Wide QRS complex tachycardia due to typical atrial flutter with accessory pathway conduction

A 62-year-old male patient was admitted with regular wide QRS complex tachycardia. After ajmaline administration, the heart rate slowed down disclosing atrial flutter with variable QRS morphologies. Electrocardiography after conversion to sinus rhythm showed narrow QRS complexes. Decremental atrial stimulation during electrophysiological study caused progressive pre-excitation. Spontaneously, typical atrial flutter occurred with pre-excited QRS complexes. Both accessory pathway and atrial flutter were ablated in the same session.

Time-domain control of ultrahigh-frequency nanomechanical systems

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.