Tachycardic ventricular pacing in a patient with permanent pacemaker demonstrates stress-induced ischaemia on myocardial perfusion scan

A 67-year-old diabetic and hypertensive man underwent permanent pacemaker implantation at right ventricular apical (RVA) site. After 11 years follow-up, the patient's New York Heart Association class changed from II to III. Coronary angiography revealed the presence of triple vessel disease [involving left anterior descending artery (LAD) (90%), OM1 (diffuse), and right coronary artery (70%)]. Thallium-201 (Tl-201) stress myocardial perfusion single-photon-emission computed tomography (SPECT) (MPS) was planned for assessment of ischaemic burden and viability. Tachycardic ventricular pacing stress was planned. The pacemaker was programmed to a rate of 120/min for 2 min and 111 MBq Tl-201 was injected intravenously. Pacing was continued for 1 min post-injection. Stress and 3 h delayed rest redistribution SPECT images were acquired. Moderate-to-severe stress-induced ischaemia (SII) was noted in the distal anterior wall, distal anteroseptal wall and apex (LAD territory), and mild SII in the inferolateral wall (OM1 territory) (Figure). Whole left ventricular myocardium was viable. Demonstration of ischaemia and viability on MPS aided decision making and the surgeon proceeded with coronary artery bypass grafting. Pharmacological vasodilator stress is routinely used as a stress modality in patients with permanent RVA pacing undergoing MPS. A recent study has shown that dipyridamole and tachycardic atrial pacing stress produce similar results regarding detection, localization, and severity of ischaemia on MPS. In the present case, we performed tachycardic ventricular pacing stress using a pacemaker programmer, which is a non-invasive and safer alternative. The full-length version of this report can be viewed at: http://www.escardio.org/communities/EHRA/publications/ep-case-reports/Documents/tachycardic-ventricular.pdf