Modulation of Electrical Microvolt Level T-Wave Alternans and Left Ventricular Late Potentials Evaluated by Heart Rate Variability Indices, QT Dispersion, and Plasma Catecholamine Levels

2000 ◽  
Vol 5 (3) ◽  
pp. 262-269
Author(s):  
Akira Kurita ◽  
Takemi Matsui ◽  
Toshiaki Ishizuka ◽  
Bonpei Takase ◽  
Kimio Satomura
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Qt Dispersion ◽  
Left Ventricular ◽  
Plasma Catecholamine ◽  
Late Potentials ◽  
Ventricular Late Potentials ◽  
T Wave ◽  
T Wave Alternans ◽  
Catecholamine Levels

P991Predicting arrhythmic risk in dilated cardiomyopathy: a systematic review & meta-analysis of clinical parameters

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Sammani ◽  
E Kayvanpour ◽  
L P Bosman ◽  
F Sedaghat-Hamedani ◽  
T Proctor ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Risk ◽  
Dilated Cardiomyopathy ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Gadolinium Enhancement ◽  
T Wave ◽  
History Of ◽  
T Wave Alternans

Abstract Background Patients with non-ischemic dilated cardiomyopathy (NIDCM) are at increased risk of ventricular arrhythmias and sudden cardiac death (SCD). However, identifying patients at high risk for life-threatening ventricular arrhythmia (LTVA) who may benefit from an implantable cardioverter defibrillator (ICD) remains challenging. Methods We searched MEDLINE and EMBASE for prognostic studies describing predictors of LTVA (defined as sustained ventricular tachycardia (VT), haemodynamically unstable VT, ventricular fibrillation, (aborted) SCD or appropriate ICD intervention) in patients with NIDCM. We excluded articles with composite heart failure and arrhythmic endpoints but lacking (subgroup) analysis for LTVA. Study quality and risk of bias was assessed using the QUIPS-tool, and articles with high risk of bias in ≥2 areas were excluded from analysis. Univariable hazard ratios of reported predictors were pooled from the remaining studies in a meta-analysis using a random-effects model and presented with 95% confidence interval (CI). Results Out of 1996 unique citations, 51 studies were included comprising 9798 patients with 1493 arrhythmic events. 28 studies were pooled for meta-analysis (mean age 55±4.1 years, 72% male) with a mean follow-up of 3.7±1.9 years. Crude event rate was 4.3% (95% CI 4.02–4.57) per year. From our meta-analysis, hypertension (HR 1.95; CI [1.26–3.00]), history of out of hospital cardiac arrest or sustained VT (HR 4.15; CI [1.32–13.02]), T-wave alternans (HR 6.50; CI [2.46–17.14]), LVEDV per 10ml/m2 increase (HR 1.10; CI [1.10–1.10]), LVESV per 10ml/m2 increase (HR 1.10; CI [1.00–1.22]) and delayed gadolinium enhancement (HR 5.55; CI [4.02–7.67]) were significantly associated with LTVA (figure). The quality of evidence was moderate and there was significant heterogeneity (median i2 57%; IQR 76%) among studies. Additionally from data that could not be pooled, decreased LVEF, history of nsVT and decreased heart rate variability were significantly associated with LTVA. Summary of meta-analysis results Conclusion The risk of LTVA in NIDCM is 4.3% per year and is considerably higher in patients with hypertension, history of LTVA, decreased LVEF, high LVEDV, high LVESV, T-wave alternans, history of nsVT, decreased heart rate variability and delayed gadolinium enhancement. These results may help determine appropriate candidates for ICD implantation. The high heterogeneity in reported results indicate the need for future multicentre studies to further improve risk stratification in NIDCM. Acknowledgement/Funding ERA-CVD JTC2016: DETECTIN-HF, 680969 & Dutch Heart Foundation (2016T096)

scholarly journals No modulation of postprandial metabolism by transcutaneous auricular vagus nerve stimulation: a cross-over study in 15 healthy men

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Andreas Vosseler ◽  
Dongxing Zhao ◽  
Louise Fritsche ◽  
Rainer Lehmann ◽  
Konstantinos Kantartzis ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Vagus Nerve Stimulation ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Plasma Catecholamine ◽  
Oral Glucose Tolerance ◽  
Catecholamine Levels

AbstractExperimental evidence suggests a crucial role of the autonomic nervous system in whole body metabolism with major regulatory effects of the parasympathetic branch in postprandial adaptation. However, the relative contribution of this mechanism is still not fully clear in humans. We therefore compared the effects of transcutaneous auricular vagus nerve stimulation (taVNS, Cerbomed Nemos) with sham stimulation during an oral glucose tolerance test in a randomized, single-blind, cross-over design in 15 healthy lean men. Stimulation was performed for 150 min, 30 min before and during the entire oral glucose tolerance test with stimulation cycles of 30 s of on-phase and 30 s of off-phase and a 25 Hz impulse. Heart rate variability and plasma catecholamine levels were assessed as proxies of autonomic tone in the periphery. Neither analyzed heart rate variability parameters nor plasma catecholamine levels were significantly different between the two conditions. Plasma glucose, insulin sensitivity and insulin secretion were also comparable between conditions. Thus, the applied taVNS device or protocol was unable to achieve significant effects on autonomic innervation in peripheral organs. Accordingly, glucose metabolism remained unaltered. Therefore, alternative approaches are necessary to investigate the importance of the autonomic nervous system in postprandial human metabolism.

Assessment and clinical relevance of the dynamic parameters of ventricular repolarization in patients with grade I left ventricular diastolic dysfunction

2019 ◽  
Vol 97 (6) ◽  
pp. 577-580
Author(s):  
Antoinette Oliveira Blackman ◽  
José Sobral Neto ◽  
Melchior Luiz Lima ◽  
Tânia Maria Andrade Rodrigues ◽  
Otoni Moreira Gomes
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Diastolic Dysfunction ◽  
Qt Dispersion ◽  
Left Ventricular Diastolic Dysfunction ◽  
Left Ventricular ◽  
Ventricular Repolarization ◽  
Premature Ventricular Complex ◽  
Increased Risk ◽  
Ventricular Diastolic Dysfunction

Imbalance in ventricular repolarization parameters are related to increased risk of severe arrhythmia and sudden cardiac death. There is limited research regarding markers to detect patients at risk in this early stage. We aimed to assess the influence of grade I left ventricular diastolic dysfunction on repolarization parameters in asymptomatic patients. Ambulatory patients with grade I left ventricular diastolic dysfunction were studied and compared with a control group. We assessed the QT dispersion circadian variation, heart rate variability in the time and frequency domains, and dynamics of QT using a 12-lead Holter. In the diastolic dysfunction group, 8 (30%) patients had QT dispersion > 80 ms. One (3.8%) patient presented premature ventricular complex > 10/h. The comparison between the 2 groups showed that the difference between the standard deviation of normal-to-normal intervals and low frequency power in both groups was statistically significant. We therefore conclude that increased parameters of ventricular repolarization and depressed heart rate variability reflect an imbalance in autonomic responses in patients with grade I left ventricular diastolic dysfunction without cardiovascular symptoms, enabling the identification of patients that are at a higher risk for cardiovascular events.

Abstract 2148: Abnormal T Wave Alternans Could Provide Additional Risk Stratification in Patients with Prolonged QRS Duration

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Takanao Mine ◽  
Tetsuzou Kanemori ◽  
Hiroaki Nakamura ◽  
Tohru Masuyama ◽  
Mitsumasa Ohyanagi
Keyword(s):  
Heart Rate ◽  
Risk Stratification ◽  
Cardiac Death ◽  
Heart Diseases ◽  
Qt Dispersion ◽  
Additional Risk ◽  
T Wave ◽  
Life Threatening ◽  
Qrs Duration ◽  
T Wave Alternans

QT dispersion, signal averaged electrocardiogram (SAECG) and T wave alternans (TWA) have been found to be increased susceptibility to life-threatening arrhythmias or cardiac death (LTA/CD). Patients with heart diseases often present prolonged QRS duration (p-QRSd), however the risk stratification in patients with p-QRSd still remains. We investigated whether QT dispersion, SAECG and TWA would provide additional risk stratification in patients with p-QRSd. We studied 52 patients (47 males, mean age 66±9 yrs) with QRS duration ≥ 120ms (34 RBBB type and 18 LBBB type) who had heart diseases (45 coronary artery disease and 7 dilated cardiomyopaty). QT dispersion was measured from standard 12-lead ECG. The filtered QRS duration (f-QRS) and root mean square voltage of the terminal 40ms of the QRS complex (RMS40) were obtained by SAECG. TWA was measured with the CH 2000. TWA was considered positive when the alternans with alternans voltage ≥ 1.9μV and alternance ratio ≥ 3 was sustained ≥ 1 minute in vector magnitude, X, Y, Z, V4 or two precordal leads at heart rate ≤ 110bpm. TWA was classified negative when the alternans wasn’t presented at heart rate ≤ 110bpm and considered indeterminate if the record didn’t meet either positively or negatively. Abnormal TWA was defined as positive or indeterminate. An abnormal TWA test was present in 56% (23 patients had negative TWA, 11 had indeterminate and 18 had positive). During the follow-up periods (69±41 months), 15 patients had life-threatening arrhythmias (n=12) and/or cardiac death (n=7). Univariate analysis revealed left ventricular ejection fraction (LVEF), RMS40 and abnormal TWA (n=29) as significant variables, however there was no significant difference in LTA/CD rate between BBB types, and no associations between QT dispersion and LTA/CD. On logistic regression analysis, only LVEF (p=0.02) and abnormal TWA (p=0.02, odds ratio 9.803 [95%CI 1.430 to 67.207]) were independently associated with LTA/CD. Abnormal T wave alternans could provide additional risk stratification in patients with prolonged QRS duration.

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