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Background: Pulmonary vein (PV) occlusion is crucial for adequate lesion formation during cryoballoon-guided pulmonary vein isolation (CB-PVI). PV occlusion is usually confirmed by angiographies over the inflated balloon device. The aim of our study was to analyze the safety and efficacy of pressure waveform-based PV occlusion assessment during CB-PVI utilizing a novel fully integrated pressure analysis tool. Methods: Consecutive patients with symptomatic atrial fibrillation (AF) scheduled for CB-PVI were prospectively enrolled for pressure waveform-based PV occlusion assessment. A patient cohort receiving conventional angiographies served as control group. Patients with common PV ostia were excluded. Results: The study group consisted of 40 patients (16 females, mean age was 64.5 ± 9.7, 45% persistent AF). The control group consisted of 40 matched patients. All 160 PVs in the study group were successfully isolated without the use of additional venograms confirming PV occlusion. The mean procedure duration was 69 ± 12 min in the study group with a mean fluoroscopy duration of 11.5 ± 4.4 min. The mean contrast medium volume was 22 ± 9 ml in the study group and 36 ± 12 ml in the control group (p = 0.0001). Mean procedure duration, mean balloon temperatures, and mean ablation application durations did not differ significantly between the study and the control group. No periprocedural complications occurred. Conclusion: CB-PVI utilizing a fully integrated pressure waveform analysis tool to assess PV occlusion is feasible and safe and significantly reduces the amount of contrast medium without impact on procedural parameters and freedom from arrhythmia recurrence. [ABSTRACT FROM AUTHOR]

Background Waveform parameters derived from pressure‐only Windkessel models are related to cardiovascular disease risk and could be useful for understanding arterial system function. However, prior reports varied in their adjustment for potential confounders. Methods and Results Carotid tonometry waveform data from 2539 participants (mean age 63±11 years, 58% women) of the Framingham Heart Study were used to derive Windkessel measures using pressure and assuming a linear model with fixed diastolic time constant (τdias) and variable asymptotic pressure (Pinf, median 54.5; 25th, 75th percentiles: 38.4, 64.9 mm Hg) or nonlinear model with inverse pressure‐dependent τdias and fixed Pinf (20 mm Hg). During follow‐up (median 15.1 years), 459 (18%) participants had a first cardiovascular disease event. In proportional hazards models adjusted for age, sex, total cholesterol, high‐density lipoprotein cholesterol, smoking, antihypertensive medication use, diabetes mellitus, and physician‐acquired systolic blood pressure, only the systolic time constant (τsys) derived from the nonlinear model was related to risk for cardiovascular disease events (hazard ratio=0.91 per 1 SD, 95% CI=0.84–0.99, P=0.04). When heart rate was added to the model, τsys (hazard ratio=0.92, CI=0.84–1.00, P=0.04) and reservoir pressure amplitude (hazard ratio=1.14, CI=1.01–1.28, P=0.04) were related to events. In contrast, measures derived from the linear model were not related to events in models that adjusted for risk factors including systolic blood pressure (P>0.31) and heart rate (P>0.19). Conclusions Our results suggest that pressure‐only Windkessel measures derived by using a nonlinear model may provide incremental risk stratification, although associations were modest and further validation is required.

• We propose a fitting method to model the pressure pulse waveform. • We extract the coefficients of the proposed model as feature. • The fitting residuals of proposed method are smaller than the traditional methods. • The classification performance of the proposed feature is higher than the previous features. Background and objectives: Radial artery pulse diagnosis has been playing an important role in traditional Chinese medicine (TCM). For its non-invasion and convenience, the pulse diagnosis has great significance in diseases analysis of modern medicine. The practitioners sense the pulse waveforms in patients' wrist to make diagnoses based on their non-objective personal experience. With the researches of pulse acquisition platforms and computerized analysis methods, the objective study on pulse diagnosis can help the TCM to keep up with the development of modern medicine. Methods: In this paper, we propose a new method to extract feature from pulse waveform based on discrete Fourier series (DFS). It regards the waveform as one kind of signal that consists of a series of sub-components represented by sine and cosine (SC) signals with different frequencies and amplitudes. After the pulse signals are collected and preprocessed, we fit the average waveform for each sample using discrete Fourier series by least squares. The feature vector is comprised by the coefficients of discrete Fourier series function. Results: Compared with the fitting method using Gaussian mixture function, the fitting errors of proposed method are smaller, which indicate that our method can represent the original signal better. The classification performance of proposed feature is superior to the other features extracted from waveform, liking auto-regression model and Gaussian mixture model. Conclusions: The coefficients of optimized DFS function, who is used to fit the arterial pressure waveforms, can obtain better performance in modeling the waveforms and holds more potential information for distinguishing different psychological states. [ABSTRACT FROM AUTHOR]

Purpose: Pressure waveform analysis has the potential for facilitated assessment of pulmonary vein occlusion during cryoballoon ablation for atrial fibrillation. Data on clinical outcomes using this method are lacking. We sought to validate through clinical outcomes the use of pressure waveform analysis as the primary method of determining pulmonary vein occlusion during cryoballoon ablation.Methods: A study was performed of 122 consecutive patients with atrial fibrillation (85% paroxysmal) undergoing cryoballoon ablation from May 2014 through July 2015 at a single institution using pressure waveform analysis as the primary method of assessing pulmonary vein occlusion.Results: Cryoballoon ablation, with additional segmental radiofrequency ablation in 13.7%, resulted in complete pulmonary vein isolation in 100% of patients. The single procedure freedom from recurrence of atrial arrhythmia beyond the initial 3-month post-ablation was 81.2% at a mean follow-up of 237 days. Recurrence of atrial arrhythmia within 3-month post-ablation was 11.1%, and predicted recurrence beyond 3 months. Repeat ablation was performed in 12.0% of patients.Conclusions: In the largest study to date on this topic and the only study to focus on clinical outcomes, pressure waveform analysis as the primary method of determining pulmonary vein occlusion in cryoballoon ablation of atrial fibrillation resulted in acute and long-term procedural success rates comparable to those reported with use of routine pulmonary venography. Controlled study is needed to confirm these findings and to determine if this technique affects variables such as procedure duration and radiation exposure. [ABSTRACT FROM AUTHOR]

Background The J-curve relationship between brachial diastolic blood pressure (DBP) and mortality is believed to be mediated through reduced myocardial perfusion. This study aimed to determine the relationship between DBP and subendocardial perfusion in patients with and without coronary artery disease (CAD) and to examine central hemodynamic variables that may explain the risk associated with low DBP (aortic stiffness, central pulse pressure, and augmentation index). Methods Brachial DBP and radial tonometry were measured in 134 patients with CAD (aged 76±7years; 69% male), 134 individuals without a prior cardiovascular event (control subjects) (aged 77±2years; 69% male) and 47 patients (aged 63±10years) during dobutamine stress echocardiography. Central hemodynamics and subendocardial viability ratio (SEVR), a marker of subendocardial perfusion, were recorded by tonometry. Results There was no difference in DBP or SEVR between control subjects and CAD patients (P > 0.05), nor was there a difference in SEVR across quartiles of DBP in CAD patients (P = 0.07) or control subjects (P = 0.14). After adjustment for age and height, associations between DBP and SEVR in control subjects (r = 0.185; P = 0.03) and CAD patients (r = 0.204; P = 0.02) were attenuated (P = 0.07 and P = 0.11, respectively). There were no significant relationships between DBP and central hemodynamics (P > 0.05 for all). At peak dobutamine stress, SEVR was significantly reduced in patients with inducible ischemia vs. those with nonischemic response (84±17 vs. 101±22%; P = 0.01). However, DBP was not significantly different (65±14 vs. 67±15mm Hg; P = 0.32). Conclusions Brachial DBP is a poor marker of subendocardial perfusion. The J-curve relationship between DBP and mortality is unlikely attributable to reduced myocardial perfusion or adverse central hemodynamics. [ABSTRACT FROM AUTHOR]

Abstract: Post-occlusive reactive hyperemia is a noninvasive maneuver to assess microvascular reactivity related to the bioavailability and/or bioactivity of endothelial-derived factors. The inability to respond to endogenous vasodilator substances is mostly described by a low peak flow after an event associated with a peak flow. The aim of this study is to propose a model to describe post-occlusive responses observed in the pressure waveforms after occlusion release. Model variables were investigated in search of those representatives of the endothelial response to the ischemic process. Radial pressure pulse waveforms were acquired in the anterior region of the wrist, superficial to the radial artery, using a piezoelectric transducer acquired by a 12 bits acquisition board model at a sampling rate of 1.0kHz to increase the temporal resolution. The occlusion maneuver was performed using an arm-cuff placed over the brachial artery. A time series of pulse pressure (PP) values, calculated from successive values of beat-to-beat systolic and diastolic pressures, was found to be a useful variable representing blood pressure signal in the model. This data time series of the pulse pressure presents reduced initial values compared with the baseline measurement, and an increasing value until a steady state behavior was sustained after approximately 60s. This behavior for the pulse pressure series was described by a hyperbolic tangent model with parameters K (rate of change of PP), PP 0 (first value of PP after cuff release), and ΔPP (change in PP). The model was applied to pulse pressure signals from normotensive and hypertensive subjects. The observed responses between groups suggest that PP 0 and ΔPP are related to an endothelial response to the ischemic process and could be used as a clinical tool to assess endothelial function in hypertension. [Copyright &y& Elsevier]

Background Waveform parameters derived from pressure-only Windkessel models are related to cardiovascular disease risk and could be useful for understanding arterial system function. However, prior reports varied in their adjustment for potential confounders. Methods and Results Carotid tonometry waveform data from 2539 participants (mean age 63±11 years, 58% women) of the Framingham Heart Study were used to derive Windkessel measures using pressure and assuming a linear model with fixed diastolic time constant (τ dias ) and variable asymptotic pressure (P inf , median 54.5; 25th, 75th percentiles: 38.4, 64.9 mm Hg) or nonlinear model with inverse pressure-dependent τ dias and fixed P inf (20 mm Hg). During follow-up (median 15.1 years), 459 (18%) participants had a first cardiovascular disease event. In proportional hazards models adjusted for age, sex, total cholesterol, high-density lipoprotein cholesterol, smoking, antihypertensive medication use, diabetes mellitus, and physician-acquired systolic blood pressure, only the systolic time constant (τ sys ) derived from the nonlinear model was related to risk for cardiovascular disease events (hazard ratio=0.91 per 1 SD, 95% CI=0.84-0.99, P=0.04). When heart rate was added to the model, τ sys (hazard ratio=0.92, CI=0.84-1.00, P=0.04) and reservoir pressure amplitude (hazard ratio=1.14, CI=1.01-1.28, P=0.04) were related to events. In contrast, measures derived from the linear model were not related to events in models that adjusted for risk factors including systolic blood pressure ( P>0.31) and heart rate ( P>0.19). Conclusions Our results suggest that pressure-only Windkessel measures derived by using a nonlinear model may provide incremental risk stratification, although associations were modest and further validation is required.