Determinants of a reduced heart rate variability in chronic atrial fibrillation

BACKGROUND

We aimed to evaluate whether clinical factors, which influence heart rate variability (HRV) in the presence of undisturbed sinus rhythm, have any associations with HRV in patients with permanent atrial fibrillation (AF).

METHODS

One hundred ninety-seven consecutive patients with permanent AF were included (122 males, 75 females, aged 64 ± 11 years, range 25-85). In each patient a 24-hour electrocardiographic recording was performed and an HRV fraction (HRVF)-the index based on scatter plot numerical processing-was calculated. Additionally, standard HRV measures were analyzed. Reduced HRVF was defined as its value lower than lower normal limit. Demographic and clinical factors were examined for their association with a reduced HRVF by means of a univariate and multivariate logistic regression analysis.

RESULTS

The reduced HRVF was associated with advanced age, clinical diagnosis of a previous MI or dilated cardiomyopathy, presence of diabetes, depressed left ventricular function, NYHA class > II, treatment regimen, use of digoxin, diuretics or antiarrhythmic agents, nonuse of beta-blockers, and increased heart rate. The independent determinants that sustained after multivariate analysis were: heart rate (per 10 bpm increase, odds ratio 2.77 [1.88-4.07]), age (per 5 years increase 1.43 [1.1-1.85]), depressed left ventricular EF (<30% vs higher 2.26 [1.19-4.31]), and presence of diabetes (3.45 [1.1-10.85]). The HRVF correlated moderately with standard HRV measures. This index showed also the strongest correlation with left ventricular ejection fraction.

CONCLUSION

We concluded that advanced age, left ventricular systolic dysfunction, increased heart rate, and presence of diabetes are cofactors of a reduced HRV in AF patients. Thus, the determinants of heart rate variability in the presence of atrial fibrillation are the same as those in sinus rhythm.

[Composed angioplasty of the multilevel right common and internal carotid artery stenoses with implantation stents with used of proximal and distal protection system]

We present a case of a 73 year-old man with, long-segment thigh stenosis in the right common and internal carotid artery with occlusion left common carotid artery. Complex angioplasty with modification proximal and distal system protection was successful performed. There were no procedure-related complications. We concluded that in very complex, multilevel lesions in carotid artery, there is a place for safe double system protection. This maneuver can increase safe of the carotid artery stenting and minimise potential complications.

Pivotal role of paracrine effects in stem cell therapies in regenerative medicine: can we translate stem cell-secreted paracrine factors and microvesicles into better therapeutic strategies?

Although regenerative medicine is searching for pluripotent stem cells that could be employed for therapy, various types of more differentiated adult stem and progenitor cells are in meantime being employed in clinical trials to regenerate damaged organs (for example, heart, kidney or neural tissues). It is striking that, for a variety of these cells, the currently observed final outcomes of cellular therapies are often similar. This fact and the lack of convincing documentation for donor-recipient chimerism in treated tissues in most of the studies indicates that a mechanism other than transdifferentiation of cells infused systemically into peripheral blood or injected directly into damaged organs may have an important role. In this review, we will discuss the role of (i) growth factors, cytokines, chemokines and bioactive lipids and (ii) microvesicles (MVs) released from cells employed as cellular therapeutics in regenerative medicine. In particular, stem cells are a rich source of these soluble factors and MVs released from their surface may deliver RNA and microRNA into damaged organs. Based on these phenomena, we suggest that paracrine effects make major contributions in most of the currently reported positive results in clinical trials employing adult stem cells. We will also present possibilities for how these paracrine mechanisms could be exploited in regenerative medicine to achieve better therapeutic outcomes. This approach may yield critical improvements in current cell therapies before true pluripotent stem cells isolated in sufficient quantities from adult tissues and successfully expanded ex vivo will be employed in the clinic.

Low-flow severe aortic stenosis with preserved ejection fraction, N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiovascular remodeling

BACKGROUND AND AIM OF THE STUDY

Severe aortic stenosis (AS) with preserved systolic function may coexist with 'low flow' and a lower stroke volume (SV). As the mechanisms of this phenomenon are not fully understood, the study aim was to assess the cardiac and vascular mechanisms of 'low-flow' severe AS with a preserved left ventricular ejection fraction (LVEF).

METHODS

Forty-four consecutive patients (mean age 69.7 +/- 7.6 years) with severe degenerative AS [mean effective orifice area (EOA) 0.7 +/- 0.3 cm2] and preserved LVEF (> 50%) were enrolled into the study, and allocated to two groups depending on their stroke volume index (SVI) (< 35 and > or = 35 ml/m2, respectively). The clinical data, N-terminal pro-brain natriuretic peptide (NT-proBNP) serum levels and ultrasound assessment of LV geometry and function [stroke work (SW), relative wall thickness (RWT)], AS severity, indices of systemic arterial hemodynamics [systemic arterial compliance (SAC), systemic vascular resistance (SVR)] and remodeling [flow-mediated dilatation (FMD), pulse wave velocity (PWV)], as well as valvuloarterial impedance (Z(va)) were analyzed for all study patients.

RESULTS

Twenty-four patients (56%; 13 females, 11 males) had low-flow LV output, and 20 (44%; four females, 16 males) had a normal LV output. The mean NT-proBNP serum levels were comparable between the study groups. An analysis of LV remodeling and function revealed a lower LV end-diastolic volume (LVEDV; 85.5 +/- 24.1 versus 160.4 +/- 60.9 ml, p = 0.001), LV end-systolic volume (LVESV; 40.3 +/- 18.5 versus 66.8 +/- 44.2 ml, p = 0.03), LV mass index (LVMI; 150.1 +/- 53.4 versus 183.7 +/- 57.5 g/m2, p = 0.07) and SW (95.6 +/- 23.7 versus 183.2 +/- 50.6 mmHg x ml, p < 0.0001) in the group with SVI < 35 ml/m2. The average RWT was higher in the group with SVI < 35 ml/m2 (48.7 +/- 14.8 versus 40.0 +/- 7.5, p = 0.04). The indices of systemic arterial hemodynamics were significantly different between the groups: the SAC was lower, and the SVR and Z(va) were higher, in patients with SVI < 35 ml/m2 while FMD values were significantly greater in patients with SVI < 35 ml/m2 (11.85 +/- 6.4 versus 7.29 +/- 6.3%, p = 0.035). However, the brachial artery diameter (BAd) was smaller in the latter group, and no differences were found in the FMD x BAd index values. The PWV values were comparable in both study groups.

CONCLUSION

The low-flow phenomenon in severe AS with preserved LVEF is related to smaller LV dimensions, LV concentric hypertrophy, and an increased systemic arterial afterload without differences in plasma NT-proBNP levels. 'Paradoxically' higher values of FMD observed in this population may be associated with a higher proportion of females and a smaller BAd.

Computed tomography in patients with cardiac pacemakers: difficulties and solutions

The presence of cardiac pacemaker systems may significantly limit interpretation of multi-slice computed tomography (MSCT) images. In 80 patients (45 men; aged 69.5 ± 13.4) with previously implanted anti-arrhythmic devices, a 64-slice CT (Aquilion-64) was performed. In 61 patients (76.3%), ECG gating was used (coronaries visualization) and in 19 patients (23.7%) without ECG gating (not coronaries visualization). In all 19 patients without ECG gating MSCT images were diagnostic. In 37 (60.6%) patients of 61, there was no problem with gating process and image quality was diagnostic. In 24 (39.4%) with visible spikes in the ECG-gating group, there were difficulties in differentiating the R spike from an artificial spike (unipolar pacing) by MSCT software. In 15 patients (24.6%) after reprogramming, it was possible to obtain good quality images. In nine (14.7%) patients, it was not possible to reprogram devices due to old unipolar leads, but in two cases (3.3%), ECG gating was corrected manually and good image quality was obtained. In seven (11.5%) patients, it was not possible to perform ECG gating. The ECG gating process was identified as the main cause of the imaging problems. Bipolar leads working as bipolar pacing seem to be necessary to perform MSCT with ECG gating. A unipolar system lead may cause serious problems with reconstructions.

Preoperative quantification of aortic valve stenosis: comparison of 64-slice computed tomography with transesophageal and transthoracic echocardiography and size of implanted prosthesis

Precise measurements of aortic complex diameters are essential for preoperative examinations of patients with aortic stenosis (AS) scheduled for aortic valve (AV) replacement. We aimed to prospectively compare the accuracy of transthoracic echocardiography (TTE), transoesophageal echocardiography (TEE) and multi-slice computed tomography (MSCT) measurements of the AV complex and to analyze the role of the multi-modality aortic annulus diameter (AAd) assessment in the selection of the optimal prosthesis to be implanted in patients surgically treated for degenerative AS. 20 patients (F/M: 3/17; age: 69 ± 6.5 years) with severe degenerative AS were enrolled into the study. TTE, TEE and MSCT including AV calcium score (AVCS) assessment were performed in all patients. The values of AAd obtained in the long AV complex axis (TTE, TEE, MSCT) and in multiplanar perpendicular imaging (MSCT) were compared to the size of implanted prosthesis. The mean AAd was 24 ± 3.6 mm using TTE, 26 ± 4.2 mm using TEE, and 26.9 ± 3.2 in MSCT (P = 0.04 vs. TTE). The mean diameter of the left ventricle out-flow tract in TTE (19.9 ± 2.7 mm) and TEE (19.5 ± 2.7 mm) were smaller than in MSCT (24.9 ± 3.3 mm, P < 0.001 for both). The mean size of implanted prosthesis (22.2 ± 2.3 mm) was significantly smaller than the mean AAd measured by TTE (P = 0.0039), TEE (P = 0.0004), and MSCT (P < 0.0001). The implanted prosthesis size correlated significantly to the AAd: r = 0.603, P = 0.005 for TTE, r = 0.592, P = 0.006 for TEE, and r = 0.791, P < 0.001 for MSCT. Obesity and extensive valve calcification (AV calcium score ≥ 3177Ag.U.) were identified as potent factors that caused a deterioration of both TTE and MSCT performance. The accuracy of AAd measurements in TEE was only limited by AV calcification. In multivariate regression analysis the mean value of the minimum and maximum AAd obtained in MSCT-multiplanar perpendicular imaging was an independent factor (r = 0.802, P < 0.0001) predicting the size of implanted prosthesis. In patients with AS echocardiography remains the main diagnostics tool in clinical practice. MSCT as a 3-dimentional modality allows for accurate measurement of entire AV complex and facilitates optimal matching of prosthesis size.

[Transapical closure of mitral paravalvular leaks in a patient with haemolytic anaemia and heart failure - a case report]

We present a case of a 72 year-old male who underwent successful closure of two mitral paravalvular leaks with the Amplatzer vascular Plug II using a transapical approach.

Cardiac myxoma - clinical presentation and long-term post-operative follow-up

BACKGROUND

Myxoma is the commonest cardiac neoplasm. Due to varying symptomatology, its diagnosis can prove difficult. It is agreed to have an excellent prognosis.

AIM

Assessing the clinical course in patients operated on due to cardiac myxoma in two departments of cardiac surgery over the course of a decade.

METHODS

The medical records of patients operated on due to cardiac myxoma between 1999 and 2009 were analysed. The patients were then invited for an ambulatory visit, during which transthoracic and transoesophageal echocardiographic examinations were performed.

RESULTS

There were 61 patients (47 females) with histologically confirmed myxoma operated upon. The commonest symptoms leading to diagnosis were heart failure (16 patients, 26%) and syncope (12 patients, 20%). There were five (8%) in-hospital deaths and two (3%) non-fatal strokes. Follow-up duration ranged between one and ten years (6.1 ± 3.2 years). Nine (15%) deaths occurred during follow-up. In four (7%) patients, myxoma recurred in the original location. Echocardiography performed at follow-up visit revealed one recurrence of myxoma, and minor pathologies in 20 patients. Patients who died perioperatively were significantly older compared to those who survived (69 ± 9.7 years vs 56 ± 13, p = 0.02). Patients who died during the follow-up were also significantly older than those who were alive at the time of the contact visit (65 ± 15 years vs 56 ± 12, p = 0.02). Death during follow-up occurred four times more often in males than females (36% vs 8.5%, p = 0.02). There were more deaths during the follow-up in patients whose initial presenting symptom was dyspnea: five deaths (31%) vs four deaths (9%, p = 0.04). The recurrence of myxoma was significantly more frequent in patients with a shorter duration of symptoms before the operation: 8.6 ± 15 weeks with relapse vs 33.9 ± 40 weeks without relapse (p = 0.04).

CONCLUSIONS

Both, serious and benign events following myxoma excision are common. Clinical and echocardiographic surveillance should be implemented in all patients who undergo a myxoma operation.