Novel indexes of heterogeneity of ventricular repolarization in subjects with early repolarization pattern (original) (raw)
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Exercise electrocardiographic mapping in normal subjects
Journal of Electrocardiology, 1985
To investigate the spectrum of change in multiple-lead exercise electrocardiograms, 120-lead body surface potential maps (BSPM) in normal adult subjects during upright, graded, submaximal exercise testing were recorded. Results showed that in the normal group, exercise was associated with substantial electrocardiographic changes on the body surface, many of which persisted during early recovery. The QRS waveform was minimally altered during exercise. Despite, however, no change in QRS duration, there was significant reduction in QRS potential range with consequent reduction QRS integral value. The ST waveforms changed markedly with exercise, showing abbreviated duration and increased slope. This was reflected by significantly increased ST potential range from rest to immediate cessation of exercise, which returned towards resting value during recovery. The effect of the altered ST-segment waveform was also reflected in torso potential distributions at two time instants during the ST-segment. When a spatially-fixed position on the ST-T waveform was evaluated (ST-segment offset), exercise resulted in small potential changes, especially over the torso area occupied by the standard V l to V 6 chest leads. However, when a temporally-fixed point (80 ms after QRS offset) was evaluated, there were large increases in potential over the precordium with exercise. Isointegral STsegment maps, which reflect both spatial and temporal ST properties, showed that exercise was associated with substantial decreases in values over the precordium and inferior torso, and although diminished, they tended to persist through five minutes of recovery. Thus, electrocardiographic repolarization parameters are particularly affected by physiological exercise and, although the underlying causes of these changes remain undefined, they should be taken into account when evaluating the population at risk.
QRS-T morphology measured from exercise electrocardiogram as a predictor of cardiac mortality
Europace, 2011
Total cosine R-to-T (TCRT) measured from the standard 12-lead electrocardiogram (ECG) reflects the spatial relationship between depolarization and repolarization wavefronts and a low TCRT value is a marker of poor prognosis. We tested the hypothesis that measurement of TCRT or QRS/T angle from exercise ECG would provide even more powerful prognostic information.
Exercise worsening of electromechanical disturbances: a predictor of arrhythmia in long qt syndrome
Clinical Cardiology
Background: Electromechanical (EM) coupling heterogeneity is significant in long QT syndrome (LQTS), particularly in symptomatic patients; EM window (EMW) has been proposed as an indicator of interaction and a better predictor of arrhythmia than QTc. AIM: To investigate the dynamic response of EMW to exercise in LQTS and its predictive value of arrhythmia. METHODS: Forty-seven LQTS carriers (45±15 years, 20 with arrhythmic events) and 35 controls underwent exercise echocardiogram. EMW was measured as the time difference between aortic valve closure on Doppler and the end of QT interval on the superimposed ECG. Measurements were obtained at rest, peak exercise (p.e.) and 4 minutes into recovery. RESULTS: Patients did not differ in age, gender, heart rate or LV ejection fraction but had a negative resting EMW compared to controls (-42±22 vs 17±5ms, p<0.0001). EMW became more negative at p.e. (-89±43 vs 16±7ms, p=0.0001) and recovery (-65±39 vs 16±6ms, p=0.001) in patients, particularly the symptomatic, but remained unchanged in controls. P.e. EMW was a stronger predictor of arrhythmic events than QTc (AUC:0.765 vs 0.569, P<0.001). B-Blockers did not affect EMW at rest but was less negative at p.e. (BB:-66±21 vs no-BB:-113±25ms, p<0.001). LQT1 patients had worse p.e. EMW negativity than LQT2. CONCLUSION: LQTS patients have significantly negative EMW, which worsens with exercise. These changes are more pronounced in patients with documented arrhythmic events and decrease with B-blocker therapy. Thus, EMW assessment during exercise may help improve risk stratification and management of LQTS patients.
Significance of T wave normalization in the electrocardiogram during exercise stress test
American Heart Journal, 1987
Signifiicance df T wave atien in the electrocardiogram during exercise ~WBGS teat Although normaliratlon of previously inverted T waves in the ECG is not uncommon during exercise treadmill testing, the cllnical significance of this finding is still unclear. This was investigated in 45 patients during thallium-201 exercise testing. Patients with secondary 1 wave abnormalities on the restlng ECG and ischemlc exercise ST segment depression were excluded. On the thallium-201 scani, the left ventricle was divided Into anterior-septal and Inferior-porterlor segments; these were considered ciqulvalent to T wave changes in leads V, and VI, and aV,, respectively. A positive thallium-201 scan was found in 43 of 45 (96%) patients and In 49 of 52 (94%) cardiac segments that showed 1 wave normalization. When thallium scans and T wave changes were matched to sites of involvement, 76%~ of T wave normalization In lead aV, was associated with positive thallium scans In the inferior-Posterior segments, and 77% of T wave normalization in V, and Vs was associated with posltive thallirim scans in the anterior-septal segments. These site correlations were similar for reveisible and fixed thQlum defects, and for patients not on dlgoxin therapy. Similar correlations were noted for the sites of T wave chaliges and coronary artery lesions in 12 patients who had angiography. In patienti with a high prevalence for coronary artery disease, exercise T wave normalkatfon is highly specific for the presence of the disease. In addition, it represents predominantly either previouk injury or exercise-induced ischemic changes over the site of ECG involvement, rather than reciprocal changes of the opposite ventiicular wall.
Outcomes in athletes with marked ECG repolarization abnormalities
New England Journal …, 2008
Background Young, trained athletes may have abnormal 12-lead electrocardiograms (ECGs) without evidence of structural cardiac disease. Whether such ECG patterns represent the initial expression of underlying cardiac disease with potential long-term adverse consequences remains unresolved. We assessed long-term clinical outcomes in athletes with ECGs characterized by marked repolarization abnormalities. Methods From a database of 12,550 trained athletes, we identified 81 with diffusely distributed and deeply inverted T waves (≥2 mm in at least three leads) who had no apparent cardiac disease and who had undergone serial clinical, ECG, and echocardiographic studies for a mean (±SD) of 9±7 years (range, 1 to 27). Comparisons were made with 229 matched control athletes with normal ECGs from the same database. Results Of the 81 athletes with abnormal ECGs, 5 (6%) ultimately proved to have cardiomyopathies, including one who died suddenly at the age of 24 years from clinically undetected arrhythmogenic right ventricular cardiomyopathy. Of the 80 surviving athletes, clinical and phenotypic features of hypertrophic cardiomyopathy developed in 3 after 12±5 years (at the ages of 27, 32, and 50 years), including 1 who had an aborted cardiac arrest. The fifth athlete demonstrated dilated cardiomyopathy after 9 years of follow-up. In contrast, none of the 229 athletes with normal ECGs had a cardiac event or received a diagnosis of cardiomyopathy 9±3 years after initial evaluation (P = 0.001). Conclusions Markedly abnormal ECGs in young and apparently healthy athletes may represent the initial expression of underlying cardiomyopathies that may not be evident until many years later and that may ultimately be associated with adverse outcomes. Athletes with such ECG patterns merit continued clinical surveillance.
European Journal of Applied Physiology, 2022
The cardiac T-wave peak-to-end interval (Tpe) is thought to reflect dispersion in ventricular repolarisation, with abnormalities in Tpe associated with increased risk of arrhythmia. Extracellular K + modulates cardiac repolarisation and since arterial plasma K + concentration ([K + ]) rapidly increases during and declines following exercise, we investigated the relationship between [K + ] and Tpe with exercise. Methods Serial ECGs (Tpe, Tpe/QT ratio) and [K + ] were obtained from 8 healthy, normokalaemic volunteers and 22 patients with end-stage renal disease (ESRD), at rest, during and after exhaustive exercise. Results Post-exercise [K + ] nadir was 3.1 ±0.1, 5.0 ±0.2 and 4.0 ±0.1 mmol.L-1 (mean ± SEM) for healthy participants and ESRD patients before and after HD, respectively. In healthy participants, compared to pre-exercise, recovery-induced low [K + ] was associated with a prolongation of Tpe (110 ±8 vs. 87 ±5 ms, respectively, p=0.03) and an increase in Tpe/QT ratio (0.28 ±0.01 vs. 0.23 ±0.01, respectively, p=0.01). Analyses of serial data revealed [K + ] as a predictor of Tpe in healthy participants (β =-0.54 ±0.11, p=0.0007), in ESRD patients (β =-0.72 ±0.1, p < 0.0001) and for all data pooled (β =-0.64 ±0.52, p = 0.0007). The [K + ] was also a predictor of Tpe/QT ratio in healthy participants and ESRD patients. Conclusions Tpe and Tpe/QT ratio are predicted by [K + ] during exercise. Low [K + ] during recovery from exercise was associated with increased Tpe and Tpe/QT, indicating accentuated dispersion of ventricular repolarisation. The findings suggest that variations in [K + ] with physical exertion may unmask electrophysiological vulnerabilities to arrhythmia.
Journal of Electrocardiology, 1996
Consecutive electrocardiographic (ECG) analysis is very useful in acute coronary ischemia, but it is known that ECG patterns can be misleading in subjects with left ventricular hypertrophy, mainly during the repolarization phase. An automated system was developed to collect, store, and follow-up all heterogeneous data concerning a cohort of 1,898 subjects (1,039 men), 45-65 years old, 50% of whom were physically active. The reliability of several ECG markers of ischemia was tested during chronic follow-up study (1993)(1994)(1995) in 23 healthy, sedentary men without hypertension (group 1) recorded in our database, as well as in 9 subjects performing regular sporting activity (SA) (group 2). The same parameters were evaluated in the intensive care unit in nine patients affected by coronary artery disease, during either successful or unsuccessful thrombolytic therapy of acute myocardial infarction (AMI) (group 3). Twelve-lead ECGs were recorded, analyzed by the Hannover ECG system program, compressed, and stored according to the Standard Communication Protocol in each of the three groups. The changes in ST amplitude 20, 60, and 80 ms after the J point were very small in each subject of groups 1 and 2, while upsloping from 1 to 10 mm in several leads was observed slowly, rapidly, or intermittently in group 3 patients during ischemia. The ST slope and the concordance of the T wave and ST amplitude were helpful in differentiating normal and SA subjects from AMI patients. These results, obtained in resting conditions, underline that the difference among ST-T abnormalities in subjects with left ventricular hypertrophy due to SA are consistently different from those observed in patients with AMI. The serial digital ECG can be helpful to underline these differences. Key words: ST amplitude, T amplitude, ST slope, sports, acute myocardial infarction.
The American Journal of Cardiology, 2013
Negative T waves (NTWs) in right precordial leads (V 1 to V 3 ) may be observed on the electrocardiogram (ECG) of healthy subjects but can also represent the hallmark of an underlying arrhythmogenic right ventricular cardiomyopathy (ARVC). It has been a consistent observation that NTWs usually become upright with exercise in healthy subjects without underlying heart disease. No systematic study has evaluated exerciseinduced changes of NTWs in ARVC. We assessed the prevalence and relation to the clinical phenotype of exercise-induced right precordial NTWs changes in 35 patients with ARVC (19 men, mean age 22.2 -6.2 years). Forty-one healthy subjects with right precordial NTWs served as controls. At peak of exercise (mean power 149 -43 W, mean heart rate 83.6 -12.6% of target), NTWs persisted in 3 patients with ARVC (9%), completely normalized in 12 (34%), and partially reverted in 20 (57%). Patients with ARVC with or without NTWs normalization showed a similar clinical phenotype. The overall prevalence of right precordial T waves changes during exercise (normalization plus partial reversal) did not differ between patients with ARVC and controls (92% vs 88%, p [ 1.0), whereas there was a statistically nonsignificant trend toward a greater prevalence of complete normalization in controls (56% vs 34%, p [ 0.06). In conclusion, our study demonstrated that right precordial NTWs partially or completely revert with exercise in most patients with ARVC, and NTWs normalization is unrelated to the clinical phenotype. Exercise-induced NTWs changes are inaccurate in differentiating between ARVC patients and benign repolarization abnormalities. Ó 2013 Elsevier Inc. All rights reserved. (Am J Cardiol 2013;112:411e415)