... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Met... more ... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Methodological aspects of the use of heart rate stratified RR interval histograms in the analysis of atrioventricular conduction during atrial fibrillation, Cardiovasc. Res., vol. ...
Previous in vitro studies have suggested full repolarization of the epicardium coincides with the... more Previous in vitro studies have suggested full repolarization of the epicardium coincides with the peak of the T wave (T(peak)) and that of the M cells coincides with the end of the T wave (T(end)). However, in vivo validation of the theory is lacking. Monophasic action potentials (MAPs) were recorded using the CARTO mapping system from 51 +/- 10 epicardial sites and 64 +/- 9 endocardial sites of the left ventricle in 10 pigs and from 41 +/- 4 epicardial sites and 53 +/- 2 endocardial sites of the right ventricle in two of the 10 pigs. End of repolarization (EOR) times over the epicardium (EOR(epi)), endocardium (EOR(endo)), and over both (EOR(total)) were obtained. QT(peak) and QT(end) intervals were measured from simultaneously recorded 12-lead ECG. Minimal and maximal EOR(total) were observed in the left ventricle in all pigs. Minimal EOR(total) was on the epicardium in five pigs, and maximal EOR(total) was on the endocardium in nine pigs. Minimal, mean, and maximal QT(peak) intervals all were significantly smaller than maximal EOR(epi) (322 +/- 23 ms, P <.01). No significant difference was found between maximal QT(end) interval (338 +/- 30 ms) and maximal EOR(endo) (339 +/- 24 ms, difference = 1 +/- 19 ms, P =.92), between maximal QT(end) interval and maximal EOR(total) (341 +/- 24 ms, difference = 2 +/- 18 ms, P =.69), or between minimal QT(peak) interval (283 +/- 28 ms) and minimal EOR(total) (282 +/- 20 ms, difference = 0 +/- 15 ms, P =.95). In in vivo pig models, T(peak) does not coincide with full repolarization of the epicardium but coincides well with the earliest EOR, whereas the T(end) corresponds with the latest EOR. These findings suggest that not only the transmural gradients but also the apicobasal repolarization gradients contribute to genesis of the T wave.
A new non-invasive technique is presented for the characterization of time-dependent spectral pro... more A new non-invasive technique is presented for the characterization of time-dependent spectral properties of atrial fibrillation in the surface ECG. The method uses the Wigner-Ville distribution for time-frequency analysis and the cross Wigner-Ville is used to compute trends which describe the instantaneous frequency of the atrial activity. Preliminary results indicate that short-term variations exist in the fibrillation cycle lengths and that the variations can exhibit similar behavior in the leads V1-V3
Inter-atrial conduction delay in patients with atrial fibrillation (AF) has been reported. Howeve... more Inter-atrial conduction delay in patients with atrial fibrillation (AF) has been reported. However, the area of this conduction delay has not been well identified. The activation time and conduction velocity over the right atrial endocardium were evaluated during sinus rhythm using the CARTO mapping technique in 6 patients with paroxysmal AF (AF group) and 11 patients without history of AF (control group). No significant differences were observed between the 2 groups in the mean activation times and conduction velocities from the earliest activation site to the superior septum, His bundle area and coronary sinus ostium, or in the total activation times of the right atrium. There was no significant difference between the two groups in the local conduction velocity between 2 adjacent sites in the free wall, septum and bottom of the right atrium. This study suggests the previously reported conduction delay in the posteroseptal region in patients with paroxysmal AF might locate within the posterior inter-atrial septum.
To evaluate the feasibility of monophasic action potential (MAP) mapping using a modified-tip Nav... more To evaluate the feasibility of monophasic action potential (MAP) mapping using a modified-tip NaviStar catheter in swine and humans. MAP mapping was performed using the modified-tip catheter at 71 +/- 21 atrial and 60 +/- 16 ventricular sites in 10 healthy pigs and at 56 ventricular sites in one patient, and using an ordinary Navi-Star catheter at 30 atrial sites in one patient and 50 +/- 14 ventricular sites in four patients. In an additional 20 patients, MAPs were also recorded at 9 +/- 2 atrial sites using the modified-tip catheter or at 12 +/- 9 atrial sites using the ordinary catheter. In pigs, the plateau amplitudes of the MAPs recorded using the modified-tip catheter were 4.1 +/- 3.2 mV for the atrial and 9.5 +/- 4.3 mV for the ventricular MAPs. In patients, both the ventricular and atrial MAPs recorded using the modified-tip catheter were significantly higher than using the ordinary catheters, 15.7 +/- 8 and 3.0 +/- 0.9 mV vs 9.5 +/- 3.9 and 2.0 +/- 0.6 mV for the ventricular and atrial MAPs, respectively (p < 0.0001). The baseline disturbances were <10% of the MAP amplitude in 95% of the pig and 96% of the patient MAPs. A modified-tip Navi-Star catheter could be used in swine and in humans for prompt recording of MAPs with acceptable amplitudes and baselines. MAP mapping using the modified-tip catheter is safe and feasible for clinical use.
The aim of this study was to evaluate the global sequence of repolarization over the ventricular ... more The aim of this study was to evaluate the global sequence of repolarization over the ventricular endocardium. Disturbances in myocardial repolarization are associated with the genesis of arrhythmias. However, little is known about the global sequence of repolarization. Monophasic action potentials (MAPs) were recordedfrom 61 +/- 18 LV and/or RV sites in ten healthy pigs and from 43 +/- 15 LV or RV sites in eight patients using the CARTO system. Local activation time (AT), end-of-repolarization (EOR) time, and MAP duration were calculated and three-dimensional global maps of AT, EOR, and MAP duration constructed. LV maps were obtained from all ten pigs and RV maps from three pigs. Five RV maps and five LV maps were obtained from the eight patients. (1) EOR sequence was recognizable in 12 of 13 pig maps and in all the patient maps. (2) EOR followed the sequence of activation in 12 of 13 pig maps and 8 of 10 patient maps. (3) The longest MAPs were recorded in or near the earliest activation area, and the shortest ones in or near the latest activation area in all the pig maps and in nine often and eight often patient maps, respectively. (4) In all maps, MAP duration and AT were negatively correlated, and EOR and AT positively correlated. In conclusion, repolarization gradients exist over the pig and the human ventricular endocardium. The activation sequence is a determinant for the repolarization sequence. The magnitude of the progressive MAP shortening with progressively later activation, relative to local AT, is a critical factor governing the direction and pattern of the EOR.
Journal of Interventional Cardiac Electrophysiology, 2005
The ECG interval from the peak to the end of the T wave (T peak-T end) has been used as an index ... more The ECG interval from the peak to the end of the T wave (T peak-T end) has been used as an index of transmural dispersion of ventricular repolarization (DVR). The correlation between the T peak-T end interval and the global DVR, however, has not been well-evaluated. Methods: Monophasic action potentials (MAPs) were recorded from 51 ± 10 epicardial and 64 ± 9 endocardial sites in the left ventricles of 10 pigs, and from 41 ± 4 epicardial and 53 ± 2 endocardial sites in the right ventricles of 2 of the 10 pigs using the CARTO mapping system. The end of repolarization times over the epi- and endocardium were measured, and the end of repolarization dispersions over the epicardium (DVR-epi), over the endocardium (DVR-endo) and over both (DVR-total) were calculated. The QTpeak, QTend and T peak-T end intervals as well as the QTpeak and QTend dispersions were obtained from the simultaneously recorded 12-lead ECG. Results: The maximal T peak-T end intervals (57 ± 7 ms) were consistent with the DVR-total (58 ± 11 ms, p > 0.05), and significantly correlated with the DVR-total (r = 0.64, p < 0.05). However, the mean T peak-T end intervals (44 ± 5 ms), and T peak-T end intervals from lead II (41 ± 6 ms) and V 5 (43 ± 5 ms) were all significantly smaller than and poorly correlated with the DVR-total, as were the QTpeak and QTend dispersions (15 ± 2 ms vs. 21 ± 4 ms). Conclusion: The maximal T peak-T end interval may be used as a noninvasive estimate for the global DVR, but not the QTpeak and QTend dispersions, nor the mean T peak-T end interval and that from a single lead.
... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Met... more ... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Methodological aspects of the use of heart rate stratified RR interval histograms in the analysis of atrioventricular conduction during atrial fibrillation, Cardiovasc. Res., vol. ...
Previous in vitro studies have suggested full repolarization of the epicardium coincides with the... more Previous in vitro studies have suggested full repolarization of the epicardium coincides with the peak of the T wave (T(peak)) and that of the M cells coincides with the end of the T wave (T(end)). However, in vivo validation of the theory is lacking. Monophasic action potentials (MAPs) were recorded using the CARTO mapping system from 51 +/- 10 epicardial sites and 64 +/- 9 endocardial sites of the left ventricle in 10 pigs and from 41 +/- 4 epicardial sites and 53 +/- 2 endocardial sites of the right ventricle in two of the 10 pigs. End of repolarization (EOR) times over the epicardium (EOR(epi)), endocardium (EOR(endo)), and over both (EOR(total)) were obtained. QT(peak) and QT(end) intervals were measured from simultaneously recorded 12-lead ECG. Minimal and maximal EOR(total) were observed in the left ventricle in all pigs. Minimal EOR(total) was on the epicardium in five pigs, and maximal EOR(total) was on the endocardium in nine pigs. Minimal, mean, and maximal QT(peak) intervals all were significantly smaller than maximal EOR(epi) (322 +/- 23 ms, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.01). No significant difference was found between maximal QT(end) interval (338 +/- 30 ms) and maximal EOR(endo) (339 +/- 24 ms, difference = 1 +/- 19 ms, P =.92), between maximal QT(end) interval and maximal EOR(total) (341 +/- 24 ms, difference = 2 +/- 18 ms, P =.69), or between minimal QT(peak) interval (283 +/- 28 ms) and minimal EOR(total) (282 +/- 20 ms, difference = 0 +/- 15 ms, P =.95). In in vivo pig models, T(peak) does not coincide with full repolarization of the epicardium but coincides well with the earliest EOR, whereas the T(end) corresponds with the latest EOR. These findings suggest that not only the transmural gradients but also the apicobasal repolarization gradients contribute to genesis of the T wave.
... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Met... more ... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Methodological aspects of the use of heart rate stratified RR interval histograms in the analysis of atrioventricular conduction during atrial fibrillation, Cardiovasc. Res., vol. ...
Previous in vitro studies have suggested full repolarization of the epicardium coincides with the... more Previous in vitro studies have suggested full repolarization of the epicardium coincides with the peak of the T wave (T(peak)) and that of the M cells coincides with the end of the T wave (T(end)). However, in vivo validation of the theory is lacking. Monophasic action potentials (MAPs) were recorded using the CARTO mapping system from 51 +/- 10 epicardial sites and 64 +/- 9 endocardial sites of the left ventricle in 10 pigs and from 41 +/- 4 epicardial sites and 53 +/- 2 endocardial sites of the right ventricle in two of the 10 pigs. End of repolarization (EOR) times over the epicardium (EOR(epi)), endocardium (EOR(endo)), and over both (EOR(total)) were obtained. QT(peak) and QT(end) intervals were measured from simultaneously recorded 12-lead ECG. Minimal and maximal EOR(total) were observed in the left ventricle in all pigs. Minimal EOR(total) was on the epicardium in five pigs, and maximal EOR(total) was on the endocardium in nine pigs. Minimal, mean, and maximal QT(peak) intervals all were significantly smaller than maximal EOR(epi) (322 +/- 23 ms, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.01). No significant difference was found between maximal QT(end) interval (338 +/- 30 ms) and maximal EOR(endo) (339 +/- 24 ms, difference = 1 +/- 19 ms, P =.92), between maximal QT(end) interval and maximal EOR(total) (341 +/- 24 ms, difference = 2 +/- 18 ms, P =.69), or between minimal QT(peak) interval (283 +/- 28 ms) and minimal EOR(total) (282 +/- 20 ms, difference = 0 +/- 15 ms, P =.95). In in vivo pig models, T(peak) does not coincide with full repolarization of the epicardium but coincides well with the earliest EOR, whereas the T(end) corresponds with the latest EOR. These findings suggest that not only the transmural gradients but also the apicobasal repolarization gradients contribute to genesis of the T wave.
A new non-invasive technique is presented for the characterization of time-dependent spectral pro... more A new non-invasive technique is presented for the characterization of time-dependent spectral properties of atrial fibrillation in the surface ECG. The method uses the Wigner-Ville distribution for time-frequency analysis and the cross Wigner-Ville is used to compute trends which describe the instantaneous frequency of the atrial activity. Preliminary results indicate that short-term variations exist in the fibrillation cycle lengths and that the variations can exhibit similar behavior in the leads V1-V3
Inter-atrial conduction delay in patients with atrial fibrillation (AF) has been reported. Howeve... more Inter-atrial conduction delay in patients with atrial fibrillation (AF) has been reported. However, the area of this conduction delay has not been well identified. The activation time and conduction velocity over the right atrial endocardium were evaluated during sinus rhythm using the CARTO mapping technique in 6 patients with paroxysmal AF (AF group) and 11 patients without history of AF (control group). No significant differences were observed between the 2 groups in the mean activation times and conduction velocities from the earliest activation site to the superior septum, His bundle area and coronary sinus ostium, or in the total activation times of the right atrium. There was no significant difference between the two groups in the local conduction velocity between 2 adjacent sites in the free wall, septum and bottom of the right atrium. This study suggests the previously reported conduction delay in the posteroseptal region in patients with paroxysmal AF might locate within the posterior inter-atrial septum.
To evaluate the feasibility of monophasic action potential (MAP) mapping using a modified-tip Nav... more To evaluate the feasibility of monophasic action potential (MAP) mapping using a modified-tip NaviStar catheter in swine and humans. MAP mapping was performed using the modified-tip catheter at 71 +/- 21 atrial and 60 +/- 16 ventricular sites in 10 healthy pigs and at 56 ventricular sites in one patient, and using an ordinary Navi-Star catheter at 30 atrial sites in one patient and 50 +/- 14 ventricular sites in four patients. In an additional 20 patients, MAPs were also recorded at 9 +/- 2 atrial sites using the modified-tip catheter or at 12 +/- 9 atrial sites using the ordinary catheter. In pigs, the plateau amplitudes of the MAPs recorded using the modified-tip catheter were 4.1 +/- 3.2 mV for the atrial and 9.5 +/- 4.3 mV for the ventricular MAPs. In patients, both the ventricular and atrial MAPs recorded using the modified-tip catheter were significantly higher than using the ordinary catheters, 15.7 +/- 8 and 3.0 +/- 0.9 mV vs 9.5 +/- 3.9 and 2.0 +/- 0.6 mV for the ventricular and atrial MAPs, respectively (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The baseline disturbances were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10% of the MAP amplitude in 95% of the pig and 96% of the patient MAPs. A modified-tip Navi-Star catheter could be used in swine and in humans for prompt recording of MAPs with acceptable amplitudes and baselines. MAP mapping using the modified-tip catheter is safe and feasible for clinical use.
The aim of this study was to evaluate the global sequence of repolarization over the ventricular ... more The aim of this study was to evaluate the global sequence of repolarization over the ventricular endocardium. Disturbances in myocardial repolarization are associated with the genesis of arrhythmias. However, little is known about the global sequence of repolarization. Monophasic action potentials (MAPs) were recordedfrom 61 +/- 18 LV and/or RV sites in ten healthy pigs and from 43 +/- 15 LV or RV sites in eight patients using the CARTO system. Local activation time (AT), end-of-repolarization (EOR) time, and MAP duration were calculated and three-dimensional global maps of AT, EOR, and MAP duration constructed. LV maps were obtained from all ten pigs and RV maps from three pigs. Five RV maps and five LV maps were obtained from the eight patients. (1) EOR sequence was recognizable in 12 of 13 pig maps and in all the patient maps. (2) EOR followed the sequence of activation in 12 of 13 pig maps and 8 of 10 patient maps. (3) The longest MAPs were recorded in or near the earliest activation area, and the shortest ones in or near the latest activation area in all the pig maps and in nine often and eight often patient maps, respectively. (4) In all maps, MAP duration and AT were negatively correlated, and EOR and AT positively correlated. In conclusion, repolarization gradients exist over the pig and the human ventricular endocardium. The activation sequence is a determinant for the repolarization sequence. The magnitude of the progressive MAP shortening with progressively later activation, relative to local AT, is a critical factor governing the direction and pattern of the EOR.
Journal of Interventional Cardiac Electrophysiology, 2005
The ECG interval from the peak to the end of the T wave (T peak-T end) has been used as an index ... more The ECG interval from the peak to the end of the T wave (T peak-T end) has been used as an index of transmural dispersion of ventricular repolarization (DVR). The correlation between the T peak-T end interval and the global DVR, however, has not been well-evaluated. Methods: Monophasic action potentials (MAPs) were recorded from 51 ± 10 epicardial and 64 ± 9 endocardial sites in the left ventricles of 10 pigs, and from 41 ± 4 epicardial and 53 ± 2 endocardial sites in the right ventricles of 2 of the 10 pigs using the CARTO mapping system. The end of repolarization times over the epi- and endocardium were measured, and the end of repolarization dispersions over the epicardium (DVR-epi), over the endocardium (DVR-endo) and over both (DVR-total) were calculated. The QTpeak, QTend and T peak-T end intervals as well as the QTpeak and QTend dispersions were obtained from the simultaneously recorded 12-lead ECG. Results: The maximal T peak-T end intervals (57 ± 7 ms) were consistent with the DVR-total (58 ± 11 ms, p > 0.05), and significantly correlated with the DVR-total (r = 0.64, p < 0.05). However, the mean T peak-T end intervals (44 ± 5 ms), and T peak-T end intervals from lead II (41 ± 6 ms) and V 5 (43 ± 5 ms) were all significantly smaller than and poorly correlated with the DVR-total, as were the QTpeak and QTend dispersions (15 ± 2 ms vs. 21 ± 4 ms). Conclusion: The maximal T peak-T end interval may be used as a noninvasive estimate for the global DVR, but not the QTpeak and QTend dispersions, nor the mean T peak-T end interval and that from a single lead.
... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Met... more ... 265275. [3] DS Bayard, Statistical plant set ... [5] N. Cai, CM Dohnal, and SB Olsson, Methodological aspects of the use of heart rate stratified RR interval histograms in the analysis of atrioventricular conduction during atrial fibrillation, Cardiovasc. Res., vol. ...
Previous in vitro studies have suggested full repolarization of the epicardium coincides with the... more Previous in vitro studies have suggested full repolarization of the epicardium coincides with the peak of the T wave (T(peak)) and that of the M cells coincides with the end of the T wave (T(end)). However, in vivo validation of the theory is lacking. Monophasic action potentials (MAPs) were recorded using the CARTO mapping system from 51 +/- 10 epicardial sites and 64 +/- 9 endocardial sites of the left ventricle in 10 pigs and from 41 +/- 4 epicardial sites and 53 +/- 2 endocardial sites of the right ventricle in two of the 10 pigs. End of repolarization (EOR) times over the epicardium (EOR(epi)), endocardium (EOR(endo)), and over both (EOR(total)) were obtained. QT(peak) and QT(end) intervals were measured from simultaneously recorded 12-lead ECG. Minimal and maximal EOR(total) were observed in the left ventricle in all pigs. Minimal EOR(total) was on the epicardium in five pigs, and maximal EOR(total) was on the endocardium in nine pigs. Minimal, mean, and maximal QT(peak) intervals all were significantly smaller than maximal EOR(epi) (322 +/- 23 ms, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.01). No significant difference was found between maximal QT(end) interval (338 +/- 30 ms) and maximal EOR(endo) (339 +/- 24 ms, difference = 1 +/- 19 ms, P =.92), between maximal QT(end) interval and maximal EOR(total) (341 +/- 24 ms, difference = 2 +/- 18 ms, P =.69), or between minimal QT(peak) interval (283 +/- 28 ms) and minimal EOR(total) (282 +/- 20 ms, difference = 0 +/- 15 ms, P =.95). In in vivo pig models, T(peak) does not coincide with full repolarization of the epicardium but coincides well with the earliest EOR, whereas the T(end) corresponds with the latest EOR. These findings suggest that not only the transmural gradients but also the apicobasal repolarization gradients contribute to genesis of the T wave.
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