Enlarged left atrium and sudden death risk in hypertrophic cardiomyopathy patients with or without atrial fibrillation.

BACKGROUND: The relationships among enlarged left atrial dimension (LAD), the presence or absence of atrial fibrillation (AF), and sudden death risk in patients with hypertrophic cardiomyopathy (HCM) remain unclear. The aim of this study was to evaluate the impact of enlarged LAD on sudden death risk in HCM patients with or without documented AF. METHODS: This study included 564 HCM patients (follow-up period: 10.8±7.4 years). LAD was measured from the parasternal long-axis view as the antero-posterior linear diameter at end-systole. Sudden death was defined as the combined endpoint of sudden cardiac death and potentially lethal arrhythmic events, and log-rank tests and Cox proportional hazards models were applied to evaluate the impact of LAD enlargement on the combined endpoint. RESULTS: The proportions of patients with sudden death and potentially lethal arrhythmic events were significantly higher among patients with enlarged LAD (≥48mm, N=86) compared with those without enlarged LAD (19.8% vs. 8.2%; p=0.002). However, enlarged LAD was not identified as an independent determinant of sudden death risk in multivariate analysis of all study HCM patients [adjusted hazard ratio (HR): 1.83; 95% confidence interval (CI): 0.95-3.53; p=0.071]. Among patients without documented AF during the follow-up periods, enlarged LAD was an independent determinant of sudden death risk (adjusted HR: 5.23; 95% CI: 2.17-12.58; p<0.001), although there was no significant difference in sudden death risk between patients with and without enlarged LAD in patients with documented AF (adjusted HR: 0.77; 95% CI: 0.31-1.90; p=0.567). CONCLUSIONS: These results suggest that the relationship between LAD and outcome is influenced by the presence or absence of AF in HCM patients. It may thus be necessary to consider the need to prevent sudden death in LAD-enlarged HCM patients without documented AF.

Catheter ablation of atrial fibrillation in patients with severely impaired left ventricular systolic function.

Little is known about the outcome of catheter ablation of atrial fibrillation (AF) in patients with heart failure (HF) and a severely reduced left ventricular ejection fraction (LVEF). We aimed to clarify the effectiveness of catheter ablation of AF in patients with a severely low LVEF. This retrospective study included 18 consecutive patients with HF and an LVEF of ≤ 35 % who underwent catheter ablation of AF. We investigated the clinical parameters, echocardiographic parameters and the incidence of hospitalizations for HF. During a median follow-up of 21 months (IQR, 13-40) after the final procedure (9 with repeat procedures), 11 patients (61 %) maintained sinus rhythm (SR) (6 with amiodarone). The LVEF and NYHA class significantly improved at 6 months after the CA in 12 patients (67 %) who were in SR or had recurrent paroxysmal AF (from 25.8 ± 6.3 to 37.0 ± 11.7 %, P = 0.02, and from 2.3 ± 0.5 to 1.5 ± 0.7, P < 0.01, respectively) but not in patients who experienced recurrent persistent AF. The patients with SR or recurrent paroxysmal AF had significantly fewer hospitalizations for HF than those with recurrent persistent AF after the AF ablation (log-rank test; P < 0.01). Catheter ablation of AF improved the clinical status in patients with an LVEF of ≤ 35 %. A repeat ablation procedure and amiodarone were often necessary to obtain a favorable outcome.

Prognostic difference between paroxysmal and non-paroxysmal atrial fibrillation in patients with hypertrophic cardiomyopathy.

BACKGROUND: The association of atrial fibrillation (AF) with sudden death and the difference in prognostic significance between paroxysmal and non-paroxysmal AF remains unclear in patients with hypertrophic cardiomyopathy (HCM). Our aim was to investigate the clinical significance of AF, and to assess the prognostic difference between paroxysmal and non-paroxysmal AF in HCM patients. METHODS: The study included 430 HCM patients. Documentation of AF was based on electrocardiograms obtained either after the acute onset of symptoms or fortuitously during routine examination of asymptomatic patients. RESULTS: AF was detected in 120 patients (27.9%). In the patients with AF, syncope and non-sustained ventricular tachycardia were more frequent and the left atrial dimension was larger. Multivariate analysis showed that AF was an independent determinant of the outcome, including the risk of HCM-related death (adjusted hazard ratio 3.57, p<0.001) and sudden death (adjusted hazard ratio 2.61, p=0.038). When patients with AF were divided into subgroups with paroxysmal AF (n=75) or non-paroxysmal AF (n=45), only paroxysmal AF was identified as an independent determinant of the outcome, including the risk of HCM-related death (adjusted hazard ratio 5.24, p<0.001) and sudden death (adjusted hazard ratio 4.67, p=0.002). CONCLUSIONS: AF is a common supraventricular arrhythmia in HCM and has an adverse influence on the prognosis. In addition, each type of AF had a different clinical impact, with paroxysmal AF being a significant independent determinant of an adverse outcome, including sudden death.

Unusual "ratchet syndrome": spontaneous lead retraction after a generator exchange.

A 72-year-old female with idiopathic dilated cardiomyopathy underwent a generator exchange for a cardiac resynchronization therapy defibrillator with a full-pocket capsulectomy. The lead position after the operation was identical to that before the operation on the chest X-ray. After 4 months, a subacute exacerbation of her heart failure was caused by cardiac resynchronization therapy failure due to a dislodgement of the left ventricular lead. An aggressive adhesiotomy of the connective tissue around the leads made it possible for the lead to retract by a ratchet-like movement through the suture sleeve, so-called "ratchet syndrome", after the generator exchange.

Left brachiocephalic vein occlusion in a patient with an aortic arch aneurysm: Rare cause of obstraction for a pacemaker implantation.

Venous occlusions or anatomic variants are unexpectedly encountered during transvenous pacing lead implantation procedures. A 78-year-old man, who had been medically treated for a thoracic and abdominal dissecting aortic aneurysm was referred to our hospital for treatment of congestive heart failure due to complete atrioventricular block with bradycardia. At the time of the pacemaker implantation, the guidewire for inserting the introducer sheath could not be advanced into the left brachiocephalic vein. A venogram and contrast-enhanced chest multi-detector computed tomography revealed an obstruction of the left brachiocephalic vein at the confluence of the left internal jugular and left subclavian veins, and there was collateral blood circulation. We abandoned introducing the pacemaker lead from the left side, and implanted the pacemaker in his right anterior chest. In this case, the left brachiocephalic vein was occluded due to dilatation and elongation of the aortic arch aneurysm and the deviated left common carotid artery. This case illustrates the importance of the assessment of the patency of the left brachiocephalic vein prior to the central venous approach from the left internal jugular and left subclavian veins in patients with aortic arch aneurysms. .

Localized reentrant tachycardia in the aorta contiguity region mimicking perimitral atrial flutter in the context of atrial fibrillation ablation.

We describe a case with a focal atrial tachycardia (AT) masquerading as perimitral atrial flutter revealed after circumferential pulmonary vein antral isolation for atrial fibrillation. It was successfully terminated and became noninducible by a point ablation on the left atrial anterior wall (LAAW) near the mitral annulus in contact with the aortic root and on the left superior pulmonary vein-left atrial appendage ridge, without any linear ablation, using electroanatomical mapping and conventional precise mapping with a maximum amplified gain within the low-voltage area. The AT revealed in our case was an LAAW-aorta contiguity area-related AT.

Impact of diastolic dysfunction on the outcome of catheter ablation in patients with atrial fibrillation.

OBJECTIVE: To evaluate the impact of diastolic dysfunction on the outcome of atrial fibrillation (AF) ablation. METHODS: Eighty consecutive patients with drug-refractory symptomatic AF who underwent AF ablation were enrolled (65 males, 58 ± 10 years, 65 paroxysmal AF, 15 persistent AF). All patients underwent extensive pulmonary vein isolation with a double lasso technique using CARTO MERGE. Diastolic dysfunction was defined as a ratio of the mitral inflow early filling velocity to the velocity of the early medial mitral annular ascent of >10. The clinical and echocardiographic data were compared between the patients with and without diastolic dysfunction, and between the patients with and without AF recurrences after the AF ablation. RESULTS: Twenty-nine out of all the patients (36.3%) had diastolic dysfunction. Compared with the patients without diastolic dysfunction, the patients with diastolic dysfunction had higher brain natriuretic peptide (p=0.001) and C-reactive protein (p=0.023) levels, and a larger left atrial diameter (P=0.019). The AF-free rate after a single or repeat AF ablation procedure in the patients with diastolic dysfunction was lower than that in those without diastolic dysfunction (p=0.005 and p=0.013 by the log-rank test, respectively). In the univariate analysis, the patients with persistent AF and diastolic dysfunction were likely to have AF recurrences after a single AF ablation. The multivariate analysis indicated diastolic dysfunction as the only independent predictor of an AF recurrence after a single AF ablation (P=0.023). CONCLUSION: The patients with diastolic dysfunction had a worse outcome of the AF ablation not only for a single procedure but also a repeat procedure.

Long-term results of a cardiovascular implantable electronic device wrapped with an expanded polytetrafluoroethylene sheet.

The use of an expanded polytetrafluoroethylene (ePTFE) sheet wrapping device for patients with pacemaker contact dermatitis is still controversial. This study aimed to retrospectively investigate the occurrence rate of allergies and other complications after implantation of a cardiovascular implantable electronic device (CIED) wrapped with an ePTFE sheet. A total of 4,497 procedures of CIED implantation were performed at our institution between January 1993 and April 2010. Among 19 patients who underwent implantation of an electronic cardiac device wrapped with an ePTFE sheet, device implantation was performed in 11 patients for secondary prevention of device contact sensitivity, in 7 patients for primary prevention of device contact sensitivity, and in 1 patient for avoiding over-sensing of myopotentials. During follow-up periods (mean 46 ± 34 months), there were no allergic or inflammatory reactions to components of the device or ePTFE itself. Among 11 patients with a device wrapped with an ePTFE sheet for secondary prevention, 5 patients completed device replacement due to battery depletion and 3 patients had infections from the device. Wrapping implantable devices with an ePTFE sheet is an effective way of preventing device sensitivity in patients who require CIED therapy. However, the risk of infection from the device should be taken into consideration.

Clinical implications of midventricular obstruction in patients with hypertrophic cardiomyopathy.

OBJECTIVES: We investigated the prevalence, clinical characteristics, and prognosis of hypertrophic cardiomyopathy (HCM) patients with midventricular obstruction (MVO). BACKGROUND: Previous descriptions of patients with MVO have been confined to case reports or small patient series, and this subgroup of HCM patients has therefore remained underrecognized. METHODS: The study population included 490 HCM patients. Left ventricular MVO was diagnosed when the peak midcavitary gradient was estimated to be ≥30 mm Hg. RESULTS: MVO was identified in 46 patients (9.4%). Patients with MVO were more likely to be symptomatic than those without. MVO was found to be an independent determinant of HCM-related death in multivariate models (hazard ratio [HR]: 2.23, p = 0.016), and this trend was especially pronounced for the combined endpoint of sudden death and potentially lethal arrhythmic events (HR: 3.19, p < 0.001). Apical aneurysm formation was identified in 28.3% of patients with MVO and strongly predicted HCM-related death (HR: 3.47, p = 0.008) and the combined endpoint of sudden death and potentially lethal arrhythmic events (HR: 5.08, p < 0.001). In addition, MVO without apical aneurysm was also identified as an independent determinant of the combined endpoint of sudden death and potentially lethal arrhythmic events (HR: 2.43, p = 0.045). CONCLUSIONS: This analysis identified MVO as an independent predictor of adverse outcomes, especially the combined endpoint of sudden death and potentially lethal arrhythmic events. Our results suggest that longer periods of exposure to MVO might lead to unfavorable consequences. They also support the principle that the presence of MVO in patients with HCM has important pathophysiological implications.

Image integration of three-dimensional cone-beam computed tomography angiogram into electroanatomical mapping system to guide catheter ablation of atrial fibrillation.

AIMS: To evaluate the feasibility of integrating three-dimensional images created by intra-procedural cone-beam computed tomography (CBCT) into three-dimensional electroanatomical maps (EAM) and compare its accuracy with that of pre-procedural multi-slice CT (MSCT). METHODS AND RESULTS: In 24 patients with drug-refractory atrial fibrillation (AF), atriography using CBCT with pulmonary arterial contrast injection was performed at the beginning of the AF ablation procedure. Intra-procedural CBCT images and pre-procedural MSCT images were individually imported into the EAM system and compared their integration accuracy (point-to-surface distance) of each image and EAM just before ablation. The CBCT images were assessed qualitatively and quantitatively in comparison with MSCT images. All CBCT images were graded as optimal or useful in delineating the left atrium-pulmonary vein anatomy and were successfully integrated with the EAM. Overall, integration accuracy was similar for CBCT and MSCT. However, in 11 patients, the MSCT was performed 5 or more days prior to EAM, resulting in significantly shorter surface-to-point distance in CBCT than that in MSCT (P = 0.047). Radiation exposure with CBCT was significantly reduced compared with MSCT (P < 0.001). CONCLUSION: It is feasible to integrate CBCT image into EAM, and the integration is relatively accurate. Intra-procedural atriography by CBCT may replace pre-procedural MSCT as the imaging source for image integration.

Possible acute and chronic synergistic effect of dual chamber pacing and disopyramide in obstructive hypertrophic cardiomyopathy: a case report.

It remains unclear whether the combination of dual-chamber (DDD) pacing and disopyramide can achieve prolonged left ventricular outflow tract (LVOT) gradient reduction and symptom relief in patients with obstructive hypertrophic cardiomyopathy (HCM). In an HCM patient with a severe LVOT gradient, the combination of DDD pacing and disopyramide achieved marked improvement of gradient in the catheter laboratory and also after medium-term follow-up. The patient's severe dyspnoea was alleviated during the follow-up period. This combination might enable physicians to treat and manage elderly symptomatic obstructive HCM patients with a severe LVOT gradient more effectively and less invasively.