[Therapeutic management of nonvalvular atrial fibrillation]. / Therapeutisches Management des nichtvalvulären Vorhofflimmerns.

Atrial fibrillation (AF) is the most frequent persistent cardiac arrhythmia and is associated with an increased mortality. Therefore, an effective differential treatment of patients is mandatory. After a risk stratification oral anticoagulation (OAC) should be initiated depending on the individual stroke risk of each patient. Alternatively, in the presence of contraindications for OAC and an increased risk for bleeding and/or stroke, the implantation of a left atrial appendage closure device can be considered. Symptomatic patients should undergo a rhythm control strategy if possible. Based on the risk-benefit considerations, catheter ablation (CA) of AF plays an increasingly important role in establishing long-term medicinal rhythm control. A pulmonary vein isolation can lead to freedom from AF for 1 year in 70-80% of patients with paroxysmal AF (and approximately 50% in persistent AF). So far, a survival advantage of CA could only be shown in patients with heart failure, so that in most cases this is only a symptomatic treatment for improvement in the quality of life.

Influence of periprocedural anticoagulation strategies on complication rate and hospital stay in patients undergoing catheter ablation for persistent atrial fibrillation.

BACKGROUND: The use of non-vitamin K antagonists (NOACs), uninterrupted (uVKA) and interrupted vitamin K antagonists (iVKA) are common periprocedural oral anticoagulation (OAC) strategies for atrial fibrillation (AF) ablation. Comparative data on complication rates resulting from OAC strategies for solely persistent AF (persAF) undergoing ablation are sparse. Thus, we sought to determine the impact of these OAC strategies on complication rates among patients with persAF undergoing catheter ablation. METHODS: Consecutive patients undergoing persAF ablation were included. Depending on preprocedural OAC, three groups were defined: (1) NOACs (paused 48 h preablation), (2) uVKA, and (3) iVKA with heparin bridging. A combined complication endpoint (CCE) composed of bleeding and thromboembolic events was analyzed. RESULTS: Between 2011 and 2014, 1440 persAF ablation procedures were performed in 1092 patients. NOACs were given in 441 procedures (31 %; rivaroxaban 57 %, dabigatran 33 %, and apixaban 10 %), uVKA in 488 (34 %), and iVKA in 511 (35 %). Adjusted CCE rates were 5.5 % [95 % confidence interval (CI) (3.1-7.8)] in group 1 (NOACs), 7.5 % [95 % CI (5.0-10.1)] in group 2 (uVKA), and 9.9 % [95 % CI (6.6-13.2)] in group 3. Compared to group 1, the combined complication risk was almost twice as high in group 3 [odd's ratio (OR) 1.9, 95 % CI (1.0-3.7), p = 0.049)]. The major complication rate was low (0.9 %). Bleeding complications, driven by minor groin complications, are more frequent than thromboembolic events (n = 112 vs. 1, p < 0.0001). CONCLUSIONS: Patients undergoing persAF ablation with iVKA anticoagulation have an increased risk of complications compared to NOACs. Major complications, such as thromboembolic events, are generally rare and are exceeded by minor bleedings.

Real-Time Prediction of Neurally Mediated Syncope.

Neurally mediated syncope (NMS) patients suffer from sudden loss of consciousness, which is associated with a high rate of falls and hospitalization. NMS negatively impacts a subject's quality of life and is a growing cost issue in our aging society, as its incidence increases with age. In this paper, we present a solution for prediction of NMS, which is based on the analysis of the electrocardiogram (ECG) and photoplethysmogram (PPG) alone. Several parameters extracted from ECG and PPG, associated with reflectory mechanisms underlying NMS in previous publications, were combined in a single algorithm to detect impending syncope. The proposed algorithm was evaluated in a population of 43 subjects. The feature selection, distance metric selection, and optimal threshold were performed in a subset of 30 patients, while the remaining data from 13 patients were used to test the final solution. Additionally, a leave-one-out cross-validation scheme was also used to evaluate the performance of the proposed algorithm yielding the following results: sensitivity (SE)--95.2%; specificity (SP)--95.4%; positive predictive value (PPV)--90.9%; false-positive rate per hour (FPRh)-0.14 h(-1), and prediction time (aPTime)--116.4 s.

Assessment of cardiovascular function from multi-Gaussian fitting of a finger photoplethysmogram.

Monitoring of cardiovascular function on a beat-to-beat basis is fundamental for protecting patients in different settings including emergency medicine and interventional cardiology, but still faces technical challenges and several limitations. In the present study, we propose a new method for the extraction of cardiovascular performance surrogates from analysis of the photoplethysmographic (PPG) signal alone.We propose using a multi-Gaussian (MG) model consisting of five Gaussian functions to decompose the PPG pulses into its main physiological components. From the analysis of these components, we aim to extract estimators of the left ventricular ejection time, blood pressure and vascular tone changes. Using a multi-derivative analysis of the components related with the systolic ejection, we investigate which are the characteristic points that best define the left ventricular ejection time (LVET). Six LVET estimates were compared with the echocardiographic LVET in a database comprising 68 healthy and cardiovascular diseased volunteers. The best LVET estimate achieved a low absolute error (15.41 ± 13.66 ms), and a high correlation (ρ = 0.78) with the echocardiographic reference.To assess the potential use of the temporal and morphological characteristics of the proposed MG model components as surrogates for blood pressure and vascular tone, six parameters have been investigated: the stiffness index (SI), the T1_d and T1_2 (defined as the time span between the MG model forward and reflected waves), the reflection index (RI), the R1_d and the R1_2 (defined as their amplitude ratio). Their association to reference values of blood pressure and total peripheral resistance was investigated in 43 volunteers exhibiting hemodynamic instability. A good correlation was found between the majority of the extracted and reference parameters, with an exception to R1_2 (amplitude ratio between the main forward wave and the first reflection wave), which correlated low with all the reference parameters. The highest correlation ([Formula: see text] = 0.45) was found between T1_2 and the total peripheral resistance index (TPRI); while in the patients that experienced syncope, the highest agreement ([Formula: see text] = 0.57) was found between SI and systolic blood pressure (SBP) and mean blood pressure (MBP).In conclusion, the presented method for the extraction of surrogates of cardiovascular performance might improve patient monitoring and warrants further investigation.

A novel multi-parametric algorithm for faint prediction integrating indices of cardiac inotropy and vascular tone.

Neurally medicated syncope (NMS) patients suffer from sudden loss of consciousness, which is associated with a high rate of falls and hospitalization. NMS negatively impacts a subject's quality of life and is a growing cost issue for the healthcare systems in particular since mainly elderly are at risk of NMS in our aging societies. In the present paper we present an algorithm for prediction of NMS, which is based on the analysis of the electrocardiogram (ECG) and photoplethysmogram (PPG) signals. Several parameters extracted from ECG and PPG, which have been associated in previous works with reflectory mechanisms underlying NMS, were combined in a single algorithm to detect impending syncope. The proposed algorithm was validated in 43 subjects using a 3-way data split scheme and achieved the following performance: sensitivity (SE) - 100%; specificity (SP) - 92%; positive predictive value (PPV) - 85%; false positive rate per hour (FPRh) - 0.146h(-1) and; average prediction time (aPTime) - 217.58s.

Vagal heart rate control in patients with atrial fibrillation: impact of tonic activation of peripheral chemosensory function in heart failure.

Heart failure (HF) and atrial fibrillation (AF), emerging as two epidemics of the twenty-first century, are commonly associated with each other. Both have been mechanistically linked to changes in cardiac vagal control. The importance of peripheral chemosensors, located in the carotid body, has not been elucidated so far. We therefore investigated whether tonic activation of excitatory chemoreceptor afferents contributes to the altered vagal control in HF patients with a history of AF. In 18 patients (72 ±9 year, 7 male) with sinus rhythm and a history of AF (n=9, without any evidence of structural heart disease, AF group; n=9 with structural heart disease and clinical presentation of HF, AFHF group) we investigated the impact of chemosensory deactivation (by breathing 100% oxygen) on heart rate, blood pressure, cardiac output, total peripheral resistance, oxygen saturation and breathing rate. Ten healthy individuals served as a control group. In addition, we performed a deep breathing test demonstrating an impaired heart rate variation in patients with and without HF as compared with controls (expiration/inspiration difference: 23.9±6.9 vs. 6.9±6.1 bpm, and 23.9±6.9 vs. 7.8±4.8 bpm; p<0.05). In both control and AF groups, heart rate decreased during chemoreceptor deactivation (control: -4.8±3.4%; AF: -5.1±3.0%; p<0.05), whereas heart rate did not change in AFHF patients. This resulted in impaired cardiac chemoreflex sensitivity in AFHF patients (1.9±1.6 vs. 0.5±1.2 ms/mmHg; p<0.05). In conclusion, our data suggest that tonic activation of excitatory chemoreceptor afferents contributes to a low vagal tone in heart failure patients with a history of AF (Clinical Trials NCT01262508).