The potential of dynamic 99mTc-sestamibi cadmium zinc telluride-single-photon emission computed tomography camera assessing myocardial flow reserve in patients with heart failure with preserved ejection fraction.

Aims: Coronary microvascular dysfunction (CMD) is related to the pathophysiology, mortality, and morbidity of heart failure with preserved ejection fraction (HFpEF). A novel single-photon emission computed tomography (SPECT) camera with cadmium zinc telluride (CZT) detectors allows for the quantification of absolute myocardial blood flow and myocardial flow reserve (MFR) in patients with coronary artery disease. However, the potential of CZT-SPECT assessing for CMD has never been evaluated in patients with HFpEF. Methods and results: The clinical records of 127 consecutive patients who underwent dynamic CZT-SPECT were retrospectively reviewed. Rest and stress scanning were started simultaneously with 3 and 9 MBq/kg of 99mTc-sestamibi administration, respectively. Dynamic CZT-SPECT imaging data were analysed using a net-retention model with commercially available software. Transthoracic echocardiography was performed in all patients. The MFR value was significantly lower in the HFpEF group (mean ± SEM = 2.00 ± 0.097) than that in the non-HFpEF group (mean ± SEM = 2.74 ± 0.14, P = 0.0004). A receiver operating characteristic analysis indicated that if a cut-off value of 2.525 was applied, MFR could efficiently distinguish HFpEF from non-HFpEF. Heart failure with preserved ejection fraction had a consistently low MFR, regardless of the diastolic dysfunction score. Heart failure with preserved ejection fraction patients with MFR values lower than 2.075 had a significantly higher incidence of heart failure exacerbation. Conclusion: Myocardial flow reserve assessed by CZT-SPECT was significantly reduced in patients with HFpEF. A lower MFR was associated with a higher hospitalization rate in these patients. Myocardial flow reserve assessed by CZT-SPECT has the potential to predict future adverse events and stratify the severity of disease in patients with HFpEF.

Head-to-head comparison of acute and chronic pulmonary vein stenosis for cryoballoon versus radiofrequency ablation.

BACKGROUND: Cryoballoon (CB) applications to pulmonary veins (PVs) can cause stenosis just as radiofrequency (RF) energy deliveries. The goal of the present study was to clarify whether or not there was any difference in the extent of acute or chronic PV narrowing after PV isolation between the two different energy sources. METHODS: Consecutive patients with paroxysmal atrial fibrillation who were scheduled to undergo a PV isolation were randomized 1:1 to receive CB or RF ablation. The endpoints were any acute PV narrowing assessed with the use of intracardiac ultrasound during the procedure and PV stenosis measured with cardiac computed tomography at the 3-month follow-up. RESULTS: An acute reduction in the luminal area of the left superior PV (mean ± standard deviation, -6.8 ± 8.7 vs -19.9 ± 14.7%; P < 0.001) and left inferior PV (-5.1 ± 20.2 vs -15.3 ± 11.6%; P = 0.03) was significantly smaller in the CB arm (N = 25) than the RF arm (N = 25). There was no difference in the extent of PV stenosis 3 months after the ablation between the arms (0-25% stenosis, 90% vs 88%, 25-50% stenosis, 10% vs 12%, >50% stenosis, both 0%; P = 0.82). A greater acute PV narrowing was likely to lead to chronic stenosis in the RF arm (P = 0.004). CONCLUSIONS: CB ablation may reduce the acute narrowing of the left-sided PVs as compared to RF ablation.

Assessment of autonomic nervous system modulation after novel catheter ablation techniques for atrial fibrillation using multiple short-term electrocardiogram recordings.

PURPOSE: The effect of novel catheter ablation techniques for atrial fibrillation (AF) on the autonomic nervous system (ANS) is unclear. This study aimed to assess the ANS after three novel catheter ablation techniques for paroxysmal AF by evaluating heart rate variability (HRV) parameters using a 3-min electrocardiogram recording. METHODS: Two hundred and thirty-five patients who underwent catheter ablation for paroxysmal AF (119 in irrigated-tip, 51 in contact-force sensing-guided, and 65 patients in second-generation cryoballoon ablation) were included. HRV analysis was performed at baseline and 1, 3, 6, and 12 months after the ablation. RESULTS: The three ablation groups had similarly decreased HRV parameters after the ablation, and this change was maintained > 1 year. A reduction in parasympathetic nervous function was more apparent after the ablation, compared to changes in the sympathetic nervous function. Of the total population, 45 patients had recurrence. Ln high frequency (HF) 12 months after the ablation was significantly higher in the recurrence group than in the non-recurrence group (1.52 ± 0.47 vs. 1.26 ± 0.57 ms2, p = 0.007). Multivariate analysis demonstrated that AF duration (hazards ratio 1.09, 95% confidence interval 1.04-1.15, p = 0.001) and ln HF 12 months after ablation (hazards ratio 1.91, 95% confidence interval 1.12-3.25, p = 0.017) were independent predictors of AF recurrence after the ablation. CONCLUSIONS: ANS modulation after the three catheter ablation methods was similar and maintained > 1 year after the procedure. Higher parasympathetic nervous function at 1 year after ablation was associated with AF recurrence after the ablation.

Impaired renal function is associated with recurrence after cryoballoon catheter ablation for paroxysmal atrial fibrillation: A potential effect of non-pulmonary vein foci.

BACKGROUND: Atrial fibrillation (AF) and chronic kidney disease (CKD) are closely related. The present study aimed to evaluate the association between estimated glomerular filtration rate (eGFR) and outcomes after cryoballoon catheter ablation for AF. METHODS: We included a total of 110 patients (64.0±10.1 years, 64% men) with paroxysmal AF who underwent second-generation cryoballoon catheter ablation in this study. Recurrence and change in renal function after ablation were assessed by stratification of eGFR sub-groups. RESULTS: During a mean follow-up period of 9 months, 20 (18%) patients had AF recurrence after the first catheter ablation procedure. Multivariate Cox regression analysis showed that eGFR [hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.93-0.99, p=0.047], non-pulmonary vein (PV) ectopic beats at initial ablation (HR 2.92, 95% CI 1.03-8.27, p=0.043), and history of stroke (HR 7.47, 95% CI 2.30-24.2, p=0.001) were independent predictors of recurrence after the ablation. Among the CKD groups, recurrence was found in 7% (1/15), 12% (9/73), and 46% (10/22) of the eGFR ≥90mL/min/1.73m2, eGFR 60-89.9mL/min/1.73m2, and eGFR 30-59.9mL/min/1.73m2 groups, respectively (p=0.001). Kaplan-Meier survival curves demonstrated that patients with eGFR 30-59.9mL/min/1.73m2 had significantly worse prognosis than did the other groups (log-rank p<0.001). In addition, non-PV ectopic beats at initial ablation were detected in 7% (1/15), 14% (10/73), and 50% (11/22) of the patients among the three CKD groups, respectively (p<0.001). No patients developed contrast-induced nephropathy after the catheter ablation procedure. CONCLUSIONS: Low eGFR at baseline was an independent predictor of recurrence after cryoballoon ablation for paroxysmal AF. The presence of non-PV ectopic beats was significantly increased in patients with impaired renal function, which might be associated with a poor outcome.

An ECG Index of P-Wave Force Predicts the Recurrence of Atrial Fibrillation after Pulmonary Vein Isolation.

BACKGROUND: Although several prognostic factors of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) have been investigated, the accurate prediction of AF recurrence remains difficult. We propose an electrocardiogram (ECG) index, the P-wave force (PWF), which is the product of the amplitude of the negative terminal phase of the P wave in the V1 electrode and the filtered P-wave duration, obtained by a signal-averaged P-wave analysis. This study was conducted to evaluate the impact of the PWF on the recurrence of AF after PVI. METHODS: We retrospectively evaluated 79 paroxysmal AF patients (64 ± 9 years, 56 males) who underwent PVI by cryoballoon ablation. Standard 12-lead ECG and a P-wave signal-averaged electrocardiogram (SAECG) were recorded the day before and 1 month after the PVI procedure. RESULTS: During the mean follow-up of 10.2 months, AF recurred in 11 (14%) patients. The PWF 1 month after ablation was significantly higher in the recurrence group compared to that in the nonrecurrence group (8.8 ± 3.1 mVms vs 6.5 ± 2.9 mVms, P = 0.017). The patients with a PWF value ≥9.3 mVms had a significantly greater risk of recurrence after the ablation compared to the patients with a PWF value <9.3 mVms (log-rank test, P < 0.001). CONCLUSION: Higher PWF after cryoballoon ablation was associated with poor prognosis during follow-up. The PWF may be a useful and noninvasive marker to predict the recurrence of AF.

Effect and Significance of Early Reablation for the Treatment of Early Recurrence of Atrial Fibrillation After Catheter Ablation.

There are few reports on early reablation (ER) for early recurrence of atrial fibrillation (AF) after catheter ablation. The present study evaluated the efficacy and significance of ER for early recurrence within a blanking period of 3 months after ablation of both paroxysmal and persistent AF, using a propensity-matched analysis. Of 874 patients who underwent catheter ablation of AF, 389 (45%) had early recurrence. Of these, 78 patients underwent an ER procedure. A total of 132 matched patients (66 in the ER and 66 in the non-ER groups, 82 patients with paroxysmal AF) were included in the analysis. During a mean follow-up of 15.4 months, the patients who underwent ER had a significantly lower recurrence rate than those who did not (29 [44%] vs 42 patients [64%], p = 0.023). The benefit of ER was especially apparent in patients with paroxysmal AF (p = 0.008) but not in those with persistent AF (p = 0.774). However, 24 patients (36%) in the non-ER group did not experience recurrence after a blanking period without any reablation procedure. The total number of reablation sessions was higher in the ER group than in the non-ER group (1.2 ± 0.5 vs 0.4 ± 0.6, p <0.001). Nonetheless, mean number of arrhythmia outpatient clinic visits at follow-up was significantly fewer in the ER group than in the late reablation group. In conclusion, ER for early recurrence of AF after catheter ablation might be effective for preventing recurrence during follow-up, especially for paroxysmal AF.