| 1. |
|
|
| 2. |
- Almer, Jakob, et al.
(författare)
-
Ischemic QRS prolongation as a biomarker of severe myocardial ischemia.
- 2016
-
Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 49:2, s. 139-147
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and increased rate of myocardial cell death during coronary occlusion. The aims of this study were to evaluate ischemic QRS prolongation as a biomarker of severe ischemia by establishing the relationship between prolongation and collateral flow experimentally in a dog model, and test if the same pattern of ischemic QRS prolongation occurs in man.
|
|
| 3. |
- Elmberg, Viktor, et al.
(författare)
-
A 12-lead ECG-method for quantifying ischemia-induced QRS prolongation to estimate the severity of the acute myocardial event.
- 2016
-
Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 49:3, s. 272-277
-
Tidskriftsartikel (refereegranskat)abstract
- Studies have shown terminal QRS distortion and resultant QRS prolongation during ischemia to be a sign of low cardiac protection and thus a faster rate of myocardial cell death. A recent study introduced a single lead method to quantify the severity of ischemia by estimating QRS prolongation. This paper introduces a 12-lead method that, in contrast to the previous method, does not require access to a prior ECG.
|
|
| 4. |
- Martínez, Juan Pablo, et al.
(författare)
-
The STAFF III Database : ECGs recorded during acutely induced myocardial ischemia
- 2017
-
Ingår i: Computing in Cardiology. - 2325-8861. ; 44
-
Tidskriftsartikel (refereegranskat)abstract
- The STAFF III database was acquired with the aim of better understanding the ECG signatures observed during acute ischemia, with special focus on high-frequency QRS components. The database contains recordings from 104 patients undergoing elective balloon percutaneous coronary intervention. The database has not only been analyzed in numerous clinical studies, but also turned out to be an excellent tool for methodological development. Its use has, by far, exceeded the original aim. Inspired by this fact, the database has now been made publicly available at Physionet.
|
|
| 5. |
|
|
| 6. |
- Pettersson, Jonas, et al.
(författare)
-
Spatial, individual and temporal variation of the high frequency QRS amplitudes in the 12 standard electrocardiographic leads
- 2000
-
Ingår i: American Heart Journal. - 1097-6744. ; 139:2, part 1, s. 352-358
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Analysis of high-frequency QRS amplitudes (HF-QRS) may provide an additional diagnostic tool in patients with heart disease, but the basic properties of these waveforms have not been sufficiently investigated. This study describes the spatial, individual, and temporal variation at rest of HF-QRS recorded with the 12 standard electrocardiographic leads in patients with ischemic heart disease. METHODS AND RESULTS: Two consecutive electrocardiographic recordings from 67 patients were signal averaged and analyzed within a bandwidth of 150 to 250 Hz. The HF-QRS values were expressed as root mean square values. There was a spatial variation in HF-QRS among the 12 leads, with higher amplitudes in V(2) through V(4), II, aVF, and III. The individual variation among the patients was large for all leads. The sum of the HF-QRS for all 12 leads in each patient ranged from 20 to 75 microV (mean 36 +/- 11 microV). The mean of the temporal variation in HF-QRS for all 12 leads between the 2 recordings was only 0.10 +/- 0. 09 microV. CONCLUSIONS: Because of the large individual variation, analysis of HF-QRS is probably most applicable in monitoring situations when it is possible to track changes in a patient over time. The temporal variation in HF-QRS at rest is small, both in patients with and those without prior myocardial infarction.
|
|
| 7. |
- Ringborn, Michael, et al.
(författare)
-
Comparison of high-frequency QRS components and ST-segment elevation to detect and quantify acute myocardial ischemia.
- 2010
-
Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 43, s. 113-120
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study tests the ability of high-frequency components of the depolarization phase (HF-QRS) vs conventional ST-elevation criteria to detect and quantify myocardial ischemia. METHODS: Twenty-one patients admitted for elective percutaneous coronary intervention were included. Quantification of the ischemia was made by myocardial scintigraphy. High-resolution electrocardiogram before and during percutaneous coronary intervention was recorded and signal averaged. The HF-QRS were determined within the frequency band 150 to 250 Hz. ST-segment deviation was measured in the standard frequency range (<100 Hz). RESULTS: HF-QRS criteria were met by 76% of the patients, whereas 38% met the ST-elevation criteria (P = .008). Both HF-QRS reduction and ST elevation correlated significantly with the amount of ischemia (HF-QRS: r = 0.59, P = .005 for extent and r = 0.69, P = .001 for severity; ST elevation: r = 0.49, P = .023 for extent and r = 0.57, P = .007 for severity). CONCLUSIONS: This study suggests that HF-QRS analysis could provide valuable information both to detect acute ischemia and to quantify myocardial area at risk.
|
|
| 8. |
- Ringborn, Michael, et al.
(författare)
-
Evaluation of depolarization changes during acute myocardial ischemia by analysis of QRS slopes.
- 2011
-
Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:4, s. 416-424
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study evaluates depolarization changes in acute myocardial ischemia by analysis of QRS slopes. METHODS: In 38 patients undergoing elective percutaneous coronary intervention, changes in upward slope between Q and R waves and downward slope between R and S waves (DS) were analyzed. In leads V1 to V3, upward slope of the S wave was additionally analyzed. Ischemia was quantified by myocardial scintigraphy. Also, conventional QRS and ST measures were determined. RESULTS: QRS slope changes correlated significantly with ischemia (for DS: r = 0.71, P < .0001 for extent, and r = 0.73, P < .0001 for severity). Best corresponding correlation for conventional electrocardiogram parameters was the sum of R-wave amplitude change (r = 0.63, P < .0001; r = 0.60, P < .0001) and the sum of ST-segment elevation (r = 0.67, P < .0001; r = 0.73, P < .0001). Prediction of extent and severity of ischemia increased by 12.2% and 7.1% by adding DS to ST. CONCLUSIONS: The downward slope between R and S waves correlates with ischemia and could have potential value in risk stratification in acute ischemia in addition to ST-T analysis.
|
|
| 9. |
|
|
| 10. |
- Ringborn, Michael, et al.
(författare)
-
The absence of high-frequency QRS changes in the presence of standard electrocardiographic QRS changes of old myocardial infarction
- 2001
-
Ingår i: American Heart Journal. - : Elsevier BV. - 1097-6744 .- 0002-8703. ; 141:4, s. 573-579
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This study compares the high-frequency QRS components (HF-QRS) in patients with and without standard electrocardiogram (ECG) changes indicative of old myocardial infarction (MI). Previous studies have indicated that patients with an old MI differ in their HF-QRS compared with healthy subjects. The HF-QRS has been reported to be decreased during acute coronary occlusion and increased after reperfusion. However, there is controversy about the appearance of HF-QRS after the acute phase of MI. METHODS: A total of 154 patients were included, 57 with and 97 without QRS changes of old MI on the standard ECG. The patients with old MI were divided into subgroups on the basis of the MI location indicated by the standard ECG. Signal-averaged ECGs from the 12 standard leads were recorded. The root-mean-square values of the HF-QRS were determined within two frequency bands: 150 to 250 Hz and 80 to 300 Hz. RESULTS: There was a large interindividual variation in HF-QRS in patients without MI as well as in those with different MI locations. There were no significant differences between the groups in the summed HF-QRS of all 12 leads or in the pattern of lead distribution of the HF-QRS. Not even the patients with the greatest QRS changes of old MI could be differentiated from those without any changes of old MI on the standard ECG. The results were the same in both analyzed frequency bands. CONCLUSIONS: This study shows, contrary to previous studies, that analysis of HF-QRS cannot differentiate between patients with and without old MI.
|
|
