RV Function in Stable and Unstable VT: Is There a Need for Hemodynamic Monitoring in Future Defibrillators?

Abstract

During electrophysiological investigation of 22 patients with VT or aborted sudden cardiac death, arterial and RV pressures were measured. The time courses of mean arterial pressure (MAP), RV pulse pressure (RVPP), RV pulse pressure integral (RVPPI), and maximum right ventricular dP/dt (RV dP/dtmax) were followed during the first 15 seconds after VT induction. Compared to basal (preinduction) conditions, the RVPPI decreased by 41+/-10% (mean +/- SD) after 10-15 seconds of VT in 11 patients with stable VT and by 75+/-8% in 11 patients with unstable VT (MAP < 60 mmHg 15 s after VT onset). RVPP decreased by 13+/-11% after 10-15 seconds of VT in the stable VT group and by 50+/-16% in the unstable VT group. For RV dP/dtmax, these decreases were 4+/-22% in the stable VT group and 37+/-24% in the unstable VT group. There was a good correlation between percent decrease in MAP and percent decrease in RVPPI, RVPP, and RV dP/dtmax at 5-10 seconds (r = 0.86, 0.81, and 0.73, respectively) and 10-15 seconds (r = 0.84, 0.82, and 0.69, respectively) after VT onset. There was hardly any overlap of distributions of the individual values with the RVPPI parameter between the two VT groups. Comparing and correlating the percent decrease in mean arterial pressure with the RVPPI, RVPP, and RV dP/dtmax during induced VT, RVPPI demonstrated the most significant and specific changes in discriminating stable from unstable rhythms. However, by comparing RVPPI and RVPP using the area under the receiver operating characteristic curves, there was no significant statistical difference between the two parameters. By integrating rate criteria, electrogram signal analysis, and RVPPI or RVPP as a hemodynamic criterion, detection and treatment algorithms could improve the performance of future implantable defibrillators and avoiding shocks in VTs that can be terminated by antitachycardia pacing.

Right Ventricular Pressure Changes During Induced Ventricular Tachycardias Predict Clinical Symptoms of Cerebral Hypoperfusion: Implications for a Reduction of Unnecessary, Painful ICD Shocks

“…The reduction of RV pulse pressure as a short‐term marker of untolerated VTs was previously described by Ellenbogen 18 et al 17 Our data confirm these results in a larger sample and in a different context. In particular, we used a set of clinical features to define untolerated VTs rather than the absolute decrease of mean AP below 60 mmHg.…”

“…A decrease of the absolute value of the mean AP below 60 mmHg has been used to define untolerated VTs in previous studies 17 . We verified the ability of this cut‐off point to discriminate tolerated and untolerated VTs, defined using our clinical criteria.…”

“…In previous studies, 17,18 RV pulse pressure integral was found to work even better than peak RV pulse pressure. We did not include this parameter in the analysis because of its high sensitivity to noise, making it unsuitable for a fully automatic analysis, at least in our series.…”

“…Since direct long‐term monitoring of the arterial pressure (AP) is not feasible, several indexes derived from right ventricular pressures (RVPs), transthoracic impedence, Doppler technique, or oxygen saturation were evaluated. In particular, the right ventricular (RV) pulse pressure and its integral were found to be highly correlated with the decrease of the mean AP in the first seconds after the VT onset 17 . However, no previous studies evaluated the correlation between changes in intravascular pressures and clinical symptoms of cerebral hypoperfusion early in the time‐course of VTs, a desirable information in order to define treatment urgency and the most appropriate, possibly painless, electrical therapy delivered by ICDs.…”

Hemodynamic sensing using subcutaneous photoplethysmography

“…The estimated optima derived from PPG and AoP were Clinical applications. Incorporation of a PPG sensor into the body or header of a pacemaker, implantable cardioverterdefibrillator (ICD), or hemodynamic monitor would avoid the need for special leads and implant procedures that other approaches to hemodynamic sensing require, e.g., intravascular pressure measurement (21). The potential clinical applications of subcutaneous PPG are numerous, and many represent revolutionary changes in diseases management.…”