1990s: EP and pacing

In the last decade of the twentieth century, HRS experienced many technical advances that simplified the diagnostics of the specialty, including computerized electrogram waveform acquisition, retrieval, and archiving (transitioning from paper recording systems), multielectrode surgical mapping (from single point probe mapping), and intracardiac device electrogram storage. The pacemaker and the ICD were integrated into one device. Due to biphasic waveform development, the ICD was miniaturized, and with the laser sheath, device lead extraction was enhanced and simplified. Akin to the 1970s-1980s, when pacemaker implantation migrated from the operating theater to the catheterization laboratory, the same occurred in the 1990s for ICD implantation and most cardiac ablations, including AVNRT, AT, WPW, and VT. AF ablation begins in the mid-decade. Mayo clinical databases continue to allow Mayo investigators charting of longitudinal follow-up of arrhythmias in a variety of well-defined populations over extended periods of time: surgically corrected tetralogy of Fallot, Wolff-Parkinson-White syndrome, sudden death in epilepsy, AF-generated tachycardia-induced cardiomyopathy, childhood syncope, and sudden death in young adults. The merger of patient genotyping and phenotyping (LQTS) emerges and will prove to be a powerful tool in the quest to risk stratify patients for advanced therapies beyond medications, like ICDs, stellate ganglionectomy, and catheter ablation.