Pacemaker Rhythm Recorded by a Cardiac Resynchronization Device Capable of Left Ventricular Sensing

Abstract

cardiac resynchronization, cardiac pacing, left ventricular sensing, T wave oversensing sensing, implantable cardioverter-defibrillatorClinical Summary A 60-year-old man received a transvenous cardiac resynchronization device (Biotronik Lumax 340 HF-T, Biotronik, Berlin, Germany) 1 in 2009 for a nonischemic cardiomyopathy congestive heart failure (left ventricular [LV] ejection fraction = 26%), and complete left bundle branch block. LV pacing and sensing were performed from the tip and ring electrodes of the LV lead. Infrequent intermittent T-wave oversensing by the right ventricular (RV) channel involving only one or two spontaneous beats was first detected in November 2012. The RV sensitivity was left at 0.8 mV but the sensing LV amplifier was turned off. At the time of a follow-up 1 month later, the parameters were as follows: Low rate = 60 pulses per minute (ppm), RV and LV upper rate = 130 ppm (upper rate interval = 460 ms, RVURI = RV upper rate interval, LVURI = LV upper rate interval), postventricular atrial refractory period = 250 ms (475 ms after a ventricular premature complex [VPC]), paced atrioventricular (AV) delay = 100 ms, sensed AV delay = 80 ms, upper threshold = 75% (programmed sensitivity becomes 75% of the maximum, lasting for 350 ms), amplitude mode for detection of the peak R wave, and high pass 1 = 20 Hz, LV lead impedance = 545 Ohms. LV blanking after sensing was 200 ms before the LV-sensing amplifier was turned off. The AV control (AVC) window (discrimination after atrial sensing) was 350 ms, interventricular delay basically zero (triggered delay = 3-5 ms), and triggered function (LV-paced events [LVp]) after RV sensing (RVs) was within the AVC window. The LV sensitivity was not reprogrammed and

Inhibition of Left Ventricular Pacing during Cardiac Resynchronization

“…In contrast, Biotronik CRT devices (the only other CRT devices with LV sensing) feature an LVURI. In these devices, the LVURI is initiated by LV sensed or RV sensed events according to the status of the LV T‐wave protection function being either on or off, respectively . An inhibited LVP with Biotronik CRT devices also initiates an LVURI …”

Loss of cardiac resynchronization therapy in a patient with a biventricular implantable cardioverter‐defibrillator

“…The difference is about LV sensed events. When the left ventricle T‐wave protection (LVTP) function is on, LV sensed events will start an LVURI, but when LVTP is programmed off, then the device cannot sense LV events and instead sensed RV events will initiate and reset an LVURI [1,2].…”

Understanding the Timing Cycles of a Cardiac Resynchronization Device Designed with Left Ventricular Sensing

“…When the sensing amplifier is turned off, the device initiates an LVURI with the emission of LVp and upon sensing RV events in the same way as when the LVTP is programmed off at a time when the LVs amplifier is turned on . The only difference was absence of recorded LV electrograms when the sensing amplifier is turned off.…”