ABSTRACT
The aim of the study was to assess the time-domain parameters of atrial signal-averaged ECG (ASAECG) and ventricular signal-averaged ECG (SAECG) in patients with mitral valve prolapse (MVP) and healthy ones. Fifty patients with MVP (15 men, 35 women, mean age--37.1 +/- 8.9 years) and 50 healthy controls (36 men, 14 women, mean age 38.2 +/- 4.7 years) were studied). The following time-domain parameters of ASAECG were analysed: the root mean square voltage of the terminal 10, 20, 30 ms of filtered P wave (RMS10, 20, 30) and the total duration of filtered P wave (PWD). The atrial late potentials (ALP) were defined as the presence: RMS10 < 4 microV i PWD > 123 ms. As the time-domain parameters of SAECG we analysed: the root mean square voltage of the terminal 40, 50 ms of the filtered QRS (RMS 40, 50), the total filtered QRS duration (t-QRS) and the low-amplitude signal duration < 40 microV in the terminal QRS (LPD). The ventricular late potentials (VLP) were defined as the presence of at least two of the following criteria: t-QRS > 114 ms, RMS 40 < 20 microV i LPD > 38 ms. There was no difference in the time-domain parameters of ASAECG between patients with MVP and controls: RMS 10: 4.5 +/- 1.8 microV vs 4.8 +/- 1.9 microV, RMS 20: 6.3 +/- 2.2 microV vs 6.1 +/- 2.2 microV, RMS 30: 8.3 +/- 2.5 microV vs 7.1 +/- 2.7 microV and PWD 113 +/- 11.7 ms vs 116 +/- 15.2 ms, respectively. Three patients with MVP (6%) and 5 controls (10%) revealed ALP. THE time-domain parameters of SAECG did not differ in patients with MVP and controls: RMS 40: 40.2 +/- 29.1, microV vs 35.5 +/- 18.2 microV, RMS 50: 68.2 +/- 40.1 microV vs 64.4 +/- 33.6 microV and t-QRS-101.4 +/- 10.7 ms vs 101.8 +/- 10.9 ms i LPD--28.7 +/- 10.0 ms vs 28.3 +/- 10.0 ms, respectively. VLP were found in 7 patients with MVP (14%) and 5 controls (10%). Our findings suggest that time-domain parameters of ASAECG and SAECG could not differentiate patients with MVP and healthy ones. Moreover, the presence of ALP and VLP in MVP group did not correlate with supraventricular and ventricular arrhythmias recorded on ambulatory ECG.
Subject(s)
Atrial Function , Electrocardiography/methods , Mitral Valve Prolapse/diagnosis , Ventricular Function , Adult , Arrhythmias, Cardiac/diagnosis , Female , Humans , Male , Middle AgedABSTRACT
Recording of ventricular signal-averaged ECG (VSAE) were carried out in 19 patients suffering from ischemic heart disease before and after intravenously administration of amiodarone using a commercially available machine HIPEC-200 HA device of Aerotel's. The high gain ECG was recorded during basic rhythm with orthogonal Frank leads X, Y, Z. These combined into a vector magnitude and the QRS duration (QRS), the duration of low amplitude signals < 40 microV (LPD) and the root mean square voltage of the signals in the last 40 and 50 ms of the filtered QRS (RMS 40,50) were calculated for VSAE. It was time-domain analysis of VSAE. In frequency domain analysis were calculated the following parameters in range from 40 Hz to 400 Hz in linear scale: area ratio 20-50 Hz/0-20 Hz, peak and magnitude ratio and in logarithmic scale: energy spectrum > -60 dB and decibel drop at 40 Hz. Subsequently amiodarone hydrochloride was given intravenously 5 mg/kg c.c. and again time-domain and frequency domain analysis were done. Data presented are mean +/- standard deviation. Statistical comparisons were performed with paired t-Student test. Significance refers to a p values < 0.05. Time-domain analysis of VSAE didn't show any significant differences after amiodarone injection. During frequency-domain analysis of VSAE statistically significant differences were displayed in Frank lead X and Y for energy spectrum > -60 dB. In Frank lead X decrease of this parameter after amiodarone (from 3322 +/- 1057 dB-Hz to 2628 +/- 733) and in lead Y increase (from 2793 +/- 500 dB-Hz to 3199 +/-938 dB-Hz) was noticed. Our observation have indicated that intravenously application of amiodarone hydrochloride didn't change parameters in time-domain analysis. Statistically significant differences were noticed only during frequency analysis VSAE in logarithmic scale -energy spectrum > -60 dB but only in two leads X and Y.
Subject(s)
Amiodarone/administration & dosage , Anti-Arrhythmia Agents/administration & dosage , Myocardial Ischemia/drug therapy , Aged , Electrocardiography , Female , Humans , Injections, Intravenous , Male , Middle Aged , Myocardial Ischemia/diagnosis , Myocardial Ischemia/physiopathology , Signal Processing, Computer-AssistedABSTRACT
The aim of the study was to assess whether the P-wave triggered signal-averaged ECG (SAECG) used in patients with idiopathic mitral valve prolapse syndrome could predict the risk of the development of supraventricular arrhythmias. Fifty patients with idiopathic mitral valve prolapse syndrome (15 men, 35 women, mean age: 37 +/- 9 years) were prospectively studied. P-wave triggered SAECG was recorded with a commercially available system (HIPEC-200HA Aerotel). The following parameters were calculated: the root-mean-square voltage for the terminal 10, 20, 30 ms of filtered P-wave (RMS10,20,30) and time duration of filtered P-wave (PWD). Nine patients with mitral valve prolapse syndrome (18%) revealed the occurrence of supraventricular arrhythmias on Holter monitoring whereas of the remaining 41 (82%), no clinically relevant supraventricular arrhythmias were detected. We found PWD values to be significantly longer in patients with supraventricular arrhythmias when compared with those without arrhythmias: 119.8 +/- 6.9 ms vs. 111.7 +/- 12.1 ms, respectively, P < 0.02. We conclude that P-wave triggered SAECG could be a useful technique for detecting patients with idiopathic mitral valve prolapse syndrome at risk of paroxysmal supraventricular arrhythmias.
