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Cardiac implantable electronic devices (CIEDs) generate substantial data, often stored in image or PDF formats. Remote monitoring, now an integral component of patient care, places considerable administrative burdens on clinicians and staff, in large part due to the challenge of integrating these data seamlessly into electronic health records. Since 2006, the Heart Rhythm Society, in collaboration with the CIED industry, has led an initiative to establish a unified standard nomenclature. This effort has harmonized terminology, aligning diverse terms with single terms approved by the Institute of Electrical and Electronics Engineers. With this foundational work complete, attention now turns to developing technical standards for interoperability, which would enable the smooth communication of CIED data between information technology systems used in clinical practice. In this article, by leveraging Health Level 7 Fast Healthcare Interoperability Resources, we present a road map for the technical committee to guide this endeavor. We identify critical data exchange points between remote transceivers, electronic health records, and third-party platforms commonly used for CIED patient data management. Our objective is to establish bidirectional communication among these resources, ensuring the accuracy, timeliness, and accessibility of clinical data for clinicians. We also anticipate substantial benefits for both clinical research and administrative efficiency through the implementation of this interoperability framework.

The most frequently proposed mechanism for vasodepressor syncope is based on cardiac mechanoreceptor activation by augmented sympathetic tone. Because of the central role of the autonomic nervous system in this response, we hypothesized that the responses of the sympathetic ana parasympathetic nervous systems (as assessed by analysis or heart rate variability) to orthostatic stress would differentiate patients with a positive from those with a negative tilt-table response. We therefore evaluated 28 patients undergoing tilt-table testing for presumed vasodepressor syncope. Based on 5-minure electrocardiographic samples obtained during the supine and upright phases (without isoproterenol infusion), we computed the mean RR interval, reflecting integrated cardiac sympathetic and parasympathetic tone, as well as the root-mean-square of successive differences of the RR intervals (RMSSD), a measure of high-frequency heart rate variability that is correlated with parasympathetic tone. Eleven patients had a negative and 17 a positive tilt response. There were no differences between the groups at baseline. In response to upright tilt, the mean RR decreased by a similar magnitude in both groups. In contrast, RMSSD decreased by 36% (p = 0.05) in response to upright tilt in patients with a negative response, but did not change significantly in patients with a positive tilt response. Absence or a decrease in RMSSD in response to orthostatic stress had 100% specificity and 41% sensitivity for predicting a positive test result. Thus, failure of withdrawal of parasympathetic tone (as assessed by RMSSD) during upright tilt predicts a positive tilt response. These results suggest that a greater increase in sympathetic tone is necessary in these patients to maintain heart rate and blood pressure in response to orthostasis, and are consistent with the hypothesis that augmented sympathetic tone may be central to the development of vasodepressor syncope.

In nonlinear dynamics, chaos refers to a system that is aperiodic but deterministic (nonrandom). Although the ventricular response during atrial fibrillation (AF) is commonly described as chaotic, it has yet to be demonstrated that this represents chaos in the mathematical sense. A defining characteristic of chaotic systems is sensitive dependence on initial conditions; i.e. similar sequences evolve similarly in the near future, but then diverge exponentially. We developed a nonlinear predictive forecasting algorithm to search for evidence of short-term predictability and sensitive dependence on initial conditions in recordings of 2000 ectopy-and artifact-free RR intervals obtained during routine activity in 5 pts with AF. The algorithm: 1) uses the technique of lags to reconstruct phase spaces with embedding dimensions from 3 to 10,2) the 3 nearest neighbors of a given trajectory are used to predict the evolution of the trajectory from 1 to 10 intervals into the future and 3) the correlation coefficient between predicted and actual evolution is computed for all RR intervals in the time series. The results were compared to test sequences from linear oscillators with high and low signal-noise ratios and a system with chaotic dynamics (the logistic map). Distinct from each of the test sets, the ventricular response in AF was only weakly predictable at all time scales, and did not exhibit sensitive dependence on initial conditions.

Although β-blockers are preferred agents for therapy of vasodepressor syncope (VDS), they are not uniformly effective and their mechanism of action is incompletely understood. Since we have previously shown a differential therapeutic response to β-blocker therapy between pts with isoproterenol-independent [iso(-)] and isoproterenol-dependent [iso(+)] VDS during tilt table testing we sought to determine whether this was due to a differential heart rate (HR) response to orthostasis during β-blockade. We therefore examined immediate HR and blood pressure responses to upright tilt before and after initiation of therapy with atenolol (12.5–50mg daily) in 62 pts with VDS and positive tilt tests. The protocol comprised upright tilt (60°) for up to 60min followed by repeat tilt for 15min during isoproterenol (iso) infusion. Supine HR, mean arterial pressure (MAP) and pulse pressure (PP) were determined as the mean of 3 consecutive 1-min samples during supine rest; orthostatic HR, MAP, and PP were the mean of the samples recorded in the first 3min after upright tilt (before infusion of iso). Response to atenolol required completion of tilt with and without infusion of iso. There were 15 iso(-) pts and 47 iso(+) pts. The groups did not differ significantly in blood pressure response (MAP, PP) to orthostasis. Supine HR fell and the ΔHR in response to orthostasis was blunted during therapy in both groups:Baseline (Mean ± SD)Rx (Mean ± SD)Iso(+)Iso(-)pIso(+)Iso(-)pSupine HR69±1368±9NS57±958±8NSOrthostatic ΔHR8±712±9NS3±53±4NS

A major complication of radiofrequency catheter ablation is thromboembolism, although the mechanism underlying this is unknown. We compared coagulation factor activation during catheter ablation and diagnostic electrophysiologic study and sought to determine whether IV heparin is effective in preventing it.