Left atrial strain analysis and new-onset atrial fibrillation in patients with ST-segment elevation myocardial infarction: A prospective echocardiography study

BACKGROUND

New-onset atrial fibrillation (NOAF) is a well-known complication of ST-segment elevation myocardial infarction (STEMI), probably due to left atrial (LA) remodelling. LA strain (LAS) can predict NOAF in several cardiovascular diseases.

OBJECTIVE

To assess whether LAS predicts NOAF in sinus rhythm patients with STEMI during hospitalization.

METHODS

Adults with a STEMI and transthoracic echocardiography performed within 48hours of admission were included. LAS analysis, performed by automated software, recorded LAS during the reservoir phase (LASr), the conduit phase (LAScd) and the contraction phase (LASct).

RESULTS

From May 2021 to November 2022, 175 patients were included, 21 (12%) of whom developed NOAF. NOAF patients were older (median [Q1-Q3]: 67 [59-80] vs 59 [51-67]years; P=0.006) and had a higher Thrombolysis In Myocardial Infarction scores (4 [2-7] vs 3 [1-4]; P=0.005). All LAS parameters were significantly impaired in NOAF patients, especially LASr (13.0% [10.5-28.4] vs 36.6% [29.0-44.9]; P=0.001). An LASr cut-off of 27% had a sensitivity of 81% and a specificity of 80% to identify patients with NOAF. In a multivariable model, LASr was significantly associated with NOAF (odds ratio 1.18, 95% confidence interval 1.09-1.26; P=0.003). The cumulative risk of NOAF during hospital stay was 30% (18-43 with LASr<27% and 4% [1.5-8.5] with LASr≥27% [P<0.0001]).

CONCLUSION

NOAF is a frequent complication of STEMI. LASr seems helpful for identifying patients at high risk of NOAF during hospitalization.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm

BACKGROUND

Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave.

OBJECTIVES

The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS).

METHODS

After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping.

RESULTS

In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%.

CONCLUSIONS

An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Atrial fibrillation in severe aortic stenosis: Prognostic value and results of aortic valve replacement

OBJECTIVES

Although atrial fibrillation (AF) is common, its impact on long-term mortality has not been reliably determined in patients with aortic stenosis (AS). We aimed to assess whether AF is associated with survival in patients with severe AS and to determine the impact of AF on the results of aortic valve replacement (AVR).

METHODS

The study included 1838 consecutive patients with severe AS (77 ± 11 years, male 47%). Upon AS diagnosis, patients were screened for AF using a 12-lead electrocardiogram. The treatment strategy (conservative management or AVR) was selected by the heart team in accordance with current guidelines. The effect of AVR on survival was analyzed as a time-dependent covariate using the entire follow-up period.

RESULTS

AF, diagnosed in 593 (32%) patients was associated with poor survival at 5 years (55 ± 2% vs 74 ± 1% for patients in sinus rhythm, P < .001), even after adjustment for established outcome predictors (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.33-1.84; P < .001). In patients with AF, AVR was associated with lower mortality (HR, 0.16; 95% CI, 0.12-0.22; P < .001) even in those with no or minimal symptoms (HR, 0.12; 95% CI, 0.08-0.20; P < .001). However, among patients who underwent AVR, those in AF had an excess mortality (HR, 1.59; 95% CI, 1.22-2.08; P < .001).

CONCLUSIONS

In severe AS, AF is a strong predictor of mortality even in asymptomatic or minimally symptomatic patients. After AVR, AF remains associated with poorer survival than sinus rhythm. In patients in AF, AVR is associated with lower mortality compared with conservative treatment. Further studies are needed to confirm the benefits of AVR in asymptomatic patients in AF with severe AS.

Arrhythmic mitral valve prolapse in 2023: Evidence-based update

Patients with mitral valve prolapse (MVP) may develop ventricular arrhythmias, ranging from premature ventricular contractions through more complex non-sustained ventricular tachycardia to sustained life-threatening ventricular arrhythmias. The prevalence of MVP in autopsy series of young adults who died suddenly has been estimated to be between 4% and 7%. Thus, "arrhythmic MVP" has been reported as an underappreciated cause of sudden cardiac death, leading to a renewed interest in the study of this association. The term "arrhythmic MVP" refers to a small subset of patients who have, in the absence of any other arrhythmic substrate, MVP, with or without mitral annular disjunction, and frequent or complex ventricular arrhythmias. Our understanding of their coexistence in terms of contemporary management and prognosis is still incomplete. While literature regarding the arrhythmic MVP may be contrasting despite recent consensus document, the present review summarizes the relevant evidence concerning the diagnostic approach, prognostic implications, and targeted therapies for MVP-related ventricular arrhythmias. We also summarize recent data supporting left ventricular remodeling, which complicates the coexistence of MVP with ventricular arrhythmias. As the evidence for a putative link between MVP-associated ventricular arrhythmias and sudden cardiac death is scarce and based on scant and retrospective data, risk prediction remains a challenge. Thus, we aimed at listing potential risk factors from available seminal reports for further use in a more reliable prediction model that requires additional prospective data. Finally, we summarize evidence and guidelines on targeted therapies of ventricular arrhythmias in the setting of MVP, including implantable cardioverter defibrillators and catheter ablation. Our review highlights current knowledge gaps and provides an action plan for structured research on the pathophysiological genesis, diagnosis, prognostic impact, and optimal management of patients with arrhythmic MVP.

Sex Differences in the Outcomes of Cryoablation for Atrial Fibrillation

Background

The literature data on the outcomes of radiofrequency catheter ablation for atrial fibrillation (AF) in women are contradictory.

Aim

To determine and compare the outcomes and complications of cryoballoon pulmonary vein isolation (cryo-PVI) in men vs. women, and to identify predictors of atrial tachyarrhythmia (ATa) recurrence.

Methods

We included all consecutive patients having undergone cryo-PVI for the treatment of symptomatic AF in our center since 2012. Peri-operative complications were documented. All patients were prospectively monitored for the recurrence of ATa, and predictors were assessed.

Results

A total of 733 patients were included (550 men (75%) and 183 (25%) women). Paroxysmal AF was recorded in 112 (61%) female patients and 252 male patients (46%; p < 0.001). Female patients were older (p < 0.001) and had a greater symptom burden (p = 0.04). Female patients were more likely to experience complications (p = 0.02). After cryo-PVI for paroxysmal AF, 66% of the female patients and 79% of the male patients were free of ATa at 24 months (p = 0.001). Female sex was the only independent predictive factor for ATa recurrence (hazard ratio [95% confidence interval] = 1.87 [1.28; 2.73]; p = 0.001). After cryo-PVI for non-paroxysmal AF, 37% of the male patients and 39% of the female patients were free of ATa at 36 months (p = 0.73). Female patients were less likely than male patients to undergo repeat ablation after an index cryo-PVI for non-paroxysmal AF (p = 0.019).

Conclusion

A single cryo-PVI procedure for paroxysmal AF was significantly less successful in female patients than in male patients. Overall, the complication rate was higher in women than in men.

Arrhythmias in Patients With Valvular Heart Disease: Gaps in Knowledge and the Way Forward

The prevalence of both organic valvular heart disease (VHD) and cardiac arrhythmias is high in the general population, and their coexistence is common. Both VHD and arrhythmias in the elderly lead to an elevated risk of hospitalization and use of health services. However, the relationships of the two conditions is not fully understood and our understanding of their coexistence in terms of contemporary management and prognosis is still limited. VHD-induced left ventricular dysfunction/hypertrophy and left atrial dilation lead to both atrial and ventricular arrhythmias. On the other hand, arrhythmias can be considered as an independent condition resulting from a coexisting ischemic or non-ischemic substrate or idiopathic ectopy. Both atrial and ventricular VHD-induced arrhythmias may contribute to clinical worsening and be a turning point in the natural history of VHD. Symptoms developed in patients with VHD are not specific and may be attributable to hemodynamical consequences of valve disease but also to other cardiac conditions including arrhythmias which are notably prevalent in this population. The issue how to distinguish symptoms related to VHD from those related to atrial fibrillation (AF) during decision making process remains challenging. Moreover, AF is a traditional limit of echocardiography and an important source of errors in assessment of the severity of VHD. Despite recent progress in understanding the pathophysiology and prognosis of postoperative AF, many questions remain regarding its prevention and management. Furthermore, life-threatening ventricular arrhythmias can predispose patients with VHD to sudden cardiac death. Evidence for a putative link between arrhythmias and outcome in VHD is growing but available data on targeted therapies for VHD-related arrhythmias, including monitoring and catheter ablation, is scarce. Despite growing evidences, more research focused on the prognosis and optimal management of VHD-related arrhythmias is still required. We aimed to review the current evidence and identify gaps in knowledge about the prevalence, prognostic considerations, and treatment of atrial and ventricular arrhythmias in common subtypes of organic VHD.

Myocardial Contraction Fraction for Risk Stratification in Low-Gradient Aortic Stenosis With Preserved Ejection Fraction

BACKGROUND

Myocardial contraction fraction (MCF) is a volumetric measure of myocardial shortening independent of left ventricular size and geometry. This multicenter study investigates the usefulness of MCF for risk stratification in low-gradient severe aortic stenosis with preserved ejection fraction.

METHODS

We included 643 consecutive patients with low-gradient severe aortic stenosis with preserved ejection fraction in whom MCF was computed at baseline and analyzed mortality during follow-up.

RESULTS

Throughout follow-up with medical and surgical management (34.9 [16.1-65.3] months), lower MCF tertiles had higher mortality than the highest tertile. Eighty-month survival was 56±4% for MCF>41%, 41±4% for MCF 30% to 41%, and 40±4% for MCF<30% (P<0.001). After comprehensive adjustment, mortality risk remained high for MCF 30% to 41% (adjusted hazard ratio, 1.53 [1.08-2.18]) and for MCF<30% (adjusted hazard ratio, 1.82 [1.24-2.66]) versus MCF>41%. The optimal MCF cutoff point for mortality prediction was 41%. Age, body mass index, Charlson index, peak aortic velocity, and ejection fraction were independently associated with mortality. MCF (χ² to improve 10.39; P=0.001), provided greater additional prognostic value over the baseline parameters than stroke volume (SV) index (χ² to improve 5.41; P=0.042), left ventricular mass index (χ² to improve 2.15; P=0.137), or global longitudinal strain (χ² to improve 3.67; P=0.061). MCF outperformed ejection fraction for mortality prediction. When patients were classified by SV index and MCF, mortality risk was low when SV index was ≥30 mL/m² and MCF>41%, higher for patients with SV index ≥30 mL/m² and MCF≤41% (adjusted hazard ratio, 1.47 [1.05-2.07]) and extremely high for patients with SV index <30 mL/m² (adjusted hazard ratio, 2.29 [1.45-3.62]).

CONCLUSIONS

MCF is a valuable marker of risk in low-gradient severe aortic stenosis with preserved ejection fraction and could improve decision-making, especially in normal-flow low-gradient severe aortic stenosis with preserved ejection fraction.

Long-term follow-up of a patient with type 2 Timothy syndrome and the partial efficacy of mexiletine

We report a detailed case of type 2 TS due to a p.(Gly402Ser) mutation in exon 8 of the CACNA1C gene. The patient shows a marked prolongation of repolarization with a mean QTc of 540 ms. He shows no structural heart disease, syndactyly, or cranio-facial abnormalities. However, he shows developmental delays, without autism, and dental abnormalities. The cardiac phenotype is very severe, with a resuscitated cardiac arrest at 2.5 years of age, followed by 26 appropriate shocks during nine years of follow-up. Adding mexiletine to nadolol resulted in a reduction of the QTc and a slight decrease in the number of appropriate shocks.

Excess Mortality and Undertreatment of Women With Severe Aortic Stenosis

Background

Although women represent half of the population burden of aortic stenosis (AS), little is known whether sex affects the presentation, management, and outcome of patients with AS.

Methods and Results

In a cohort of 2429 patients with severe AS (49.5% women) we aimed to evaluate 5‐year excess mortality and performance of aortic valve replacement (AVR) stratified by sex. At presentation, women were older (P<0.001), with less comorbidities (P=0.030) and more often symptomatic (P=0.007) than men. Women had smaller aortic valve area (P<0.001) than men but similar mean transaortic pressure gradient (P=0.18). The 5‐year survival was lower compared with expected survival, especially for women (62±2% versus 71% for women and 69±1% versus 71% for men). Despite longer life expectancy in women than men, women had lower 5‐year survival than men (66±2% [expected‐75%] versus 68±2% [expected‐70%], P<0.001) after matching for age. Overall, 5‐year AVR incidence was 79±2% for men versus 70±2% for women (P<0.001) with male sex being independently associated with more frequent early AVR performance (odds ratio, 1.49; 1.18–1.97). After age matching, women remained more often symptomatic (P=0.004) but also displayed lower AVR use (64.4% versus 69.1%; P=0.018).

Conclusions

Women with severe AS are diagnosed at later ages and have more symptoms than men. Despite prevalent symptoms, AVR is less often performed in women and 5‐year excess mortality is noted in women versus men, even after age matching. These imbalances should be addressed to ensure that both sexes receive equivalent care for severe AS.

Improvement of the Prognosis Assessment of Severe Tricuspid Regurgitation by the Use of a Five-Grade Classification of Severity

It is well known that some patients present with "more than severe" tricuspid regurgitation (TR). We aimed to assess the prognosis of these very severe TR patients. We defined very severe TR using 3 simple echocardiographic parameters: a coaptation gap≥10mm, a laminar TR flow and a systolic reversal of the hepatic vein flow. We included 259 consecutive patients (76 ± 13 years; 46% men) with moderate-to-severe TR (n = 114) and severe TR (n = 145). The primary end point was the combination of hospitalisation for right heart failure (RHF) and cardiovascular mortality. Median follow-up was 24(7 to 47) months. In patients with severe TR, 52 (36%) met the definition of very severe TR. These patients were younger, had more history of RHF and were more frequently treated with loop diuretics than those with moderate-to-severe TR (all p < 0.001). Four-year event-free survival rates were 68 ± 5%, for moderate-to-severe TR, 48 ± 6% for severe TR and only 35 ± 7% for very-severe TR (p < 0.001). On multivariable analysis, after adjustment for outcome predictors including age, comorbidity, RHF, TR etiology, left and right ventricular dysfunction, and tricuspid valve surgery, patients with very severe TR had a worsened prognosis than those with moderate-to-severe TR (Adjusted Hazard Ratio [95% Confidence Interval] = 2.43 [1.18 to 5.53]; p = 0.002) and than those with severe TR (Adjusted Hazard Ratio [95% Confidence Interval] = 2.23 [1.06 to 5.56]; p = 0.015). In conclusion, very severe TR is frequent in patients with severe TR, corresponds to a more advanced stage of the disease and is associated with poor outcomes. Therefore, the use of a 5-grade classification of TR severity is justified in routine clinical practice. (ID-RCB: 2017-A03233-50).

Overcoming challenges in the management of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) appears in most patients to be an inherited disease characterized by fibrofatty replacement of myocytes extending from the epicardium to the endocardium in the right ventricle. The disease process results in life‑threatening ventricular arrhythmias and ventricular dysfunction. In the absence of a gold‑standard diagnostic test and despite the progress in imaging techniques, ARVC is often misdiagnosed and earlier detection of the disease is challenging. Preprocedural identification and localization of the substrate can be determined from the analysis of surface electrocardiography and cardiac magnetic resonance imaging. Typically, perivalvular arrhythmogenic substrate, defined by electroanatomic mapping, is present and can be isolated to the epicardium. Ablation targets are further identified with activation, entrainment, and local electrogram abnormalities based on detailed electroanatomic mapping. Extensive combined endo / epicardial ablation performed in experienced centers is frequently required to prevent ventricular tachycardia (VT). Catheter ablation significantly reduces recurrences of VT, appropriate implantable cardioverter‑defibrillator shocks, and the use of antiarrhythmic drugs and cardiac transplant as a management strategy for refractory arrhythmias is rarely required. Progression of the disease is poorly understood and may require a distinct triggering mechanism. Biventricular involvement is more common than previously recognized. However, left ventricular involvement leading to significant terminal heart failure is fortunately uncommon and left ventricular tachycardias are also infrequent. Many questions remain regarding prevention and management of coexisting tricuspid valve regurgitation, atrial arrhythmias, and intracardiac thrombosis. Although data on genotype‑phenotype correlations is growing, long‑term follow‑up studies of families with ARVC are still lacking. Ongoing research will contribute to better understanding of this pathological condition.

Impact of Right Ventricular Systolic Dysfunction on Outcome in Aortic Stenosis

Background:

Pulmonary hypertension is an established outcome predictor in patients with aortic stenosis (AS), but the prognostic impact of right ventricular dysfunction has not been well studied.

Methods:

We included 2181 patients (50.4% men; mean age, 77 years) with aortic valve area <1.3 cm 2 and analyzed the occurrence of all-cause death during follow-up according to tricuspid annular plane systolic excursion (TAPSE) quartiles.

Results:

Patients in the lowest quartile (TAPSE <17 mm) were at a high risk of death, whereas survival was comparable for the 3 other quartiles. Five-year survival was 55±2% for TAPSE <17 mm, 72±2% for TAPSE of 17 to 20 mm, 71±2% for TAPSE of 20 to 24 mm, and 73±2% for TAPSE >24 mm (overall P <0.001). TAPSE <17 mm was associated with increased mortality after adjustment for established prognostic factors (adjusted hazard ratio [HR], 1.55 [95% CI, 1.21–1.97]) and after further adjustment for aortic valve replacement (AVR; adjusted HR, 1.47 [95% CI, 1.15–1.87]). The excess mortality risk associated with TAPSE <17 mm was noticed in both patients managed initially conservatively (adjusted HR, 1.46 [95% CI, 1.20–1.76]) and patients who underwent early (within 3 months after diagnosis) AVR (adjusted HR, 1.61 [95% CI, 1.03–2.52]). In asymptomatic patients with severe AS and preserved ejection fraction, TAPSE <17 mm was independently predictive of mortality (adjusted HR, 2.14 [95% CI, 1.31–3.51]). Early AVR was associated with similar survival benefit in TAPSE <17 and ≥17 mm (adjusted HR, 0.23 [95% CI, 0.16–0.34] for TAPSE <17 mm, adjusted HR, 0.26 [95% CI, 0.19–0.35] for TAPSE ≥17 mm; P for interaction, 0.97).

Conclusions:

Right ventricular dysfunction is an important and independent predictor of mortality in AS. TAPSE <17 mm at the time of AS diagnosis is a marker of poor survival under conservative management and after AVR even in asymptomatic patients with severe AS. AVR was associated with a pronounced reduction in mortality independent of TAPSE suggesting that AVR should be discussed before right ventricular dysfunction occurs in severe AS.

Utility of ripple mapping for identification of slow conduction channels during ventricular tachycardia ablation in the setting of arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Ripple mapping displays every deflection of a bipolar electrogram and enables the visualization of conduction channels (RMCC) within postinfarction ventricular scar to guide ventricular tachycardia (VT) ablation. The utility of RMCC identification for facilitation of VT ablation in the setting of arrhythmogenic right ventricular cardiomyopathy (ARVC) has not been described.

OBJECTIVE

We sought to (a) identify the slow conduction channels in the endocardial/epicardial scar by ripple mapping and (b) retrospectively analyze whether the elimination of RMCC is associated with improved VT-free survival, in ARVC patients.

METHODS

High-density right ventricular endocardial and epicardial electrograms were collected using the CARTO 3 system in sinus rhythm or ventricular pacing and reviewed for RMCC. Low-voltage zones and abnormal myocardium in the epicardium were identified by using standardized late-gadolinium-enhanced (LGE) magnetic resonance imaging (MRI) signal intensity (SI) z-scores.

RESULTS

A cohort of 20 ARVC patients that had undergone simultaneous high-density right ventricular endocardial and epicardial electrogram mapping was identified (age 44 ± 13 years). Epicardial scar, defined as bipolar voltage less than 1.0 mV, occupied 47.6% (interquartile range [IQR], 30.9-63.7) of the total epicardial surface area and was larger than endocardial scar, defined as bipolar voltage less than 1.5 mV, which occupied 11.2% (IQR, 4.2 ± 17.8) of the endocardium (P < 0.01). A median 1.5 RMCC, defined as continuous corridors of sequential late activation within scar, were identified per patient (IQR, 1-3), most of which were epicardial. The median ratio of RMCC ablated was 1 (IQR, 0.6-1). During a median follow-up of 44 months (IQR, 11-49), the ratio of RMCC ablated was associated with freedom from recurrent VT (hazard ratio, 0.01; P = 0.049). Among nine patients with adequate MRI, 73% of RMCC were localized in LGE regions, 24% were adjacent to an area with LGE, and 3% were in regions without LGE.

CONCLUSION

Slow conduction channels within endocardial or epicardial ARVC scar were delineated clearly by ripple mapping and corresponded to critical isthmus sites during entrainment. Complete elimination of RMCC was associated with freedom from VT.

Electrophysiological Basis for Early Repolarization Syndrome

During last centuries, Early Repolarization pattern has been interpreted as an ECG manifestation not linked to serious cardiovascular events. This view has been challenged on the basis of sporadic clinical observations that linked the J-wave with ventricular arrhythmias and sudden cardiac death. The particular role of this characteristic pattern in initiating ventricular fibrillation has been sustained by clinical descriptions of a marked and consistent J-wave elevation preceding the onset of the ventricular arrhythmia. Until now, Early Repolarization syndrome patients have been evaluated using ECG and theorizing different interpretations of the findings. Nonetheless, ECG analysis is not able to reveal all depolarization and repolarization properties and the explanation for this clinical events. Recent studies have characterized the epicardial substrate in these patients on the basis of high-resolution data, in an effort to provide insights into the substrate properties that support arrhythmogenicity in these patients. An overview for the current evidence supporting different theories explaining Early Repolarization Syndrome is provided in this review. Finally, future developments in the field directed toward individualized treatment strategies are examined.

Coronary Sinus Activation and ECG Characteristics of Roof-Dependent Left Atrial Flutter After Pulmonary Vein Isolation

BACKGROUND

The electrocardiographic and intracardiac activation features of left atrial roof-dependent macroreentrant flutter have been incompletely characterized.

METHODS

Patients post-pulmonary vein (PV) isolation with roof-dependent atrial flutter based on activation and entrainment mapping were included. ECG and coronary sinus activation were compared with mitral annular (MA) flutter.

RESULTS

The roof-dependent left atrial flutter circled the right PVs in 32 of 33 cases. Two forms of roof flutters were identified, posteroanterior, ascendant on posterior wall and descendant on anterior wall (n=24); and anteroposterior, ascendant on the anterior wall and descendent on the posterior wall (n=9). Both forms had positive large amplitude P waves in V₁ through V₂ with decreasing amplitude in V₃ through V₆. Posteroanterior roof flutters had positive P wave in the inferior and negative P wave in leads I and aVL similar to counterclockwise MA flutter, but coronary sinus activation was simultaneous for roof and proximal to distal for counterclockwise. Anteroposterior roof flutters were similar to clockwise MA flutter with negative P in inferior leads and transition to flat or negative P in V₃ through V₆. Coronary sinus activation time ≤39 ms identified roof versus MA flutter (sensitivity: 100% and specificity: 97%).

CONCLUSIONS

Roof-dependent flutter around right PVs is more common than around left PVs. The ECG pattern for roof-dependent flutter around right PVs is similar to MA flutter with frontal plane axis dictated by septal activation. Roof-dependent flutter can be distinguished from MA flutter by more simultaneous rather than sequential coronary sinus activation.

Association of regional epicardial right ventricular electrogram voltage amplitude and late gadolinium enhancement distribution on cardiac magnetic resonance in patients with arrhythmogenic right ventricular cardiomyopathy: Implications for ventricular tachycardia ablation

BACKGROUND

Criteria for identification of anatomic ventricular tachycardia substrates in arrhythmogenic right ventricular cardiomyopathy (ARVC) on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) are unclear.

OBJECTIVE

The purpose of this study was to define (1) the association of regional right ventricular (RV) epicardial voltage amplitude with the distribution of LGE; and (2) appropriate image signal intensity (SI) thresholds for ventricular tachycardia substrate identification in ARVC.

METHODS

Preprocedural LGE-CMR and epicardial electrogram mapping were performed in 10 ARVC patients. The locations of epicardial electrogram map points, obtained during sinus rhythm with intrinsic conduction or RV pacing, were retrospectively registered to the corresponding LGE image regions. Standardized SI z-scores (standard deviation distance from the mean) were calculated for each 10-mm region surrounding map points.

RESULTS

In patient-clustered, generalized estimating equations models that included 3205 epicardial electroanatomic points and corresponding SI measures, bipolar (-1.43 mV/z-score; P <.001) and unipolar voltage amplitude (-1.22 mV/z-score; P <.001) were associated with regional SI z-scores. In contrast to the QRS-late potential (LP) interval (P = .362), the LP activation index, defined as electrogram duration divided by QRS-LP, was associated with regional SI z-scores (P <.001). SI z-score thresholds >0.05 (95% confidence interval -0.05 to 0.15) and <-0.16 (95% confidence interval -0.26 to 0.06) corresponded to bipolar voltage measures <0.5 and >1.0 mV, respectively.

CONCLUSION

Increased RV gadolinium uptake is associated with lower epicardial bipolar and unipolar electrogram voltage amplitude. Standardized LGE-CMR SI z-scores may augment preprocedural planning for identification of low-voltage zones and abnormal myocardium in ARVC.

Prevalence and predictive factors of left atrial tachycardia occurring after second-generation cryoballoon ablation of atrial fibrillation

INTRODUCTION

Assess the prevalence and predictors of left atrial tachycardia (LAT) after cryoballoon ablation of pulmonary veins.

METHODS AND RESULTS

Patients who underwent catheter ablation of pulmonary veins with a second-generation cryoballoon for symptomatic paroxysmal (151 of 270, 56%) or persistent (119 of 270, 44%) atrial fibrillation were entered in a single-center prospective registry. Patients who experienced postcryoballoon LAT (pcryo-LAT) were selected on the basis of 12-lead ECG characteristics. Left atrial origin was confirmed during conventional EP study and electroanatomical activation mapping, and patients were treated by RF catheter ablation. Pcryo-LAT was observed in 15 (5.6%) of 270 patients and was attributed to a reentrant mechanism in 11 patients (73%). The other four cases of pcryo-LAT were due to focal atrial tachycardia associated with reconnection of one pulmonary vein. In comparison with patients who remained in sinus rhythm, LA area (HR = 1.09; CI 1.01, 1.2; P = 0.02), LVEF (HR = 0.94; CI 0.90, 0.97; P < 0.001), and LVEF <50% (HR = 8.5; CI 3.1, 23.6; P < 0.001) were predictors of pcryo-LAT. After multivariate Cox analysis, only left ventricular ejection fraction < 50% remained predictive of pcryo-LAT, (HR = 7.8, CI 2.3 26.7, P = 0.002). With a mean survival of 23 months, 73% of patients who experienced pcryo-LAT were in sinus rhythm versus 78% of patients without pcryo-LAT (log rank P = 0.85).

CONCLUSION

The prevalence of pcryo-LAT in patients with atrial fibrillation is low. Left ventricular ejection fraction < 50% is associated with an increased risk of pcryo-LAT. When treated by RF catheter ablation, the presence of pcryo-LAT is not a predictive factor of subsequent recurrence of atrial fibrillation during follow-up.

Normal pulmonary veins anatomy is associated with better AF-free survival after cryoablation as compared to atypical anatomy with common left pulmonary vein

BACKGROUND

Pulmonary vein cryoablation (PVC) is a new approach in the treatment of recurrent atrial fibrillation (AF). Computed tomography (CT) can be used to evaluate the left atrium anatomy and PVs dimensions to facilitate the procedure. In radiofrequency procedures, some anatomic variants such as common left (CLPV) or right (CRPV) PV were reported as factors associated with technical procedure difficulties and potential long-term complications. We hypothesized that the absence of CLPV as determined by CT would predict better AF-free survival after PVC.

METHODS AND RESULTS

We included 118 consecutive patients (mean age 56 ± 10 years; 77% males) with drug refractory paroxysmal (72%)/persistent (28%) AF, with more than 6 months follow-up, who underwent PVC. On CT scanning images performed within 1 month prior to ablation, we evaluated PV anatomic patterns: presence of CLPV or CRPV. Each patient was evaluated by 24-hour Holter monitoring within 1 and 3 months and all patients were periodically evaluated at 1, 3, and 6 months, and every 6 months thereafter. Patients were asked to record their 12-lead electrocardiogram whenever they experienced symptoms suggestive of AF. Recurrence was defined as AF that lasted at least 30 seconds. CLPV was present in 30 (25%) patients and no patients with CRPV were identified. At the end of the 13 months follow-up, patients with normal PVs had significantly better AF-free survival compared to patients with CLPV (67% vs 50%, P = 0.02). The difference was present in patients with paroxysmal AF (P = 0.008) but not in patients with persistent AF (P = 0.92).

CONCLUSION

In patients undergoing cryoballoon PV isolation for AF, the presence of normal PVs pattern is associated with better AF-free survival as compared to atypical PV anatomy with CLPV, particularly in patients with paroxysmal AF.

Fluorescent advanced glycation end products in the detection of factual stages of cartilage degeneration

Patients treated for knee disorders were included in this study. They were examined clinically (Lequesne and Tegner scores) and by standard X-ray investigation. Patients underwent a surgical procedure, either arthroscopy or knee replacement. At the initial phase of surgery, a sample of cartilage was taken for laboratory examination. Progression of the disorder and the clinical examination was correlated with the actual state of the cartilage using a novel fluorescence approach. The intrinsic fluorescence of cartilages was shown as a suitable and sensitive method for detection of the actual state of cartilages because the correlation with X-ray examination and clinical status was found. Intrinsic fluorescence properties of cartilages from patients with chondropathy and osteoarthritis were described and found to be age-dependent. We also observed a higher concentration of advanced glycation end products due to inflammatory and/or degenerative processes in the cartilage. In addition, acute pathological changes due to diseases such as meniscal lesions or anterior cruciate ligament rupture caused a significant increase of formation of advanced glycation end products even in the group of young patients. In fact, such an observation could be crucial and important for the detection of knee conditions suspected of early meniscal and/or ACL lesions especially among young patients.

Protein structure and dynamics determined by protein modeling combined with spectroscopic techniques

Beside of the protein crystals, another attractive option in protein structure analysis has recently appeared: computer modeling of the protein structure based on homology and similarity with proteins of already known structures. We used the combination of computer modeling with spectroscopic techniques, such as steady-state or time-resolved fluorescence spectroscopy or Raman spectroscopy, and with molecular biology techniques. This method could achieve reliable results comparable with resolution obtained from crystal structures. Molecular modeling of the ATP site within the H4-H5-loop revealed eight amino acids residues, namely besides the previously reported amino acids Asp443, Lys480, Lys501, Gly502 and Arg544, also Glu446, Phe475 and Gln482, which form the complete ATP recognition site. Moreover, we proved that a hydrogen bond between Arg423 and Glu472 supported the connection of two opposite halves of the ATP-binding pocket. Similarly, the conserved residue Pro489 is important for the proper interaction of the third and fourth-strands, which both contain residues that take part in the ATP-binding (Ref. 34).