Effectiveness of Implantable Cardioverter-Defibrillator Therapy for Heart Failure Patients according to Ischemic or Non-Ischemic Etiology in Korea

BACKGROUND AND OBJECTIVES: This study was performed to describe clinical characteristics of patients with left ventriculars (LV) dysfunction and implantable cardioverter-defibrillator (ICD), and to evaluate the effect of ICD therapy on survival in Yeongnam province of Korea. SUBJECTS AND METHODS: From a community-based device registry (9 centers, Yeongnam province, from November 1999 to September 2012), 146 patients with LV dysfunction and an ICD implanted for primary or secondary prophylaxis, were analyzed. The patients were divided into two groups, based on the etiology (73 with ischemic cardiomyopathy and 73 with non-ischemic cardiomyopathy), and indication for the device implantation (36 for primary prevention and 110 for secondary prevention). The cumulative first shock rate, all cause death, and type and mode of death, were determined according to the etiology and indication. RESULTS: Over a mean follow-up of 3.5 years, the overall ICD shock rate was about 39.0%. ICD shock therapy was significantly more frequent in the secondary prevention group (46.4% vs. 16.7%, p=0.002). The cumulative probability of a first appropriate shock was higher in the secondary prevention group (p=0.015). There was no significant difference in the all-cause death, cardiac death, and mode of death between the groups according to the etiology and indication. CONCLUSION: Studies from this multicenter regional registry data shows that in both ischemic and non-ischemic cardiomyopathy patients, the ICD shock therapy rate was higher in the secondary prevention group than primary prevention group.

A Case of Congenital Long OT Syndrome with Pseudo - Atrioventricular Block

The congenital long-QT syndrome (LQTS) is characterized by recurrent syncope, prolonged QT intervals, QT interval lability, polymorphic ventricular tachycardia, and sudden death. We report a case of congenital long QT syndrome in a 28-day-old male infant who presented with syncope, bradycardia with 2: 1 pseudo-atrioventricular block and a markedly prolonged QT inteval. One episode occured after crying and degenerated into ventricular fibrillation and terminated after cardioversion. A VVI type cardiac pacemaker was implanted. Subsequently, the infant's heart rate was over 110/min and 2: 1 AV block and any other arrhythmia were absent. The infant recovered from the accompanied pneumonia and sepsis and was discharged 47 days after adrnission. However, 13 days after discharge, the infant returned to our hospital ER with syncope. Ventricular fibrillation ceased after cardioversion. Despite medication with propranolol, ventricular tachycardia persisted. The infant expired the day after he was discharged against medical advice.

Evaluation of Left Ventricular Systolic Function by-M-Mode Echo/Phonocardiography and Automated Border Detection(ABD) Echocardiography

BACKGROUND: The rate of rise of left ventricular(LV) systolic pressure, dp/kt, and the peak ejection rate(PER) of LV may be more accurate indices for assessing LV systolic function than ejection fraction(EF). Both can be easily obtained by noninvasive methods, M-mode echo/phonocardiography and automated border detection(ABD) echocardiography, respectively. Mean dp/dt by M-mode echo/phonocardiography and PER by ABD echocardiography were compared with mean dp/dt by Doppler echocardiography. METHODS: Twenty-one adult patients who had normal sinus rhythm, mitral regurgitant signals by continuous wave Doppler echocardiography and an apical 4 chamber view of LV in which at least 75% of the endocardium was clearly visualized were selected for our study. The off-line estimation of LV end-diastolic volume (1) were performed by the method of disc, after manually tracing the endocardial border on the apical 4 chamber view and EF was calculated. M-mode echocardiography of the aortive valve and phonocardiography were simultaneously recorded on the strip chart to measure the isovolumic contraction time(dtM). A blood pressure (2) and LV end-diasolic pressure(LVEDP) was assigned 20mmHg in patients with Q wave myocardial infarction or EF< or =40% and 10mmHg in others. The mean dp/dtM during isovolumic contraction time was calculated as (aortic diastolic pressure-LVEDP)/dtM and was compared with the Doppler-derived mean rate of LV pressure rise(dp/dtDoppler) over the time period between velocities of 1 and 3m/sec on the ascending slope of the Doppler velocity spectrum. ABD system was used to measure the changes in LV volume and PER on the apical four chamber view. PER was compared with mean dp/dtDoppler. RESULTS: Mean dp/dtM positively correlated with mean dp/dtDoppler(r=0.73, p<0.001), but the limits of agreement between two methods were somewhat wide(-659-937mmHg/sec). PER also positively correlated with dp/dtDoppler and EF(r=0.73, p<0.001 ; r=0.80, p<0.001). CONCLUSIONS: Mean dp/dtM by M-mode echo/phomocardiography and PER by ABD echocardiography may be useful indices for assessing LV systolic function.

On-Line Assessment of Left Ventricular Function by Automated Border Detection Echocardiography : Comparison with Gated Cardiac Blood Pool Scintigraphy

BACKGROUND: Automated border detection(ABD) is a new echocardiographic modality providing continuous on-line measurements of left ventricular(LV) cavitary ares, volume, and ejection fraction(EF) throughout the cardiac cycle. Previous study showed that LV volume and EF measurements with ABD system approximate manually traced LV volume and EF obtained with conventional 2-dimensional echocardiography. But further clinical validation needs a comparison of LV function between the ABD system and established methods. The purpose of this study is to compare EF, peak ejection rate(PER) and peak filling rate(PFR) between on-line ABD system and the gated cardiac blood pool scinitigraphy. METHOD: 27 patients with an apical 4 chamber view of LV in which at least 75% of the endocardium was clearly seen were selected for this study. They had a normal sinus rhythm and underwent echocardiographic study on the same day of or one day before gated cardiac blood pool scintigraphic study. The off-line estimation of LV volume was performed by the method of disc, after manually tracing the endocardial border on the apical 4 chamber view and EFoff was calculated. Also on that view the ABD system was turned on, and EFABD, PEABD, PEABD were calculated automatically from LV volume curve. They were compared with EFRI, PERRI, and PERRI obtained by the gated cardiac blood pool scintigraphy. RESULTS: 1) EFoff and EFABD were highly correlated with EFRI(r=0.78, 0.90 respectively : p0.05). The mean difference between PERRI and PEABD was -0.8+/-0.8EDV/sec, and the limits of agreement were -2.4~+0.8EDV/sec. PEABD were greater than PERRI(p<0.01). CONCLUSION: EF, PER, PER measurements by the ABD system and the gated cardiac blood pool scintigraphy have significant correlations. Thus ABD echocardiography is a useful method for assessement of LV function.