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Electrical Impact of the Left Ventricular Pacing Site in CRT Introduction Recent studies have demonstrated that left ventricular (LV) pacing site is a critical parameter in optimizing cardiac resynchronization therapy (CRT). The present study evaluates the effect of pacing from different LV locations on QRS duration (QRSd) and their relationship to acute hemodynamic response in congestive heart failure patients. Methods and Results Thirty-five patients with nonischemic dilated cardiomyopathy and left bundle branch block referred for CRT device implantation were studied. Eleven predetermined LV pacing sites were systematically assessed in random order: epicardial: coronary sinus (CS); endocardial: basal and mid-cavity (septal, anterior, lateral, and inferior), apex, and the endocardial site facing the CS pacing site. For each patient QRSd and +dP/dtmax during baseline (AAI) and DDD LV pacing at 2 atrioventricular delays were compared. Response to CRT was significantly better in patients with wider baseline QRSd (≥150 milliseconds). Hemodynamic response was inversely correlated to increase of QRSd during LV pacing (short atrioventricular [AV] delay: r = 0.44, P < 0.001; long AV delay: r = 0.59, P < 0.001). Compared to baseline, LV pacing at the site of shortest QRSd significantly improved +dP/dtmax (+18 ± 25%, P < 0.001) but was not superior to other conventional strategy (lateral wall, CS pacing, and echo-guided) and was inferior to a hemodynamically guided strategy. Conclusions In our study, we have demonstrated that changes of QRSd during LV pacing correlated with acute hemodynamic response and that LV pacing location was a primary determinant of paced QRSd. Although QRSd did not predict the maximum hemodynamic response, our results confirm the link between electrical activation and hemodynamic response of the LV during CRT. [ABSTRACT FROM AUTHOR]

Depression and Cardiac Resynchronization Therapy. Background: The relationship between depression and heart failure is neither coincidental nor trivial, since depression is a powerful predictor of re-hospitalization and mortality. We prospectively studied the prevalence and impact of depression on the clinical outcomes of patients attending for cardiac resynchronization therapy (CRT). We specifically examined whether patients with depression have a different rate of response to CRT and whether CRT has an effect on depressive symptoms. Methods: Sixty-eight recipients of CRT systems were included. The depressive status was evaluated before implant and after 6 months by a structured diagnostic interview measuring Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria of major depression and by a self-report questionnaire (Center for Epidemiological Studies Depression Scale, CES-D). The CRT response was assessed at 6 months by a clinical composite score. Results: At inclusion, DSM-IV criteria of major depression were identified in 41% of the population, while using the self-report questionnaire 65% were observed to have mild to major depressive symptoms (CES-D ≥ 16). Only 4 patients were taking antidepressants. At 6 months, 75% were considered responders to CRT. Response to CRT did not differ between those with and without depression at baseline. The rate of patients with depression at 6 months was significantly lower in responders to CRT compared with nonresponders. Conclusions: We found a high prevalence of depressive symptoms in patients receiving CRT systems. Patients with depression should not be excluded from CRT, because they demonstrate a similar rate of response than the persons without depression and the responders are less likely to be depressed at 6 months. (J Cardiovasc Electrophysiol, Vol. 23, pp. 631-636, June 2012) [ABSTRACT FROM AUTHOR]

Cardiac pacemakers with preerosion are often reimplanted. Preerosion may be caused by an evolving local infectious process affecting the entire pacing system or by mechanical migration of the device causing ischemic necrosis of the skin tissues. We examined the long-term outcome of 33 patients who underwent pocket or scar revision and submuscular reimplantation of cardiac pacemakers in our institution. Before undergoing pocket or scar revision and reimplantation, all patients (1) had negative serial blood cultures, (2) had no vegetation on transesophageal echocardiography, (3) had a normal blood C-reactive protein concentrations, (4) were afebrile, (5) had no cutaneous breakthrough, and (6) presented with preerosion of the pulse generator or granulomatous-like scar abnormality. The mean follow-up was 37 ± 12 months. Among 16 patients presenting with preerosion associated with signs of local cutaneous inflammation, 62.5% developed an infection of the pacing system requiring later explantation. Of eight patients presenting initially with migration of the pulse generator and mechanical protrusion, none required subsequent explantation of the system. Among nine patients presenting initially with granulomatous-like scar abnormalities, 55.6% underwent explantation of the pacing system during follow-up for management of documented local infection. The reimplantation of pulse generators with preerosion in the presence of local inflammatory manifestations or granulomatous-like changes of the scar is complicated by documented cardiac pacemaker infection in >50% of cases. In these patients, the explantation of the pacing system is recommended before the development of prognostically much more serious spread of infection to the leads and cardiac tissues. (PACE 2011; 34:150-154) [ABSTRACT FROM AUTHOR]

Aims: A recent study suggested that no single echocardiographic index of cardiac dyssynchrony can reliably identify candidates for cardiac resynchronization therapy (CRT). We examined the value of three simple echocardiographic indices for predicting the 6-month clinical and echocardiographic responses to CRT. [ABSTRACT FROM PUBLISHER]

Introduction: Recent expert consensus guidelines mention that one of the principles for infected device replacement following removal is to “reevaluate carefully if there is a continued need for a new cardiac device replacement.” This is a Class I recommendation, which nevertheless suffers from a very low level of evidence (level of evidence C), since no study has revisited the systematic practice of reimplanting the same device based on a meticulous clinical reassessment. In the present paper, we examined the safety of withholding the implantation of pacing systems in selected patients. Methods and Results: Between January 2005 and December 2007, 188 consecutive patients underwent extractions of infected pacing systems at 2 medical centers. “Low-risk” patients were identified by (1) a spontaneous heart rate >45 bpm, (2) no symptomatic asystole during monitoring, (3) QRS duration <120 ms when history of AV block was noted, (4) no high-degree AV block during continuous monitoring. They remained device-free, unless an adverse clinical event occurred mandating the reimplantation. The primary study endpoint was rate of sudden death and syncope after a 12-month follow-up. Among the 74 (39.4%) “low-risk” patients, a single patient suffered a bradycardia-related syncopal event corresponding to a 1.3% (95% CI, 0.0–3.9) rate of primary endpoint. Pacing systems were also reimplanted in 24 patients (32.4%) for syncope (n = 1), nonsevere bradycardia-reated symptoms (n = 17), cardiac resynchronization (n = 2), and for reassurance in 4 asymptomatic patients. Conclusion: After removal of infected pacing systems, these preliminary data demonstrated that a strategy of nonsystematic device reimplantation associated with close surveillance was safe in “low-risk” patients, allowing the administration of antimicrobials in a device-free state. (J Cardiovasc Electrophysiol, Vol. 21, pp. 540-544, May 2010) [ABSTRACT FROM AUTHOR]

Introduction: Biventricular pacing is associated with various electrocardiographic patterns depending on the position of the left ventricular (LV) lead. We aimed to develop an electrocardiogram-based algorithm to predict the position of the LV lead. Methods: The algorithm was developed in 100 consecutive recipients of cardiac resynchronization therapy (CRT) systems. QRS axis, morphology, and polarity were analyzed with a view to define the specific electrocardiographic characteristics associated with the various LV lead positions . The algorithm was prospectively validated in 50 consecutive CRT device recipients. Results: The first analysis of the algorithm was the QRS morphology in V1. A positive R wave in V1 suggested LV lateral or posterior wall stimulation. A QS pattern was specific of anterior LV leads. In the presence of an R wave in V1, V6 was analyzed to distinguish between an inferior and anterior LV lead. Inferior leads were never associated with a positive V6. To differentiate between lateral and posterior positions, we analyzed the pattern in V2. Lateral leads were associated with an R morphology in V1 and a negative V2. Posterior leads were associated with an R morphology in V1 and V2. The algorithm allowed a reliable distinction between an inferior or anterior and a lateral or posterior lead position in 90% of patients. Inferior, anterior, lateral, and posterior positions were reliably distinguished in 80% of patients. Conclusion: This algorithm predicted the position of the LV lead with a high sensitivity and predictive value. [ABSTRACT FROM AUTHOR]

Introduction: The peak of endocardial acceleration (PEA) is an index of myocardial contractility. We aimed to (1) demonstrate that the PEA measured by the noninvasive cutaneous precordial application of an accelerometer sensor is related to left ventricular (LV) d P/d t max and (2) assess the usefulness of PEA monitoring during graded ischemia and during different configurations of sequential biventricular pacing. Methods and Results: Measurements of invasive LV d P/d t max were compared with measurements of transcutaneous PEA in seven pigs at baseline and during acute drug infusions; increased heart rate; right, left, biventricular and sequential biventricular pacing before and after graded ischemia induced by the constriction of the left anterior descending coronary artery. A consistent PEA signal was obtained in all animals. PEA changes were highly related to LV d P/d t max changes ( r= 0.93; P < 0.001). The changes of LV contractility induced by the different pacing configurations were detected by PEA analysis in the absence of ischemia ( r= 0.94; P < 0.001) and in the presence of ischemic LV dysfunction ( r= 0.91; P < 0.001). Conclusion: Noninvasive PEA measurement allows monitoring of left ventricular contractility and may be a useful tool to detect global effect of ventricular ischemia and to optimize the choice of both pacing site and pacing configuration. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) is recommended in patients with ejection fraction <35%, QRS width> 120 ms, and New York Heart Association (NYHA) functional class III or IV despite optimal medical therapy. We aimed to define demographic, clinical, and electrocardiographic predictors of positive clinical response to CRT. Methods and Results: Hundred consecutive patients fulfilling the recommended criteria were implanted with a CRT device. Demographic, clinical, two-dimensional echocardiographic and electrographic parameters were measured at baseline and after 6 months of simultaneous biventricular pacing. A positive response to CRT included an improvement of at least one NYHA functional class associated with an absence of hospitalization for worsening heart failure. At the end of follow-up, 12 patients were dead and 71% of the patients were classified as responders. After 6 months of CRT, the ejection fraction was significantly higher (P = 0.035) in responders versus nonresponders. Multivariate analysis identified three independent predictors of positive response to CRT: an idiopathic origin of the cardiomyopathy (P = 0.043), a wider QRS before implantation (P = 0.017), and a narrowing of the QRS after implantation (P = 0.037). Conclusion: An idiopathic origin of the cardiomyopathy, a wider QRS before implantation, and a narrowing of the QRS width after implantation were identified as independent predictors of clinical positive response to CRT. [ABSTRACT FROM AUTHOR]

Introduction: Radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) can be performed using different types of ablation catheter. Gold tip electrodes have the theoretical advantage of creating bigger lesions than standard platinum-iridium electrode. This prospective, randomized study compares the clinical efficacy of 8-mm gold tip catheter, externally irrigated and 8-mm platinum-iridium tip (Pt tip) catheters. Methods and Results: Sixty consecutive patients (51 men, 60 ± 10 years) undergoing de novo CTI ablation for documented typical atrial flutter were randomized to one of the following ablation catheters: 8-mm gold tip catheter, an externally irrigated-tip (Irr. tip) catheter, or an 8-mm Pt tip catheter. The procedural endpoint was achievement of bidirectional isthmus conduction block with ≤ 20 minutes of RF energy application. The latter was achieved equally with the 3 catheters (95% for gold tip, 100% for irrigated tip, 95% for Pt tip) and the durations of RF (10 ± 6, 10 ± 4, 13 ± 8 minutes), fluoroscopy (12 ± 6, 12 ± 7, 15 ± 12 minutes) and the procedure (34 ± 23, 38 ± 24, 40 ± 30 minutes) were similar in all groups. The maximal targeted power could not be reached in at least one location in 40% of patients with gold tip and in 35% of patients with Pt tip catheters whereas it was always achieved with an Irr. tip catheter (P = 0.003, P = 0.008). The reduction in impedance during RF delivery was greater with Irr. tip (11 ± 7 Ω) than with gold (7 ± 4 Ω, P = 0.02) or Pt tip (5 ± 3 Ω, P = 0.001) catheters. Conclusion: This study demonstrates equivalent efficacies of gold, platinum-iridium and externally Irr. tip catheters for successful de novo ablation of the CTI. [ABSTRACT FROM AUTHOR]

The search for a mechanism to explain atrial fibrillation (AF) has lasted for over a century and continues. Significant progress in understanding this arrhythmia accelerated with the era of operative treatment of this arrhythmia and intensified with the advent of catheter ablation. Through considerable trial and some error, effective “curative” therapies have evolved for paroxysmal AF and are evolving for persistent AF. It is becoming clear that no single mechanism suffices to explain AF in all its forms and multiple mechanisms are playing a role in the most complicated cases. [ABSTRACT FROM AUTHOR]

Background: The incidence of endocarditis related to pacemakers is increasing, while the diagnosis and management remain difficult. The objective of this study was to evaluate the clinical features and management of endocarditis after implantation of pacemakers (PM) or cardioverter defibrillators (ICD). Methods: We analyzed the hospital course of 60 consecutive patients (48 men, mean age 68 ± 12 years) admitted to our center for PM (n = 59) or ICD (n = 1) endocarditis between 1998 and 2004. Results: Fever (78%), asthenia (65%), and local symptoms (35%) were common. Positive cultures were obtained in 53 cases (Staphylococcus 89%). Sixteen patients (27%) had pulmonary embolism. Vegetations (mean size 15.2 ± 8 mm, range 5 to 35 mm) were found in 54 cases (90%), with transthoracic echocardiography in 26 cases (43%), and transesophageal echocardiography (TEE) in 50 cases (89% of the 56 patients who had TEE). Devices were removed surgically (n = 20) or percutaneously (n = 37). In the surgical group, vegetations were larger (17.9 ± 7 mm vs 13.2 ± 7 mm, P = 0.01). After removal, 42 patients (70%) had a new PM. Mortality factors (6 deaths – follow up 3.4 ± 2 years) were the number of vegetations and absence of extraction of the device (P < 0.02). Clinical features and management of the 37 patients with early onset endocarditis (within 1 year after implantation) did not differ from those with late onset. Conclusions: PM endocarditis was essentially staphylococcal. TEE was required for the diagnosis of vegetations. Complete removal of the device is required and associated with a favorable outcome. [ABSTRACT FROM AUTHOR]

Background: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI. Methods and Results: Data were collected prospectively from 181 patients (153 male; age 54 ± 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration ≤7 days). Clinical variables were evaluated with regard to their ability of predicting noninducibility of sustained AF (≤10 minutes) after PVI. Univariate analysis was performed on all collected variables followed by multivariate analysis for variables showing a P value <0.1. After PVI, sustained AF was noninducible in 97 (54%) patients. The following clinical variables showed a significant difference between the groups: body weight, longest AF episode, duration of AF history, presence or absence of structural heart disease, left ventricular (LV) hypertrophy, prior cardioversion, left atrial (LA) parasternal, and longitudinal diameters and LV diameters. On multivariate analysis, three independent predictors of noninducibility were identified: a shorter duration of AF episodes (AF <12 hours: RR 0.01 (0.002–0.06), P < 0.001; AF 12–48 hours: RR 0.07 (0.01–0.37), P = 0.001); LA longitudinal diameter <57 mm (RR 0.33 (0.13–0.82), P = 0.016); and absence of LV hypertrophy (RR 0.15 (0.04–0.63), P = 0.01). Conclusions: Shorter AF episodes, smaller LA longitudinal diameter, and absence of LV hypertrophy are independent predictors of noninducibility of sustained AF after PVI. [ABSTRACT FROM AUTHOR]

FAUCHIER, L.et al.: Potential Cost Savings by Telemedicine-Assisted Long-Term Care of Implantable Cardioverter Defibrillator Recipients. Home monitoring (HM) of cardioverter defibrillators (ICD) with its automated wireless remote data access, may decrease the rate of patient visits. This study examined the potential cost savings for the long-term care of ICD assisted by HM. A French database including 502 patients from 6 university hospitals was used. Costs of conventional follow-up (FU) of ICD were calculated without, and compared with the expected cost of FU with HM. Calculations included number of visits, including physician's fees, electrocardiograms, and specific ICD surveillance, and transportation costs. The mean distance between home and institutions performing follow-ups was 69± 57 km. For each visit, a mean overall cost of$215 was calculated, including$121 for transportation and$94 for medical services. HM may obviate up to 2 visits per year. Over the 5 years of expected life of the device, the decrease in costs for FU visits was estimated at$2,149. With an additional cost of$1,200 for the HM system, saving began after a mean FU of 33.5 months. The time to onset of cost saving by HM ranged between 17.4 months for patients living>150 km from the medical facility to 52.2 months for those living<50 km away. It is concluded that the HM may considerably reduce the overall costs of ICD FU by saving on transportation cost, particularly when the distance between home and medical facility is>100 km.(PACE 2005; 28:S255–S259) [ABSTRACT FROM AUTHOR]

Biventricular and LV Pacing Comparison. Introduction:We conducted an acute echocardiographic study comparing hemodynamic and ventricular dyssynchrony parameters during left ventricular pacing (LVP) and biventricular pacing (BVP). We sought to clarify the mechanisms responsible for similar hemodynamic improvement despite differences in electrical activation.Methods and Results:Thirty-three patients underwent echocardiography prior to implantation with a multisite pacing device (spontaneous rhythm[SR]) and 2 days after implantation (BVP and LVP). Interventricular dyssynchrony (pulsed-wave Doppler), extent of myocardium displaying delayed longitudinal contraction (%DLC; tissue tracking), and index of LV dyssynchrony (pulsed-wave tissue Doppler imaging) were assessed. Compared to SR, BVP and LVP caused similar significant improvement of cardiac output (LVP: 3.2± 0.5, BVP: 3.1± 0.7, SR: 2.3± 0.6 L/min; P<0.01) and mitral regurgitation (LVP: 25.1± 10, BVP: 24.7± 11, baseline: 37.9± 14% jet area/left atria area; P<0.01). LVP resulted in a smaller index of LV dyssynchrony than BVP (29± 10 vs 34± 14; P<0.05). However, LVP exhibited a longer aortic preejection delay (220± 34 vs 186± 28 msec; P<0.01), longer LV electromechanical delays (244.5± 39 vs 209.5± 47 msec; P<0.05), greater interventricular dyssynchrony (56.6± 18 vs 31.4± 18; P<0.01), and higher%DLC (40.1± 08 vs 30.3± 09; P<0.05), leading to shorter LV filling time (387± 54 vs 348± 44 msec; P<0.05) compared to BVP.Conclusion:Although LVP and BVP provide similar hemodynamic improvement, LVP results in more homogeneous but substantially delayed LV contraction, leading to shortened filling time and less reduction in postsystolic contraction. These data may influence the choice of individual optimal pacing configuration.(J Cardiovasc Electrophysiol, Vol. 15, pp. 1-6, December 2004) [ABSTRACT FROM AUTHOR]

Unlabelled: We sought to assess right, left and biventricular pacing effects on myocardial function by using pulsed-Doppler tissue imaging (DTI) and automated border detection (ABD) techniques which provide electromechanical delay (EMD) assessment of the different left ventricular walls. Methods: 15 patients (67+/-7 years) with drug-resistant primitive dilated cardiomyopathy and QRS> or =140 ms received a pacemaker for multisite ventricular pacing. Echocardiography was performed after 1 month of biventricular pacing (BVP). Echocardiographic measurements were recorded during spontaneous rhythm (SpR), right ventricular pacing (RVP), left ventricular pacing (LVP) and BVP. Results: LV ejection fraction was statistically similar between the four rhythms. BVP showed a significant EMD decrease for the lateral LV wall vs. SpR, RVP and even LVP. LVP resulted in significantly longer aortic pre-ejection time vs. BVP while the EMD temporal dispersion (time between the shortest regional EMD and the longest one) was similar in the two modes. Conclusions: BVP and LVP substantially reduce the EMD temporal dispersion of the four LV walls, but with a longer aortic pre-ejection time for LVP. In RVP, LVP and BVP, the septal LV wall is always activated later than during SpR. BVP and LVP are associated with a mitral regurgitation reduction. [ABSTRACT FROM AUTHOR]

GARRIGUE, S., et al.: Sleep Apnea: A New Indication for Cardiac Pacing? In the general adult population, prevalence of sleep apnea syndrome reaches 4% in men and 2% in women. Continuous positive airway pressure is the most efficient treatment. At the present time, although severe atrial bradycardias could occur during sleep apnea episodes, cardiac pacing has not been demonstrated as an efficient treatment for those bradycardias. Treating sleep apnea generally reduces the number of bradyarrhythmias. However, recent studies reported a beneficial effect of atrial pacing on the sleep apnea burden. The mechanisms rely on two phenomena: first to counteract nocturnal hypervagotonia, and second to treat heart failure. By increasing the heart rate, cardiac output improves, which mitigates pulmonary subedema. Consequently, stimulation of the pulmonary afferent vagal fibers is diminished, which reduces central sleep apnea incidence. During nocturnal hypervagotonia, snoring and obstructive apnea episodes are increased, mainly due to an excessive muscular relaxation of the upper airway area inducing cyclical substantial decreases in the airway caliper. In patients with a low heart rate, atrial pacing can counteract hypervagotonia by enhancing the sympathetic tone and modifying the degree of vigilance. Accordingly, in the near future, sleep apnea treatment might potentially rely on atrial pacing in bradycardic patients with hypervagotonia (with or without heart failure). The role of the physician would then be not only to diagnose sleep apnea, but also to identify potential responders to cardiac pacing. (PACE 2004; 27:204–211) [ABSTRACT FROM AUTHOR]

Presents a study which examined the effects of various combinations of pacing sites on the activation pattern of both ventricles during ischemia and identified specific precipitating factors of ventricular arrhythmia. Methods; Results and discussion.

Presents a study which determined the radiation exposure to patient and medical staff during atrial fibrillation compared with that measured during ablation of other arrhythmias in the same laboratory. Methods; Results and discussion; Conclusion.

The implantation of permanent pacemakers in patients with congenital heart disease can be challenging. This report describes the complexity of pacemaker implantation in a patient with Ebstein's disease, tricuspid valve replacement, and right atrial abnormalities like severe intra- and interatrial conduction block that prevented dual chamber pacing from conventional sites. This case illustrates the promising possibility to circumvent the interatrial conduction block with single left atrial pacing instead of biatrial pacing which was not suitable here. [ABSTRACT FROM AUTHOR]

Biventricular (BV) pacing is a promising treatment of end-stage heart failure. This article describes our experience with a strictly endocardial BV pacing system in patients with severe congestive heart failure. Three women and eight men (age 65 ± 9 years) with drug-resistant end-stage CHF underwent implantation of an endocardial BV pacing system. In the first seven patients, the left ventricular lead was placed via a combined femoral and internal jugular approach. In the last four patients, the transseptal puncture was directly performed via the right internal jugular vein with a dedicated kit The procedure was successful in all 17 patients. The acute left ventricular and BV thresholds were 1.3 ± 0.6 V and 2.4 ± 1 V, respectively. The QBS duration decreased from 214 ± 57 to 176 ± 25 ms. A functional improvement was noted in ten patients with a decrease in mean NYHA functional class from 3.7 ± 0.5 before, to 2.6 ± 0.9 after system implantation. A significant decrease in pulmonary capillary wedge pressure and increase in cardiac output were measured in eight patients. During follow-up, four patients died from CHF (n = 3) or ventricular fibrillation (n = 1). Under oral anticoagulation, no thromboembolic event was observed but one transient ischemic attack occurred in one patient whose anticoagulation was interrupted. Endocardial BV pacing is technically feasible and appears safe, though further studies are needed before it is used on a larger scale. [ABSTRACT FROM AUTHOR]

Multisite ventricular pacing acutely improves the hemodynamic status in heart failure, though longer-term observations require invasive procedures. The hemodynamics of multisite ventricular pacing were assessed by echocardiography and peak endocardial acceleration (PEA) measured by a pacemaker sensor. PEA variations are highly correlated with those of dP/dt. Thirteen end-stage heart failure patients (left ventricular ejection fraction < 0.30) with a QRS ≥140 ms received a DDD PEA sensor-driven pacemaker allowing right (RV), left (LV) and biventricular (BV) pacing. Ten days after implantation, standard echocardiographic parameters and variations in PEA were measured after 20 minutes at each pacing mode. The aortic systolic preejection time interval was statistically comparable between RV and LV pacing (218 ± 24 vs 219 ± 34 ms; P = NS), and significantly shorter with BV pacing (196 ± 27 ms; P = 0.013). Aortic ejection duration was nonsignificantly shorter during BV pacing than during LV pacing (-.061, P = 0.09). The aortic velocity time integer increased during LV pacing versus RV pacing (+21 %, P < 0.05) and during BV pacing versus BV pacing (+37%, P = 0.05). As a result, the values of the PEA variations over a 15-minute period were significantly greater during LV pacing and BV pacing versus RV pacing (+43%, P < 0.05, and +38%, P = 0.05, respectively) and were statistically comparable between BV pacing and LV pacing (+5.9% for LV pacing, P = NS). During various ventricular pacing configurations, PEA measurements were consistent with echocardiographic data, showing comparable hemodynamic effects of BV and LV pacing. The PEA sensor is a promising tool for long-term hemodynamic monitoring and serial evaluation of the effects of multisite ventricular pacing in heart failure patients. [ABSTRACT FROM AUTHOR]

Biventricular (BV) pacing acutely improves the hemodynamic status of patients with chronic heart failure (CHF) and wide QRS complex. Long-term data are few. This study examined the relationship between hemodynamic and clinical status of BV-paced CHF patients over an intermediate duration of follow-up. Forty-seven patients (mean age 64 ± 11 years 19% women LVEF 0.23 ± 0.07) with QRS ≥140 ms received a DDD-BVP device for management of CHF due to ischemic disease m 21 (45%) patients. Clinical, electrocardiographic, exercise testing, and hemodynamic measurements were followed over an 8-month period. Seven patients died during the study, four patients suddenly. A significant decrease in NYHA class, from 3.3 ± 0.6 before implantation, to 2.5 ± 0.57 months after device implantation (P < 0.01) was measured, although 23% of patients reported no symptomatic improvement. Paced QHS narrowing by BVP was unchanged throughout follow-up (166 ± 28 vs 159 ± 23 ms, P = NS). Maximal VO₂ values did not change (15.7 ± 5 vs 16 ± 8 mL/kg per min, P = NS) Echocardiographic parameters showed that the degree of mitral regurgitation was significantly decreased during BV pacing compared with no pacing (1.8 ± 1.0 before implantation vs 1.3 ± 0.7, P < 0.01). The radionuclide LVEF was not statistically different during no pacing, versus BV pacing at 3 months or 8 months after pacemaker implantation (24 ± 9 vs 26 ± 11 vs 25 ± 10%, respectively, P = NS). Of nine patients whose QRS duration was by BV pacing, two were not hemodynamically and clinically improved at the end of follow-up. Patients not improved by BV pacing had the same degree of QRS shortening (203 ± 39 vs 167 ± 26 ms, P < 0.01) as patients who were clinically improved during follow-up (193 ± 40 to 171 ± 24 ms, P < 0.01). In multivariate analysis, ischemic heart disease (P = 0.025), absence of mitral regursitation regression (P = 0.01), and older age (P = 0.04) predicted the absence of improvement by BV pacing. By standard nominvasive measures, intermediate-term BV pacing was associated with no objective hemodynamic improvement, though more than three fourths of the patients reported being clinically improved. A global improvement in left ventricular function by BV pacing may become apparent only over longer periods of observations. Patients with CHF unimproved by BV pacing are more likely to suffer from ischemic heart disease and less likely to have BV pacing induced regression of mitral resursltation regardless of changes in QRS duration. [ABSTRACT FROM AUTHOR]

This report describes two patients with atrial fibrillation in whom an implanted CHORUS DDD pacemaker programmed to the DDI mode produced an irregular ventricular stimulation rate. The lower rate timing of these devices is atrial-based only when an atrial event opens an A V interval shorter than the programmed A V delay. In the DDI mode, if Api represents the time when an atrial paced event (Ap) would have occurred if it had not been inhibited by a previous atrial sensed event (As), then Api-Vp constitutes the implied AV interval where Vp is a paced ventricular event. Although the As-Vp interval (As-Api + Api-Vp) generates an atrial refractory period during its entire duration, the pacemaker can sense an atrial event (AR) during the implied AV interval. AR cannot start another AV delay, hut it can initiate the atrial-based lower rate interval. This timing mechanism can cause irregular prolongation of Vp-Vp intervals to a value longer than the programmed lower interval with a maximal extension equal to the programmed AV delay. Such behavior of the CHORUS pacemaker should not be interpreted as malfunction. [ABSTRACT FROM AUTHOR]

Simultaneous right and left ventricular pacing was performed in a 73-year-old man with coronary artery disease end-stage congestive heart failure and DDD pacemaker implanted for sick sinus syndrome. An endocardial LV lead was introduced transseptally after unsuccessful attempts to enter the coronary sinus. This new approach for multisite pacing offers an alternative to epicardial LV from the coronary sinus or by thoracotomy. [ABSTRACT FROM AUTHOR]

Atrial arrhythmias (AA) are commonly encountered in DDD paced patients. Newer dual chamber pacemakers (PM) possess mode switching functions that convert pacing to an asynchronous mode when AAs are detected. The lack of a reliable mode switch leading to rapid, irregular ventricular responses may result from AA undersensing. To avoid this, the DDDR PM Chorum 7234 Ela Medical AA diagnosis is based on a statistical approach: the PM constantly compares arrhythmic and sinus cycles and, based on ‘strong’ and ‘weak’ criteria, provides for rapid or slower mode switch. The aim of the study was to evaluate the efficiency and reliability of these two criteria. Thirty-one patients with a Chorum 7234 implanted for AV block (11), sinus dysfunction (10), both (5), or hypertrophic obstructive cardiomyopathy (5) were evaluated at 24 hours and 1 month using the internal memory (IM) of the PM, surface 24-hour Holter recordings, and exercise testing. Interrogation of the IM on the first day of study showed that 8 patients had mode switching episodes, based only on the strong criterion confirmed by the surface Holter recording. At 1 month, the IM revealed mode switching episodes in 12 patients, 6 of whom had used the weak criterion. No inappropriate mode switching episode was recorded during exercise testing at the 1-month follow-up. These results confirm the reliability and efficiency of this algorithm as well as the requirement for a specific algorithm to compensate for transient loss of sensing during AA. [ABSTRACT FROM AUTHOR]

Complete data concerning long-term results of transcatheter electrical ablation of the atrioventricular junction is not available. At the request of the French Cardiac Arrhythmia Working group we undertook an inquiry in October 1983. All centers potentially able to perform such procedures were asked to report their experience. Eight centers have performed one case or more, over a period of 3 years, for a total of 91 patients. The mean follow-up completed in all patients in April 1986 was 12 ± 10 months. The procedure was indicated for a supraventicular arrhythmia resistant to a mean of 3.9 ±1.3 classes of antiarrhythmic agents. Atrial flutter or fibrillation in 54 (59%) and atrioventricular nodal reentry in 17 (18%) were the most common arrhythmias. A mean of 2.6 ± 2.3 electrical shocks (range 1-14 shocks) with a stored energy of 130-400 joules was delivered during 1-5 sessions. Complete heart block was obtained in 83 patients and persisted at the time of discharge from the hospital in 46 patients (50.5%). The immediate complication (within 24 hours after the procedure) included ventricular fibrillation successfully converted (one patient) and nonsustained ventricular tachycardia (three patients). Late complications included one death 3 days after the procedure, in a patient in whom sustained ventricular tachycardia was documented, nonsustained ventricular tachycardia in two patients, sepsis in three patients and pericardial effusion in one patient. At the time of the follow-up, there were three additional deaths related to sepsis due to pacemaker pocket infection in one patient and to preexisting congestive heart failure in two patients. Chronic complete heart block was present in 36 patients (41%) high degree heart block (2 nd degree or advanced) in seven patients (8%) first degree in 16 patients (18%). The remaining patients had either normal PR interval or were in atrial fibrillation. Seventy-five patients (82%) were asymptomatic including 39 patients with resumption of AV conduction with (28 patients, 30%) or without (11 patients, 12%) antiarrhythmic therapy. The procedure failed in 12 patients (13%). This experience suggests that AV functional transcatheter ablation is a highly effective procedure. However, the potential of early and late complications including arrhythmic death leads us to reserve this technique to patients with drug-refractory supraventicular tachyarrhythmias and in whom other forms of therapy are not applicable. [ABSTRACT FROM AUTHOR]

Introduction: Some posteroseptal accessory pathways (APs) can be successfully ablated by radiofrequency current only from inside the coronary sinus (CS) or Its branches, because of' an absolute or relatively epicardial location. The aim of this study was to identify ECG features of manifest posteroseptal APs requiring ablation in the CS or the middle cardiac veins (MCVs). Methods and Results: One hundred seventeen consecutive patients with manifest posteroseptal APs successfully ablated: (1) &ges; 1 cm deep inside the MCV (group MCV: n = 13); (2) Inside the CS, including the area adjacent to the MCV ostium (group CS: n = 10); (3) at the right (group R: n = 60); or (4) the left posteroseptal endocardial region (group L: a = 34) were In- cluded. We reviewed delta wave polarity (initial 40 msec) and QRS morphology during sinus rhythm and atrial pacing as well as electrogram characteristics In these patients. The local target site electrogram In groups MCV and CS was characterized by a longer atrial to ventricular electrogram Interval, suggesting a longer course of the pathway and more frequent recording of a presumptive AP potential compared to the group ablated at the right or left endocardium. The most sensitive ECG feature for group CS or group MCV was a negative delta wave in lead II In sinus rhythm (87%), but specificity (79%) and positive predictive value (50%) were relatively low. A steep positive delta wave in aVR during maximal preexcitation possessed the highest specificity and positive predictive value (98% and 88%, sensitivity 61%) which Increased to 99% and 91 %, respectively, when combined with a deep S wave In V6 (R wave &les; S wave). Conclusion: These data suggest that posteroseptal APs ablated Inside the coronary venous system have highly specific features, Including the combination of a steep positive delta wave In lead aVR and a deep S wave in lead V6 (R wave &les; S wave) during maximal preexcitation. The highest sensitivity is provided by a negative delta wave In lead LI. These findings may be helpful for anticipating and planning an epicardial ablation strategy. [ABSTRACT FROM AUTHOR]

His bundle recordings and programmed electrical stimulation were performed in a 70-year-old woman with bidirectional tachycardia; the recordings demonstrated the infra-Hissian origin of the tachycardia. Occurrence of the His deflection slightly after the onset of ventricular depolarization suggested that the origin of the tachycardia was located near the His bundle bifurcation. Recording of three atrial sites during tachycardia allowed the study of retrograde atrial activation. Two sets of fairly constant and alternating VA intervals were recorded. This fact is consistent with two ventricular circuits used alternatively. The tachycardia could also be interrupted with a single atrial or ventricular premature beat. It is postulated that the tachycardia is due to macroreentry involving the two fascicles of the left branch. Thu study suggests that reentry may be a possible mechanism in some cases of bidirectional tachycardia. (PACE, Vol. 5, September-October, 1982) [ABSTRACT FROM AUTHOR]

Alternate Wenckebach periods have been defined as episodes of 2:1 atrioventricular {AV} block in which conducted P waves exhibit progressive PR prolongation until two or three successively blocked P waves. Ocurrence of this phenomenon during atrial pacing has been established. Thirty-six patients were studied and right atrial pacing was achieved at increasing rates up to 350 beats/min in order to induce alternate Wenckebach periods. His bundle recording's were obtained in every patient. The patients were subdivided into three groups according to the AV nodal conduction time (AH interval): normal AH (75-130 ms) was present in 15 patients, short AH (70 ms) in 13 patients and prolonged AH (130 ms) in eight patients. Alternate Wenckebach periods were observed in 29 patients (80.5%). In every patient alternate Wenckebach periods occurred at the AV node level. Atrial pacing failed to induce alternate Wenckebach periods in seven patients, six of whom belonged to the short AH group. In four patients 3:1 block never appeared because of block ot the atrial level. Two patients presented 2:1 and 3:1 infrahissian block without significant AH prolongation. The remaining patient developed atrial fibrillation. Alternate Wenckebach periods were observed in six of nine patients after intravenous atropine. This study suggests: 1. pacing-induced alternate Wenckebach periods at the AV node level are a physiologic phenomenon; and 2. total or partial bypass (or accelerated AV conduction) atrial refractoriness or vulnerability or block at a lower level may prevent its occurrence. [ABSTRACT FROM AUTHOR]

Reliability and Reproducibility of QRS Duration. Background: A QRS >120 ms remains the recommended criterion for the selection of cardiac resynchronization therapy (CRT) candidates. However, the reproducibility of this measurement has not been studied thoroughly. Methods: QRS duration was measured by 3 experienced cardiologists and by automatic measurement on 228 electrocardiograms (ECGs) randomly collected from 188 subjects, including neonates, healthy adults, patients with complete and incomplete bundle branch block, and CRT candidates. All ECGs were recorded at a 25 mm/s sweep speed. Forty recordings were duplicated and 50 ECGs were recorded at both 25 and 50 mm/s. Results: Significant interobserver differences (P < 0.001) were found between each combination of paired observers, with an up to 50-ms absolute variability between cardiologists and low concordance with computerized measurements. Intraobserver absolute variability was also significant (P < 0.01) for the 3 observers. These significant differences persisted (P < 0.01) when focusing our interest on the ECGs in the 100–140 ms range (defined as at least one out of the 4 measures in this range). Considering the 120 ms limit, 22 (27.5%) ECGs were differently classified by at least one of the cardiologists. We observed similar interobserver differences between each combination of paired observers with a 50 mm/s sweep speed. Conclusion: Manual QRS duration measurements were associated with significant inter- and intraobserver variability and low concordance with computerized measurements. The measurement of QRS is, therefore, operator-dependent and a reevaluation of the measurement methods may be essential to develop clinical and investigative standards. (J Cardiovasc Electrophysiol, Vol. 21, pp. 890-892, August 2010) [ABSTRACT FROM AUTHOR]

Radioprotection for Cardiac Device Implant. Introduction: Pacemaker implants are associated with a high cumulative exposure of the operators to radiation. Standard radiation protection with lead aprons is incomplete and the cause of spine disorders. A radiation protection cabin offers complete protection by surrounding the operator, without requiring a lead apron. Methods: We randomly and evenly assigned 60 patients undergoing implantations of permanent pacemakers or cardioverter defibrillators (ICD) with (a) a radiation protection cabin (cabin group, n = 30) versus (b) standard protection with a 0.5 mm lead-equivalent apron (control group, n = 30). Radiation exposure was measured using personal electronic dosimeters placed on the thorax, back, and head of the operator. Results: The patient, procedural, and device characteristics of the 2 study groups were similar. All procedures in the cabin group were performed as planned without increase in duration or complication rate compared with the control group. The mean radiation dose to the head, normalized for fluoroscopy duration, was significantly lower in the cabin (0.040 ± 0.032 μSv/min) than in the control (1.138 ± 0.560 μSv/min) group (p < 0.0001). The radiation doses to the thorax (0.043 ± 0.027 vs 0.041 ± 0.040 μSv/min) and back (0.038 ± 0.029 vs 0.033 ± 0.018 μSv/min) in the cabin versus control group (under the apron) were similar. Conclusions: The use of a radiation protection cabin markedly decreased the exposure of the operator to radiation, and eliminated the need to wear a lead apron, without increasing the procedural time or complication rate during implantation of pacemaker and ICD. (J Cardiovasc Electrophysiol, Vol. 21, pp. 428–430, April 2010) [ABSTRACT FROM AUTHOR]

The article discusses the mechanism of the medical case of a 52-year-old female with Brugada syndrome. Details related to the episodes of irregular electrical activity of the implanted cardioverter-defibrillator are presented. The case illustrates the consequences of lead-to-lead interaction which supports the need to remove the previous leads at the time of reimplantation.

In a patient with severe congestive heart failure and ischemic disease, frequent episodes of ventricular tachycardia were completely suppressed by an implantable cardioverter defibrillator with biventricalar pacing [ABSTRACT FROM AUTHOR]

A response by Akihiko Kandori et al to a letter to the editor about their article on a method of risk-stratification of asymptomatic individuals with Brugada syndrome is presented.