In the setting of ischemic heart disease (IHD), ventricular tachycardia (VT) commonly originates from areas of incomplete scar tissue. High-density electroanatomic mapping has enhanced our understanding of VT circuits, predominantly characterised by dense scar and surviving myocyte bundles. We present a case of a 58-year-old male with IHD and sustained monomorphic VT, successfully treated with radiofrequency ablation following high-density mapping and entrainment techniques. Two inducible VT phenotypes were identified, with ablation at one site effectively terminating both VT morphologies. This case illustrates the importance of precise circuit localisation and targeted ablation in managing post-infarction VT, leading to a satisfactory patient outcome.
A 60-year-old woman presented with recurrent episodes of palpitations, documented short RP, narrow QRS tachycardia and absence of preexcitation in the electrocardiogram during sinus rhythm. During an electrophysiology study, programmed stimulation induced a narrow QRS tachycardia with cycle length of 380 ms, VA interval of 164 ms and earliest atrial activation in the His region. Ventricular overdrive pacing failed to entrain the atrium even with isoprenaline infusion and atrial burst pacing repeatedly terminated the tachycardia. Difference in AH interval with pacing and SVT was 27 msec. Simultaneous atrial and ventricular pacing was done with atrial pacing from the high right atrium and showed a His signal as the first return electrogram suggestive of atrioventricular nodal reentrant tachycardia (AVNRT). The manoeuvre was repeated with atrial pacing from the proximal coronary sinus and showed an atrial signal as the first return electrogram suggestive of atrial tachycardia (AT). What is the explanation for the conflicting results of the two pacing maneuvers?
Introduction: The causes of atrial undersensing in a dual chamber pacemaker include true undersensing (low amplitude electrogram), functional undersensing (related to the effect of special timing cycles in the presence of an adequate signal) and paradoxical undersensing. This case report describes paradoxical atrial undersensing at a higher programmed atrial sensitivity and with the return of normal atrial sensing at a lower programmed sensitivity.
Leadless pacemakers have provided new treatment modalities that can be especially useful in patients with complex cardiac anatomy and contraindications toward other pacemaker approaches. The Aveir™ single-chamber (VR) leadless pacemaker (LP) (Abbott Laboratories, Chicago, IL) is a recently approved device that can be placed in the right ventricle for patients with bradycardia. In this case, we present a novel use for the device through placement in the atrium to control atrial flutter in a patient with a hypoplastic right ventricle.
Despite lack of concrete evidence, right ventricular thrombus is generally considered to be a contraindication for intracardiac lead placement. We present a case of successful placement of a right ventricular defibrillator lead and left bundle branch pacing lead and atrioventricular node ablation in a patient with chronic right ventricle thrombus.