| 1. |
- Aagaard, Philip, et al.
(författare)
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Early Repolarization in Middle-Age Runners-Cardiovascular Characteristics.
- 2014
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 46:7, s. 1285-1292
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study aimed to assess the prevalence and patterns of early repolarization (ER) in middle-age long-distance runners, its relation to cardiac structure and function, and its response to strenuous physical activity. Methods: Male first-time cross-country race participants >45 yr were assessed pre-and postrace by medical history and physical examination, 12-lead ECG, vectorcardiography, blood tests, and echocardiography. ER was defined either as ST elevation or J wave and categorized according to localization and morphology. Results: One hundred and fifty-one subjects (50 +/- 5 yr) were evaluated before the race, and 47 subjects were evaluated after the race. Altogether, 67 subjects (44%) had ER. Subjects with versus without ER had a lower resting HR (56 +/- 8 vs 69 +/- 9 bpm, P = 0.02), lower body mass index (24 +/- 2 vs 25 +/- 3 kg.m(-2), P < 0.001), higher training volume (3.0 +/- 2.6 vs 2.1 +/- 2.7 h.wk(-1), P = 0.03), and faster 30-km running times (194 +/- 28 vs 208 +/- 31 min, P = 0.01). Vectorcardiography parameters in subjects with ER showed more repolarization heterogeneity: vector gradient (QRS-T-area) (120 +/- 25 vs 92 +/- 29 mu Vs, P < 0.001), T-area (105 +/- 18 vs 73 +/- 23 mu Vs, P < 0.001), and T-amplitude (0.63 +/- 0.13 vs 0.53 +/- 0.16 mm, P < 0.001); these parameters were inversely related to HR (r = -0.37 to -0.48, P < 0.001). ER disappeared in 15 (75%) of 20 subjects after the race. Conclusions: ER is a common finding in middle-age male runners. This ECG pattern, regardless of morphology and localization, is associated with normal cardiac examinations including noninvasive electrophysiology, features of better physical conditioning, and disappears after strenuous exercise in most cases. These findings support that ER should be regarded as a common and training-related finding also in middle-age physically active men.
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| 2. |
- Andersson, Eva A, 1958-, et al.
(författare)
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Maximal Aerobic Power versus Performance in Two Aerobic Endurance Tests among Young and Old Adults
- 2011
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Ingår i: Gerontology. - : S. Karger AG. - 0304-324X .- 1423-0003. ; :Aug, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aerobic fitness is of great value for reducing risk of mortality and cardiovascular diseases. Objective: This study evaluated the performance in and correlations between a new test (five-minute pyramid test, 5MPT), the six-minute walk-test (6MWT) and maximal oxygen uptake (VO(2max)) among old and young adults. Methods: Forty-four habitually active adults (females and males), 23 old (64-79 years) and 21 young (20-32 years) participated. In the 5MPT, the participants moved back and forth along a short walkway (5.5 m) over boxes (height: 'old people' 0.42 m, 'young people' 0.62 m) arranged like an elongated step pyramid for 5 min. Power in the pyramid test (5MPT(power)) was calculated as the product of numbers of laps, body weight, gravity and highest box level divided by time. A 6MWT and a maximal cycle ergometer test for direct measurements of VO(2max) were also performed. In all tests heart rate, with on-line electrocardiography, and perceived exertion were recorded. Results: There was a strong correlation between the 5MPT(power) and VO(2max) for the entire group studied (r = 0.98), and each of the four subgroups old and young females and males separately (r = 0.78-0.98). Contrary to several earlier studies, especially involving people with various diseases, the present data showed that 6MWT cannot be used to predict VO(2max) among old females and young adults. The correlation with VO(2max) was weaker for the 6MWT than for the 5MPT(power). The relative performance values for the old compared to the young (ratio old/young × 100) were considerably lower in 5MPT(power) and VO(2max) (47-55%) than in distance and 'work' in the 6MWT (82-86%). Conclusions: The results, with age and gender variations, can be valuable information in health-fitness contexts, since measuring physical aerobic capacity is very significant in connection with risk evaluations of mortality and various diseases. The 5MPT is a rapid, functional, easy and inexpensive tool for predicting assessed maximal aerobic power.
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| 3. |
- van Deursen, Caroline J M, et al.
(författare)
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Vectorcardiographic QRS area as a novel predictor of response to cardiac resynchronization therapy.
- 2015
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 48:1, s. 45-52
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Tidskriftsartikel (refereegranskat)abstract
- QRS duration and left bundle branch block (LBBB) morphology are used to select patients for cardiac resynchronization therapy (CRT). We investigated whether the area of the QRS complex (QRSAREA) on the 3-dimensional vectorcardiogram (VCG) can improve patient selection.
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| 4. |
- van Deursen, Caroline J M, et al.
(författare)
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Vectorcardiography for Optimization of Stimulation Intervals in Cardiac Resynchronization Therapy.
- 2015
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Ingår i: Journal of cardiovascular translational research. - : Springer Science and Business Media LLC. - 1937-5395 .- 1937-5387. ; 8:2, s. 128-137
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Tidskriftsartikel (refereegranskat)abstract
- Current optimization of atrioventricular (AV) and interventricular (VV) intervals in cardiac resynchronization therapy (CRT) is time consuming and subject to noise. We aimed to prove the principle that the best hemodynamic effect of CRT is achieved by cancelation of opposing electrical forces, detectable from the QRS morphology in the 3D vectorcardiogram (VCG). Different degrees of left (LV) and right ventricular (RV) pre-excitation were induced, using variation in AV intervals during LV pacing in 20 patients with left bundle branch block (LBBB) and variation in VV intervals during biventricular pacing in 18 patients with complete AV block or atrial fibrillation. The smallest QRS vector area identified stimulation intervals with minimal systolic stretch (median difference [IQR] 20ms [-20, 20ms] and maximal hemodynamic response (10ms [-20, 40ms]). Reliability of VCG measurements was superior to hemodynamic measurements. This study proves the principle that VCG analysis may allow easy and reliable optimization of stimulation intervals in CRT patients.
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| 5. |
- Wecke, Liliane
(författare)
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Cardiac memory studies in two human models
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Cardiac memory is a form of electrical remodeling of the ventricles, where the T vector follows ("remembers') a previously altered QRS vector. On the electrocardiogram (ECG), it presents as T-wave inversions. It has been observed after periods of ventricular pacing, ventricular tachycardia, intermittent bundle branch block and after periods of preexcitation in patients with the Wolff-Parkinson-White (WPW) syndrome. Aims: To study the occurrence, development and dissipation of cardiac memory in two human models, ventricular pacing and WPW ablation. In addition to conventional ECG analysis, the spatial vectorcardiogram (VCG) was analyzed in 3 dimensions, including T-vector loop morphology. Studies I-II Twenty patients who received DDD-R pacemakers due to symptomatic sinus bradycardia were followed daily for 1 week (n=6) or weekly for 5-8 weeks (n=14). A baseline ECG and VCG were recorded prior to pacemaker implantation. The patients were all paced endocardially in the right ventricle and the pacemakers were programmed to a short AV delay to achieve maximum ventricular stimulation. At each follow-up, the pacemakers were temporarily programmed to AM mode to re-establish normal ventricular activation and an ECG and VCG were recorded. After this protocol, the 14 patients who were studied weekly had their pacemakers reprogrammed to individually optimized AV delays and, after 4-5 weeks, they were seen at one last follow-up. Repolarization changes assessed by T vector amplitude and morphology changes were already present within 24 hours after the initiation of pacing. Cardiac memory was fully developed within one week and the VCG revealed a backward and upward rotation of the maximum T vector. After the cessation of ventricular pacing, cardiac memory disappeared within 4 weeks. When ventricular pacing was continued, cardiac memory was preserved in proportion to the percentage of ventricular pacing. After the abrupt termination of ventricular pacing, the prolongation of repolarization time (QTc) and changes in T-loop morphology suggested unfavorable effects on repolarization. During continuous ventricular pacing, the repolarization time decreased. Study III The effects of ventricular pacing on repolarization and cardiac memory were compared in 15 patients with hypertrophic obstructive cardiomyopathy (HOCM) and the patients from Studies I and II. A baseline ECG was recorded prior to pacemaker implantation. The HOCM patients were evaluated after 3 months of right ventricular endocardial pacing with a short AV delay. An ECG was first recorded during DDD pacing and then during sinus rhythm after pacing was temporarily switched off. T-wave inversions consistent with cardiac memory were observed in all HOCM patients and similar to controls. In contrast to sick sinus patients, there was no change in repolarization time in the HOCM group. Baseline myocardial structure and function thus make a difference to the repolarization response related to cardiac memory. Studies IV- V The occurrence and dissipation of cardiac memory after an accessory pathway ablation in WPW patients were studied retrospectively (Study IV) and prospectively (Study V). In Study IV, T-wave inversions in leads II, aVF and III were evaluated on ECGs from 125 patients ablated due to a posteroseptal (PS) accessory pathway. Within one day after ablation, 123 (98%) of the patients showed cardiac memory (T-wave inversions). In most patients, cardiac memory disappeared within 3 months. In Study V, ECGs and VCGs were used to compare the occurrence of cardiac memory after the ablation of PS (n=11) and left lateral (LL) (n=6) accessory pathways. Cardiac memory in the form of T-wave inversions on ECG was only seen in the PS group. Evaluation by VCG, however, revealed T-vector changes in the transverse plane in the LL group and vertical T-vector changes in the PS group. In 82% of the patients, cardiac memory disappeared within 3-4 weeks. Conclusions: In humans, cardiac memory developed and reached steady state within 1 week after the onset of right ventricular endocardial pacing. After WPW ablation, cardiac memory was present, independent of accessory pathway site. Cardiac memory is probably an adaptation mechanism of the heart, involving a gradual change in repolarization when the activation sequence (depolarization) is altered. VCG including T-vector loop morphology is a useful and sensitive method for evaluating repolarization changes.
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| 6. |
- Wecke, Liliane, et al.
(författare)
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Repolarization changes in patients with heart failure receiving cardiac resynchronization therapy-signs of cardiac memory
- 2011
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:5, s. 590-598
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose Cardiac memory is known as T-wave inversions and other repolarization changes after a period of altered ventricular activation, previously mainly studied in structurally normal hearts. We investigated repolarization changes in failing hearts undergoing cardiac resynchronization therapy (CRT). Methods Electrocardiogram and vectorcardiogram were recorded before and 1 day and 2 weeks after initiation of CRT in 23 patients with heart failure and left bundle-branch block. Results After 1 day of CRT, the T vector during intrinsic conduction (left bundle-branch block) had rotated toward the direction of the paced QRS vector; T-vector size had increased with further increase after 2 weeks (T-vector amplitude, 889 ± 277 vs 651 ± 225 μV; T area, 169 ± 70 vs 102 ± 39 μVs; P < .01) accompanied by prolonged repolarization (T peak-to-end, 174 ± 34 vs 127 ± 16; QT interval corrected for heart rate, 541 ± 59 vs 493 ± 33 milliseconds; P < .01). Conclusions Repolarization changes are present in patients with heart failure, although less pronounced compared with after right ventricular pacing in structurally normal hearts.
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| 7. |
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| 8. |
- Wecke, Liliane, et al.
(författare)
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Vectorcardiography shows cardiac memory and repolarization heterogeneity after ablation of accessory pathways not apparent on ECG
- 2013
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 166:1, s. 152-157
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pacing induced cardiac memory is an established phenomenon, but following successful WPW ablation, cardiac memory was present on ECG in variable proportions of patients depending on accessory pathway (AP) location. We hypothesized that vectorcardiography (VCG), which is more sensitive than ECG, would show cardiac memory after WPW ablation independent of AP location. METHODS: Thirty-six patients were followed after successful AP ablation, 11 with overt posteroseptal (PS), 13 with overt left-sided (LS) and 12 with concealed APs (controls). VCGs were recorded the day before and after the procedure, ≥once/week for 6-8weeks and after ≥3months. T vector and T-vector loop parameters were analyzed and compared. RESULTS: After ablation of overt APs, there was a correlation between the directions of the preexcited maximum QRS-vector and the post-ablation maximum T-vector, confirming the presence of cardiac memory. Ablation of overt APs was followed by cardiac memory apparent in different directions. Thus, ablation of PS APs was followed by most pronounced changes in T-vector elevation and LS APs with significant changes only in T-vector azimuth. Cardiac memory disappeared within a month in >80% of cases. Furthermore, T-vector loop morphology changes suggested a period of repolarization heterogeneity immediately after ablation of overt APs. CONCLUSIONS: According to VCG analysis cardiac memory was present after ablation of overt APs independent of location as consistently as after ventricular pacing, and disappeared within a similar time frame during normal ventricular activation. In addition, signs of transient repolarization heterogeneity were observed after ablation of overt APs.
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| 9. |
- Wecke, Liliane, et al.
(författare)
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Younger People Show More Changes in Repolarization with Exercise
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: Cardiac repolarization is a complex phenomenon that depends on heart rate (HR), autonomic nervous system (ANS) activity, age, gender and diseases/pathological conditions etc. Cardiovascular events in LQT1 mutation carriers are also typically related to age, gender, and QT interval, and are triggered by physical exercise. We studied the repolarization response to heavy exercise in healthy subjects.Material and methods:Vectorcardiography (VCG) was recorded with the Coronet II system (Ortivus AB, Danderyd, Sweden) using the Frank orthogonal leads (X, Y and Z) at supine rest before and after a maximal cycle ergometer test in 42 healthy subjects. They were of different age and gender, 21 old (64-79 years) and 21 young (20-32 years), 23 were women and 19 men. Maximum T-vector amplitude and direction were assessed as well as T-area, QTc-interval and other VCG parameters.Results:At baseline most parameters differed between old and young subjects, but only QRS-duration, QRS-area and T-amplitude between women and men. Younger subjects had lower HR (59 vs 72 bpm; p<0.01), higher T-amplitude (530 vs 395 μV; p<0.01), larger T-area (73 vs 48 μVs; p<0.001), shorter QTc (417 vs 430 ms; p<0.01) and a narrower QT-angle (25 vs 59°; p<0.01).The response to strenuous exercise was much more pronounced in the younger subjects with an increase in resting HR by 35 bpm compared with 17 bpm for the old subjects (p<0.001). This was accompanied by a more pronounced decrease in T-amplitude (-138 vs -27 μV; p<0.01) and T-area (-20 vs -7 μVs; p<0.01) but a larger prolongation of QTc (54 vs 10 ms; p<0.001).Conclusion:Young people seem to have a more active ANS, which results in a more pronounced repolarization response to heavy exercise. This might explain why patients with LQT1 more likely suffer from malignant arrhythmias at ages below 40 years.
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| 10. |
- Wecke, Liliane, et al.
(författare)
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Younger People Show More Changes in Repolarization with Exercise
- 2012
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Ingår i: Younger People Show More Changes in Repolarization with Exercise.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Cardiac repolarization is a complex phenomenon that depends on heart rate (HR), autonomic nervous system (ANS) activity, age, gender and diseases/pathological conditions etc. Cardiovascular events in LQT1 mutation carriers are also typically related to age, gender, and QT interval, and are triggered by physical exercise. We studied the repolarization response to heavy exercise in healthy subjects.Method:Vectorcardiography (VCG) was recorded with the Coronet II system (Ortivus AB, Danderyd, Sweden) using the Frank orthogonal lead system (X, Y and Z) at supine rest before and after a maximal cycle ergometer test in 42 healthy subjects. They were of different age and gender, 21 old (64-79 years) and 21 young (20-32 years), 23 were women and 19 men. Maximum T-vector amplitude and direction were assessed as well as T-area, QTc-interval and other VCG parameters.Summary:At baseline most parameters differed between old and young subjects, but only QRS-duration, QRS-area and T-amplitude between women and men. Younger subjects had lower HR (59 vs 72 bpm; p<0.01), higher T-amplitude (530 vs 395 μV; p<0.01), larger T-area (73 vs 48 μVs; p<0.001), shorter QTc (417 vs 430 ms; p<0.01) and a narrower QT-angle (25 vs 59°; p<0.01).The response to strenuous exercise was much more pronounced in the younger subjects with an increase in resting HR by 35 bpm compared with 17 bpm for the old subjects (p<0.001). This was accompanied by a more pronounced decrease in T-amplitude (-138 vs -27 μV; p<0.01) and T-area (-20 vs -7 μVs; p<0.01) but a larger prolongation of QTc (54 vs 10 ms; p<0.001).Conclusion:Young people seem to have a more active ANS, which results in a more pronounced repolarization response to heavy exercise. This might explain why patients with LQT1 more likely suffer from malignant arrhythmias at ages below 40 years.
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