ABSTRACT
Aim To evaluate Attain Performa (Medtronic, Dublin, Ireland) quadripolar lead performance in clinical practice and, secondarily, to compare its long term clinical outcomes vs bipolar leads for left ventricular (LV) pacing. Methods and results We retrospectively analyzed clinical, procedural and follow-up data of 215 patients implanted with a quadripolar lead. One hundred and twenty one patients implanted with bipolar lead were selected to compare long-term clinical outcomes. The quadripolar lead was implanted in the target vein in 196 patients (91%) without acute dislodgements. In 50% of patients the chosen final pacing configuration at implant would not have been available with bipolar leads. A dedicated quadripolar pacing vector was chosen more frequently when the LV tip location was apical than otherwise (65.6% vs 42.7%, p = 0.003). After a median follow-up of 14 months, the LV pacing threshold was less than 2.5 V at 0.4 ms in 98 patients (90%) with a safety margin between phrenic nerve and LV pacing threshold >3 V in 97 patients (89%). We observed a slight trend toward a lower risk of heart failure worsening and a lower incidence of ventricular arrhythmias and pulmonary congestion in patients implanted with quadripolar leads compared with the control group. Conclusion Quadripolar leads improve the management of phrenic nerve stimulation at no trade-off with pacing threshold and lead stability. Quadripolar leads seems to be associated with a lower incidence of VT/VF and pulmonary congestion, when compared with bipolar leads, but further investigations are necessary to confirm that this positive effect is associated with better LV reverse remodeling.
ABSTRACT
Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. Apropos of a patient with bilateral diaphragmatic paralysis, we review the clinical manifestations and methods for assessing the strength of the respiratory muscles. In patients with severe respiratory muscle weakness, vital capacity and total lung capacity are reduced but are a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for one second (PIMax and PEMax). The sniffmanoeuvre is natural and probably easier to perform. Sniff pressures are more reproducible and useful measure of diaphragmatic strength. However, the PIMax-PEMax and sniff manoeuvres are volition dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch esophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. Systematic clinical evaluation and additional laboratory tests allow the diagnosis in most patients with respiratory muscle weakness.
La evaluación de la fuerza de los músculos respiratorios permite diagnosticar y cuantificar la gravedad de la debilidad muscular en diferentes enfermedades. A propósito de un paciente con parálisis diafragmática bilateral, hemos revisado el cuadro clínico y los procedimientos diagnósticos para evaluar la fuerza de los músculos respiratorios. En los pacientes con debilidad muscular respiratoria severa, disminuye la capacidad vital y la capacidad pulmonar total, pero es una medida inespecífica y relativamente insensible. Tradicionalmente, la fuerza muscular respiratoria es evaluada midiendo la presión inspiratoria y espiratoria máximas en la boca sostenidas durante un segundo (PIMax y PEMax). La medición de la presión inspiratoria máxima en la nariz (SNIP) es una maniobra natural, más simple de medir y más reproducible, siendo útil en la evaluación de la fuerza diafragmática. Sin embargo, estas técnicas no invasivas son operador dependiente, por lo tanto, esfuerzos submáximos es más probable que ocurran en pacientes graves o con disnea. Las mediciones de las presiones esofágica, gástrica y transdiafragmática mediante estimulación eléctrica o magnética del nervio frénico no son dependientes de la voluntad y son más confiables. Sin embargo, la estimulación eléctrica del nervio frénico es técnicamente difícil y puede ser incómoda y dolorosa. La estimulación magnética del nervio frénico es menos dolorosa y la medición de la presión transdiafragmática es reproducible en sujetos normales. La evaluación clínica sistemática y los exámenes de laboratorio complementarios permiten establecer el diagnóstico en la mayoría de los pacientes con debilidad de los músculos respiratorios.
Subject(s)
Humans , Male , Aged , Respiratory Paralysis/diagnosis , Respiratory Muscles/physiology , Muscle Strength/physiology , Respiratory Insufficiency/pathology , Clinical Laboratory Techniques/methodsABSTRACT
La terapia de resincronización cardíaca (TRC) es un método terapéutico bien establecido para el tratamiento de pacientes con insuficiencia cardíaca. La TRC revierte la remodelación del ventrículo izquierdo (VI) dilatado en pacientes sintomáticos con una función sistólica deprimida y complejos QRS anchos, a pesar de recibir una terapia farmacológica óptima, mejorando la clase funcional y reduciendo tanto la sintomatología como la morbilidad, la mortalidad y la hospitalización. La proporción de pacientes que no responden a la TRC se estima en alrededor del 20-40%, según algunos estudios, asociándose a una tasa de complicaciones no despreciables, como son los desplazamientos de electrodos y la estimulación diafragmática. Estudios recientes sugieren que la TRC con un electrodo cuadripolar (EC) en el VI está asociada con excelentes umbrales de estimulación, bajas tasas de desplazamiento de estimulación del nervio frénico y mejora en el gasto cardíaco, en el seguimiento a corto y mediano plazo. Por último, serán necesarios estudios randomizados comparando EC con catéteres bipolares convencionales para evaluar la eficacia, complicaciones y el costo-eficacia.
Results of patients with cardiac resynchronization therapy using a quadripolar left ventricular lead Cardiac resynchronization therapy (CRT) is a well-established therapeutic for the treatment of patients with heart failure. CRT reverses remodelling of the dilated left ventricle (LV) and reduces morbidity and mortality in patients with symptomatic heart failure, prolonged electrical delay, and impaired systolic function receiving optimal pharmacological therapy, enhancing the functional class and reducing the symptoms and morbidity, mortality and hospitalization. The proportion of patients who do not respond to CRT is estimated at about 20-40%, according to some studies associated to a not insignificant complication rate, such as dislocation and phrenic nerve stimulation (PNS). Recent studies suggest that CRT with a quadripolar left ventricular (LV) lead results in excellent pacing thresholds, low rates of dislocation, PNS and improvement in cardiac output at short-term and at medium-term follow-up. Finally, it will be necessary quadripolar LV lead randomized trials comparing conventional bipolar catheter to assess the efficacy, complications and cost-effectiveness.
Resultados de pacientes com terapia de ressincronização cardíaca utilizando um eletrodo quadripolar no ventrículo esquerdo A terapia de ressincronização cardíaca (TRC) é uma abordagem terapêutica bem estabelecida para o tratamento de pacientes com insuficiência cardíaca. A TRC reverte remodelamento do ventrículo esquerdo (VE) em pacientes sintomáticos com função sistólica deprimida dilatada e complexos QRS largos, apesar de receber tratamento medicamentoso otimizado, melhorando a classe funcional e reduzindo os sintomas e a morbidade, mortalidade e hospitalização. A proporção de pacientes que não respondem a TRC é estimada em cerca de 20-40%, de acordo com alguns estudos, associado a uma taxa de complicação não insignificante, como o deslocamento de eletrodos e estimulação do nervo frênico (ENF). Estudos recentes sugerem que a TRC com eletrodo quadripolar (EQ) no VE está associada com excelentes limiares de estimulação, baixas taxas de deslocamento, ENF e melhor monitorização do débito cardíaco, a curto e médio prazo. Finalmente, serão necessários ensaios clínicos randomizados que comparam EQ com cateter bipolar convencional para avaliar a eficácia, as complicações e custo-efetividade.
ABSTRACT
Two patients with respiratory paralysis by cervical(C) injury were treated by sequential four-pole stimulation of the phrenic nerves to pace the diaphragm. With sequential four-pole nerve stimulator, full-time bilateral electroventi-lation were achieved and the conditioning of the diaphragm have been performed in 72 hours. According to other papers using unipolar or bipolar electrode, conditioning of the hypotrophic diaphragm took 2 to 1l months, and full-time electroventilation was possible in only about half of the patients, so part-time mechanical ventilation was needed in remained half of the patients. These results suggest that the conditioning time in patients with high quadriplegia could be significantly shortened and it should be possible to achieved independence from the mechani-cal ventilator when sequential four-pole stimulator was used.