Clinical utility of QRS duration normalized to left ventricular volume for predicting cardiac resynchronization therapy efficacy in patients with "mid-range" QRS duration.

BACKGROUND: Cardiac resynchronization therapy (CRT) is effective for patients with heart failure with QRS duration (QRSd) ≥150 ms. However, its beneficial effect seems to be limited for those with "mid-range" QRSd (120-149 ms). Recent studies have demonstrated that modifying QRSd to left ventricular end-diastolic volume (LVEDV)-modified QRSd-improves the prediction of clinical outcomes of CRT. OBJECTIVE: The purpose of this study was to investigate the clinical impact of the modified QRSd on the efficacy of CRT in patients with "mid-range" QRSd. METHODS: We conducted a retrospective, multicenter, observational study, with heart failure hospitalization (HFH) after CRT as the primary endpoint. Modified QRSd is defined as QRSd divided by LVEDV, determined through the Teichholtz method of echocardiography. RESULTS: Among the 506 consecutive patients considered, 119 (mean age 61 ± 15 years; 80% male, QRSd 135 ± 9 ms) with a "mid-range" QRSd who underwent de novo CRT device implantation were included for analysis. During median follow-up of 878 days [interquartile range 381-1663 days], HFH occurred in 45 patients (37%). Fine-Gray analysis revealed modified QRSd was an independent predictor of HFH (hazard ratio [HR] 0.97; 95% confidence interval [CI] 0.96-0.99; P <.01). Receiver operating characteristic curve analysis revealed a cutoff value of 0.65 ms/mL for the modified QRSd in predicting HFH. Patients above the threshold exhibited a significantly lower incidence of HFH than patients below the threshold (HR 0.46; 95% CI 0.25-0.86; P = .01). CONCLUSION: Modified QRSd can effectively predict the efficacy of CRT in patients with a "mid-range" QRSd.

Impacts of sinus rhythm maintenance with catheter ablation on exercise tolerance in patients with paroxysmal atrial fibrillation.

BACKGROUND: It has been recently reported that sinus rhythm (SR) maintenance with catheter ablation therapy improves exercise tolerance (ET) in patients with persistent atrial fibrillation (AF). However, it remains to be elucidated whether this is also the case for patients with paroxysmal AF (PAF). METHODS: We enrolled consecutive 54 patients with PAF (age; 63 ± 10 [SD] years old, male/female 46/8) and 26 patients with persistent AF (non-PAF) (age; 57 ± 12 [SD] years old, male/female 23/3) who underwent AF ablation without recurrence. ET and cardiac function were evaluated by cardio-pulmonary exercise test and ultrasound echocardiography before and 6 months after ablation. RESULTS: The parameters of cardiopulmonary exercise test were comparable between the 2 groups. When PAF group was divided into 2 groups according to the time since diagnosis, peak oxygen uptake (peak VO2) before ablation was significantly lower in patients with PAF duration of more than 1 year (n = 26), compared with those with less than 1 year (n = 28) (18.1 ± 3.7 vs 21.3 ± 5.8 ml/kg/min, P = 0.022). At 6 months after SR maintenance without AF burden, peak VO2 significantly improved in both PAF (19.8 ± 5.1 to 22.0 ± 4.8 ml/kg/min, P = 0.0001) and non-PAF (20.6 ± 3.9 to 23.4 ± 5.0 ml/kg/min, P < 0.01). Furthermore, the improvement rate of peak VO2 after successful ablation had a highly significant inverse relationship with peak VO2 at baseline in patients with PAF (r = - 0.48, P = 0.0003). CONCLUSIONS: These results indicate that SR maintenance with ablation improves ET in patients with PAF, especially in those with reduced ET.

Prognosis and risk stratification in cardiac sarcoidosis patients with preserved left ventricular ejection fraction.

BACKGROUND: Although recent reports showed that left ventricular ejection fraction (LVEF) is a prognostic factor in patients with cardiac sarcoidosis (CS), advances in diagnostic imaging have enabled us to detect CS patients with preserved LVEF in the early stage of the disorder. In the present study, we examined the prognosis and risk stratification in CS patients with preserved LVEF. METHODS AND RESULTS: We retrospectively examined 91 consecutive CS patients at our hospital from October 1998 to December 2015 (age, 57±11 years; male/female, 25/66) for the relationship between LVEF and major adverse cardiac events (MACE), including ventricular tachycardia and fibrillation (VT/VF), heart failure (HF) admission, complete atrioventricular block, and all-cause death. CS patients with preserved LVEF (≥50%), as compared with those with reduced LVEF (<50%), showed significantly higher survival free from total MACE or VT/VF (log-rank p<0.001) and significantly smaller LV myocardial damaged area as evaluated by magnetic resonance imaging (MRI) (p<0.001). Although CS patients with preserved LVEF had a good prognosis in general, persistent right ventricular (RV) pacing and reduced EF were significant predictors for MACE after 1 year from introduction of steroid therapy (hazard ratio, 5.25; 95% confidence interval, 1.31-22.50, p=0.020, hazard ratio, 9.01; 95% confidence interval, 2.45-72.09; p=0.001). Patients with the 2 factors (LVEF reduction rate >13.9% per year and persistent RV pacing) had significantly higher risk for MACE, compared with those without them (log-rank p<0.001). CONCLUSION: The present study demonstrates that CS patients with preserved LVEF have better long-term prognosis than those with reduced LVEF in general. However, we should carefully follow them up, since chronological reduction in LVEF and persistent RV pacing could predict worse prognosis in those patients.

Prognostic Significance of PR Interval Prolongation in Adult Patients With Total Correction of Tetralogy of Fallot.

BACKGROUND: Several studies have demonstrated the importance of mechanoelectrical interaction in patients with surgically corrected tetralogy of Fallot. However, the significance of atrioventricular conduction disturbance, that is PR interval prolongation, on adverse cardiac events in those patients remains to be elucidated. METHODS: We examined electrocardiograms at baseline and their temporal change in a total of 176 patients with repaired tetralogy of Fallot (49% men; median age, 17.4 years). Then, we evaluated their correlation with right ventricular volume and function measured by cardiac magnetic resonance and the significance as a risk factor of adverse cardiac events: lethal ventricular arrhythmias, atrial arrhythmias, heart failure hospitalization, complete atrioventricular block (AVB), and all-cause death. RESULTS: First-degree AVB was noted in 25 patients (14%). During a median follow-up of 10.0 (5.0-14.2) years, there was a progressive prolongation of PR interval (2.00±3.99 ms/y). Importantly, there were significant correlations between PR interval prolongation and right ventricular enlargement or right ventricular dysfunction. In contrast, in patients who underwent pulmonary valve replacement (n=23), significant shortening of PR interval by pulmonary valve replacement was noted (204±32 versus 176±34 ms; P=0.007). Cox regression analysis showed that first-degree AVB was an independent risk factor for lethal ventricular arrhythmias (hazard ratio, 5.479; 95% CI, 1.181-25.42; P=0.030) and complete AVB (hazard ratio, 27.67; 95% CI, 4.152-184.3; P<0.001) and had a tendency for heart failure hospitalization (hazard ratio, 3.301; 95% CI, 0.864-11.80; P=0.069). In addition, PR interval prolongation >2 ms/y was also a significant risk factor for lethal ventricular arrhythmias, regardless of the presence or absence of first-degree AVB at enrollment (hazard ratio, 24.18; 95% CI, 2.080-281.1; P=0.011). CONCLUSIONS: These results indicate that progressive atrioventricular conduction disturbance is correlated with right ventricular enlargement and could be a useful predictor for increased risk of lethal ventricular arrhythmias in patients with repaired tetralogy of Fallot.

Prognostic Significance of Late Potentials in Outpatients with Type 2 Brugada Electrocardiogram.

Brugada syndrome is characterized by distinguishing electrocardiogram (ECG) patterns (coved and saddle-back types with day-to-day variation) and occurrence of lethal tachy-arrhythmias. The appearance of coved type ECG (type 1) is required for the diagnosis of Brugada syndrome, whereas the significance of saddle-back type ECG (type 2), which is inadequate for the diagnosis, has not been fully established. We enrolled 34 consecutive patients with type 2 ECG on outpatient-clinic. Among them, 7 patients were ventricular fibrillation (VF) survivors who were diagnosed as Brugada syndrome with transient appearance of type 1 ECG, and showed type 2 ECG on their first outpatient-clinic visit after the VF event (VF group). The remaining 27 were asymptomatic and never showed type 1 ECG on repeated ECG examinations (control group). The VF group showed significantly longer RJ intervals in leads V1 and V2 and QTc intervals in lead V2 compared with the control group (P < 0.030, P < 0.017, and P < 0.030, respectively). Late potentials, detected on the signal-averaged ECG (SA-ECG), reflect conduction abnormalities and are known as one of the risk markers of arrhythmic events. Among the 34 patients, late potentials were negative in 12 patients belonging to the control group. In conclusion, the SA-ECG could be helpful to identify high-risk patients for its high negative predictive value as the first step, and ECG parameters, including RJ intervals in leads V1 and V2 and QTc interval in lead V2, could be useful for further risk stratification in patients with type 2 Brugada ECG.