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Biomedical subjects

H Kasanuki

Publications and source records attributed to H Kasanuki.

At least 127 records · Page 7Linked to original sources
PubMed1990

Detection of the spatial distribution of late potentials by body surface mapping using forty-five unipolar, leads.

For evaluating the spatial location of late potentials (LPs), the authors designed a new system for the body surface mapping of signal-averaged, filtered ECGs using forty-five thoracic unipolar leads (5 x 9 array). The signals from patients with old myocardial infarction (MI, N = 7) and arrhythmogenic right ventricular dysplasia (ARVD, N = 1) were amplified and passed through a bandpass (100-300 Hz) filter. The departure maps, LP isopotential maps, and LP30 area maps were generated and superimposed. The LP30 duration was determined as the section between the filtered QRS endpoints and points thirty milliseconds (ms) before. Isopotential maps of the LPs showed distinct positive and negative regions. In 7 cases with MI, the extreme was related to the zones indicated by the departure maps, and the LP30 area maps also corresponded to the departure areas. In 1 case of ARVD, endocardial fragmented activity directly recorded at the right ventricle closely corresponded with the region on the LP30 area map. In conclusion, body surface LP isopotential maps and LP30 area maps may provide useful information concerning the spatial distribution of endocardial fragmentation.

Arrhythmias, Cardiac↗
PubMed1989

Differentiation and mechanisms of prevention and termination of verapamil-sensitive sustained ventricular tachycardia.

The purpose of this study was to differentiate by means of electrophysiologic study, a drug's ability to terminate or to prevent ventricular tachycardia (VT). Differences between the 2 effects were examined in patients with VT and the underlying mechanisms were studied in verapamil-responsive idiopathic sustained VT. The clinical significance of the distinction for chronic oral drug therapy is discussed. Thirty-five cases of inducible sustained VT were studied. A drug was considered "preventive" if it prevented VT induction and repetitive ventricular response, and "terminating" if it stopped induced VT within 15 complexes or could stop VT after its intravenous administration. Prevention and termination occurred together in 13 of 19 cases (68%) with disopyramide, in 10 of 19 cases (53%) with procainamide, in 8 of 12 cases (67%) with lidocaine, in 11 of 15 cases (73%) with mexiletine, and in 10 of 16 cases (63%) with verapamil. In the 16 in which verapamil terminated VT, VT rate immediately before termination slowed markedly from 167 +/- 33 to 134 +/- 28 beats/min. In the 6 cases without preventative effects, minimal and maximal premature intervals for VT induction increased significantly, from 291 +/- 70 to 335 +/- 85 ms and 323 +/- 68 to 423 +/- 109 ms, respectively, after verapamil administration. In 2 cases in which verapamil had a terminating effect, 5 mg of verapamil restored sinus rhythm but 10 mg caused premature beats resembling VT complexes. In another 2, 5 mg of verapamil lengthened the minimal premature interval; 10 mg increased both minimal and maximal premature intervals and lengthened the VT cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Cryosurgical ablation of accessory atrioventricular pathways without cardiopulmonary bypass: an epicardial approach for Wolff-Parkinson-White syndrome.

An epicardial approach has been developed and applied to 31 Kent bundles (23 parietal, 1 right anteroseptal, and 7 posteroseptal bundles) in 28 patients with Wolff-Parkinson-White syndrome. Our technique consists of dissection of the atrioventricular fat pad of the Kent bundle site using an ultrasonic aspirator and subsequent cryosurgical ablation. For the left parietal and posteroseptal pathways, the apex of the heart has to be retracted upward, but this maneuver was well tolerated in all patients. Moreover, even through a narrow operative field, the ultrasonic aspirator permitted deliberate dissection on the beating heart without injury to major coronary vessels or the atrial wall. In 89% of the patients, operation was performed without the use of heart-lung bypass. All patients were free from preexcitation. With this technique, all Kent bundles except that adjacent to the atrioventricular node can be ablated on the beating heart, usually without heart-lung bypass.

Adolescent↗
PubMed1989

Mechanism and prediction of sudden cardiac death in arrhythmia patients using electrophysiological studies.

Thirty nine cases, in which sudden cardiac death (SCD) was suspected, were studied to evaluate the mechanism and the prediction of SCD in arrhythmia-patients using electrophysiological studies (EPS). The 39 cases (28 male and 11 female) were located by surveying 2098 patients who underwent EPS for the evaluation of arrhythmias. Age at time of EPS ranged from 4 to 86 years, average 50.5 years. Time from EPS to death was 2 to 163 months, average 27.9 months. Underlying heart disease was: dilated cardiomyopathy in 11, old myocardial infarction in 5, ischemic heart disease in 5, hypertensive heart disease in 5, valvular heart disease in 3, hypertrophic cardiomyopathy in 2, arrhythmogenic right ventricular dysplasia in 1, myocarditis in 1, sarcoidosis in 1, cor pulmonale in 1, and no obvious heart disease in 4. Fifteen had a permanent pacemaker implanted. SCD in cases without a permanent pacemaker (24 cases): 2 had chronic complete A-V block (one BH block, one HV block), 1 had advanced A-V block (HV block), 3 had bundle branch block with first degree HV block, 9 had ventricular tachycardia (VT), 3 had sick sinus syndrome (SSS), 3 had paroxysmal atrial flutter, 1 had WPW syndrome and paroxysmal atrial fibrillation, 1 had paroxysmal atrial tachycardia, and 3 had premature ventricular beats and first degree HV block. SCD in cases with permanent pacemaker (15 cases): 5 had SSS, and 10 had A-V block. In 3 of the 5 with SSS and 7 of the 10 with A-V block, VT was found before pacemaker implantation. In our study, brady and tachyarrhythmias coexisted in 25 cases (64%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Direct arrhythmia surgery in ventricular tachycardia: an experience with 18 consecutive patients].

18 patients with ventricular tachycardia (VT) underwent direct arrhythmia surgery between 1984 and 1988. There were 8 patients with ischemic VT, and 10 with nonischemic VT. Operative technique consisted of ablative procedures of the arrhythmogenic area determined by pre- and intraoperative mapping. Induced VT was usually unstable and transient during operation, so that instantaneous multi-point mapping was necessary in almost cases. For VT originated in the left ventricle or interventricular septum, the earliest excitation point determined by the epicardial mapping did not always predict the endocardial arrhythmogenic focus. Pre- and/or intraoperative endocardial mapping was important in this regard. Cryocoagulation (-150 degrees C, 120 sec) was mainly used as an ablative procedure; for ischemic VT, endocardial resection was added, and in nonischemic VT originated in the right ventricular outflow tract, transmural resection was combined with the cryoablation. In performing surgery for nonischemic VT, care must have been taken to make transmural cryocoagulation because the arrhythmogenic focus could exist intramurally. There were no operative deaths. In one patient with nonischemic VT, reoperation was required. After a mean follow-up of 17 month, all the patients are free from sustained VT.

Adolescent↗
PubMed1988

Clinical significance of Vanghan Williams classification for treatment of ventricular tachycardia: study of class IA and IB antiarrhythmic agents.

UNLABELLED: Ninety-eight cases of ventricular tachycardia (VT) were studied using clinical electrophysiological (EP)-pharmacological assessment to compare the efficacy of class IA (disopyramide-DP, procainamide-PA) and class IB (mexiletine-Mex, Lidocaine-Lid, aprindine-AP) agents available in Japan, and to evaluate the clinical significance of class subdivisions for the treatment of VT. In assessing the efficacy of drugs, we evaluated their ability to prevent and terminate induced sustained VT as well as their ability to suppress spontaneous premature ventricular beats (VPB). I. EP properties: DP significantly extended QTc, ERPRV, and the coupling interval by which VT or repetitive ventricular response (RVR) was induced. On the other hand, Mex and AP had no effect. Although no significant extension of QRS width was found, the significant extension of the interval from extrastimulus to the first induced VT or RVR complex by the three drugs indicates that all have suppressive effects on conduction velocity within the reentry circuit. II. CLINICAL SIGNIFICANCE: Correspondence of preventive effects was 67% for DP and PA (class IA), 54% for Mex and Lid (class IB), 55% for DP and Mex, 27% for AP and Mex, and 25% for AP and DP. Correspondence of terminating effect was 85% for DP and PA, 80% for DP and AP, 77% for DP and Mex, 75% for Mex and Lid, and 63% for Mex and AP. For suppression of spontaneous VPB's, correspondence rate was 100% for DP and PA, 39% for DP and Mex, 64% for Mex and Lid, 61% for Mex and AP, and 69% for DP and AP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Pacemaker ECG].

Explore the source record for details and available documents.

Aged↗
PubMed1988

[Detection of late potentials on the signal averaged body surface ECG using X, Y, Z and anterior chest leads].

We developed the system of high-frequency analysis of the signal-averaged body surface ECG to detect low amplitude signals in the terminal portion of the QRS. Thirty-five patients four or more weeks after transmural myocardial infarction (MI) and 30 normal volunteers were studied. All patients were in normal sinus rhythm and did not have bundle branch block. Body surface ECG recording using bipolar X, Y, and Z leads was performed in a shielded room. One lead served as the reference. The three-channel amplifier was a commercially-available ECG system. The common mode rejection ratio was 120 dB. The signal from each lead was amplified and passed through an analogue filter (NF FV 624) with a low-cut frequency of 100 Hz and a high-cut frequency of 300 Hz. Then AD conversion was performed with 12-bit accuracy, 1024 samples/sec. The filtered signals for the three leads were displayed separately for each channel and were combined into a vector magnitude, square root of X2+Y2+Z2. The percent ratio of the root mean square voltage in the last 40 msec of the QRS complex to that of the total filtered QRS (%RMS40) and the duration of the filtered QRS were automatically calculated. These parameters obtained from the three groups were compared. Signal-averaged, non-filtered and filtered body surface ECGs were recorded using 25 (5 x 5 array) anterior chest unipolar leads in 20 normal volunteers and in patients with late potential. The departure index was calculated as the voltage differences between the mean value (M) in normal persons and the value in patients (Xi) with MI using the formula (Xi-M/SDi) at intervals every four msec. The departure maps, capable of identifying the location of the MI, were made from the departure index at four msec intervals; then the late potential (LP) area maps were superimposed on the departure maps. To determine the late potential, we used the filtered ECG of X, Y, and Z leads and quantitative values (%RMS 40) obtained from a vector magnitude incorporated in these three leads. Six MI patients, four anterior and two inferior, with the late potential had low amplitude signals at the end of the filtered QRS complex. The %RMS 40 was 6.8 +/- 2.9% (p less than 0.001) in MI patients with the late potential, 2.8 +/- 8.5% (p less than 0.01) in MI patients without the late potential, and 37 +/- 11% in normal subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrocardiography↗