12 lead ECG immediately after exercise in a patient with a CRT-D
A 74-year-old male patient with a medical history of hypertrophic obstructive cardiomyopathy (HOCM) with a narrow QRS had a primary prevention Medtronic CRT-D implanted as part of a clinical trial. The device was optimised using echocardiography with paced and sensed AV intervals programmed to 120 ms and 90 ms respectively. CRT therapy was programmed on with LV only pacing using an extended bipolar configuration of LV1 to RVcoil. A follow up device check was performed with the device function deemed as satisfactory. LV pace percentage was 92.8%. There was appropriate atrial and ventricular sensing, pacing thresholds and lead impedances. The patient then underwent a 6-minute walk test with the ECG in figure 1 recorded immediately after exercise. Additional device settings are displayed below.
PVAB: 150ms Partial +
Sensitivity: Atrial 0.3mV Ventricular 0.3mV
12 lead ECG recorded immediately post 6-minute walk test. Standard ECG settings – paper speed 25mm/s, amplitude 10mm/mV