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1.
J Cardiovasc Electrophysiol ; 32(9): 2498-2503, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34245479

RESUMO

BACKGROUND: Pacing at sites of late intraventricular activation (QLV) or long interventricular conduction (right ventricle [RV]-left ventricular [LV]) have been associated with improved cardiac resynchronization therapy (CRT) outcomes. Quadripolar leads improve CRT outcomes by allowing for electrical repositioning to optimize pacing sites. However, little is known regarding the effect of such repositioning on electrical delay. OBJECTIVE: Determine the relationship between different electrical bipoles from a quadripolar lead and measures of electrical delay. METHODS: Forty-six patients underwent CRT with a quadripolar lead. The RV-LV and QLV intervals were measured for both the proximal and distal bipoles and the difference (Δ) between bipoles for each measure were calculated. Multivariate analyses were performed to identify predictors of electrical delays. RESULTS: This was a typical CRT population with a mean age of 65 years and ejection fraction of 27%, with left bundle branch block (LBBB) present in 70%. The regression model for ΔQLV was significant (p = .05), with both gender (p = .008) and LBBB status (p = .020) significant predictors. The overall regression model for ΔRV-LV was not significant. ΔQLV and ΔRV-LV were significant among LBBB patients. Among non-LBBB, only ΔRV-LV was significant (mean: 7.2 ms, p = .006). ΔRV-LV versus ΔQLV were strongly correlated in LBBB (R2 = .92) but not non-LBBB (R2 = .06). CONCLUSION: In LBBB, ΔRV-LV and ΔQLV are closely correlated suggesting that the proximal bipole and thus basal LV pacing sites should be selected when feasible. Greater variation in activation pattern is present in non-LBBB, so pacing sites should be individualized.


Assuntos
Terapia de Ressincronização Cardíaca , Insuficiência Cardíaca , Idoso , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/terapia , Eletrocardiografia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/terapia , Ventrículos do Coração , Humanos
2.
J Cardiovasc Electrophysiol ; 30(12): 2892-2899, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31691436

RESUMO

BACKGROUND: Optimization of atrioventricular (AV) intervals for cardiac resynchronization therapy (CRT) programming is typically performed in supine patients at rest, which may not reflect AV timing in other conditions. OBJECTIVE: To evaluate the effects of posture, exercise, and atrial pacing on intrinsic AV intervals in patients with CRT devices. METHODS: Rate-dependent A-V delay by exercise was a multicenter, prospective trial of patients in sinus rhythm following CRT implantation. Intracardiac electrograms were recorded to analyze atrial to right ventricular (ARV), atrial to left ventricular (ALV), and RV to LV (VV) time intervals. Heart rate was increased with incremental atrial pacing in different postures, followed by an exercise treadmill test. RESULTS: This study included 36 patients. At rest, AV intervals changed minimally with posture. With atrial pacing, AV interval immediately increased compared with sinus rhythm, with ARV slopes being 8.1 ± 7.7, 8.8 ± 13.4, and 6.8 ± 6.5 milliseconds per beat per minute (ms/bpm) and ALV slopes being 8.2 ± 7.7, 9.1 ± 12.8, and 7.0 ± 6.5 ms/bpm for supine, standing and sitting positions, respectively. As the paced heart rate increased, ARV and ALV intervals increased more gradually with similar trends. Interventricular conduction times changed less than 0.2 ms/bpm with atrial pacing. During exercise, the direction of change of intrinsic ARV intervals, as heart rate increased, was variable between patients with relatively small overall group changes (0.1 ± 1.4 and 0.2 ± 1.2 ms/bpm for ARV and ALV, respectively). CONCLUSION: Posture and exercise have a smaller effect on AV timing compared with atrial pacing. However, individualized optimization and dynamic rate related changes may be needed to maintain optimal fusion with left ventricular (LV) stimulation.


Assuntos
Dispositivos de Terapia de Ressincronização Cardíaca , Terapia de Ressincronização Cardíaca , Técnicas Eletrofisiológicas Cardíacas , Teste de Esforço , Sistema de Condução Cardíaco/fisiopatologia , Insuficiência Cardíaca Sistólica/terapia , Frequência Cardíaca , Posicionamento do Paciente , Postura , Função Ventricular Esquerda , Potenciais de Ação , Idoso , Feminino , Insuficiência Cardíaca Sistólica/diagnóstico , Insuficiência Cardíaca Sistólica/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Processamento de Sinais Assistido por Computador , Fatores de Tempo , Resultado do Tratamento
3.
J Cardiovasc Electrophysiol ; 20(8): 894-900, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19302480

RESUMO

BACKGROUND: Chronotropic incompetence is common among patients with advanced heart failure (HF), thus atrial pacing (AP) is frequently utilized in this population. The hemodynamic effects of AP during cardiac resynchronization therapy (CRT) have not been well studied. OBJECTIVE: The purpose of this study was to compare the acute hemodynamic response during CRT of AP with that during atrial sensing (AS). METHODS: This study included 26 patients undergoing CRT. At implant, invasive left ventricular (LV) dP/dt was measured by a micromanometer catheter during biventricular pacing in AS and AP modes at 5 different atrioventricluar delays (AVD), tested in randomized order. Postimplant, echocardiography was performed to obtain aortic and mitral flow velocity integrals at baseline (no CRT) and during CRT. RESULTS: Compared with intrinsic rhythm, CRT increased LV dP/dt by 11 +/- 11% during AS (heart rate: 74 +/- 13 bpm) and by 17 +/- 11% during AP (heart rate: 86 +/- 12 bpm, P < 0.001). The AVD associated with maximal hemodynamic response (AVD(max)) during AP was 72 +/- 40 ms longer than during AS. However, aortic and mitral flow velocity integrals decreased by 15-20% during AP. The aortic and mitral flow velocities at AVD(max) for LV dP/dt(max) were highly correlated with their maximum values (r > 0.98). CONCLUSION: AP increases LV dP/dt during CRT, but requires a substantially longer AV delay. However, AP results in modest reductions of LV filling and stoke volume. Further studies are needed to assess the long-term impact of AP on HF functional status and LV remodeling.


Assuntos
Função Atrial/fisiologia , Estimulação Cardíaca Artificial/métodos , Hemodinâmica/fisiologia , Idoso , Bloqueio de Ramo/fisiopatologia , Bloqueio de Ramo/terapia , Feminino , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
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