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Background: Tartrate-resistant acid phosphatase type 5b (TRACP5b) is derived from osteoclasts, and has been used as a marker of osteoporosis (bone resorption). Although heart failure (HF) is associated with catabolic bone remodelling, serum TRACP5b levels have not been rigourously examined in patients with HF. Methods: We conducted a prospective observational study of 688 decompensated HF patients who had been discharged and whose TRACP5b had been measured. These patients were divided into tertiles on the basis of serum TRACP5b levels: first (TRACP5b < 316 mU/dL, n = 229), second (TRACP5b 316-489 mU/dL, n = 229), and third (TRACP5b ≥ 490 mU/dL, n = 230). We compared the patient baseline characteristics, exercise capacity, and their postdischarge prognosis, including cardiac mortality and cardiac events such as cardiac death and worsening HF. Results: Age was significantly higher, and prevalence of female sex and anemia was significantly higher in the third tertile than in the first and second tertiles (P < 0.05, respectively). Circulating TRACP5b levels were correlated with peak breath-by-breath oxygen consumption, but not with left ventricular ejection fraction. In the Kaplan-Meier analysis (mean follow-up, 426 days), cardiac mortality and cardiac event rates progressively increased from the first to the third tertiles (P < 0.05, respectively). In the multivariable Cox proportional hazard analysis, the third tertile was an independent predictor of cardiac mortality and cardiac events (cardiac mortality hazard ratio, 2.493; P = 0.040; cardiac events hazard ratio, 1.687; P = 0.030). Conclusions: High serum levels of TRACP5b, a marker of bone resorption, are associated with high cardiac mortality and cardiac events, accompanied by impaired exercise capacity. Résumé: Introduction: La TRACP5b (de l’anglais, tartrate-resistant acid phosphatase type 5b, soit l’isoforme 5 b de la phosphatase acide résistante au tartrate) qui est dérivée des ostéoclastes a été utilisée comme marqueur de l’ostéoporose (la résorption de l’os). Bien que l’insuffisance cardiaque (IC) soit associée au remodelage osseux catabolique, les concentrations sériques de TRACP5b n’ont pas été rigoureusement examinées chez les patients atteints d’IC. Méthodes: Nous avons mené une étude prospective observationnelle auprès de 688 patients atteints d’IC décompensée qui avaient obtenu leur sortie de l’hôpital et pour lesquels nous avions les mesures de TRACP5b. Nous avons réparti ces patients en tertiles en fonction des concentrations sériques de TRACP5b : le premier (TRACP5b < 316 mU/dL, n = 229), le deuxième (TRACP5b 316-489 mU/dL, n = 229) et le troisième (TRACP5b ≥ 490 mU/dL, n = 230). Nous avons comparé les caractéristiques initiales des patients, leur capacité à l’effort et leur pronostic après la sortie de l’hôpital, à savoir la mortalité d’origine cardiaque et les événements cardiaques tels que la mort cardiaque et l’aggravation de l’IC. Résultats: L’âge était significativement plus élevé, et la prévalence du sexe féminin et de l’anémie était significativement plus élevée dans le troisième tertile que dans les premier et deuxième tertiles (P < 0,05, respectivement). Les concentrations circulantes de TRACP5b corrélaient avec la consommation d’oxygène maximale « respiration par respiration », mais non avec la fraction d’éjection ventriculaire gauche. Dans l’analyse de Kaplan-Meier (durée moyenne de suivi, 426 jours), les taux de mortalité d’origine cardiaque et d’ événements cardiaques augmentaient progressivement du 1er tertile au 3e tertile (P < 0,05, respectivement). Dans l’analyse multivariable selon le modèle des risques proportionnels de Cox, le 3e tertile était un prédicteur indépendant de la mortalité d’origine cardiaque et des événements cardiaques (rapport de risque de mortalité d’origine cardiaque, 2,493; P = 0,040; rapport de risque d’événements cardiaques, 1,687; P = 0,030). Conclusions: Les concentrations sériques élevées de TRACP5b, un marqueur de la résorption de l’os, sont associées à la hausse des taux de mortalité d’origine cardiaque et d’ événements cardiaques, accompagnés de la diminution de la capacité à l’effort.

Background: Several studies reported that cavotricuspid isthmus-dependent atrial flutter (typical AFL) frequently coexists with atrial fibrillation (AF); however, the underlying mechanisms have not been fully investigated. This study aimed to reveal the mechanisms of the initiation of typical AFL and the association between typical AFL and AF. Methods: Among 154 consecutive patients undergoing a first catheter ablation of AF, we investigated the appearance and mechanism of spontaneous initiation of typical AFL during catheter ablation. Then, we retrospectively investigated 67 consecutive patients without a previous AF episode who underwent typical AFL ablation. The occurrence and predictors of AF after catheter ablation were evaluated. Results: During AF ablation, spontaneous initiation of typical AFL occurred during sinus rhythm in eight (5.2%) patients. The initiations of typical AFL were pulmonary vein (PV) firings except in one patient, in whom paroxysmal AF following superior vena cava firing initiated reverse typical AFL after PV isolation. After typical AFL ablation, AF occurred in 23 (34.3%) patients (mean follow up, 28.2±20.3 months). Kaplan-Meier analysis showed the occurrence of AF after typical AFL ablation to be significantly higher in the patients with a larger left atrial diameter over 40 mm (log-rank test, P=0.046). Conclusions: PV firing through AF played an important role in initiating typical AFL. The occurrence of AF after typical AFL ablation was high, and a dilated left atrium was associated with increased occurrence of AF. These findings disclosed the close relationship between typical AFL and AF, especially PV firing.

Background: Recent studies have shown that high levels of serum phosphate are associated with adverse cardiovascular events. However, little is known about the relation between phosphate levels and improvement of cardiac function in chronic heart failure (CHF) patients who underwent cardiac resynchronization therapy (CRT). The purpose of this study was to examine whether serum phosphate levels were able to predict responders to CRT and adverse cardiac events. Methods: The study population consisted of 30 CHF patients (24 males, mean age 65.7±8.5 years) who received CRT with defibrillator (CRT-D) implantation. Levels of serum phosphate were measured before, and 6 months after, CRT-D implantation. Left ventricular end-diastolic volume and end-systolic volume were assessed simultaneously by echocardiography. In addition, the rate of re-hospitalization due to worsening of heart failure was investigated. All patients were divided into 2 groups: responders (Group-R, n=18) and non-responders (Group-NR, n=12) to CRT-D. Responders were defined as patients who showed >15% reduction in left ventricular end-systolic volume. We compared these parameters between the 2 groups. Results: Serum phosphate levels were significantly lower in Group-R than in Group-NR (3.3±0.2 vs. 3.7±0.4 mg/dL, p=0.01). The rate of re-hospitalization was lower in Group-R than in Group-NR (0% vs. 33%, p=0.018). Multivariate analysis showed that serum phosphate levels had a predictive power to determine responders to CRT (odds ratio 0.008, 95% confidence interval 0.000–0.348, p=0.015). Conclusions: These results suggest that serum phosphate levels might predict both responders to CRT, and adverse cardiac events, in CHF patients with CRT-D.

Background: T-wave alternans is useful for predicting the occurrence of ventricular tachyarrhythmias and sudden cardiac death in various heart diseases. However, little is known about the clinical significance of T-wave alternans measurement in survivors of ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT). Methods: We studied 28 patients with organic heart disease who survived VF or hemodynamically unstable VT (20 males, mean age 63 years). Echocardiography, electrocardiogram (QRS duration and QTc intervals), and Holter monitoring (heart rate variability, heart rate turbulence and T-wave alternans) were performed before implantable cardioverter-defibrillator (ICD) implantation. Positive T-wave alternans was defined as >65 μV. During the follow-up period (10.2±6.2 months), ventricular tachyarrhythmias requiring appropriate shock therapy occurred in eight patients (29%). The subjects were divided into two groups, based on whether appropriate shock therapy was required (n=8, Group A) or not (n=20, Group B). Parameters from echocardiography, electrocardiogram, and Holter monitoring were compared between the two groups in order to investigate their relationship with the incidence of shock therapy after ICD implantation. Results: The prevalence of positive T-wave alternans was significantly higher in Group A than in Group B (88% vs. 15%, P=0.004). Univariate Cox proportional hazard analysis showed that, among the variables measured, only T-wave alternans had predictive power for recurrent ventricular tachyarrhythmias (hazard ratio, 13.17; 95% confidence interval: 1.606–108.1, P=0.016). Conclusions: These results suggest that T-wave alternans by Holter monitoring is useful for predicting recurrent ventricular tachyarrhythmias in survivors of VF or hemodynamically unstable VT.

Placement of an implantable cardioverter–defibrillator (ICD) is the only powerful treatment modality for Brugada syndrome in patients presenting with ventricular fibrillation (VF). For those whose first presentation is an electrical storm, pharmacologic therapy is typically used to control VF followed by ICD implantation. We report an alternative approach whereby, before ICD implantation, emergency catheter ablation of the VF-triggering premature ventricular contraction (PVC) resulted in long-term VF-free survival. The results suggest that, because VF triggers appear in a narrow time window, ablation of the culprit PVCs that initiate VF before the index PVCs subside is a reasonable alternative approach.