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- Aunes-Jansson, Maria, et al.
(författare)
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T wave inversions following ablation of 125 posteroseptal accessory pathways
- 2006
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Ingår i: Int J Cardiol. - : Elsevier BV. - 0167-5273. ; 106:1, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cardiac memory, electrophysiological remodeling induced by periods of altered ventricular activation, has been observed after resumption of normal activation following ablation of overt accessory pathways. We studied the occurrence and temporal characteristics of cardiac memory (inferior T wave inversions) after ablation of overt posteroseptal accessory pathways. METHODS: T wave changes were assessed in the frontal plane (leads II, aVF, and III) up to one year after the ablation in 125 consecutive patients. T wave polarity immediately after ablation was compared with the pre ablation delta wave polarity and the dominant QRS force in each lead. The number of inferior leads (0-3) with post ablation T wave changes (estimate of degree of cardiac memory) was analyzed in relation to estimates of the degree of preexcitation (accessory pathway refractoriness and QRS duration) prior to ablation. RESULTS: Electrocardiogram (ECG) signs of cardiac memory were present in 123 (98%) of the patients within one day after ablation. The post ablation T wave vector had the same direction as the vector of the pre-excited QRS complex (and delta wave) creating inferior T wave inversions. There was no correlation between the degree of preexcitation pre ablation and the extent of cardiac memory post ablation. A majority (about 90%) of ECGs recorded 3-6 months after the procedure, showed complete or almost complete normalization. CONCLUSIONS: T wave inversions were present in the vast majority of patients, persisted in some patients beyond 3 months, and might be misinterpreted as inferior wall ischemia.
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- Engels, E. B., et al.
(författare)
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The synthesized vectorcardiogram resembles the measured vectorcardiogram in patients with dyssynchronous heart failure
- 2015
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 0022-0736 .- 1532-8430. ; 48:4, s. 586-592
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Tidskriftsartikel (refereegranskat)abstract
- Background: The use of vectorcardiography (VCG) has regained interest, however, original Frank-VCG equipment is rare. This study compares the measured VCGs with those synthesized from the 12-lead electrocardiogram (ECG) in patients with heart failure and conduction abnormalities, who are candidate for cardiac resynchronization therapy (CRT). Methods: In 92 CRT candidates, Frank-VCG and 12-lead ECG were recorded before CRT implantation. The ECG was converted to a VCG using the Kors method (Kors-VCG) and the two methods were compared using correlation and Bland-Altman analyses. Results: Variables calculated from the Frank- and Kors-VCG showed correlation coefficients between 0.77 and 0.90. There was a significant but small underestimation by the Kors-VCG method, relative bias ranging from -1.9%+/- 4.6% (QRS-T angle) to -9.4%+/- 20.8% (T area). Conclusion: The present study shows that it is justified to use Kors-VCG calculations for VCG analysis, which enables retrospective VCG analysis of previously recorded ECGs in studies related to CRT. (C) 2015 Elsevier Inc. All rights reserved.
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- Nowinski, K., et al.
(författare)
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Pacing-induced electrophysiological remodeling in hypertrophic obstructive cardiomyopathy--observations on cardiac memory
- 2005
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Ingår i: Pacing Clin Electrophysiol. - : Wiley. - 0147-8389 .- 1540-8159. ; 28:6, s. 561-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hypertrophic cardiomyopathy carries an increased risk for sudden cardiac death. While pacing therapy reduces the left ventricular outflow tract gradient and improves symptoms in a subgroup of hypertrophic obstructive cardiomyopathy (HOCM) patients, its electrophysiological consequences are unknown and were therefore assessed in this prospective study. METHODS AND RESULTS: Fifteen consecutive HOCM patients were studied and compared with 14 patients without HOCM paced because of sinus bradycardia. ECG intervals were measured before pacemaker implantation and after > or =3 months of DDD pacing in HOCM patients and > or =5 weeks in controls. Both groups showed similar ECG signs of cardiac memory development. In HOCM patients, with baseline QTc 447 +/- 33 ms, cardiac memory development was not associated with any significant changes in ECG intervals. In contrast, baseline repolarization in control patients was significantly prolonged by 6% (QTc 429 +/- 33 vs 454 +/- 46 ms; P < 0.05). Furthermore, in HOCM patients repolarization was 7% shorter during DDD pacing compared to sinus rhythm (JTc 329 +/- 25 vs 353 +/- 21 ms; P < 0.05), despite a significantly prolonged ventricular activation time (QRS duration 155 +/- 16 vs 91 +/- 9 ms; P < 0.01). CONCLUSIONS: Importantly, the development of cardiac memory-induced different repolarization responses depending on baseline structure and electrophysiology. In HOCM patients repolarization was shorter during right ventricular apical pacing than during normal activation despite prolonged activation time.
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- Rubulis, Aigars, 1974, et al.
(författare)
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T vector and loop characteristics in coronary artery disease and during acute ischemia
- 2004
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Ingår i: Heart Rhythm. - 1547-5271. ; 1:3, s. 317-25
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Three-dimensional characterization of the ventricular repolarization by the T vector and T vector loop morphology in coronary artery disease (CAD), and their response to short-term (no flow) ischemia induced by coronary occlusion during a percutaneous intervention (PCI). BACKGROUND: The risk for sudden cardiac death is increased in conditions of acute or permanently heterogeneous ventricular repolarization, for which ischemia is a risk factor. METHODS: Fifty-six CAD patients without visible collateral circulation were studied during an elective single-vessel PCI, and 10 healthy controls twice at rest. T vector parameters (Televation, Tazimuth, and QRS-T angle), and T loop parameters (Tarea, Tavplan, and Teigenv) were measured by vectorcardiography. ST vector magnitude (ST-VM) and its change (STC-VM) were used for reference. RESULTS: At rest, T vector loop morphology (Tarea, Teigenv) was significantly different in CAD patients and controls, while T vector angles did not separate the groups. Ischemia induced significant changes in T loop parameters in the entire CAD group, whereas in the LAD subgroup significant changes were seen also in T vector angle. The T loop morphology was significantly different at baseline and a more pronounced response to ischemia (Tarea) was seen in patients with, than in those without, a history of hypertension. CONCLUSION: T loop morphology, rather than the T vector angle, separated CAD patients from healthy controls. Coronary occlusion had significant impact on ventricular repolarization, as assessed by T vector and morphology analysis, and most prominently in the LAD group. Hypertensive patients appeared especially vulnerable to ischemia.
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