S. Serge Barold

REFERENCES 1. Left ventricular sensing by cardiac resynchronization devices. Pacing Clin Electrophysiol. 2019; 42: 1081-1085. 2, , , et al. Left ventricular sensing in cardiac resynchronization devices-opportunities and pitfalls for device programming. J Cardiovasc Electrophysiol. 2019; 30: 1352-1361. 3, , , et al. Causes of impaired biventricular pacing in cardiac resynchronization devices with left ventricular sensing. Pacing Clin Electrophysiol. 2020; 43: 332-340. 4, , , .

Corresponding Author Bengt Herweg MD Morsani College of Medicine, University of South Florida, Tampa, Florida, USA Correspondence S. Serge Barold, MD, University of Rochester School of Medicine and Dentistry, 601 Elmwood Av, Rochester, NY 14642, USA. Email: ssbarold@aol.com Bengt Herweg, MD,  Morsani College of Medicine, University of South Florida, 2 Tampa General Cir (Fifth floor), Tampa, FL 33606, USA. Email: Bengt@usf.edu Search for more papers by this author

Whether a pacemaker can sense concealed ventricular extrasystoles still remains debatable since its occurrence was first proposed in 1972. It must remain a diagnosis of exclusion if it really exists. Isoelectric complexes and all the causes of oversensing especially discrete false signals generated by a defective pacemaker lead must be excluded before concealed ventricular extrasystoles can be postulated.