Cryoballoon ablation without use of contrast for the treatment of paroxysmal atrial fibrillation.

BACKGROUND: Cryoballoon ablation (CBA) for atrial fibrillation (AF) is usually preceded by demonstrating pulmonary vein (PV) occlusion using contrast. The aim of the study was to determine efficacy and safety of a simplified protocol for CBA performed without demonstrating PV occlusion and compare achieved results with conventional CBA. METHODS: Paroxysmal AF patients undergoing a first-time CBA were prospectively included. In the non-contrast (NC) group CBA was performed using standardized protocol without demonstrating PV occlusion. In the conventional contrast (CC) group ablations were performed after confirmation of PV occlusion. RESULTS: The NC and CC groups comprised 51 and 22 patients, respectively. PVI according to the group assignment was achieved in 34 (67%) and 21 (95.5%) patients from the NC and CC groups, respectively (p < 0.001). In the NC group, 184 (90%) out of 204 veins were isolated without venography. There were no differences between the NC and CC groups in terms of procedure duration (89.7 ± 22.6 vs. 90.0 ± 20.6 min; p = 0.7) and fluoroscopy time (15.3 ± 6.3 vs. 15 ± 4.5 min; p = 0.8). In the NC group, the use of contrast was significantly lower compared to the CC group (4.9 ± 10.1 vs. 19.4 ± 8.6 mL, p < 0.001). There were no serious adverse events in both groups. A 1-year freedom from AF was achieved in 73.5% and 71.5% of patients from the NC and CC groups, respectively (p = 1). CONCLUSIONS: Cryoballoon ablation without demonstrating vein occlusion with contrast is safe and feasible. Proposed simplified approach enables isolation of the vast majority of pulmonary veins with a significant reduction in the amount of contrast used.

Bipolar Endo-Epicardial Radiofrequency Ablation of Therapy-Resistant Ventricular Arrhythmias: A Brief Case Series.

Despite extensive conventional endoepicardial ablation, significant intramural arrhythmogenic substrate may remain out of reach of unipolar radiofrequency ablation (RFA). The authors present clinical findings and procedural workflow for bipolar radiofrequency ablation (B-RFA) with 1 catheter placed against the endocardium and the other in the pericardial sac to ablate refractory ventricular arrhythmias. No serious adverse events occurred during B-RFA procedures, and the short-term and midterm clinical results were satisfactory. Optimal catheter choice and ablation parameters settings for B-RFA remain to be determined.

Atrial electrogram amplitude variability during atrial fibrillation ablation.

INTRODUCTION: Variability of the bipolar atrial electrogram amplitude may affect voltage maps created during ablation procedures, and thus also the extent of ablations. Therefore, the aim of the study was to assess the beat-to-beat electrogram amplitude variability in the left atrium in patients undergoing atrial fibrillation ablation. METHODS: In 11 patients undergoing ablation for atrial fibrillation, 362 mapping points were collected in two series. At each point, three consecutive beats were recorded and verified including the bipolar electrogram amplitude, contact force (CF), and orientation of the catheter tip. The repeatability and reproducibility of obtained measurements between consecutive beats and series were assessed by the Pearson correlation coefficient (r), the Bland-Altman test, repeatability coefficient (RC), relative standard deviation (RSD), and concordance correlation coefficient (CCC). RESULTS: A total of 1086 beats were analyzed. The correlation coefficient for bipolar atrial electrogram amplitude for the first two beats, and for the first and the third beats were 0.94 and 0.86, respectively. The average of differences between the first two beats and between the first and the third beats were 0.06 and 0.13 mV with 95% limits of agreement (LoA) within ±0.98 and ±1.74 mV, respectively. For CF values ≤5 and ≥20 g, the 95% LoA were narrower compared to other CF ranges and were ±0.49 and ±0.71 mV from the average value, respectively. When the analyzes were performed within the predefined ranges of bipolar electrogram amplitude: 0.05-1; 1-2; 2-3 mV, the 95% LoA were within ±0.33, ±0.98, and ±0.84 mV from the average value, respectively. RC and RSD were 1.41 mV and 20.8%, respectively. For repeated measurement between series, CCC ranged from 0.67 to 0.71 and the 95% LoA were within ±2.7 to 2.9 mV from the average value. CONCLUSION: Bipolar atrial electrogram amplitude recorded at a given site during ablation procedures is variable to an extent that may be clinically relevant. The magnitude of the observed variability is greater during remapping.

Simultaneous Entrainment Response Assessment at Multiple Sites.

BACKGROUND: The entrainment response, defined as the difference between the postpacing interval and the tachycardia cycle length (TCL) recorded from a mapping catheter, allows to track down the components of the tachycardia loop. OBJECTIVES: The aim of this study was to evaluate if the postpacing interval measured simultaneously from multiple sites that are remote from the pacing site (PPIR) could be clinically useful in mapping re-entrant circuits. METHODS: Ninety-two episodes of entrainment response in 29 patients with different macro-re-entrant tachycardias were evaluated using a standardized entrainment protocol. The spatial distribution of different values of PPIR-TCL in a simulation and a computational model of an entrained re-entrant tachycardia was also analyzed. RESULTS: The PPIR exceeded TCL by more than 20 milliseconds only if both pacing and recording sites were outside the tachycardia circuit. The PPIR-TCL at in-circuit sites was always ≤20 milliseconds. Sites with negative PPIR-TCL values were found either outside or inside the tachycardia circuit. CONCLUSIONS: Assessment of entrainment response from catheters remote from the pacing site may enhance spatial mapping of the tachycardia circuit. The PPIR-TCL above 20 milliseconds has an excellent positive predictive value in identifying sites outside the tachycardia circuit.

Successful primary percutaneous coronary intervention determines the very long-term prognosis in ST-segment elevation myocardial infarction even in survivors of the acute phase. The ANIN Myocardial Infarction Registry.

INTRODUCTION: Successful primary percutaneous coronary intervention (pPCI) saves lives in the acute phase of ST-elevation myocardial infarction (STEMI) and improves the mid-term prognosis. Whether that benefit remains significant in very long-term follow-up and is associated with total ischaemic time (TIT), especially in survivors of the acute phase of STEMI, is unknown. AIM: We sought to investigate the impact of initial and final thrombolysis in myocardial infarction (TIMI) flow on long-term survival in a homogeneous, unselected group of patients with STEMI undergoing pPCI at a high-volume centre. MATERIAL AND METHODS: All consecutive STEMI patients treated with pPCI in our tertiary centre were enrolled in the ANIN Myocardial Infarction Registry. RESULTS: Among 1064 patients 871 (82%) had an occluded infarct artery (IRA) at baseline, while pPCI was successful in 885 (83%) patients. At 9 years all-cause and cardiovascular (CV) mortality were 28% (294 patients) and 19% (196 patients), respectively. Failure of pPCI was an independent predictor of long-term all-cause and CV mortality (OR = 1.5, 95% CI: 1.1-2.0, p = 0.03 and OR = 1.8, 95% CI: 1.3-2.7, p = 0.001, respectively). In survivors of the acute phase, occluded IRA at baseline was an independent predictor of all-cause mortality (OR = 1.5, 95% CI: 1.0-2.3, p = 0.04), while pPCI failure predicted CV mortality (OR = 1.8, 95% CI: 1.2-2.8, p = 0.005). Mortality rate increased with TIT even in patients with pPCI success. CONCLUSIONS: Angiographic results of pPCI determine the very long-term survival of STEMI patients, even in survivors of the acute phase of STEMI. Shortening of TIT is crucial.

Bedside prediction of 9-year mortality after ST­segment elevation myocardial infarction treated with primary percutaneous coronary intervention.

BACKGROUND: Despite similar underlying pathogenesis, clinical features, and management of ST­segment elevation myocardial infarction (STEMI), the long­term prognosis of patients is highly variable. The ability to stratify an individual's long­term mortality risk could facilitate development of focused interventions aimed at reducing poor long­term outcomes. AIMS: This study aimed to develop and validate a simple risk score based on routinely collected data for all­cause and cardiovascular 9-year mortality in a homogeneous group of patients with STEMI undergoing primary percutaneous coronary intervention (pPCI). METHODS: All consecutive patients with STEMI treated with pPCI were randomly divided into 2 groups. The first group was called the building group and was used to develop logistic regression models that were converted into a simple risk scores that estimated all­cause and cardiovascular long­term mortality risk (ANIN risk score I and II, respectively) and subsequently validated in the second group, called the validating group. RESULTS: The 9-year follow­up data were available in 1059 out of 1064 patients with STEMI. We developed 4 independent risk scores with the highest predictive accuracy of ANIN risk score I. Validation cohorts identified 4 most important risk factors: age, renal dysfunction, Killip class, and thrombolysis in myocardial infarction flow. Low, intermediate, and high­risk subgroups were identified based on those factors with different long­term mortalities: 10%, 37%, and 71%, respectively. CONCLUSIONS: Long­term mortality after STEMI treated with pPCI can be accurately predicted using 4-variable bedside risk score, which is ready to calculate right after pPCI. Patients in the low­risk group have an excellent prognosis despite having experienced potentially lethal disease.

Quantification of mitral regurgitation in patients with hypertrophic cardiomyopathy using aortic and pulmonary flow data: impacts of left ventricular outflow tract obstruction and different left ventricular segmentation methods.

BACKGROUND: Cardiovascular magnetic resonance (CMR) imaging in patients with hypertrophic cardiomyopathy (HCM) enables the assessment of not only left ventricular (LV) hypertrophy and scarring but also the severity of mitral regurgitation. CMR assessment of mitral regurgitation is primarily based on the difference between LV stroke volume (LVSV) and aortic forward flow (Ao) measured using the phase-contrast (PC) technique. However, LV outflow tract (LVOT) obstruction causing turbulent, non-laminar flow in the ascending aorta may impact the accuracy of aortic flow quantification, leading to false conclusions regarding mitral regurgitation severity. Thus, we decided to quantify mitral regurgitation in patients with HCM using Ao or, alternatively, main pulmonary artery forward flow (MPA) for mitral regurgitation volume (MRvol) calculations. METHODS: The analysis included 143 prospectively recruited subjects with HCM and 15 controls. MRvol was calculated as the difference between LVSV computed with either the inclusion (LVSVincl) or exclusion (LVSVexcl) of papillary muscles and trabeculations from the blood pool and either Ao (MRvolAoi or MRvolAoe) or MPA (MRvolMPAi or MRvolMPAe). The presence or absence of LVOT obstruction was determined based on Doppler echocardiography findings. RESULTS: MRvolAoi was higher than MRvolMPAi in HCM patients with LVOT obstruction [47.0 ml, interquartile range (IQR) = 31.5-60.0 vs. 35.5 ml, IQR = 26.0-51.0; p < 0.0001] but not in non-obstructive HCM patients (23.0 ml, IQR = 16.0-32.0 vs. 24.0 ml, IQR = 15.3-32.0; p = 0.26) or controls (18.0 ml, IQR = 14.3-21.8 vs. 20.0 ml, IQR = 14.3-22.0; p = 0.89). In contrast to controls and HCM patients without LVOT obstruction, in HCM patients with LVOT obstruction, aortic flow-based MRvol (MRvolAoi) was higher than pulmonary-based findings (MRvolMPAi) (bias = 9.5 ml; limits of agreement: -11.7-30.7 with a difference of 47 ml in the extreme case). The differences between aortic-based and pulmonary-based MRvol values calculated using LVSVexcl mirrored those derived using LVSVincl. However, MRvol values calculated using LVSVexcl were lower in all the groups analyzed (HCM with LVOT obstruction, HCM without LVOT obstruction, and controls) and with all methods of MRvol quantification used (p ≤ 0.0001 for all comparisons). CONCLUSIONS: In HCM patients, LVOT obstruction significantly affects the estimation of aortic flow, leading to its underestimation and, consequently, to higher MRvol values than those obtained with MPA-based MRvol calculations.

Biventricular mechanics in prediction of severe myocardial fibrosis in patients with dilated cardiomyopathy: CMR study.

PURPOSE: The purpose of this study was to compare the ability of various parameters of myocardial mechanics to predict large amounts of biventricular fibrosis assessed via T1 mapping in patients with dilated cardiomyopathy (DCM). MATERIAL: Cardiovascular magnetic resonance feature tracking analysis and T1 mapping were performed in 26 patients with DCM [mean age: 34.4±9.1years, 15 (57.6%) males]. The values of various parameters of myocardial mechanics at predicting advanced left-ventricle (LV) and right-ventricle (RV) fibrosis were compared using logistic regression analysis and receiver operating characteristic curve (ROC) analysis. RESULTS: There were 7 (26.9%) patients with a large amount of LV fibrosis and 9 (34.6%) patients with severe RV fibrosis. ROC curve analysis revealed that the model of combined LV strain rates (AUC=0.902) offered superb ability at predicting large amounts of LV fibrosis. The models including RV strain rates (AUC=0.974), a combination of RV strains, strain rates and clinical parameters (AUC=0.993) as well as the RV radial strain rate alone model (AUC=0.961) yielded outstanding performance in discriminating large and small amounts of RV fibrosis. In multivariate analysis, the LV circumferential strain (LVCR) and RV radial (RVR) strain rate were the only independent predictors of large amounts of LV and RV fibrosis, respectively. CONCLUSIONS: Indices of myocardial deformation, especially combined with clinical features, offered a superlative ability to differentiate high from low degrees of fibrosis in DCM patients. Among all analyzed parameters of myocardial mechanics, LVCR and RVR rate alone were the independent predictors of high degrees of LV and RV fibrosis, respectively.

The value of cardiac magnetic resonance and distribution of late gadolinium enhancement for risk stratification of sudden cardiac death in patients with hypertrophic cardiomyopathy.

BACKGROUND: The presence of late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM) is associated with worse clinical outcome and the extent of LGE predicts the increased risk of sudden cardiac death (SCD). Limited data exist regarding the distribution of LGE. We attempted to verify whether the presence of LGE outside the interventricular insertion points carries additional risk for patients with HCM. METHODS: In this prospective study, 328 patients with HCM, who underwent cardiac magnetic resonance (CMR) were enrolled. Five major risk factors for SCD were assessed in all patients. The median follow-up was 37 months. RESULTS: LGE was detected in 226 (68.9%) patients. In 70 (21.3%) patients it was present only at the interventricular insertion points - LGE (+) group, while in 156 (47.6%) it was noted in other locations - LGE (++) group. Primary endpoint defined as SCD or appropriate implantable cardioverter-defibrillator intervention occurred in 14 (4.3%) patients, one in LGE (+) and 13 in LGE (++). In multivariable analysis including five traditional risk factors and left ventricular ejection fraction <50%, only the presence of LGE outside the insertion points was a significant predictor of SCD/aborted SCD (HR 10.01, 95% CI 1.21-83.86, p=0.033). The performance of the multivariable sudden cardiac death risk model was improved by the addition of LGE (++) to the traditional risk factors (likelihood ratio p=0.005). The Kaplan-Meier curves showed better event-free survival in the LGE (-) and LGE (+) patient groups compared to the LGE (++) group. CONCLUSIONS: In HCM patients, presence of LGE outside interventricular insertion points is associated with increased risk of sudden cardiac death or its equivalent as well as overall mortality. Cardiac fibrosis as a substrate for SCD in HCM may be identified on CMR and serve as an imaging biomarker of increased risk.