RESUMEN
The twiddler syndrome results in retraction and coiling of the lead in the pacemaker pocket with subsequent pacemaker malfunction. If the lead׳s parameters are not affected, then the problem can be corrected by lead repositioning. We describe the first reported case of a dramatic pacemaker lead coiling with a double level of lead compromise, with one of them being intra-cardiac. This condition affected our treatment strategy, as the repositioning of the lead was unfeasible.
Asunto(s)
Estimulación Cardíaca Artificial , Falla de Equipo , Marcapaso Artificial , Síndrome del Seno Enfermo/terapia , Potenciales de Acción , Electrocardiografía , Diseño de Equipo , Frecuencia Cardíaca , Humanos , Masculino , Valor Predictivo de las Pruebas , Síndrome del Seno Enfermo/diagnóstico , Síndrome del Seno Enfermo/fisiopatología , Factores de TiempoRESUMEN
In many arthropods, there is a change in relative segment size during post-embryonic development, but how segment differential growth is produced is little known. A new dataset of the highest quality specimens of the 429 Myr old trilobite Aulacopleura koninckii provides an unparalleled opportunity to investigate segment growth dynamics and its control in an early arthropod. Morphometric analysis across nine post-embryonic stages revealed a growth gradient in the trunk of A. koninckii. We contrastively tested different growth models referable to two distinct hypotheses of growth control for the developing trunk: (i) a segment-specific control, with individual segments having differential autonomous growth progression, and (ii) a regional control, with segment growth depending on their relative position along the main axis. We show that the trunk growth pattern of A. koninckii was consistent with a regional growth control producing a continuous growth gradient that was stable across all developmental stages investigated. The specific posterior-to-anterior decaying shape of the growth gradient suggests it deriving from the linear transduction of a graded signal, similar to those commonly provided by morphogens. A growth control depending on a form of positional specification, possibly realized through the linear interpretation of a graded signal, may represent the primitive condition for arthropod differential growth along the main body axis, from which the diverse and generally more complex forms of growth control in subsequent arthropods have evolved.
Asunto(s)
Artrópodos/crecimiento & desarrollo , Tipificación del Cuerpo/fisiología , Fósiles , Modelos Biológicos , Animales , Artrópodos/anatomía & histología , Pesos y Medidas Corporales , República Checa , Análisis de RegresiónRESUMEN
A 63-year-old man with frequent unexplained syncope was implanted with a second generation remotely monitored implantable loop recorder for continuous electrocardiogram (ECG) monitoring. He had a subsequent syncopal episode and despite accidental destruction of his patient activator, vital ECG data from the event were transmitted wirelessly, enabling a cardiac arrhythmia to be excluded. This case highlights the benefit of remote monitoring in syncope assessment, as well as a transmission system that ensures prompt analysis of the ECG data and therefore rapid optimal patient management.
Asunto(s)
Electrocardiografía Ambulatoria/instrumentación , Epilepsia Tipo Ausencia/diagnóstico , Monitoreo Fisiológico/instrumentación , Síncope/diagnóstico , Taquicardia Sinusal/diagnóstico , Telemetría/instrumentación , Ansiedad/tratamiento farmacológico , Arritmias Cardíacas/diagnóstico , Epilepsia Tipo Ausencia/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Fenotiazinas/uso terapéutico , Ácido Valproico/uso terapéuticoRESUMEN
PURPOSE: The study aim was to validate the closed loop stimulation (CLS) vs. accelerometer (ACC) rate-responsive sensors with electrodes placed in the right ventricular high septal (RVHS) or right ventricular apical (RVA) lead positions in patients following 'ablate and pace' therapy for persistent atrial fibrillation. METHODS: 'Ablate and pace' patients were randomised to either RVHS or RVA electrode placement with a dual sensor device. A double-blind crossover study comparing CLS vs. ACC rate-response pacing modes was undertaken. Subjects undertook cardiopulmonary testing with constant workload light exercise followed by a ramp protocol in addition to activity of daily living assessments. RESULTS: Twenty subjects (14 male; age, 74 +/- 8 years) were studied. Heart rate increase was greater from lying to sitting with ACC. With mental stress, heart rate increase was greater with CLS. Peak heart rates were similar for stair ascent and descent in ACC mode. With CLS mode, however, the peak heart rate was significantly lower for stair descent. There was no difference between modes in mean response time, oxygen deficit, peak VO(2), VO(2) at anaerobic threshold, peak heart rate, total exercise time and total workload. CLS function was equally optimal at both electrode sites. CONCLUSIONS: CLS rate adaptive pacing is appropriate for 'ablate and pace' patients, and this sensor functions equally well using RVA or RVHS lead positions.