Publications (11) View all
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Article: Dynamicity of early and late phases of repolarization in patients with remote anterior myocardial infarction: the interlead differences.
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ABSTRACT: Repolarization dynamicity (QT/RR) is supposed to be a prognostic marker in post-MI patients. However, data on the relationships between early and late phases of QT and RR intervals (QT peak/RR and T peak-T end/RR) are insufficient, and which ECG lead should be used for the analysis is unclear. We analyzed repolarization dynamicity in patients after anterior MI with and without VT/VF history using two leads of Holter recordings- modified V(5) and V(3) . The daytime and nighttime periods were also analyzed. Cohort of 88 patients after anterior MI (>6 months) consisted of 43 patients without VT/VF (33 males; 59 ± 12 years; LVEF: 41 ± 7%; NoVT/VF), and 45 patients with VT/VF history- ICD implanted as secondary prevention (40 males; 64 ± 10 years; LVEF: 32 ± 8%; VT/VF). QT/RR, QT peak/RR and T peak-T end/RR were calculated from 24-hour ECG for the entire recording, daytime and nighttime periods, from V(5) and V(3) leads, respectively. VT/VF patients had lower LVEF (P = 0.001). There were no differences in age and gender. VT/VF group had steeper QT/RR, QT peak/RR, and T peak-T end/RR in V(5) : 0.233 ± 0.04 versus 0.150 ± 0.05, P = 0.0001, 0.181 ± 0.04 versus 0.120 ± 0.04, P = 0.0001, 0.052 ± 0.02 versus 0.030 ± 0.02, P = 0.0001, and in V(3) : 0.201 ± 0.04 versus 0.149 ± 0.05, P = 0.0001, 0.159 ± 0.03 versus 0.118 ± 0.04, P = 0.0001, and 0.042 ± 0.02 versus 0.031 ± 0.02, P = 0.004; respectively. VT/VF patients had higher indices in V(5) than in V(3) lead (P = 0.001). QT/RR and QT peak/RR were steeper at daytime period in both leads. It was not found for T peak-T end/RR. Patients with VT/VF history are characterized by steeper relationships between repolarization duration and RR intervals. These findings are more evident in modified V(5) lead.Annals of Noninvasive Electrocardiology 04/2012; 17(2):101-7. · 1.10 Impact Factor -
Article: Correlation of heart rate variability parameters and QT interval in patients after PTCA of infarct related coronary artery as an indicator of improved autonomic regulation.
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ABSTRACT: The purpose of this study was to determine if PTCA of the infarct related coronary artery (IRA) in the late phase of myocardial infarction (MI) can improve autonomic regulation of sinus rhythm and electrical stability of the myocardium measured by heart rate variability (HRV), QT, QTc, and its dispersion (QTd) and if any correlation exists among these measures. The study was performed in 25 patients (21 male, age: 50 +/- 9 years, EF: 52% +/- 11%) in the late phase of MI (2.5 +/- 1.5 months). HRV parameters were calculated automatically. QT, QTc, and QTd were measured manually from a 12-lead surface ECG (50 mm/s). All measurements were made before and 3-5 days after PTCA. Day and night parameters of HRV were sampled over two periods: 2 pm to 10 pm (day) and 10 pm to 6 am (night). Parameters of HRV measured from whole recordings were significantly higher after successful PTCA: SDRR (116 +/- 31 vs 128 +/- 38 ms), SD (55 +/- 17 vs 62 +/- 22 ms), rMSSD (30 +/- 13 vs 36 +/- 14 ms) and HF (246 +/- 103 vs 417 +/- 224 ms2). Significant differences were found during daytime for SD, rMSSD, and HF, and during nighttime for SDRR, SDANN. QT interval duration, QT corrected to the heart rate, and QT dispersion were significantly lower after PTCA (QTd: 54 +/- 15 vs 39 +/- 12 ms). There was no correlation between HRV and QT values before PTCA. High correlations were found after the procedure, particularly between QTd and nighttime HRV. CONCLUSIONS: PTCA of IRA in the late phase of MI enhances sympathovagal regulation of the cardiac rhythm and the electrical stability of the heart, which may be prognostically important.Pacing and Clinical Electrophysiology 12/1998; 21(11 Pt 2):2407-10. · 1.35 Impact Factor -
Article: Impact of left ventricular remodeling on ventricular repolarization and heart rate variability in patients after myocardial infarction treated with primary PCI: prospective 6 months follow-up.
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ABSTRACT: The relation between postinfarction left ventricle remodeling (LVR), autonomic nervous system and repolarization process is unclear. Purpose of the study was to assess the influence of LVR on the early (QTpeak) and late (TpeakTend) repolarization periods in patients after myocardial infarction (MI) treated with primary PCI. The day-to-night differences of repolarization parameters and the relation between QT and heart rate variability (HRV) indices, as well left ventricle function were also assessed. The study cohort of 104 pts was examined 6 months after acute MI. HRV and QT indices (corrected to the heart rate) were obtained from the entire 24-hour Holter recording, daytime and nighttime periods. LVR was found in 33 patients (31.7%). The study groups (LVR+ vs LVR-) did not differ in age, the extent of coronary artery lesions and treatment. Left ventricle ejection fraction (LVEF) was lower (38%+/- 11% vs 55%+/- 11%, P < 0.001), both QTc (443 +/- 26 ms vs 420 +/- 20 ms, P < 0.001) and TpeakTendc (98 +/- 11 ms vs 84 +/- 12 ms, P < 0.005) were longer in LVR + patients, with no differences for QTpeakc. Trends toward lower values of time-domain (SDRR, rMSSD) HRV parameters were found in LVR+ pts. Day-to-night difference was observed only for SDRR, more marked in LVR-group. Remarkable relations between delta LVEF (6 months minus baseline), delta LVEDV and TpeakTendc were found, with no such relationships for QTpeakc. The patients with LVR have longer repolarization time, especially the late phase-TpeakTend, which represents transmural dispersion of repolarization. Its prolongation seems to be related to local attributes of myocardium and global function of the left ventricle but unrelated to the autonomic nervous influences. Remodeling with moderate LV systolic dysfunction is associated with insignificant decrease in HRV indices and preserved circadian variability.Annals of Noninvasive Electrocardiology 02/2008; 13(1):8-13. · 1.10 Impact Factor -
Article: QT/RR relationship in patients after remote anterior myocardial infarction with left ventricular dysfunction and different types of ventricular arrhythmias.
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ABSTRACT: QT/RR relationship was found to be both rate-dependent and rate-independent, what suggests the influence of autonomic drive and other not-autonomic related factors on it. The steeper QT/RR slope in patients after acute myocardial infarction (MI) was described, but the relationship to ventricular arrhythmias is unknown. The purpose of this study was to calculate differences in QT/RR relationship in patients after remote anterior MI with left ventricular dysfunction and different types of ventricular arrhythmias. The cohort of 95 patients (age: 63 +/- 11 years, LVEF: 35 +/- 9%) with previous anterior MI (mean 1.1 years) was divided into two well-matched groups-50 patients without episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) (NoVT/VF: 39 males, 64 +/- 12 years, LVEF 37 +/- 8%) and 45 patients with VT and/or VF (all with ICD implanted) (VT/VF: 35 males, 62 +/- 10 years, LVEF 34 +/- 10%). No true antiarrhythmics were used. QT/RR slope was calculated from 24-hour Holter ECG for the entire recording (E), daytime (D) and nighttime (N) periods. Groups did not differ in basic clinical data (age, LVEF, treatment). QT/RR slopes were steeper in VT/VF than in NoVT/VF group in all analyzed periods: E - 0.195 +/- 0.03 versus 0.15 +/- 0.03 (P < 0.001), N - 0.190 +/- 0.03 versus 0.138 +/- 0.03 (P < 0.001) and D - 0.200 +/- 0.04 versus 0.152 +/- 0.03 (P < 0.001). No significant day-to-night differences were found in both groups. Steeper QT/RR slope and complete lack of day-to-night differences in VT/VF patients show inappropriate QT adaptation to the heart rate changes. The prognostic significance of this parameter needs prospective studies.Annals of Noninvasive Electrocardiology 02/2008; 13(1):61-6. · 1.10 Impact Factor -
Article: Postextrasystolic repolarization abnormalities in ST-U segment in patients with ventricular arrhythmias.
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ABSTRACT: Changes in U-wave amplitude after premature ventricular contractions (PVC) are known as prognostic markers in the long QT syndrome dependent on bradycardia. The purpose of the study was to find correlation between postextrasystolic ST-U segment changes and a history of sustained ventricular tachycardia or ventricular fibrillation (VT/VF). The ST-U segment configurations were taken from the 24-hour ambulatory ECG. The comparison of the morphology of these segments was performed between sinus beats preceding PVC's and first postextrasystolic beats. Two groups of patients were evaluated: 1) 32 patients with VT/VF history (VT/VF group), and 2) 36 patients with potentially malignant arrhythmia (structural heart disease with frequent PVCs and/or nonsustained VT- nsVT) (non-VT/VF group). We found T-wave changes in 8 patients (25%) from the VT/VF group and in 12 patients (33.3%) from the nonVT/VF group (P = NS) and U-wave changes in 13 patients (40.6%) and 3 patients (8.3%), respectively (P < 0.05). Other ECG indexes related to PVC's were also considered: RR interval, coupling interval (CI), prematurity index (PI), and postextrasystolic pause (PP). The analysis of these ECG indices revealed, when compared with patients without T-U-wave changes, that the occurrence of U-wave changes was significantly related to longer RR interval of the sinus rhythm preceding PVC: 1025 +/- 211 vs 918 +/- 200 ms (P < 0.05). The prematurity index was lowest in patients with U-wave changes: 0.54 +/- 0.12 vs 0.65 +/- 0.16 (P < 0.01) while postextrasystolic pauses leading to the postextrasystolic U-wave changes were significantly longer: 1383 +/- 223 vs 1130 +/- 247 ms (P < 0.001). CI did not differentiate patients: 556 +/- 108 vs 584 +/- 117 ms (P = NS). Postextrasystolic changes in ST-U segment configuration are dependent on bradycardia, low prematurity index of the PVC, and the lengthening of the postextrasystolic pause. U-wave changes more frequently appeared in patients with malignant arrhythmias. Follow-up study is needed to assess if they might be predictive for the occurrence or reoccurrence of arrhythmic episodes.Annals of Noninvasive Electrocardiology 02/2002; 7(1):17-21. · 1.10 Impact Factor
