Genes associated with hypertrophic cardiomyopathy (HC) are not uniformly expressed in the atrial myocardium. Whether this may impact susceptibility to atrial fibrillation (AF) is unresolved. To ...analyze the prevalence and clinical correlates of AF in relation to genotype in a large HC cohort, prevalence and clinical profile of AF were assessed in 237 patients with HC, followed for 14 ± 10 years. Patients were divided into 3 genetic subgroups: (1) MYBPC3 (58%), (2) MYH7 (28%), and (3) “other genotypes” (14%; comprising TNNT2 , TNNI3 , TPM1 , MYL2 , complex genotypes, Z-line, and E-C coupling genes). Left atrial size was similar in the 3 subsets. AF occurred in 74 patients with HC (31%), with no difference among groups (31% in MYBPC3 , 37% in MYH7 and 18% in other genotypes, p = 0.15), paroxysmal/persistent AF (12%, 18%, and 12%, respectively; p = 0.53), paroxysmal/persistent evolved to permanent (12%, 12%, and 3%, p = 0.36) or permanent AF (7%, 7%, and 3%, p = 0.82). Age at AF onset was younger in the group with other genotypes (37 ± 10 years) compared to the first 2 groups (53 ± 14 and 51 ± 17, respectively; p = 0.05) because of early onset associated with complex genotypes and a specific JPH2 mutation associated with abnormal intracellular calcium handling. At multivariate analysis, independent predictors of AF were atrial diameter (p ≤0.05) and age at diagnosis (p = 0.09), but not genetic subtype (p = 0.35). In conclusion, in patients with HC, genetic testing cannot be used in clinical decision making with regard to management strategies for AF. Genotype is not predictive of onset or severity of AF, which appears rather driven by hemodynamic determinants of atrial dilatation. Exceptions are represented by rare genes suggesting specific molecular pathways for AF in genetic cardiomyopathies.
Atrial tachycardia (AT) and atrial fibrillation (AF) are common in pacemaker patients and are associated with bad prognoses.
The purpose of this study was to evaluate atrial antitachycardia pacing ...impact on AT/AF-induced atrial remodeling, measured by early recurrence of AT/AF (ERAF) and by change in left atrial diameter (LAD), and to evaluate the impact of AT/AF duration on ERAF incidence.
Pacemaker patients were randomized to dual-chamber pacing (Control DDDR: 385 patients), managed ventricular pacing (MVP: 398 patients), or atrial antitachycardia pacing plus MVP (DDDRP+MVP: 383 patients). LAD change, estimated by echocardiography, was considered significant if the relative difference between baseline and 24-month measurements was >10%.
At median follow-up of 34 months, ERAF incidence was significantly lower in the DDDRP+MVP arm for all AT/AF durations, in particular, ERAF followed AT/AF longer than 3 hours in 53% cases in Control DDDR, in 51% cases in MVP, and in 39% cases in DDDRP+MVP (P <.001 vs other groups). ERAF incidence showed a U-shaped pattern when evaluated as a function of previous AT/AF duration, decreasing for durations from 5 minutes to 12 hours and increasing for longer durations. Among patients with significant LAD change, the proportion of patients with a reduction in LAD was 35% in Control DDDR, 37% in MVP, and 70% in DDDRP+MVP (P <.05 vs other groups).
Our data suggest that atrial electrical remodeling becomes important after about 12 hours of continuous arrhythmia. Compared to DDDR or MVP, DDDRP+MVP reduces ERAF and favors LAD reduction, suggesting that atrial antitachycardia pacing may reverse electrical and mechanical remodeling.
Abstract Left ventricular (LV) dyssynchrony is a necessary condition for successful cardiac resynchronization therapy (CRT). Despite left bundle branch block (LBBB) representing a reliable surrogate ...of LV dyssynchrony, not all LBBB patients will respond to CRT. Our aim was to investigate the relation between QRS duration and LV dyssynchrony in LBBB patients who underwent CRT. We retrospectively studied 165 patients with LBBB who underwent CRT implantation according to the current guidelines. A 6-month reduction of LV end-systolic volume ≥15% identified responders to CRT. Baseline LV dyssynchrony was defined as the delay between peak systolic velocities of the interventricular septum and lateral wall assessed by color-coded tissue Doppler imaging. Baseline characteristics of responders (61%) and nonresponders (39%) were comparable except for larger QRS complex (172±24 ms vs 160±16 ms, p<0.001) and lower degree of LV dyssynchrony (46±42 ms vs 72±31 ms, p<0.001) in nonresponders. Receiver-operator characteristic curve analysis demonstrated that an optimal cut-off value of 3 for the ratio of QRS duration and LV dyssynchrony (QRS/LVdys) yielded a sensitivity of 66% and specificity of 80% to predict nonresponsiveness to CRT; QRS/LVdys >3 remained an independent predictor at multivariate analysis. In patients with nonischemic etiology of cardiomyopathy the linear regression analysis documented a significant inverse relationship between QRS duration and LV dyssynchrony, as dyssynchrony progressively decreased as QRS widening increased (p=0.006). This was not evident in patients with ischemic etiology. In conclusion, in LBBB patients with nonischemic etiology and marked QRS widening the absence of LV dyssynchrony may account for a lower response to CRT as compared to patients with intermediate QRS widening.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is associated with increased risk for stroke mainly due to cardiac embolism from the left atrial appendage (LAA). ...Occlusion of the LAA by means of a device represents a valid alternative to oral anticoagulation, mainly in patients who cannot tolerate this therapy because of a high bleeding risk. Recent data on the endocardial device WATCHMAN show encouraging results for this patient population in terms of stroke risk reduction compared to the expected rate as well as in terms of implant success. This article reviews all relevant publications related to the main surgical and transcatheter devices used for LAA closure (LAAC).
PROTECT-AF, the first prospective randomized trial conducted on this technique, showed that LAA occlusion using the WATCHMAN was noninferior to warfarin for a combined end-point in patients with nonvalvular AF. There is a lack of large-scale randomized trials on long-term stroke risk in patients submitted to LAAC. Most studies are relatively small and focus on the comparison of different surgical techniques with regard to complete/incomplete closure success. More recently, PROTECT-AF long-term results (4-year follow-up) demonstrated that LAAC was statistically superior to warfarin in terms of efficacy.
This review concludes that it is now appropriate to consider these techniques for patients with AF who are at high risk for stroke for whom effective conventional or novel anticoagulant therapy is not available or who present problems in managing drug treatment.
Left bundle branch block (LBBB) is the most reliable electrocardiographic predictor of responsiveness to cardiac resynchronization therapy (CRT). However, not all patients with LBBB will respond to ...CRT. Our aim was to investigate the interaction between QRS duration, LBBB-type morphology, and the responsiveness to CRT. We retrospectively analyzed electrocardiograms of 243 patients who underwent CRT implantation according to current clinical indications. A 6-month reduction of left ventricular end-systolic volume >15% was used to identify CRT responders. The clinical end point consisted of death, hospitalization for heart failure and sustained rapid ventricular tachyarrhythmias. An LBBB morphology was present in 169 patients (70%) and 101 of these (60%) were responders to CRT. Analyzing the interaction between QRS duration and CRT responsiveness in patients with LBBB, a “U shaped” distribution resulted, with nonresponders clustered between 120 and 130 ms and above 180 ms. The receiver operating characteristic curve analysis identified 178 ms as the optimal cut-off value of QRS to predict a nonresponsiveness to CRT (area under the curve = 0.67 95% confidence interval 0.57 to 0.76). At multivariate analysis, only an ischemic cause and a QRS ≥178 ms were independent predictors of nonresponsiveness to CRT (area under the curve = 0.75). Patients with LBBB with QRS ≥178 ms had greater likelihood of adverse clinical events during a mean follow-up of 32 months (p = 0.049). In conclusion, in patients with LBBB undergoing CRT, a marked QRS widening (i.e., ≥178 ms) is related to worse echocardiographic responsiveness and lower event free survival rate compared with patients with an intermediate QRS widening.
Objective To evaluate the incidence of postoperative atrial fibrillation (POAF), the predisposing factors, the results of treatment before discharge, and the impact on duration and costs of ...hospitalization. Design A prospective observational study. Methods Patients who underwent cardiac surgery from January 1, 2007 to December 31, 2007. Interventions Electrocardiography was continuously monitored after surgery. Patients with symptomatic new-onset atrial fibrillation or lasting >15 minutes were treated with amiodarone and with DC shock in prolonged cases. Results POAF occurred in 29.7%, with the higher incidence between the 1st and 4th postoperative day. Age ( p < 0.001), atrial size >40 mm ( p < 0.001), previous episodes of AF ( p < 0.001), female sex ( p = 0.010), and combined valve and bypass surgery ( p = 0.012) were multivariate predictors of POAF at logistic regression. Sinus rhythm was restored by early treatment in 205 of 215 patients. This was associated with a low incidence of cerebrovascular events (<0.5%) and with a limited increase of average length of hospitalization (24 hours) in patients with POAF. Conclusions The overall incidence of POAF in the authors' center is close to 30%; 95.3% of patients were discharged in sinus rhythm. The increase in length and costs of hospitalization (on average, 1.0 day with a burden of about €1,800/patient) were significantly lower than in previous investigations.
The sick sinus syndrome includes symptoms and signs related to sinus node dysfunction. This can be caused by intrinsic abnormal impulse formation and/or propagation from the sinus node or, in some ...cases, by extrinsic reversible causes. Careful evaluation of symptoms and of the electrocardiogram is of crucial importance, because diagnosis is mainly based on these 2 elements. In some cases, the pathophysiologic mechanism that induces sinus node dysfunction also favors the onset of atrial arrhythmias, which results in a more complex clinical condition, known as "bradycardia-tachycardia syndrome."
Cryoablation (CA) is an emerging tool for the treatment of supraventricular tachyarrhythmias. Determinants of long-term success still need clarification.
The purpose of this study was to assess which ...patients' and procedural features affect the long-term efficacy of CA for typical atrioventricular nodal reentrant tachycardia (AVNRT).
Eighty-five consecutive patients undergoing CA for typical AVNRT were divided into 3 groups of age: group A, ≤20 years, n = 20 (23.5%); group B, 21-50 years, n = 30 (35.3%); group C, ≥51 years, n = 35 (41.2%). CA was performed for 5 minutes at -75°C in all; 4-minute bonus CA was delivered if not contraindicated (ie, transient PR interval lengthening during the first application and narrow triangle of Koch). The efficacy end point was the absence of recurrences at 12-month follow-up.
CA was acutely successful in all 85 patients (100%). Bonus ablation was performed in 69 (81.2%). No permanent complications were observed. At follow-up, AVNRT recurrences occurred in 9 patients (10.6%): group A, 0 (0%); group B, 2 (6.7%), group C, 7 (20%). Incidence of recurrences was significantly different between age groups (P = .047) and between patients receiving (7.2%) and not receiving (25.0%) bonus CA (P = .038). In multivariable analysis, age groups (odds ratio OR 5.917; 95% confidence interval CI 1.372-25.518; P = .017) and bonus CA (OR 0.115; 95% CI 0.018-0.724; P = .021) were the only independent predictors of recurrences. Furthermore, age as a continuous variable remained statistically associated with recurrences (OR 1.046; 95% CI 1.002-1.091; P = .038).
CA is effective and safe for typical AVNRT ablation. Younger age and bonus CA administration are independent predictors of success at 12 months. Incidence of recurrences is low in patients younger than 21 years.
The implantation strategy appears to play a pivotal role in determining response to cardiac resynchronization therapy (CRT).
The aim of our study was to determine the association between anatomic and ...electrical interlead distance and clinical outcome after CRT implantation.
We included 216 first-time CRT recipients with left bundle branch block and sinus rhythm. On implantation, the electrical interlead distance (EID), defined as the time interval between spontaneous peak R waves detected at the right ventricular (RV) and left ventricular (LV) pacing sites, was measured. The anatomic distance between the RV and LV lead tips was determined on chest radiographs.
The mean EID was 74 ± 41 ms, and the mean horizontal corrected interlead distance (HCID) was 125 ± 73 mm. After 12 months, 87 patients (40%) displayed an improvement in their clinical composite score. The cutoff values that best predicted an improved clinical status were as follows: 84 ms for EID (area under the curve 0.59; confidence interval CI 0.52-0.66; P = .026) and 90 mm for HCID (area under the curve 0.62; CI 0.55-0.69; P = .004). On multivariate analysis, only EID >84 ms (hazard ratio 0.36; CI 0.14-0.89; P = .028) and HCID >90 mm (hazard ratio 0.45; CI 0.23-0.90; P = .025) were significantly associated with the composite endpoint of death or cardiovascular hospitalization. In particular, the presence of both conditions (EID <84 ms and HCID <90 mm) was associated with the highest rate of events (log-rank test P = .002).
The interlead anatomic and electrical distance are strongly and independently associated with patient outcome after CRT implantation. The 2 measures show an additive predictive value. (CRT MORE: Cardiac Resynchronization Therapy Modular Registry; www.clinicaltrials.gov, unique identifier: NCT01573091.)
Abstract Background The relationship between troponin and atrial fibrillation (AF) without acute coronary syndrome is still unclear. We sought to investigate the presence of coronary atherosclerosis ...and adverse outcomes in patients with AF. Methods Consecutive patients with recent-onset AF and without severe comorbidities were enrolled between 2004 and 2013. Patients with a troponin rise or with adverse outcomes were considered for coronary angiography and revascularization when “critical” stenosis (≥ 70%) was recognized. Propensity score matching was performed to adjust for baseline characteristics; after matching, no differences existed between the groups of patients with or without troponin rise. The primary end point was the composite of acute coronary syndrome, revascularization, and cardiac death at 1- and 12-month follow-ups. Results Of 3627 patients enrolled, 3541 completed the study; 202 (6%) showed troponin rise; and 91 (3%), an adverse outcome. In the entire cohort, on multivariate analysis, the odds ratio for the occurrence of the primary end point of troponin rise was 14 (95% confidence interval CI, 10-23; P < .001), and that of known coronary artery disease was 3 (CI, 2-5; P = .001). In the matching cohort, the odds ratio of troponin rise was 10 (CI, 4-22; P < .001), and that of TIMI score greater than 2 was 4 (CI, 2-9; P ≤ .001). In the entire cohort, patients with or without troponin rise achieved the primary end point in 38 (19%) and 43 (1%) patients, respectively ( P < .001). Stroke occurred in 4 (2%) and 20 (1%), respectively ( P = .018). Critical stenosis and revascularization account for 23 (12%) and 15 (1%), respectively ( P < .001). In the matching cohort, results were confirmed, but incidence of stroke was comparable. Conclusions Patients with recent-onset AF and troponin rise showed higher prevalence of coronary atherosclerosis and adverse cardiac events. Stroke per se did not succeed in justifying the high morbidity. Thus, beyond stroke, coronary atherosclerosis might have a pivotal role in poor outcomes.
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