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BACKGROUND: Left bundle branch pacing (LBBP) is a novel physiological pacing technique which may serve as an alternative to cardiac resynchronization therapy (CRT) by biventricular pacing (BVP). This study assessed ventricular activation patterns and echocardiographic and clinical outcomes of LBBP and compared this to BVP. METHODS: Fifty consecutive patients underwent LBBP or BVP for CRT. Ventricular activation mapping was obtained by ultra-high-frequency ECG (UHF-ECG). Functional and echocardiographic outcomes and hospitalization for heart failure and all-cause mortality after one year from implantation were evaluated. RESULTS: LBBP resulted in greater resynchronization vs BVP (QRS width: 170 ± 16 ms to 128 ± 20 ms vs 174 ± 15 to 144 ± 17 ms, p = 0.002 (LBBP vs BVP); e-DYS 81 ± 17 ms to 0 ± 32 ms vs 77 ± 18 to 16 ± 29 ms, p = 0.016 (LBBP vs BVP)). Improvement in LVEF (from 28 ± 8 to 42 ± 10 percent vs 28 ± 9 to 36 ± 12 percent, LBBP vs BVP, p = 0.078) was similar. Improvement in NYHA function class (from 2.4 to 1.5 and from 2.3 to 1.5 (LBBP vs BVP)), hospitalization for heart failure and all-cause mortality were comparable in both groups. CONCLUSIONS: Ventricular dyssynchrony imaging is an appropriate way to gain a better insight into activation patterns of LBBP and BVP. LBBP resulted in greater resynchronization (e-DYS and QRS duration) with comparable improvement in LVEF, NYHA functional class, hospitalization for heart failure and all-cause mortality at one year of follow up.
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Biventricular pacing (Biv) and left bundle branch area pacing (LBBAP) are methods of cardiac resynchronization therapy (CRT). Currently, little is known about how they differ in terms of ventricular activation. This study compared ventricular activation patterns in left bundle branch block (LBBB) heart failure patients using an ultra-high-frequency electrocardiography (UHF-ECG). This was a retrospective analysis including 80 CRT patients from two centres. UHF-ECG data were obtained during LBBB, LBBAP, and Biv. Left bundle branch area pacing patients were divided into non-selective left bundle branch pacing (NSLBBP) or left ventricular septal pacing (LVSP) and into groups with V6 R-wave peak times (V6RWPT) < 90 ms and ≥ 90 ms. Calculated parameters were: e-DYS (time difference between the first and last activation in V1-V8 leads) and Vdmean (average of V1-V8 local depolarization durations). In LBBB patients (n = 80) indicated for CRT, spontaneous rhythms were compared with Biv (39) and LBBAP rhythms (64). Although both Biv and LBBAP significantly reduced QRS duration (QRSd) compared with LBBB (from 172 to 148 and 152 ms, respectively, both P < 0.001), the difference between them was not significant (P = 0.2). Left bundle branch area pacing led to shorter e-DYS (24 ms) than Biv (33 ms; P = 0.008) and shorter Vdmean (53 vs. 59 ms; P = 0.003). No differences in QRSd, e-DYS, or Vdmean were found between NSLBBP, LVSP, and LBBAP with paced V6RWPTs < 90 and ≥ 90 ms. Both Biv CRT and LBBAP significantly reduce ventricular dyssynchrony in CRT patients with LBBB. Left bundle branch area pacing is associated with more physiological ventricular activation.
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AIMS: Permanent transseptal left bundle branch area pacing (LBBAP) is a promising new pacing method for both bradyarrhythmia and heart failure indications. However, data regarding safety, feasibility and capture type are limited to relatively small, usually single centre studies. In this large multicentre international collaboration, outcomes of LBBAP were evaluated. METHODS AND RESULTS: This is a registry-based observational study that included patients in whom LBBAP device implantation was attempted at 14 European centres, for any indication. The study comprised 2533 patients (mean age 73.9 years, female 57.6%, heart failure 27.5%). LBBAP lead implantation success rate for bradyarrhythmia and heart failure indications was 92.4% and 82.2%, respectively. The learning curve was steepest for the initial 110 cases and plateaued after 250 cases. Independent predictors of LBBAP lead implantation failure were heart failure, broad baseline QRS and left ventricular end-diastolic diameter. The predominant LBBAP capture type was left bundle fascicular capture (69.5%), followed by left ventricular septal capture (21.5%) and proximal left bundle branch capture (9%). Capture threshold (0.77â V) and sensing (10.6â mV) were stable during mean follow-up of 6.4 months. The complication rate was 11.7%. Complications specific to the ventricular transseptal route of the pacing lead occurred in 209 patients (8.3%). CONCLUSIONS: LBBAP is feasible as a primary pacing technique for both bradyarrhythmia and heart failure indications. Success rate in heart failure patients and safety need to be improved. For wider use of LBBAP, randomized trials are necessary to assess clinical outcomes.
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Fascículo Atrioventricular , Insuficiencia Cardíaca , Humanos , Femenino , Anciano , Estimulación Cardíaca Artificial/efectos adversos , Estimulación Cardíaca Artificial/métodos , Bloqueo de Rama/terapia , Bloqueo de Rama/etiología , Bradicardia/terapia , Bradicardia/etiología , Electrocardiografía/métodos , Resultado del TratamientoRESUMEN
The introduction of dedicated tools for pacing and defibrillator lead extraction has resulted in relatively high success and low complication rates. The confidence this elicits has broadened the indications from device infections to non-functional or redundant leads and the latter make up an increasing share of extraction procedures. Proponents of extracting these leads point to the higher complication burden of lead extraction in patients with longstanding abandoned leads when compared one-to-one with extraction when these leads become redundant. However, this does not translate into better patient outcomes on a population level: complications are rare with properly abandoned leads and thus most patients will never be subjected to an extraction procedure and the ensuing complications. Therefore, not extracting redundant leads minimises the risk for the patients and avoids many expensive procedures.
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BACKGROUND: Right ventricular pacing (RVP) induces abnormal electrical activation and asynchronous ventricular contraction and leads to pacing induced cardiomyopathy (PICM) in 10%-20% of patients. Cardiac resynchronization therapy (CRT) utilizing biventricular pacing (BVP) is the recommended treatment. Left bundle branch pacing (LBBP) is a novel physiological pacing technique which may serve as an alternative to CRT. This study assessed feasibility and outcomes of LBBP delivered CRT in patients with PICM. METHODS: Total 20 consecutive patients with PICM who received an upgrade of their pacemaker to LBBP were prospectively studied. Acute success rate, complications, functional and echocardiographic response, and hospitalization for heart failure within 6 months from implantation were evaluated. RESULTS: LBBP was successfully delivered in all patients. Median duration of RVP before upgrade to LBBP was 3.8 years and the RVP was 99%. LBBP resulted in significant QRS narrowing (from 193 ± 18 ms to 130 ± 17 ms [p < .001]), improvement in LVEF (from 32% ± 6 % to 47% ± 8% [p < .001]) and NYHA class (from 2.8 ± 0.4 to 1.4 ± 0.5 [p < .001]) at 6 months. No LBBP-related complications occurred. No patients were hospitalized for heart failure or died. CONCLUSION: LBBP is feasible and safe in delivering CRT in PICM. Preliminary analyses demonstrated significant electrical resynchronization and favorable improvement in LV function and NYHA functional class at short term follow-up. Data needs to be validated in large randomized controlled trials.
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Terapia de Resincronización Cardíaca , Cardiomiopatías , Insuficiencia Cardíaca , Fascículo Atrioventricular , Estimulación Cardíaca Artificial/efectos adversos , Estimulación Cardíaca Artificial/métodos , Terapia de Resincronización Cardíaca/efectos adversos , Terapia de Resincronización Cardíaca/métodos , Electrocardiografía/métodos , Estudios de Factibilidad , Humanos , Resultado del Tratamiento , Función Ventricular Izquierda/fisiologíaRESUMEN
BACKGROUND: Venous access for cardiac implantable electronic devices (CIED) is commonly performed by cephalic venous cut down, or axillary or subclavian vein puncture. The latter technique carries a risk of complications such as pneumothorax or lead crush. Cephalic venous cut down is free of these complications but often less successful due to technical difficulties. We report a highly successful, simplified cephalic venous access with a modified Seldinger technique. METHODS: We prospectively studied 221 patients undergoing de novo implantation of a one, two, or three lead device system performed over a 1-year period at our center, and assessed the efficacy of the cephalic vein access including the number of leads successfully placed for each procedure. RESULTS: In 83% of patients undergoing CIED implantation, a suitable cephalic vein was present. In respectively 98% and 99% of patients undergoing single- or dual-chamber CIED implantation, lead placement could be performed exclusively via the cephalic vein and in 72% of cardiac resynchronization therapy implants, all three leads were placed via cephalic access. CONCLUSION: A novel, technically simple cephalic venous catheterization technique provides high success rates for any CIED lead implantation.
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Venas Braquiocefálicas/cirugía , Dispositivos de Terapia de Resincronización Cardíaca , Implantación de Prótesis/métodos , Anciano , Femenino , Fluoroscopía , Humanos , Masculino , Estudios Prospectivos , Técnicas de SuturaRESUMEN
The 2017 Heart Rhythm Society expert consensus paper on lead management and extraction did not express a preference for either extracting or abandoning pacing or defibrillator leads that are dysfunctional or superfluous after an upgrade (hereafter referred to as redundant leads). However, no randomized or even nonrandomized trials show a better patient outcome with extraction. Many experienced centers currently advise patients to have redundant leads removed to prevent more complicated procedures after years of abandonment. According to the literature, however, not all abandoned leads need to be extracted as >90% will have an uneventful follow-up. As immediate extraction of redundant leads has a small but significant risk, this will generate more adverse events at the population level than when extraction is limited to the patients with future lead complications, even considering a higher extraction risk at that time. Lead extraction is also limited to specialized centers and often necessitates expensive tools, in contrast to abandoning leads, which can be safely performed by any experienced device specialist without additional cost.
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Identifying electrical dyssynchrony is crucial for cardiac pacing and cardiac resynchronization therapy (CRT). The ultra-high-frequency electrocardiography (UHF-ECG) technique allows instantaneous dyssynchrony analyses with real-time visualization. This review explores the physiological background of higher frequencies in ventricular conduction and the translational evolution of UHF-ECG in cardiac pacing and CRT. Although high-frequency components were studied half a century ago, their exploration in the dyssynchrony context is rare. UHF-ECG records ECG signals from eight precordial leads over multiple beats in time. After initial conceptual studies, the implementation of an instant visualization of ventricular activation led to clinical implementation with minimal patient burden. UHF-ECG aids patient selection in biventricular CRT and evaluates ventricular activation during various forms of conduction system pacing (CSP). UHF-ECG ventricular electrical dyssynchrony has been associated with clinical outcomes in a large retrospective CRT cohort and has been used to study the electrophysiological differences between CSP methods, including His bundle pacing, left bundle branch (area) pacing, left ventricular septal pacing and conventional biventricular pacing. UHF-ECG can potentially be used to determine a tailored resynchronization approach (CRT through biventricular pacing or CSP) based on the electrical substrate (true LBBB vs. non-specified intraventricular conduction delay with more distal left ventricular conduction disease), for the optimization of CRT and holds promise beyond CRT for the risk stratification of ventricular arrhythmias.
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BACKGROUND: Cardiac resynchronization therapy (CRT) based on the conventional biventricular pacing (BiV-CRT) technique sometimes results in broad QRS complex and suboptimal response. OBJECTIVE: We aimed to assess the feasibility and outcomes of CRT based on left bundle branch area pacing (LBBAP, in lieu of the right ventricular lead) combined with coronary venous left ventricular pacing in an international multicenter study. METHODS: LBBAP-optimized CRT (LOT-CRT) was attempted in nonconsecutive patients with CRT indications. Addition of the LBBA (or coronary venous) lead was at the discretion of the implanting physician, who was guided by suboptimal paced QRS complex, and/or on clinical grounds. RESULTS: LOT-CRT was successful in 91 of 112 patients (81%). The baseline characteristics were as follows: mean age 70 ± 11 years, female 22 (20%), left ventricular ejection fraction 28.7% ± 9.8%, left ventricular end-diastolic diameter 62 ± 9 mm, N-terminal pro-B-type natriuretic peptide level 5821 ± 8193 pg/mL, left bundle branch block 47 (42%), nonspecific intraventricular conduction delay 25 (22%), right ventricular pacing 26 (23%), and right bundle branch block 14 (12%). The procedure characteristics were as follows: mean fluoroscopy time 27.3 ± 22 minutes, LBBAP capture threshold 0.8 ± 0.5 V @ 0.5 ms, and R-wave amplitude 10 mV. LOT-CRT resulted in significantly greater narrowing of QRS complex from 182 ± 25 ms at baseline to 144 ± 22 ms (P < .0001) than did BiV-CRT (170 ± 30 ms; P < .0001) and LBBAP (162 ± 23 ms; P < .0001). At follow-up of ≥3 months, the ejection fraction improved to 37% ± 12%, left ventricular end-diastolic diameter decreased to 59 ± 9 mm, N-terminal pro-B-type natriuretic peptide level decreased to 2514 ± 3537 pg/mL, pacing parameters were stable, and clinical improvement was noted in 76% of patients (New York Heart Association class 2.9 vs 1.9). CONCLUSION: LOT-CRT is feasible and safe and provides greater electrical resynchronization as compared with BiV-CRT and could be an alternative, especially when only suboptimal electrical resynchronization is obtained with BiV-CRT. Randomized controlled trials comparing LOT-CRT and BiV-CRT are needed.
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Terapia de Resincronización Cardíaca , Anciano , Anciano de 80 o más Años , Terapia de Resincronización Cardíaca/métodos , Electrocardiografía/métodos , Femenino , Humanos , Persona de Mediana Edad , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular IzquierdaRESUMEN
BACKGROUND: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) is effective in patients with heart failure, left bundle branch block (LBBB), and reduced left ventricular function. Left bundle branch area pacing (LBBAP) has been reported as an alternative option for CRT. OBJECTIVE: The purpose of this study was to assess the feasibility and outcomes of LBBAP in patients who failed conventional BVP because of coronary venous (CV) lead complications or who were nonresponders to BVP. METHODS: At 16 international centers, LBBAP was attempted in patients with conventional CRT indication who failed BVP because of CV lead complications or lack of therapeutic response to BVP. Heart failure hospitalization (HFH) and death, echocardiographic outcomes, procedural data, pacing parameters, and lead complications including CV lead failure are reported. RESULTS: LBBAP was successfully performed in 200 patients (CV lead failures 156; nonresponders 44) (age 68 ± 11 years; female 35%; LBBB 55%; right ventricular pacing 23%; ischemic cardiomyopathy 28%; nonischemic cardiomyopathy 63%; left ventricular ejection fraction [LVEF] ≤35% in 80%). Procedural duration was 119.5 ± 59.6 minutes, and fluoroscopy duration was 25.7 ± 18.5 minutes. LBBAP threshold and R-wave amplitudes were 0.68 ± 0.35 V @ 0.45 ms and 10.4 ± 5 mV at implant, respectively, and remained stable during mean follow-up of 12 ± 10.1 months. LBBAP resulted in significant QRS narrowing from 170 ± 28 ms to 139 ± 25 ms (P <.001) with V6 R-wave peak times of 85 ± 17 ms. LVEF improved from 29% ± 10% at baseline to 40% ± 12% (P <.001) during follow-up. The risk of death or HFH was lower in those with CV lead failure than in nonresponders (hazard ratio 0.357; 95% confidence interval 0.168-0.756; P = .007) CONCLUSION: LBBAP is a viable alternative to CRT in patients who failed conventional BVP due to CV lead failure or who were nonresponders.
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Terapia de Resincronización Cardíaca , Insuficiencia Cardíaca , Anciano , Arritmias Cardíacas/terapia , Fascículo Atrioventricular , Bloqueo de Rama/diagnóstico , Bloqueo de Rama/etiología , Bloqueo de Rama/terapia , Estimulación Cardíaca Artificial/métodos , Terapia de Resincronización Cardíaca/métodos , Electrocardiografía/métodos , Femenino , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/terapia , Humanos , Persona de Mediana Edad , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular Izquierda/fisiologíaRESUMEN
A 72-year-old woman without cardiovascular history presented with acute substernal chest pain and dyspnoea. The electrocardiogram was normal, but the blood test analyses showed an elevated troponin T level. Emergency coronary angiography revealed normal epicardial coronary arteries, but the left ventriculogram demonstrated midventricular dilatation and akinesis with well-preserved contractility of the apex and base. The patient was diagnosed as having an atypical presentation of takotsubo cardiomyopathy. She was treated with a beta blocker and an ACE inhibitor and recovered well. A follow-up echocardiogram at 2 months showed normalization of the wall motion abnormality.
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Cardiomiopatía de Takotsubo/diagnóstico , Anciano , Femenino , Imagen de Acumulación Sanguínea de Compuerta , Humanos , Cardiomiopatía de Takotsubo/sangre , Cardiomiopatía de Takotsubo/tratamiento farmacológico , Cardiomiopatía de Takotsubo/fisiopatología , Troponina T/sangreRESUMEN
Amiodarone and sotalol are frequently used in the treatment of atrial fibrillation. However, oral and intravenous (IV) therapy with these drugs has suboptimal efficacy and is associated with serious extracardiac side effects. We hypothesized that intrapericardial (IPC) delivery produces antiarrhythmic effects at lower plasma drug concentrations than IV delivery. Goats (n = 27) were randomised into 5 groups receiving either IPC vehicle, amiodarone (IV or IPC) or dl-sotalol (IV or IPC). Epicardial and endocardial atrial effective refractory period and atrial response to burst pacing (rapid atrial response, RAR) were assessed before and after 3 hours of drug infusion at 2 mg.kg.h. IPC delivery produced steeply decreasing drug concentrations from epicardium to endocardium in both atria and ventricles. Plasma drug concentrations were significantly lower in IPC than in IV groups. IPC amiodarone and sotalol reduced epicardial RAR inducibility (-74% +/- 20% and -66% +/- 30%, respectively) compared with IV delivery (-11% +/- 17% and -17% +/- 28%, respectively; P < 0.05). Endocardial RAR inducibility was only reduced in the IPC amiodarone group (-70% +/- 17%, P < 0.05). In conclusion, IPC delivery of amiodarone and sotalol increases atrial drug concentration and antiarrhythmic effects at reduced plasma drug concentrations. These potential benefits are particularly prominent for IPC delivered amiodarone.
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Amiodarona/administración & dosificación , Antiarrítmicos/administración & dosificación , Sistemas de Liberación de Medicamentos , Fenómenos Electrofisiológicos/efectos de los fármacos , Pericardio/metabolismo , Sotalol/administración & dosificación , Amiodarona/sangre , Amiodarona/farmacocinética , Animales , Antiarrítmicos/sangre , Antiarrítmicos/farmacocinética , Función del Atrio Derecho/efectos de los fármacos , Endocardio/metabolismo , Cabras , Pericardio/efectos de los fármacos , Sotalol/sangre , Sotalol/farmacocinética , Distribución Tisular , Función Ventricular Derecha/efectos de los fármacosRESUMEN
This article illustrates the highly interesting possibilities of cardiac resynchronization therapy (CRT) yet also discusses several problems for optimal implementation. The authors have presented possible strategies to improve CRT by designing and using better measurements of mechanical dyssynchrony or discoordination, leading to better patient selection. In addition, application of CRT can be improved by developing techniques to reach the optimal pacing site(s) easier and algorithms for easier programming of optimal atrioventricular delay and interventricular interval. Also, application of CRT in patients with less severe heart failure deserves further attention. Finally, the mechanism of ventricular interaction may open new fields of application of left ventricle-based pacing in patients who have heart failure, even with a narrow QRS complex.
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Bloqueo de Rama/terapia , Estimulación Cardíaca Artificial/métodos , Insuficiencia Cardíaca/terapia , Algoritmos , Bloqueo de Rama/fisiopatología , Sistema de Conducción Cardíaco/fisiopatología , Insuficiencia Cardíaca/fisiopatología , HumanosRESUMEN
OBJECTIVES: The aim of this study was to investigate the mid-term haemodynamic and clinical results after aortic valve replacement (AVR) using the Sorin Freedom Solo (SFS) stentless bioprosthesis, compared with the standard Carpentier Edwards Perimount (CEP) stented bioprosthesis. METHODS: In this retrospective cohort study of prospectively collected data, 116 patients were included in the SFS group (53 males; median age 74 years, range 56-85 years), and 122 patients in the CEP group (85 males; median age 73 years, range 43-88 years) between July 2007 and January 2013. Echocardiography was performed at 6 weeks after surgery in our centre, and the most recent echocardiography (in our centre or in referring cardiology departments) was requested. Between September 2013 and April 2014, all patients were called by the same researcher to gain clinical follow-up data. RESULTS: Mid-term mortality was 16.4% in the SFS group (19 patients) and 21.3% in the CEP group (26 patients); (P = 0.3). The mean transvalvular gradient was 7.4 ± 3.1 mmHg in the SFS group, and 11.6 ± 3.2 mmHg in the CEP group at 6 weeks postoperatively (P < 0.001). When stratified by labelled valve size, mean gradients were significantly lower in the SFS group for every size (P ≤ 0.03). After 3.3 ± 1.4 years of follow-up, the mean gradient was still significantly lower in the SFS group than that in the CEP group (P < 0.001). Clinical follow-up showed relatively low complication rates. CONCLUSION: These data suggest that the Sorin Freedom Solo stentless bioprosthesis is as safe as the Carpentier Edwards bioprosthesis, and provides better short- and mid-term haemodynamic performance than the Carpentier Edwards bioprosthesis.
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Válvula Aórtica/cirugía , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Estenosis de la Válvula Aórtica/cirugía , Electrocardiografía , Femenino , Prótesis Valvulares Cardíacas/efectos adversos , Prótesis Valvulares Cardíacas/estadística & datos numéricos , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/mortalidad , Implantación de Prótesis de Válvulas Cardíacas/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
OBJECTIVES: The purpose of this study was to investigate whether stimulation at the left ventricular (LV) septum (LVs), alone or in combination with another site, could be an alternative way to apply cardiac resynchronization therapy (CRT) that avoids the coronary sinus and phrenic nerve stimulation and may create more physiological sequence of activation. BACKGROUND: In CRT, biventricular pacing is commonly performed from the right ventricle (RV) and the epicardium of the LV lateral wall (LVlat). In the left bundle branch block (LBBB), half of the electrical delay occurs due to impulse conduction across the septum. METHODS: Experiments were performed in 13 dogs with LBBB, 7 of them with chronic myocardial infarction (LBBB + MI). Pacing leads were positioned in the right atrium, RV, LVs, and at the LVlat epicardium. LV pump function was measured using conductance catheter and synchrony of electrical activation of the ventricles using epicardial mapping and from surface electrocardiogram. In 12 CRT patients, LV pump function was measured during temporary RV + LVs pacing and compared to RV + LVlat and RV + LVlat endo pacing. RESULTS: In the animals, electrical and hemodynamic benefits of LVs and RV + LVs pacing were comparable to those during conventional biventricular pacing and were comparable in LBBB and LBBB + MI hearts. Dispersion of repolarization was reduced by LVs stimulation, but not by LVlat pacing. In patients, hemodynamic benefits of RV + LVs, RV + LVlat and RV + LVlat endo pacing were similar. CONCLUSIONS: The use of the LVs as LV pacing site in CRT improves synchronization and acute hemodynamics comparably to conventional biventricular pacing in dyssynchronous canines and in patients. In addition, LVs stimulation may reduce dispersion of repolarization compared to epicardial pacing.
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BACKGROUND: Endocardial left ventricular (LV) pacing for cardiac resynchronization therapy (CRT) has been proposed as an alternative to traditional LV transvenous epicardial pacing with equal or superior cardiac performance. The risks of cerebral thromboembolism and possible interference with mitral valve function moderate its clinical application. OBJECTIVE: The purpose of this study was to investigate cerebral thromboembolic complications after LV endocardial lead placement. Mitral regurgitation (MR) was the secondary outcome measure. METHODS: CRT candidates with a failed coronary sinus approach or nonresponders to conventional CRT underwent endocardial LV lead implantation (45 atrial transseptal, 6 transapical). Coumarin was prescribed with a targeted international normalized ratio between 3.5 and 4.5. Patient records were checked and general practitioners were contacted regarding cerebral thromboembolic complications. MR was evaluated by echocardiography at baseline and after 6 months. RESULTS: In 7 patients, 6 ischemic strokes and 2 transient ischemic attacks occurred, corresponding to 6.1 thromboembolic events per 100 patient-years (95% confidence interval 3.4-15.8). One patient refused hospital admission; all other patients had a subtherapeutic anticoagulation level at the time of the event. No major bleeding complications occurred. There was no change in the grade of MR (grade 2, P = .727) after 6 months. CONCLUSION: Endocardial LV lead placement in patients with advanced heart failure is associated with thromboembolic risk. However, all but 1 patient had a subtherapeutic level of anticoagulation. Endocardial LV lead placement is not associated with aggravation of MR.
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Terapia de Resincronización Cardíaca/efectos adversos , Embolia Intracraneal/etiología , Trombosis Intracraneal/etiología , Anciano , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/terapia , Ventrículos Cardíacos , Humanos , MasculinoRESUMEN
BACKGROUND: Studies in canine hearts with acute left bundle branch block (LBBB) showed that endocardial left ventricular (LV) pacing improves the efficacy of cardiac resynchronization therapy (CRT) compared with conventional epicardial LV pacing. The present study explores the efficacy of endocardial CRT in more compromised hearts and the mechanisms of such beneficial effects. METHODS AND RESULTS: Measurements were performed in 22 dogs, 9 with acute LBBB, 7 with chronic LBBB combined with infarction (embolization; LBBB plus myocardial infarction, and concentric remodeling), and 6 with chronic LBBB and heart failure (rapid pacing, LBBB+HF, and eccentric remodeling). A head-to-head comparison was performed of the effects of endocardial and epicardial LV pacing at 8 sites. LV activation times were measured using ≈100 endocardial and epicardial electrodes and noncontact mapping. Pump function was assessed from right ventricular and LV pressures. Endocardial CRT resulted in better electric resynchronization than epicardial CRT in all models, although the benefit was larger in concentrically remodeled LBBB plus myocardial infarction than in eccentrically remodeled LBBB+HF hearts (19% versus 10%). In LBBB and LBBB+HF animals, endocardial conduction was ≈50% faster than epicardial conduction; in all models, transmural impulse conduction was ≈25% faster when pacing from the endocardium than from the epicardium. Hemodynamic effects were congruent with electric effects. CONCLUSIONS: Endocardial CRT improves electric synchrony of activation and LV pump function compared with conventional epicardial CRT in compromised canine LBBB hearts. This benefit can be explained by a shorter path length along the endocardium and by faster circumferential and transmural impulse conduction during endocardial LV pacing.
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Terapia de Resincronización Cardíaca/métodos , Insuficiencia Cardíaca/terapia , Infarto del Miocardio/terapia , Animales , Estimulación Cardíaca Artificial , Enfermedad Crónica , Modelos Animales de Enfermedad , Perros , Electrocardiografía , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/complicaciones , Insuficiencia Cardíaca/fisiopatología , Masculino , Infarto del Miocardio/complicaciones , Infarto del Miocardio/fisiopatología , Resultado del TratamientoRESUMEN
BACKGROUND: In cardiac resynchronization therapy (CRT), optimization of left ventricular (LV) stimulation timing is often time consuming. We hypothesized that the QRS vector in the vectorcardiogram (VCG) reflects electric interventricular dyssynchrony, and that the QRS vector amplitude (VAQRS), halfway between that during left bundle branch block (LBBB) and LV pacing, reflects optimal resynchronization, and can be used for easy optimization of CRT. METHODS AND RESULTS: In 24 canine hearts with LBBB (12 acute, 6 with heart failure, and 6 with myocardial infarction), the LV was paced over a wide range of atrioventricular (AV) delays. Surface ECGs were recorded from the limb leads, and VAQRS was calculated in the frontal plane. Mechanical interventricular dyssynchrony (MIVD) was determined as the time delay between upslopes of LV and right ventricular pressure curves, and systolic function was assessed as LV dP/dtmax. VAQRS and MIVD were highly correlated (r=0.94). The VAQRS halfway between that during LV pacing with short AV delay and intrinsic LBBB activation accurately predicted the optimal AV delay for LV pacing (1 ms; 95% CI, -5 to 8 ms). Increase in LV dP/dtmax at the VCG predicted AV delay was only slightly lower than the highest observed LV dP/dtmax (-2.7%; 95% CI, -3.6 to -1.8%). Inability to reach the halfway value of VAQRS during simultaneous biventricular pacing (53% of cases) was associated with suboptimal hemodynamic response, which could be corrected by sequential pacing. CONCLUSIONS: The VAQRS reflects electric interventricular dyssynchrony and accurately predicts optimal timing of LV stimulation in canine LBBB hearts. Therefore, VCG may be useful as a reliable and easy tool for individual optimization of CRT.
Asunto(s)
Bloqueo de Rama/terapia , Terapia de Resincronización Cardíaca/métodos , Sistema de Conducción Cardíaco/fisiopatología , Vectorcardiografía , Función Ventricular Izquierda/fisiología , Animales , Bloqueo de Rama/fisiopatología , Modelos Animales de Enfermedad , Perros , Femenino , Masculino , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Amiodarone is currently the most effective antiarrhythmic drug for sinus rhythm maintenance. However, due to serious extracardiac adverse effects, prophylactic amiodarone therapy is only appropriate for patients at high risk for postoperative atrial fibrillation (AF). We hypothesized that epicardial application of an amiodarone-releasing hydrogel would produce therapeutic myocardial drug concentrations, while systemic levels would remain low. METHODS: Goats were fitted with right atrial epicardial patch electrodes. A poly(ethylene glycol)-based hydrogel with amiodarone (1mg/kg bw) (n=10) or without drug (n=6) was applied to the right atrial epicardium. Atrial effective refractory period (AERP), conduction time and atrial response to burst pacing (rapid atrial response, RAR) were assessed up to 28days in awake goats. Myocardial, plasma and extracardiac tissue amiodarone concentrations were analysed by high-performance liquid chromatography. RESULTS: The amiodarone-loaded hydrogel produced therapeutic drug concentrations in the right atrium up to 21days after application. In this period, AERP and conduction time were prolonged, while RAR inducibility was reduced (P<0.05) compared to animals treated with drug-free hydrogel. Mean amiodarone concentrations in the right atrium were 1 order of magnitude higher than in other heart chambers and 2 orders of magnitude higher than in extracardiac tissues. Plasma amiodarone levels remained below the detection limit (<10ng/mL) during the 28-day follow-up. CONCLUSIONS: Epicardial application of an amiodarone-releasing hydrogel reduces atrial vulnerability to tachyarrhythmias up to 3weeks, while extracardiac drug levels remain low. Therefore, amiodarone-releasing hydrogel could be applied during cardiac surgery to prevent postoperative AF at minimal risk for extracardiac adverse side effects.