- Email: [email protected]
New approach to prediction of ventricular tachycardia after acute myocardial infarction
Selected Abstracts From the 21st Annual Meeting of the International Society of Electrocardiology observed in patient 1. It was notable in this patient that two types of AVNRT (common and u n c o m m o n ) were induced, and sustained u n c o m m o n type AVNRT changed spontaneously to c o m m o n type AVNRT using dual ventricular responses. Although an AV conduction curve in patient 2 showed just a single discontinuity (from the fast pathway to the slow pathway), it represented overlapping of two conduction curves due to dual ventricular responses (simultaneous conduction over the fast pathway and the very slow pathway). In patient 2, two types of AV nodal reentry were induced by atrial pacing; one was sustained slow/fast type AVNRT and the other one was very slow/fast type AV nodal echo. Radiofrequency catheter ablation at the posteroseptal right atrium between the coronary sinus ostium and tricuspid annulus eliminated slow pathway conduction completely, and instead of a single slow/fast AV nodal echo being induced, a single very slow/fast echo was induced after ablation. A postablation AV conduction curve showed an unusual curve; there was no slow pathway conduction curve and the two conduction curves overlapped at the same point, except the very slow pathway conduction curve had a much shorter refractory period than the preablation curve. These unique findings suggest that (1) there are functionally (and possibly anatomically) different antegrade triple AV nodal pathways in two patients and (2) radiofrequency ablation of AVNRT with the triple AV nodal pathways could provide valuable information on the concepts of AV nodal reentry.
Evidence of Repolarization Disparities in Arrhythmogenic Right Ventricular Dysplasia L. De Ambroggi, C. Santambrogio, M. Rovida, E. Aline, Division of Cardiology, San Donato Hospital, University of Milan, San Donato Milanese, Italy The purpose of our study was to identify signs of ventricular recovery disparities in patients with documented arrhythmogenic right ventricular dysplasia (ARVD). Body surface potential maps were recorded from 117 chest leads in 10 patients (mean age, 38 + 11 years), with mild ARVD. Data were compared with those obtained in a control group of healthy subjects. The following variables were considered: QRST integral maps, similarity index (SI), and dispersion of recovery times (RTD) on the total map and on a
77
midthorax circumferential level. The SI was computed by applying the principal component analysis to all recorded ST-T waveforms. A low value of SI indicates a large variety of ST-T waves and is considered a marker of recovery disparities. The RT was automatically measured in each lead point between the QRS onset and the time instant of the maximal positive dV/dt of the T wave. The RTD was defined as the difference between the m a x i m u m and minim u m RT. The QTc interval (QT interval corrected by the Bazett formula) measured in the standard 12lead electrocardiogram was not significantly different in the ARVD and control groups. QRST integral maps showed a clear multipolar distribution only in one ARVD patient. The m e a n value of SI was significantly lower in the ARVD patients than in the control group (62 _+ 10% vs 77 +_ 8%, P < .001). The RTD on the map and RTD at the circumferential level were significantly longer (P < .001) in the ARVD patients than in the control group ( 181 +_ 32 ms vs 134 +_ 16 ms and 164 _+ 29 ms vs 123 _+ 20 ms, respectively). Our results suggest that' even in mild forms of ARVD, body surface potential maps can reveal signs of repolarization disparities, a condition favoring ventricular arrhythmias.
New Approach to Prediction of Ventricular Tachycardia After Acute Myocardial Infarction M. Ito, Y. Watanabe, N. Nagai, M. Kinoshita, M. Sarai, S. Mori, M. Tokuda, T. Shimaji, A. Kani, K. Kato, Y. Abo, H. Kurokawa, T. Yasui, H. Nakano, H. Chikamatsu, T. Konodo, H. Hishida, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Aichi, Japan Recently, signal-averaged electrocardiograms were used for the prediction of ventricular arrhythmias, such as ventricular tachycardia (VT) or ventricular fibrillation (VF). However, an inconsistency of late potentials was a discouraging problem. Therefore, we developed a new index for the prediction of VT using body surface potential mapping. Patients with acute myocardial infarction (46 patients with anterior, 35 with inferior; age, 60 + 12 years; 69 men, I2 women) were divided into four groups according to the Lown classification of ventricular arrhythmias (group 1: Lown 0,I, group 2: Lown 2,3,4A, group 3: Lown 4B, group 4: sustained VT/VF). Body surface potential maps were obtained within 1 week and at I m o n t h from the onset of
78
Journal of Electrocardiology Vol. 28 No. 1 January 1995
myocardial infarction using an 87 lead-point system by HPM-6500 or VCM-3000 (Chunichi-Denshi, Japan). AD conversion was carried out at a sampling rate of 1,000 Hz. Frequency analysis was applied for 128 ms from the onset of the QRS w a v e by fast Fourier transformation. The distribution of spectral components of 2 5 - 5 0 Hz was displayed on the torso and classified into three categories (type A: 2 equivalent maxima, type B: 2 unequal maxima, type C: 1 maximum).
Type A Type B Type C
Group 1
Group 2
Group 3
Group 4
Total
0 3 30 33
1 I1 17 29
4 1 7 12
5 2 0 7
l0 17 54 81
AR1 and AR2 were also significantly lower in group I t h a n in group 2. Using the criteria of FPD > I25 ms and V20 ~< 3.0/zV to define atrial late potentials gave a sensitivity of 87%, a specificity of 93%, and a predictive accuracy of 92%. The criteria of AR1 < 50 or AR2 < 50 gave predictive accuracies of 79 and 73%, respectively. Compared with the predictive accuracy of the criteria of FPD > 125 ms and V20 ~ 3.0/zV, that of the criteria of AR1 < 50 or AR2 < 50 was lower. These results suggest that the SAECG is useful to predict Paf during sinus r h y t h m in patients with IHD.
A Histopathologic Study on the Conduction System in Centenarians
Chi-square = 45.2 (P < .01). Similar results were also reported that the spatial distribution of c o m p o n e n t s of 1 3 - 5 6 Hz in a patient with sustained VT after myocardial infarction showed type A distribution. Type A distribution of spectral c o m p o n e n t s of 2 5 - 5 0 Hz on the torso could be predictive for the patients prone to VT after myocardial infarction.
Prediction of Paroxysmal Atrial Fibrillation in Patients With Ischemic Heart Disease R. Abe, T. Nishida, K. Yamashita, T. Degawa, Y. Enjoji, T. Ikeda, K. Sugi, S. Yabuki, T. Yamaguchi, Third Department of Internal Medicine, Toho University, Ohashi Hospital, Tokyo, J a p a n To determine w h e t h e r paroxysmal atrial fibrillation (Paf) can be predicted during sinus r h y t h m in patients with ischemic heart disease (IHD), P wave-triggered signal-averaged electrocardiograms (SAECGs) were recorded in 77 patients with IHD. The patients were separated into two groups. Group 1 was composed of 15 patients with Paf and group 2 was composed of 62 patients without Paf. Filtered P wave duration (FPD), the r o o t - m e a n - s q u a r e voltage of the last 20 ms (V20), and the duration of'under 5/zV (DS) of the vector magnitude were measured. In addition, area ratio 1 (ARI: area of 2 0 - 6 0 Hz/ area of 0 - 2 0 Hz multiplied by 100) and area ratio 2 (AR2: area of 2 0 - 6 0 Hz/area of 1 0 - 6 0 Hz multiplied by 100) were calculated with fast Fourier transformation analysis in all patients. FPD and D5 were significantly longer, and V20 was significantly lower in group 1 than in group 2.
M. Sugiura, S. Ohkawa, C. Watanabe, Y. Ito, A. Toku, K. Ohtsubo, Y. Esaki, Department of Clinical Pathology, Tokyo Metropolitan Institute of Gerontology and D e p a r t m e n t of Pathology, Tokyo Metropolitan Geriatric Hospital, Itabashi, Tokyo, J a p a n Effects of extreme aging on the conduction system were studied in 37 centenarians a m o n g 6,900 consecutive autopsies performed over 28 years. There were 8 m e n and 29 w o m e n with ages ranging bet w e e n 100 and 106 years (mean, 102 years). Clinical diagnoses were congestive heart failure in 5 patients, cerebrovascular diseases in 3, neoplasm in 6, infection in I 0, and other in 13. Cardiac r h y t h m was sinus in 27 patients, atrial fibrillation in 8, and pacemaker r h y t h m in 2. Atrioventricular (AV) conduction time was 0 . I 6 - 0 . 2 8 seconds, and advanced AV block was found in one case. There were three right and one left bundle branch block (BBB). Heart weight was 1 7 0 - 4 3 0 g (mean, 290 g). Marked coronary stenosis with small to large myocardial infarctions was found in 7 patients. Valvular heart disease was found in three patients. Atrophy of the sinoatrial (SA) node was found in 7 cases, and quantitation of the SA nodal cells by color image analyzer ranged between 1 and 2 i % in 17 cases. A m o n g 37 cases, changes of the AV node and bundle were mild, and severe lesions were found in the branching portion of the AV bundle in 4 patients (advanced AV block in 1), unifascicular fibrosis was found in 13 (RBBB in 1), and bifascicular fibrosis was found in l l (LBBB in 1). The conduction system of centenarians was marked by a reduction of the SA nodal ceils and a high incidence of one or two fascicular lesions a m o n g three fascicles (right bundle branch and anterior and posterior fascicles of the left bundle branch).
Evidence of Repolarization Disparities in Arrhythmogenic Right Ventricular Dysplasia L. De Ambroggi, C. Santambrogio, M. Rovida, E. Aline, Division of Cardiology, San Donato Hospital, University of Milan, San Donato Milanese, Italy The purpose of our study was to identify signs of ventricular recovery disparities in patients with documented arrhythmogenic right ventricular dysplasia (ARVD). Body surface potential maps were recorded from 117 chest leads in 10 patients (mean age, 38 + 11 years), with mild ARVD. Data were compared with those obtained in a control group of healthy subjects. The following variables were considered: QRST integral maps, similarity index (SI), and dispersion of recovery times (RTD) on the total map and on a
77
midthorax circumferential level. The SI was computed by applying the principal component analysis to all recorded ST-T waveforms. A low value of SI indicates a large variety of ST-T waves and is considered a marker of recovery disparities. The RT was automatically measured in each lead point between the QRS onset and the time instant of the maximal positive dV/dt of the T wave. The RTD was defined as the difference between the m a x i m u m and minim u m RT. The QTc interval (QT interval corrected by the Bazett formula) measured in the standard 12lead electrocardiogram was not significantly different in the ARVD and control groups. QRST integral maps showed a clear multipolar distribution only in one ARVD patient. The m e a n value of SI was significantly lower in the ARVD patients than in the control group (62 _+ 10% vs 77 +_ 8%, P < .001). The RTD on the map and RTD at the circumferential level were significantly longer (P < .001) in the ARVD patients than in the control group ( 181 +_ 32 ms vs 134 +_ 16 ms and 164 _+ 29 ms vs 123 _+ 20 ms, respectively). Our results suggest that' even in mild forms of ARVD, body surface potential maps can reveal signs of repolarization disparities, a condition favoring ventricular arrhythmias.
New Approach to Prediction of Ventricular Tachycardia After Acute Myocardial Infarction M. Ito, Y. Watanabe, N. Nagai, M. Kinoshita, M. Sarai, S. Mori, M. Tokuda, T. Shimaji, A. Kani, K. Kato, Y. Abo, H. Kurokawa, T. Yasui, H. Nakano, H. Chikamatsu, T. Konodo, H. Hishida, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Aichi, Japan Recently, signal-averaged electrocardiograms were used for the prediction of ventricular arrhythmias, such as ventricular tachycardia (VT) or ventricular fibrillation (VF). However, an inconsistency of late potentials was a discouraging problem. Therefore, we developed a new index for the prediction of VT using body surface potential mapping. Patients with acute myocardial infarction (46 patients with anterior, 35 with inferior; age, 60 + 12 years; 69 men, I2 women) were divided into four groups according to the Lown classification of ventricular arrhythmias (group 1: Lown 0,I, group 2: Lown 2,3,4A, group 3: Lown 4B, group 4: sustained VT/VF). Body surface potential maps were obtained within 1 week and at I m o n t h from the onset of
78
Journal of Electrocardiology Vol. 28 No. 1 January 1995
myocardial infarction using an 87 lead-point system by HPM-6500 or VCM-3000 (Chunichi-Denshi, Japan). AD conversion was carried out at a sampling rate of 1,000 Hz. Frequency analysis was applied for 128 ms from the onset of the QRS w a v e by fast Fourier transformation. The distribution of spectral components of 2 5 - 5 0 Hz was displayed on the torso and classified into three categories (type A: 2 equivalent maxima, type B: 2 unequal maxima, type C: 1 maximum).
Type A Type B Type C
Group 1
Group 2
Group 3
Group 4
Total
0 3 30 33
1 I1 17 29
4 1 7 12
5 2 0 7
l0 17 54 81
AR1 and AR2 were also significantly lower in group I t h a n in group 2. Using the criteria of FPD > I25 ms and V20 ~< 3.0/zV to define atrial late potentials gave a sensitivity of 87%, a specificity of 93%, and a predictive accuracy of 92%. The criteria of AR1 < 50 or AR2 < 50 gave predictive accuracies of 79 and 73%, respectively. Compared with the predictive accuracy of the criteria of FPD > 125 ms and V20 ~ 3.0/zV, that of the criteria of AR1 < 50 or AR2 < 50 was lower. These results suggest that the SAECG is useful to predict Paf during sinus r h y t h m in patients with IHD.
A Histopathologic Study on the Conduction System in Centenarians
Chi-square = 45.2 (P < .01). Similar results were also reported that the spatial distribution of c o m p o n e n t s of 1 3 - 5 6 Hz in a patient with sustained VT after myocardial infarction showed type A distribution. Type A distribution of spectral c o m p o n e n t s of 2 5 - 5 0 Hz on the torso could be predictive for the patients prone to VT after myocardial infarction.
Prediction of Paroxysmal Atrial Fibrillation in Patients With Ischemic Heart Disease R. Abe, T. Nishida, K. Yamashita, T. Degawa, Y. Enjoji, T. Ikeda, K. Sugi, S. Yabuki, T. Yamaguchi, Third Department of Internal Medicine, Toho University, Ohashi Hospital, Tokyo, J a p a n To determine w h e t h e r paroxysmal atrial fibrillation (Paf) can be predicted during sinus r h y t h m in patients with ischemic heart disease (IHD), P wave-triggered signal-averaged electrocardiograms (SAECGs) were recorded in 77 patients with IHD. The patients were separated into two groups. Group 1 was composed of 15 patients with Paf and group 2 was composed of 62 patients without Paf. Filtered P wave duration (FPD), the r o o t - m e a n - s q u a r e voltage of the last 20 ms (V20), and the duration of'under 5/zV (DS) of the vector magnitude were measured. In addition, area ratio 1 (ARI: area of 2 0 - 6 0 Hz/ area of 0 - 2 0 Hz multiplied by 100) and area ratio 2 (AR2: area of 2 0 - 6 0 Hz/area of 1 0 - 6 0 Hz multiplied by 100) were calculated with fast Fourier transformation analysis in all patients. FPD and D5 were significantly longer, and V20 was significantly lower in group 1 than in group 2.
M. Sugiura, S. Ohkawa, C. Watanabe, Y. Ito, A. Toku, K. Ohtsubo, Y. Esaki, Department of Clinical Pathology, Tokyo Metropolitan Institute of Gerontology and D e p a r t m e n t of Pathology, Tokyo Metropolitan Geriatric Hospital, Itabashi, Tokyo, J a p a n Effects of extreme aging on the conduction system were studied in 37 centenarians a m o n g 6,900 consecutive autopsies performed over 28 years. There were 8 m e n and 29 w o m e n with ages ranging bet w e e n 100 and 106 years (mean, 102 years). Clinical diagnoses were congestive heart failure in 5 patients, cerebrovascular diseases in 3, neoplasm in 6, infection in I 0, and other in 13. Cardiac r h y t h m was sinus in 27 patients, atrial fibrillation in 8, and pacemaker r h y t h m in 2. Atrioventricular (AV) conduction time was 0 . I 6 - 0 . 2 8 seconds, and advanced AV block was found in one case. There were three right and one left bundle branch block (BBB). Heart weight was 1 7 0 - 4 3 0 g (mean, 290 g). Marked coronary stenosis with small to large myocardial infarctions was found in 7 patients. Valvular heart disease was found in three patients. Atrophy of the sinoatrial (SA) node was found in 7 cases, and quantitation of the SA nodal cells by color image analyzer ranged between 1 and 2 i % in 17 cases. A m o n g 37 cases, changes of the AV node and bundle were mild, and severe lesions were found in the branching portion of the AV bundle in 4 patients (advanced AV block in 1), unifascicular fibrosis was found in 13 (RBBB in 1), and bifascicular fibrosis was found in l l (LBBB in 1). The conduction system of centenarians was marked by a reduction of the SA nodal ceils and a high incidence of one or two fascicular lesions a m o n g three fascicles (right bundle branch and anterior and posterior fascicles of the left bundle branch).