%, P < 0.05) and greater LV end‐diastolic diameter (69 ± 8 mm versus 64 ± 6 mm, P<0.05) than patients with negative TWA. Other variables, including age, gender, New York Heart Association functional class, presence of bundle branch block, arrhythmias on 24‐hour ambulatory electrocardiogram, heart rate variability and baroreflex sensitivity, were not significantly different between patients with positive vs negative TWA. The prognostic significance of TWA in IDC with regard to arrhythmic events and total mortality will be determined by multivariate Cox analysis at the end of a 5‐year follow‐up in this ongoing study.
Critical Value of Baroreflex Sensitivity Determined by Spectral Analysis in Risk Stratification After Myocardial Infarction
Authors: HONZIKOVA NATASA , FISER BOHUMIL , SEMRAD BORIVOJ
Published: October 2013

The risk of cardiac death in patients after MI is predicted by a decreased baroreflex sensitivity (BRS). The critical value of BRS based on phenylephrine administration is 3 ms/mmHg. The aim of this study was to determine the critical value of BRS assessed by spectral analysis of spontaneous fluctuations in pulse intervals and blood pressure. Digital blood pressure was recorded noninvasively (3 min, controlled breathing 0.33 Hz) in 112 patients, 8–18 days after MI. Nine patients died during the first year after MI. BRS was determined as the gain between the spectrum of the variability of systolic blood pressure and the cross‐spectrum between the variability of pulse intervals and systolic blood pressure. The gain at the frequency of 0.1 Hz was taken as the measure of BRS. Sensitivity, specificity, and the positive predictive value were calculated in the range of 1–10 ms/mmHg in steps of 1 ms/mmHg. The value of BRS above which sensitivity no longer increases and specificity decreases was taken as the optimal value. The critical value of BRS determined by spectral analysis was 3 ms/mmHg (sensitivity 77%; specificity 71 %). In conclusion, the spectral critical value of BRS determined by spectral analysis of spontaneous fluctuations in pulse intervals and blood pressure corresponds to the value determined by the phenylephrine method.
Initial Clinical Experience with a Dual Chamber Rate Responsive Implantable Cardioverter Defibrillator
Authors: LUCERI RICHARD M.
Published: October 2013

The present study reports the first clinical experience with the Photon DR dual chamber rate responsive ICD. Fifty‐seven patients (mean age 67.6 ± 10 years) with a mean LVEF of 0.332 in NYHA Class I (30%), II (51%), or III (19%) met the implant criteria. Tachyarrhythmia diagnoses included VF (21%), VT (49%), or VT/VF (30%). Additional bradycardia pacing diagnoses included AV block (18%), sinus node dysfunction (5%), and sinus bradycardia (11%). All patients were followed on a long‐term basis. A device‐based direct current fibrillator (DC fibber) successfully induced VF in 96.2% of 243 attempted inductions. Detection times (2.86 ± 0.47 s) and redetection times (1.29 ± 0.32 s) compared favorably with historic controls using a morphology detection (MD) clinical data. Defibrillation energy and voltage thresholds were 10.4 ± 5.5 J (range 3–28) and 421 V ± 108 (range 230–696), respectively. Ninety‐two clinical arrhythmias were recorded. Using a nominal nonindividualized algorithm, the sensitivity for VT detection was 100% and specificity for SVT rejection 81%. There were six patient deaths (2 nonsudden arrhythmic, 2 cardiac, 2 other). In conclusion, early clinical experience with the Photon DR ICD supports its safety, efficacy, and ability to provide advanced dual chamber ICD features.
Two‐Coil Versus Single‐Coil Transvenous Cardioverter Defibrillator Systems: Comparative Data
Authors: MANOLIS ANTONIS S. , CHILADAKIS JOHN , MAOUNIS THEMOS N. , VASSILIKOS VASSILIS , COKKINOS DENNIS V.
Published: October 2013

Two types of new‐generation transvenous implantable cardioverter defibrillator (ICD) systems, incorporating a two‐coil (62 patients, group 1) versus single‐coil (32 patients, group 2) lead system were compared among 94 consecutive patients. The two groups were comparable in age (58 ± 13 vs 59 ± 14 years), presenting arrhythmia (ventricular tachycardia versus ventricular fibrillation 77%/21% vs 84%/13%), cycle length of induced VT (294 ± 4 vs 289 ± 44 ms), number of unsuccessful antiarrhythmic drugs (1.7 ± 0.8 vs 1.7 ± 0.7), and left ventricular ejection fraction (35 ± 12% vs 34 ± 9%). Both systems were successfully implanted strictly transvenously in all patients. Biphasic shocks were used in all patients. Active shell devices were used in 79% and 84% patients of groups I and II, respectively (P = NS). Intraoperative testing revealed comparable defibrillation threshold (DFT) values (10.2 ± 3.7 J in group 1 versus 9.3 ± 3.6 J in group 2 system), and pacing threshold (0.7 ± 0.3 vs 0.7 ± 0.3 V), but R wave amplitude and lead impedance were lower in group 1 (13 ± 5 vs 16 ± 5 mV, P = 0.003; and 579 ± 115 vs 657 ±111 ohms, P = 0.002, respectively). Lead insulation break requiring reoperation occurred in one patient with an Endotak lead, and two patients with Transvene leads had initially high DFT with a single one‐lead/active can system, which was converted to a two‐ or three‐endocardial‐lead/'inactive can configuration. We conclude that both single‐coil and two‐coil transvenous ICD systems were associated with high rates of successful strictly transvenous ICD implantation and a low incidence of lead‐related complications. Significant differences were noted in the sensed R wave and lead impedance, probably reflecting the active fixation characteristics of the Transvene lead. However, in order to obviate the sporadic need for implantation of additional endocardial leads, as was the case in two patients in this series, a double‐coil lead may be preferable.
Heart Graft Monitoring by the Ventricular Evoked Response
Authors: MAHAUX VÉRONIQUE , DEMOULIN JEAN‐CLAUDE , BIESSAUX YVES , RADERMECKER MARC , SCHREIER GUENTER , LIMET RAYMOND , KULBERTUS HENRI
Published: October 2013

Monitoring of the negative slew rate of the evoked T wave has been proposed as a noninvasive diagnostic tool to follow heart transplant recipients. The clinical contribution of this measurement on telemetrically recorded, paced unipolar ventricular electrograms was evaluated in the detection of grade 3 acute allograft rejection. Thirteen patients undergoing heart transplantation received a DDD pacemaker connected to two epimyocardial leads. Electrograms were recorded and digitized after each endomyocardial biopsy (EMB). The maximum slew rate of the descending slope of the repolarization phase (RSP) was extracted and normalized. A 20% downward shift of RSP from the reference value was considered abnormal. Results of signal processing were blinded during the first 6 months. Eleven patients completed the 6 months blinded period and two patients died. A total of 101 EMB were graded according to the International Society for Heart and Lung Transplantation classification. Grade 3 was assigned to 9 EMB. A significant difference was found between RSP values measured during grade 3 rejection episodes and other RSP values (P < 0.001). A diagnostic model consisting of a single threshold test confirmed the ability of RSP to predict significant signs of rejection on EMB (P < 0.0001). The sensitivity of RSP in detecting grade 3 rejections was 100%, specificity was 81%, negative predictive value 100%, and positive predictive value 35%. The use of RSP as a noninvasive monitoring tool to pose the indication for a biopsy would avoid 73% of EMB. Monitoring of transplanted hearts based on the analysis of the ventricular evoked response is promising and may markedly reduce the number of EMB.
Putative apolipoprotein A‐I, natural killer cell enhancement factor and lysozyme g are involved in the early immune response of brown‐marbled grouper, Epinephelus fuscoguttatus, Forskal, to Vibrio alginolyticus
Authors: Low C‐F , Shamsudin M N , Chee H‐Y , Aliyu‐Paiko M , Idrus E S
Published: October 2013

The gram‐negative bacterium, Vibrio alginolyticus, has frequently been identified as the pathogen responsible for the infectious disease called vibriosis. This disease is one of the major challenges facing brown‐marbled grouper aquaculture, causing fish farmers globally to suffer substantial economic losses. The objective of this study was to investigate the proteins involved in the immune response of brown‐marbled grouper fingerlings during their initial encounter with pathogenic organisms. To achieve this objective, a challenge experiment was performed, in which healthy brown‐marbled grouper fingerlings were divided into two groups. Fish in the treated group were subjected to intraperitoneal injection with an infectious dose of V. alginolyticus suspended in phosphate‐buffered saline (PBS), and those in the control group were injected with an equal volume of PBS. Blood samples were collected from a replicate number of fish from both groups at 4 h post‐challenge and analysed for immune response‐related serum proteins via two‐dimensional gel electrophoresis. The results showed that 14 protein spots were altered between the treated and control groups; these protein spots were further analysed to determine the identity of each protein via MALDI‐TOF/TOF. Among the altered proteins, three were clearly overexpressed in the treated group compared with the control; these were identified as putative apolipoprotein A‐I, natural killer cell enhancement factor and lysozyme g. Based on these results, these three highly expressed proteins participate in immune response‐related reactions during the initial exposure (4 h) of brown‐marbled grouper fingerling to V. alginolyticus infection.
Modified Enrichment Strategies Coupled with Molecular and Conventional Methods to Detect and Quantify Campylobacter jejuni in Chicken Meat from the Market
Authors: Rohonczy Kata , Rantsiou Kalliopi , Cocolin Luca
Published: October 2013

Campylobacter spp. are currently the bacterial foodborne pathogen that causes the highest number of gastrointestinal diseases in developed countries, according to the World Health Organization. The aim of this study was to compare the performance of four Campylobacter enrichment broths: Bolton broth, Bolton broth with blood, Preston broth and Preston broth with blood using both culture‐dependent methods and an optimized quantitative polymerase chain reaction (qPCR) protocol. The enrichment in Bolton broth with blood allowed most positive samples for Campylobacter jejuni to be detected when 40 chicken meat samples from the market were tested. Correlation between cultural methods and molecular methods was poor. Only in a few cases could C. jejuni and Campylobacter spp. be identified by PCR. Out of 480 colonies isolated throughout the enrichment process, only seven colonies could be identified as Campylobacter spp., three of which were C. jejuni. Enrichment of chicken meat samples with Bolton broth added with blood, coupled with qPCR resulted to be the most suitable method to detect samples contaminated with C. jejuni.

Practical Applications

Detection and identification of Campylobacter spp. in food is still a challenge and there is lack of consensus on the methodology that should be used in order to recover these fastidious microorganisms. The application of molecular methods, such as the amplification of a target gene sequence by PCR, in order to rapidly and inequivocally detect and identify foodborne pathogens in foodstuff, offers a valid alternative to traditional microbiological testing. In this study, we investigated the performances of combined enrichment strategies with a specific C. jejuni qPCR protocol. The molecular approach resulted to be superior with respect to traditional plating and was able to detect a higher number of C. jejuni positive samples. Among the enrichment broths tested, Bolton broth added with blood resulted to be the most suitable for the detection of Campylobacter spp. in poultry meat.