G.A. Myers

TL;DR: Heart rate variability was found to be reduced in cardiac patients known to be at increased risk of SCD, when compared to those not at increased Risk, suggesting that this method may be useful in categorizing cardiac patients according to risk of sudden cardiac death.

TL;DR: A generally stronger and negative relation was demonstrated between spectral and nonspectral measurements of HR variability, and indicators of sympathoexcitation, muscle sympathetic nerve activity and plasma norepinephrine.

TL;DR: The mechanisms for conduction and unidirectional block (UDB) in cardiac tissue under spatial changes in cell-to-cell coupling resistivity and resting potential were studied and discontinuities located in the border zone between normal and ischemic tissue can create exit block or propagation of a parasystolic focus.

TL;DR: Heart rate variability spectra exhibit diurnal variation consistent with physiologic expectation: respiratory sinus arrhythmia and to a lesser extent, the low-frequency spectral component are higher at night than in the daytime; the mid-frequency component is slightly higher during the day; and interpolation over ectopic beats increases the apparent power in low frequencies.

TL;DR: In this paper, the authors compared spectra of heart rate variability (HRV) computed from 24 and 48 hour Holter tapes on 34 patients with congestive heart failure, and found that HRV components in the low (0-0.05 Hz) and mid (0.15 Hz) frequency ranges were significantly (p > 0.