Where is the gap after a 90 W/4 s very-high-power short-duration ablation of atrial fibrillation?: Association with the left atrial-pulmonary vein voltage and wall thickness.

Background: Although pulmonary vein isolation (PVI) for atrial fibrillation (AF) utilizing radiofrequency (RF) applications with a very high-power and short-duration (vHPSD) has shortened the procedure time, the determinants of pulmonary vein (PV) gaps in the first-pass PVI and acute PV reconnections are unclear. Methods: An extensive encircling PVI was performed with the QDOT MICRO catheter with a vHPSD (90 W-4 s) in 30 patients with AF (19 men, 64 ± 10 years). The association of the PV gap sites (first-pass PVI failure, acute PV reconnections [spontaneous reconnections or dormant conduction provoked by adenosine triphosphate] or both) with the left atrial (LA) wall thickness and LA bipolar voltage on the PVI line and ablation-related parameters were assessed. Results: PV gaps were observed in 29 (6%) of 480 segments (16 segments per patient) in 17 patients (56%). The PV gaps were associated with the LA wall thickness, bipolar voltage, and the number of RF points (LA wall thickness, 2.5 ± 0.5 vs. 1.9 ± 0.4 mm, p < .001; bipolar voltage, 2.59 ± 1.62 vs. 1.34 ± 1.14 mV, p < .001; RF points, 6 ± 2 vs. 4 ± 2, p = .008) but were not with the other ablation-related parameters. Receiver operating characteristic curves yielded that an LA wall thickness ≥2.3 mm and bipolar voltage ≥2.40 mV were determinants of PV gaps with an area under the curve of 0.82 and 0.73, respectively. Conclusions: The LA voltage and wall thickness on the PV-encircling ablation line were highly associated with PV gaps using the 90 W/4 s-vHPSD ablation.

Clinical implication of the patient's disease awareness and adherence to medications in patients undergoing atrial fibrillation ablation.

Background: The effects of the patient's disease awareness on the management of postablation of atrial fibrillation (AF) are unknown. Methods: One hundred thirty-three AF patients undergoing an initial ablation were given a disease awareness questionnaire with a score of 16 points (8 points about AF in general and 8 points about oral anticoagulants) for the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) before and 1-year-after ablation. We divided them into the poor disease awareness group and good disease awareness group according to the median value (75%) of the total JAKQ score about AF in general, and compared the baseline patient characteristics and the 1-year changes in the JAKQ score, medication adherence, blood pressure, laboratory data, echocardiographic parameters, and AF/atrial tachycardia (AT) recurrence rate between the two groups. Results: Forty-two (31.6%) patients were classified as having poor disease awareness (<75% of the total JAKQ score), which was closely associated with poor medication adherence, hypertension, diabetes, dyslipidemia, and greater left atrial volume (LAV). These trends in the poor disease awareness group remained unchanged 1 year after the ablation. During the 25.3-month follow-up, the AF/AT recurrence rate was significantly higher in the poor disease awareness than the good disease awareness group (23.8% vs. 7.7%; p = .003 by the log-rank test). Conclusions: Poor disease awareness was linked to poor medication adherence, lifestyle-related diseases, and greater LAV before and even 1 year after the ablation, making it a potential surrogate marker for AF/AT recurrence. These findings highlight the clinical significance of disease awareness in AF management.

Trends over the recent 6 years in ablation modalities and strategies, post-ablation medication, and clinical outcomes of atrial fibrillation ablation.

Background: Ablation strategies and modalities for atrial fibrillation (AF) have transitioned over the past decade, but their impact on post-ablation medication and clinical outcomes remains to be fully investigated. Methods: We divided 682 patients who had undergone AF ablation in 2014-2019 (420 paroxysmal AFs [PAF], 262 persistent AFs [PerAF]) into three groups according to the period, that is, the 2014-2015 (n = 139), 2016-2017 (n = 244), and 2018-2019 groups (n = 299), respectively. Results: Persistent AF became more prevalent and the left atrial (LA) diameter larger over the 6 years. Extra-pulmonary vein (PV)-LA ablation was more frequently performed in the 2014-2015 group than in the 2016-2017 and 2018-2019 groups (41.1% vs. 9.1% and 8.1%; p < .001). The 2-year freedom rate from AF/atrial tachycardias for PAF was similar among the three groups (84.0% vs. 83.1% vs. 86.7%; p = .98) but lowest in the 2014-2015 group for PerAF (63.9% vs. 82.7% and 86.3%; p = .025) despite the highest post-ablation antiarrhythmic drug use. Cardiac tamponade was significantly decreased in the 2018-2019 group (3.6% vs. 2.0% vs. 0.33%; p = 0.021). There was no difference in the 2-year clinically relevant events among the three groups. Conclusion: Although ablation was performed in a more diseased LA and extra-PV-LA ablation was less frequent in recent years, the complication rate decreased, and AF recurrences for PAF remained unchanged, but that for PerAF decreased. Clinically relevant events remained unchanged over the recent 6 years, suggesting that the impact of the recent ablation modalities and strategies on remote clinically relevant events may be small during this study period.

When Is Cardiac Resynchronization Therapy with a Defibrillator Indicated in Patients with Heart Failure, Especially Elderly Patients?

One benefit of an implantable cardioverter-defibrillator is the prevention of sudden cardiac death (SCD). It is recommended for patients with a low left ventricular ejection fraction (LVEF). However, the choice of cardiac resynchronization therapy (CRT) with or without a defibrillator (CRT-D and CRT-P) in elderly patients is controversial. To understand the current situation for proper device selection, we investigated the impact of defibrillators on mortality in elderly patients with heart failure.Consecutive patients who underwent CRT implantation were retrospectively recruited. Baseline characteristics, all-cause mortality, cardiac death, and defibrillator implantation rates were investigated in patients aged > 75 or ≤ 75 years.A total of 285 patients (79 patients aged > 75 years) were analyzed. Elderly patients had more comorbidities, but a lower proportion had ventricular arrhythmia. During the mean follow-up of 47 months, 109 patients died (67 due to cardiac death). Kaplan-Meier analysis showed higher mortality in elderly patients (P = 0.0428) but no significant difference in cardiac death by age group (P = 0.7472). There were no significant differences in mortality between patients with CRT-D versus CRT-P (P = 0.3386).SCD was rare. A defibrillator had no significant impact on mortality. In elderly patients, comorbidities are common and related to mortality. The selection of CRT-D versus CRT-P should take those factors into account.

Intravenous Semaphorin 3A Administration Maintains Cardiac Contractility and Improves Electrical Remodeling in a Mouse Model of Isoproterenol-Induced Heart Failure.

The effects of recombinant semaphorin 3A (Sema3A) on myocardial contractility and electrical remodeling in mice with isoproterenol (ISP) -induced heart failure were investigated.C57BL/6J mice intraperitoneally received ISP (480 mg/kg/day, ISP group; n = 24) or saline (control group; n = 31) for 14 days. Twenty-one ISP-treated mice received 0.5 mg/kg Sema3A intravenously on days 7 and 11 (ISP+Sema3A group). The sympathetic nervous system was activated upon ISP treatment, but was reduced upon Sema3A administration. Greater myocardial tissue fibrosis was observed in the ISP group than in the control group. However, fibrosis was not significantly different between the ISP+Sema3A and control groups. Fractional shortening of the left ventricle was lower in the ISP group than in the control group and was restored in the ISP+Sema3A group (control, 53 ± 8%; ISP, 37 ± 7%; ISP+Sema3A, 48 ± 3%; P < 0.05). Monophasic action potential duration at 20% repolarization (MAPD20) was prolonged in the ISP group (compared to control group), but this was reversed upon Sema3A administration (control, 29 ± 3 ms; ISP, 35 ± 6 ms; ISP+Sema3A, 29 ± 3 ms; P < 0.05). qPCR revealed Kv4.3, KChIP2, and SERCA2 downregulation in the ISP group and upregulation in the ISP+Sema3A group; however, Western blotting revealed similar changes only for Kv4.3 (P < 0.05).Intravenous Sema3A may maintain myocardial contractility by suppressing the sympathetic innervation of the myocardium and reducing myocardial tissue damage, in addition to restoring MAPD via Kv4.3 upregulation.

Chronic Ablation Lesions after Cryoballoon and Hot Balloon Ablation of Atrial Fibrillation.

BACKGROUND: Chronological changes in ablation lesions after cryoballoon ablation (CBA) and hot balloon ablation (HBA) of atrial fibrillation (AF) remain unclear. METHODS: Of 90 patients who underwent initial balloon-based catheter ablation of AF and cardiac magnetic resonance imaging (cMRI) 3 months after ablation, data from 48 propensity score-matched patients (24 per group; 34 males; age 62±10 years) were analyzed. High-density pulmonary vein-left antrum (PV-LA) voltage mapping was performed after PV isolation, and low voltage areas around the PV ostia were defined as the total acute ablation lesion area (cm2). cMRI-derived dense fibrotic tissue localized around PVs was defined as the total chronic ablation lesion area (cm2). The percentage of total ablation lesion areas to total PV-LA surface area (%ablation lesion) was calculated during each phase, and %acute ablation lesion and %chronic ablation lesion areas were compared in patients who had undergone CBA and HBA. RESULTS: The %acute ablation lesion area was larger for the CBA group than for the HBA group (30.8±5.8% vs. 23.0±5.5%, p < 0.001). There was no difference in %chronic cMRI-derived ablation lesion area (24.8±10.8% vs. 21.1±11.6%, p = 0.26) between groups. The rates of chronic AF recurrence were 12.5% and 8.3%, respectively (p = 0.45; log-rank test). LA volume and LA surface area were strongly associated with AF recurrence, but %chronic ablation lesion area was not (27±8% vs. 23±12%, p = 0.39). CONCLUSION: Large acute ablation lesions after CBA were smaller during the chronic phase. The size of chronic ablation lesions and the rate of AF recurrence were both similar for CBA and HBA.

Novel "red-bull sign" during cavotricuspid isthmus ablation: Indication of an ablation catheter stuck in the subeustachian pouch.

Background: A subeustachian pouch (SEP) often hinders the completion of a cavotricuspid isthmus (CTI) ablation of typical atrial flutter (AFL) and sometimes causes steam-pops during a power-controlled ablation. We hypothesized that real-time bull's-eye monitoring of the catheter surface temperature might be useful to locate the SEP where the temperature can rise rapidly, and a temperature-controlled ablation might avoid steam pops. This study aimed to demonstrate this hypothesis. Methods: A temperature-controlled CTI ablation with a QDOT MICRO™ catheter (n = 10) and a conventional power-controlled CTI ablation (n = 10) were performed with an output power of 35 W. During the RF application, the bull's eye monitor for monitoring the catheter surface temperatures was assessed. A "red-bull sign" was defined as an entire red-colored bull's-eye monitor, indicating that the catheter-tip temperature of all 6 thermocouples rose rapidly over 47°C. Results: In a total of 115 lesions (12 ± 3 per patient), a "red-bull sign" was observed in 39 (33.9%) lesions where the RF output was reduced to 26 ± 8 W. All 39 "red-bull sign" lesions corresponded to the location of the SEP as delineated by ICE before the ablation. The red-bull sign accurately indicated the presence of a SEP with a sensitivity of 84.7% and specificity of 100%. Bidirectional block of the CTI was completed in all patients in either catheter group without any steam-pops. Conclusion: Real-time surface temperature monitoring and a red-bull sign might be useful to detect the SEP. A temperature-controlled CTI ablation with the QDOT MICRO catheter might be safe for avoiding steam pops.

Bradyarrhythmia Suspected to be Associated with Sleep Apnea Syndrome.

Sleep apnea syndrome (SAS) is a condition in which apnea and hypoventilation at night cause hypoxemia and impaired wakefulness during the day, resulting in a general malaise and dozing. Sleep apnea has been implicated in the development of hypertension, ischemic heart disease, arrhythmia, heart failure, and cerebrovascular disease.1) Approximately 50% of patients with sleep-disordered breathing have an arrhythmia. In severe cases with an apnea-hypopnea index (AHI) of 30 or more, the frequency of arrhythmias during sleep is two to four times that of individuals without SAS. Bradyarrhythmias such as sinus bradycardia, sinus arrest, and atrioventricular block occurs at night in about 5%-10% of patients with sleep-disordered breathing.2)During nocturnal sleep, vagal excitation causes excessive muscle relaxation of the upper airway, leading to periodic airway diameter reduction, which increases snoring and obstructive apnea. As a result, hypoxemia is likely, further increasing vagal tone and leading to bradycardia. An increase in ventilation rate and volume quickly compensates for the decrease in arterial partial pressure of oxygen during apnea, which leads to new bradycardia due to a decrease in the partial pressure of oxygen in arterial blood, which suppresses vagal tone and respiration.3)We experienced a case of a 44-year-old patient with bradyarrhythmia that might be associated with SAS. After continuous positive airway pressure treatment, AHI decreased, and very long cardiac arrests resolved.

2021 Asia Pacific Heart Rhythm Society (APHRS) practice guidance on atrial fibrillation screening.

In this paper, the Asia Pacific Heart Rhythm Society (APHRS) sought to provide practice guidance on AF screening based on recent evidence, with specific considerations relevant to the Asia-Pacific region. A key recommendation is opportunistic screening for people aged ≥65 years (all countries), with systematic screening to be considered for people aged ≥75 years or who have additional risk factors (all countries).

Prognostic value of the MELD-XI score in patients undergoing cardiac resynchronization therapy.

AIMS: Multi-organ dysfunction was recently reported to be a common condition in patients with heart failure (HF). The Model for End-stage Liver Disease eXcluding International normalized ratio (MELD-XI) score reflects liver and kidney function. The prognostic relevance of this score has been reported in patients with a variety of cardiovascular diseases who are undergoing interventional therapies. However, the relationship between the severity of hepatorenal dysfunction assessed by the MELD-XI score and the long-term clinical outcomes of HF patients receiving cardiac resynchronization therapy (CRT) has not been evaluated. METHODS AND RESULTS: Clinical records of 283 patients who underwent CRT implantation between March 2003 and October 2020 were retrospectively evaluated (mean age 67 ± 12, 22.6% female). Blood samples were collected before CRT implantation. Patients were divided into three groups based on tertiles of the MELD-XI score: first tertile (MELD-XI = 9.44, n = 95), second tertile (9.44 < MELD-XI < 13.4, n = 94), and third tertile (MELD-XI ≥ 13.4, n = 94). The primary endpoint was all-cause mortality. Compared with the other groups, the third tertile group exhibited significantly older age, higher prevalence of diabetes mellitus and hypertension, lower haemoglobin level, and higher N-terminal pro-brain natriuretic peptide level (all P < 0.05). The functional CRT response rate was also significantly lower in the third tertile group (P = 0.011). During a median follow-up of 30 months (inter-quartile range, 9-67), 105 patients (37.1%) died. Kaplan-Meier analysis revealed that patients with a higher MELD-XI score had a greater risk of all-cause mortality (log-rank test: P < 0.001). Even after adjustment for clinically relevant factors and a conventional risk score, the MELD-XI score was still associated with mortality (adjusted hazard ratio: 1.04, 95% confidence interval: 1.00-1.07, P = 0.014, and adjusted hazard ratio: 1.04, 95% confidence interval: 1.01-1.09, P = 0.005, respectively). A higher MELD-XI score was associated with a greater risk of all-cause mortality than a lower MELD-XI score regardless of whether a pacemaker or defibrillator was implanted (log-rank test: P = 0.010 and P < 0.001, respectively). CONCLUSIONS: Impaired hepatorenal function assessed by the MELD-XI score was associated with older age, higher prevalence of multiple co-morbidities, severity of HF, lower CRT response rates, and subsequent all-cause mortality in HF patients undergoing CRT implantation. These results suggest that the MELD-XI score can provide additional prognostic information and may be useful for improving risk stratification in this population.

Clinical significance of the albumin-bilirubin score in patients with heart failure undergoing cardiac resynchronization therapy.

Despite emerging recognition of interactions between heart failure (HF) and liver dysfunction, the impact of cardiac hepatopathy on patients with HF undergoing cardiac resynchronization therapy (CRT) has not been fully elucidated. Albumin-bilirubin (ALBI) score is a new assessment of liver function. The relationship between liver dysfunction severity based on ALBI score and clinical outcomes of patients with HF receiving CRT is unclear. Clinical records of 274 patients who underwent CRT device implantation between March 2003 and October 2020 were retrospectively investigated. ALBI score was calculated based on serum albumin and total bilirubin levels obtained before CRT device implantation. Patients were divided into three groups based on ALBI score: first tertile (ALBI ≤ - 2.62, n = 91)), second tertile (- 2.62 < ALBI < - 2.13, n = 92), and third tertile (ALBI ≥ - 2.13, n = 91). The study endpoint was all-cause mortality. The third tertile group had more advanced NYHA functional class, lower hemoglobin levels, and higher total bilirubin, aspartate aminotransferase, γ-glutamyl transferase, and N-terminal Pro-B-type natriuretic peptide levels (all p < 0.05). The third tertile group also had a higher prevalence of moderate or severe tricuspid regurgitation and higher tricuspid regurgitation pressure gradient (all p < 0.05). CRT response rates were significantly lower in the third tertile group. During a median (interquartile range) follow-up of 30 (9-60) months, 104 (37.9%) patients died. The third tertile group had significantly higher rates of all-cause mortality (log-rank p < 0.001). Higher ALBI score was significantly associated with all-cause mortality, even after adjusting for clinically relevant factors, a conventional validated risk score, and echocardiographic parameters related to right HF (all p < 0.01). Higher ALBI score before CRT device implantation is associated with HF severity, hepatic congestion and impairment due to right HF, lower CRT response, and higher all-cause mortality in CRT recipients.

Modified ablation index: a novel determinant of a successful first-pass left atrial posterior wall isolation.

Although a left atrial posterior wall isolation (LAPWI) in addition to a pulmonary vein isolation is a well-accepted option for persistent atrial fibrillation (AF), a complete isolation can be challenging. This study aimed to evaluate the performance of a modified ablation index (AI) (AI/bipolar voltage along the ablation line) for predicting a durable LAPWI. The study included 55 consecutive patients, aged 65 ± 11 years, who underwent an electroanatomic mapping-guided LAPWI of AF. The association between the gaps (first-pass LAPWI failure and/or acute LAPW reconnections), voltage amplitude along the roof and floor lines, and thickness of the LAPW was investigated. Gaps occurred in 22 patients (40%) and in 26 (8%) of the 330 line segments. Gaps were associated with a relatively high bipolar voltage (3.38 ± 1.83 vs. 1.70 ± 1.12 mV, P < 0.0001) and thick LA wall (2.52 ± 1.15 vs. 1.42 ± 0.44 mm, P < 0.0001). A modified AI ≤ 199 AU/mV, bipolar voltage ≥ 2.64 mV, wall thickness ≥ 2.04 mm, and roof ablation line ≥ 43.4 mm well predicted gaps (AUCs: 0.783, 0.787, 0.858, and 0.752, respectively). A high-voltage zone, thick LAPW, and long roof ablation line appeared to be determinants of gaps, and a modified AI ≥ 199 AU/mV along the ablation lines appeared to predict an acute durable LAPWI.

Resetting of atrial tachycardia by a scanned extrastimulus at a downstream site on a multielectrode catheter: a simple diagnostic maneuver for locating the macroreentrant atrial tachycardia circuit.

PURPOSE: Entrainment is a useful method for locating reentrant atrial tachycardia (AT) circuits, but alterations or termination of the AT can derail this process. We assessed whether resetting an upstream site of a neighboring electrode by a scanned extrastimulus at a downstream site (when the upstream tissue was refractory) could diagnose that site within the AT circuit. METHODS: The procedure was applied to 48 ATs with a cycle length (CL) of 238 ± 42 ms (26 common flutters, 8 perimitral flutters, 7 left atrial [LA] roof-dependent AT, 3 LA scar-related macroreentrant ATs, 2 pulmonary vein-gap reentry tachycardias, 1 right atrial scar-related macroreentrant AT, and 1 with an unidentified circuit). Entrainment and scanned extrastimulation were attempted at the cavotricuspid isthmus, LA roof, and mitral isthmus and/or critical AT isthmus. RESULTS: Within the circuit, the post-pacing interval minus the ATCL after entrainment was < 30 ms for all ATs and resetting of the AT cycle by ≥ 5 ms occurred in 94% of the ATs. No ATs were reset by extrastimulation outside the circuit. The positive predictive value of both maneuvers for locating the circuit was 100%, and the negative predictive value of the extrastimulation was similar to that of entrainment (96% vs. 100%, P = 0.25). The incidence of an AT alteration was lower with extrastimulation than with entrainment (1% vs. 9%, P = 0.01). For ATs with a CL < 210 ms, extrastimulation yielded a good diagnostic performance without any AT alterations. CONCLUSION: AT resetting by a scanned extrastimulus is diagnostic and avoids AT alterations.

Prognostic importance of the Controlling Nutritional Status (CONUT) score in patients undergoing cardiac resynchronisation therapy.

AIMS: Malnutrition is common and associated with worse clinical outcomes in patients with heart failure (HF). The Controlling Nutritional Status (CONUT) score is an integrated index for evaluating diverse aspects of the complex mechanism of malnutrition. However, the relationship between the severity of malnutrition assessed by the CONUT score and clinical outcomes of HF patients receiving cardiac resynchronisation therapy (CRT) has not been fully clarified. METHODS: Clinical records of 263 patients who underwent pacemaker or defibrillator implantation for CRT between March 2003 and October 2020 were retrospectively evaluated. The CONUT score was calculated from laboratory data obtained before CRT device implantation. Patients were divided into three groups: normal nutrition (CONUT scores 0-1, n=58), mild malnutrition (CONUT scores 2-4, n=132) and moderate or severe malnutrition (CONUT scores 5-12, n=73). The primary endpoint was all-cause mortality. RESULTS: The moderate or severe malnutrition group had a lower body mass index, more advanced New York Heart Association functional class, higher Clinical Frailty Scale score, lower levels of haemoglobin and higher levels of N-terminal probrain natriuretic peptide (all p<0.05). In the moderate or severe malnutrition group, the CRT response rate was significantly lower than for the other two groups (p=0.001). During a median follow-up period of 31 (10-67) months, 103 (39.1%) patients died. Kaplan-Meier analysis revealed that the moderate or severe malnutrition group had a significantly higher mortality rate (log-rank p<0.001). A higher CONUT score and CONUT score ≥5 remained significantly associated with all-cause mortality after adjusting for previously reported clinically relevant factors and the conventional risk score (VALID-CRT risk score) (all p<0.05). CONCLUSIONS: A higher CONUT score before CRT device implantation was strongly associated with HF severity, frailty, lower CRT response rate and subsequent long-term all-cause mortality.

Current Status and Issues Concerning Magnetic Resonance Imaging in Patients with a Magnetic Resonance Conditional Cardiac Implantable Electrical Device: A Single-center Study.

Objective Following the introduction of magnetic resonance (MR)-conditional cardiac implantable electrical devices (CIEDs), patients with CIEDs have undergone MRI scanning more frequently. As the required settings of MRI equipment for scanning patients with a CIED vary by device, a number of precautions should be taken to allow safe examinations, including the confirmation of conditions and selection of MRI modes appropriate for pacing status in individual patients. In this study, we examined the current status and issues concerning the performance of MRI examinations in patients with an MRI-conditional CIED. Method and Results We reviewed a total of 262 MRI scans. The most common site of MRI scanning was the head, followed by the spine, abdomen, and heart in order. Regarding the MRI mode, DOO was most often used, followed by OFF, AOO, and finally VOO mode, to maintain atrioventricular synchrony. Although no obvious adverse events were observed related to MRI scanning, there were several cases encountered that might have been predisposed to a significant incident or in which the patient's intrinsic pulse rates or subjective symptoms changed before and during scanning. Conclusion As MRI is a very useful diagnostic tool for cerebrovascular diseases and orthopedic disorders, the demand for MRI scanning is high when treating these areas. Although MRI scanning in patients with MR-conditional devices was performed without any adverse events, there were incidents that could have potentially led to major harm. This highlights the importance of confirming the appropriate MRI mode is being used before scanning and monitoring patients during scanning.

Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain.

Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e' and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

Formation of low-voltage zones on the anterior left atrial wall due to mechanical compression by the ascending aorta.

BACKGROUND: Although low-voltage zones (LVZs) in the left atrium (LA) are considered arrhythmogenic substrates in some patients with atrial fibrillation (AF), the pathophysiologic factors responsible for LVZ formations remain unclear. OBJECTIVE: To elucidate the anatomical relationship between the LA and ascending aorta responsible for anterior LA wall remodeling. METHODS: We assessed the relationship between existence of LVZs on the anterior LA wall and the three-dimensional computed tomography image measurements in 102 patients who underwent AF ablation. RESULTS: Twenty-nine patients (28%) had LVZs grearer than 1.0 cm2 on the LA wall in the LA-ascending aorta contact area (LVZ group); no LVZs were seen in the other 73 patients (no-LVZ group). The LVZ group (vs. no-LVZ group) had a smaller aorta-LA angle (21.0 ± 7.7° vs. 24.9 ± 7.1°, p = .015), greater aorta-left-ventricle (LV) angle (131.3 ± 8.8° vs. 126.0 ± 7.9°; p = .005), greater diameter of the noncoronary cusp (NCC; 20.4 ± 2.2 vs. 19.3 ± 2.5 mm; p = .036), thinner LA wall-thickness adjacent to the NCC (2.3 ± 0.7 vs. 2.8 ± 0.8 mm; p = .006), and greater cardiothoracic ratio (percentage of the area in the thoracic area, 40.1 ± 7.1% vs. 35.4 ± 5.7%, p < .001). The aorta-LA angle correlated positively with the patients' body mass index (BMI), and the aorta-LV angle correlated negatively with the body weight and BMI. CONCLUSION: Deviation of the ascending aorta's course and distention of the NCC appear to be related to the development of LA anterior wall LVZs in the LA-ascending aorta contact area. Mechanical pressure exerted by extracardiac structures on the LA along with the limited thoracic space may contribute to the development of LVZs associated with AF.

Three-dimensional visualization of bidirectional preferential pathway conduction of premature ventricular contractions originating from the outflow tract.

INTRODUCTION: Preferential pathway conduction is mostly detected as fractionated presystolic-potentials preceding the QRS during premature ventricular contractions (PVCs) and late-potentials during sinus rhythm (SR), but the electrophysiologic mechanisms and significance of these potentials have not been fully clarified. We describe a PVC case series in which the preferential pathway conduction was three-dimensionally visualized. METHODS: Five PVCs (two from the left coronary cusp, two from the commissure of the left and right coronary cusps, and one from the pulmonary artery) in four patients for which a fractionated presystolic-potential during the PVCs and late-potential during SR were recorded at the successful ablation site were reviewed, and three-dimensional coherent activation maps with the conduction velocity vector during the PVCs and SR were reconstructed. RESULTS: At the successful ablation site, an "M"-shaped discrete presystolic-potential and "W"-shaped discrete late-potential were recorded in all patients. The configuration of the inverted electrogram of the presystolic-potential was similar to that of the electrogram exhibiting the late-potential. We created coherent activation maps annotating the onset of the presystolic-potentials during the PVCs and offset of the late-potentials during SR, which suggested bidirectional conduction of the preferential pathway connecting the PVC origin to the myocardium. CONCLUSION: Detailed activation mapping of these PVCs is consistent with the presence of fibers along the aortic or pulmonic valve ring that have preferential directions for conduction. PVCs produce a presystolic-potential. In SR, the fiber is activated late and from the opposite direction, producing an inverted potential inscribed on the end of the QRS.