Comparison of Late Potentials for 24 Hours Between Brugada Syndrome and Arrhythmogenic Right Ventricular Cardiomyopathy Using a Novel Signal-Averaging System Based on Holter ECG

Abstract

Background— Late potentials (LP) detected with signal-averaged ECGs are known to be useful in identifying patients at risk of Brugada syndrome (BS) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Because the pathophysiology is clearly different between these disorders, we clarified the LP characteristics of these disorders. Methods and Results— This study included 15 BS and 12 ARVC patients and 20 healthy controls. All BS patients had characteristic ECG changes and symptomatic episodes. All ARVC patients had findings that were consistent with recent criteria. Three LP parameters (filtered QRS duration, root mean square voltage of the terminal 40 ms of the filtered QRS complex, and duration of low-amplitude signals [<40 µV] in the terminal, filtered QRS complex) were continuously measured for 24 hours using a novel Holter-based signal-averaged ECG system. The incidences of LP determination in BS (80%) and ARVC (91%) patients were higher than in healthy controls (5%; P <0.0001 in both) but did not differ between BS and ARVC patients. In BS patients, the dynamic changes of all LP parameters were observed, and they were pronounced at nighttime. On the contrary, these findings were not observed in ARVC patients. When the SD values of the 3 LP parameters (filtered QRS duration, root mean square voltage of the terminal 40 ms of the filtered QRS complex, and duration of low-amplitude signals [<40 µV] in the terminal, filtered QRS complex) over 24 hours were compared for the 2 patient groups, those values in BS patients were significantly greater than those in ARVC patients ( P <0.0001 in all). Conclusions— LP characteristics detected by the Holter-based signal-averaged ECG system over 24 hours differ between BS and ARVC patients. Dynamic daily variations of LPs were seen only in BS patients. This may imply that mechanisms of lethal ventricular arrhythmia in BS may be more correlated with autonomic abnormality than that of ARVC.

Signal‐averaged electrocardiography: Past, present, and future

“…Recent data derived from an ex vivo canine model challenge previous conclusions, attributing LPs to abnormal conduction or structural abnormalities in the RV epicardium; these experiments indicated that LPs in Brugada syndrome may be associated with the development of abnormal repolarization in the RV epicardium that can set the stage for concealed reentry . Interestingly, circadian periodicity has been noted in the presence of LPs; this observation, derived from Holter‐SAECG recordings, was characterized by increased incidence of LPs during the night, likely resulting from enhanced vagal tone . Based on this finding, LPs during nighttime, along with enhanced T‐wave amplitude variability, have been proposed as additional noninvasive risk‐stratification tools .…”

“…52 Interestingly, circadian periodicity has been noted in the presence of LPs; this observation, derived from Holter-SAECG recordings, was characterized by increased incidence of LPs during the night, likely resulting from enhanced vagal tone. 53 Based on this finding, LPs during nighttime, along with enhanced T-wave amplitude variability, have been proposed as additional noninvasive risk-stratification tools. 54 Nonetheless, further research is needed on this subject, prior to the clinical use of SAECG in Brugada syndrome.…”

Genotype–phenotype relationship and risk stratification in loss‐of‐function SCN5A mutation carriers

“…Finally, it is also well known that LP have important circadian variability in Brugada syndrome patients, especially in those with documented arrhythmias (Yoshioka et al., ). Furthermore, this circadian variability is absent in ARVC, another arrhythmogenic heart disease characterized by the presence of LP (Abe et al., ). Regarding fQRS, most studies used the definition proposed by Morita (Morita et al., ).…”

“…Furthermore, this circadian variability is absent in ARVC, another arrhythmogenic heart disease characterized by the presence of LP (Abe et al, 2012). Regarding fQRS, most studies used the definition proposed by Morita (Morita et al, 2008).…”

Brugada Syndrome

“…68 Recently, Abe et al found that fluctuations in LPs on signal-averaged ECG (SAECG) occurred predominantly at night, suggesting that conduction delay and, by inference, the arrhythmogenic substrate are autonomically modulated. 69 Therefore, it is plausible that at night during sleep, when vagal tone is usually increased and associated with the withdrawal of sympathetic activity, the VF substrate is modulated and more susceptible to arrhythmogenesis. Kasanuki et al also showed a sudden increase in vagal activity, as measured by heart rate variability (HRV), just before episodes of VF in a patient with BS.…”