Repolarization alternans associated with alcoholism and hypomagnesemia

Reddy, C.V.R.; Kiok, Joshua P.; Khan, Rahman; El‐Sherif, Nabil

doi:10.1016/0002-9149(84)90487-9

Cited by 60 publications

(11 citation statements)

References 5 publications

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“…3,25 In humans, using the T wave as a surrogate measure of the global repolarization characteristics, 26 Lewis 27 first reported that T wave alternation can occur during tachycardia. Subsequently, patients with long-QT syndrome, 28 Prinzmetal angina, 29 acute ischemia, 30 and electrolyte imbalances 31,32 have been found to exhibit a T wave alternation even during normal sinus rhythm. Rosenbaum et al 2 reported that the beat-tobeat T wave alternans over a broad range of physiological heart rates (95 to 150 bpm) served as a noninvasive marker of vulnerability to ventricular arrhythmias.…”

Section: Causal Relationship Between Alternans and Vfmentioning

confidence: 99%

Spatiotemporal Heterogeneity in the Induction of Ventricular Fibrillation by Rapid Pacing

Cao

Kim

et al. 1999

Circulation Research

200

176

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The mechanism by which rapid pacing induces ventricular fibrillation (VF) is unclear. We performed computerized epicardial mapping studies in 10 dogs, using 19-beat pacing trains. The pacing interval (PI) of the first train was 300 ms and then was progressively shortened until VF was induced. For each PI, we constructed restitution curves for the effective refractory period (ERP). When the PI was long, the activation cycle length (CL) was constant throughout the mapped region. However, as the PI shortened, there was an increase in the spatiotemporal complexity of the CL variations and an increase in the slope of the ERP restitution curve. In 5 dogs, we documented the initiation of VF by wavebreak at the site of long-short CL variations. Computer simulation studies using the Luo-Rudy I ventricular action potential model in simulated 2-dimensional tissue reproduced the experimental results when normal ERP and conduction velocity (CV) restitution properties were intact. By altering CV and ERP restitutions in this model, we found that CV restitution creates spatial CL variations, whereas ERP restitution underlies temporal, beat-to-beat variations in refractoriness during rapid pacing. Together, the interaction of CV and ERP restitutions produces spatiotemporal oscillations in cardiac activation that increase in amplitude as the PI decreases, ultimately causing wavebreak at the site of intrinsic heterogeneity. This initial wavebreak then leads to the formation of spiral waves and VF. These findings support a key role for both CV and ERP restitutions in the initiation of VF by rapid pacing.

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Section: Causal Relationship Between Alternans and Vfmentioning

confidence: 99%

Spatiotemporal Heterogeneity in the Induction of Ventricular Fibrillation by Rapid Pacing

Cao

Kim

et al. 1999

Circulation Research

200

176

View full text Add to dashboard Cite

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“…1 Previous studies show that TWA is a marker of electrical instability in humans and is associated with life-threatening ventricular tachyarrhythmias (VTs). 2 TWA is known to be associated with various conditions, such as long QT syndrome, 3 Prinzmetal angina, 4 acute ischemia, 5 marked electrolyte abnormalities, 6 and hypertrophic cardiomyopathy. 7 The duration from the peak of the T wave to the end of the T wave (Tpte) is associated with transmural dispersion of repolarization, which is also related to the vulnerability to ventricular arrhythmias.…”

mentioning

confidence: 99%

Defibillator Electrogram T Wave Alternans as a Predictor of Spontaneous Ventricular Tachyarrhythmias in Defibrillator Recipients

Kim

Pak

Park

et al. 2009

Circ J

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wave alternans (TWA), which is characterized by changes in the contour, amplitude or polarity of the T wave with regular rhythmicity, represents a temporal dispersion of repolarization. 1 Previous studies show that TWA is a marker of electrical instability in humans and is associated with life-threatening ventricular tachyarrhythmias (VTs). 2 TWA is known to be associated with various conditions, such as long QT syndrome, 3 Prinzmetal angina, 4 acute ischemia, 5 marked electrolyte abnormalities, 6 and hypertrophic cardiomyopathy. 7 The duration from the peak of the T wave to the end of the T wave (Tpte) is associated with transmural dispersion of repolarization, which is also related to the vulnerability to ventricular arrhythmias. 8 Tsai et al reported that TWA was a predictor of VT in a canine model of sudden cardiac death using intracardiac electrograms obtained from an implantable cardioverter defibrillator (ICD). 9 However, no one has previously investigated whether TWA and Tpte immediately precede or follow spontaneous VT in the human ambulatory setting. We hypothesized that TWA and the Tpte interval measured from the stored electrograms of ICD recipients would become prominent immediately before the spontaneous onset of clinical VTs. The purpose of this study was to determine whether TWA and the Tpte interval were measurable in the electrograms from ICD recipients, and if they were closely related to clinical VT. MethodsThis study was approved by the Institutional Review Board of Korea University Anam Hospital, and informed consent was given by each patient. Patient EnrollmentWe included 74 patients (age 55.3±12.2 years, males 79.7%) who had implanted ICDs. All patients had the transvenous-type ICD, and 5 of them underwent cardiac resynchronization therapy with a defibrillator. The ICD profiles were as follows: VENTAK MINI (Guidant Inc, Indianapolis, IN, USA), PRISM2 (Guidant Inc), GEM 7227 (Medtronic Inc, Minneapolis, MN, USA), GEM DR 7271 (Medtronic Inc), and Profile MD (St Jude Inc, Saint Paul, MN, USA). At a mean follow-up duration of 32.2±18.6 months, 17 patients had experienced 161 appropriate ICD therapies, and 5 patients received 6 inappropriate ICD shocks. Four patients with appropriate ICD therapies experienced ICD storms (>20 episodes per day). 10 Classification of ICD ElectrogramsThe total number of acquired stored ICD electrograms with tachycardia events was 167 (161 appropriate therapies, 6 inappropriate therapies). Taken together with 205 episodes of ICD shocks recorded during the measurement of (Received March 26, 2008; revised manuscript received August 22, 2008; accepted August 26, 2008; released online November 27, 2008 Defibillator Electrogram T Wave Alternans as a Predictor of Spontaneous Ventricular Tachyarrhythmias in Defibrillator RecipientsJin Won Kim, MD, PhD; Hui-Nam Pak, MD, PhD; Jae Hyung Park, BSc; Gi-Byoung Nam, MD, PhD*; Sook Kyoung Kim, MSc; Hyun Soo Lee, MPH;Jin Kun Jang, MD; Jong Il Choi, MD; Young-Hoon Kim, MD, PhDBackground Although T wave alternans (TWA) and the T ...

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“…Note that the second "short" cycle is actually the interrupted QT interval of the last supraventricular beat (shown by a star). The broken arrow indicates QTU deformity of this beat, most evident in the lower tracing Reddy et al 1984 cardiovascular" therapies (Roden 2004a). Indeed, QT prolongation and torsades de pointes have been the single most common cause of withdrawal of marketed drugs in the past decade.…”

Section: Clinical Featuresmentioning

confidence: 99%

Proarrhythmia

Roden

Anderson

Basis and Treatment of Cardiac Arrhythmias

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Repolarization alternans associated with alcoholism and hypomagnesemia

Cited by 60 publications

References 5 publications

Spatiotemporal Heterogeneity in the Induction of Ventricular Fibrillation by Rapid Pacing

Spatiotemporal Heterogeneity in the Induction of Ventricular Fibrillation by Rapid Pacing

Defibillator Electrogram T Wave Alternans as a Predictor of Spontaneous Ventricular Tachyarrhythmias in Defibrillator Recipients

Proarrhythmia

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