A new, simple, and accurate method for non-invasive estimation of pulmonary arterial pressure

Abstract

Objective: To develop and validate a new non-invasive method for the estimation of pulmonary arterial pressure (PAP) based on advanced signal processing of the second heart sound. Design: Prospective comparative study. Setting: Referral cardiology centre. Patients: This method was first tested in 16 pigs with experimentally induced pulmonary hypertension and then in 23 patients undergoing pulmonary artery catheterisation. Methods: The heart sounds were recorded at the surface of the thorax using a microphone connected to a personal computer. The splitting time interval between the aortic and the pulmonary components of the second heart sound was measured using a computer assisted spectral dechirping method and was normalised for heart rate. Conclusions: This study shows that this new non-invasive method based on advanced signal processing of the second heart sound provides an accurate estimation of the PAP. P ulmonary arterial hypertension is a frequent and serious complication of several cardiovascular or respiratory diseases that is difficult to assess non-invasively. As the options for treatment of pulmonary hypertension have expanded, the requirement for accurate and non-invasive methods to allow regular and safe estimation of pulmonary arterial pressure (PAP) has increased. Measurement of PAP by Doppler echocardiography provides a high degree of correlation (0.89 < r < 0.97) in comparison with pulmonary artery catheterisation.1-3 However, PAP cannot be estimated by Doppler echocardiography in approximately 50% of patients with normal PAP, 10-20% of patients with increased PAP, and 34-76% of patients with chronic obstructive pulmonary disease because of the absence of tricuspid regurgitation, a weak Doppler signal, or a poor signal to noise ratio (SNR). [1][2][3][4] Moreover, Doppler echocardiography cannot be used to monitor PAP continuously. Consequently, it would be useful to develop other non-invasive methods to allow frequent and accurate measurement of PAP.It is well known that the time interval between the aortic (A2) and the pulmonary (P2) components of the second heart sound (S2), as well as the dominant frequency of P2, are increased in the presence of pulmonary hypertension. [5][6][7] It has therefore been suggested that the A2-P2 splitting interval (SI) may be useful to estimate the PAP. However, the basic relation between the SI and the PAP is not well known. Moreover, the applicability of this acoustic approach is limited because the SI is relatively short (generally 100 ms) and is difficult to measure, especially in patients for whom A2 and P2 are overlapping.7 8 Recently, we have proposed a new approach based on advanced signal processing that can successfully identify and extract overlapping A2 and P2 components from S2 recordings and that can be used to measure the A2-P2 SI accurately.9 10 The objective of this work was to study the relation between the SI measured using this new acoustic method and the PAP measured by catheterisation. This relation was first studied in an animal model desi...

Impact of systemic hypertension on the assessment of aortic stenosis

“…7 After intramuscular premedication with ketamine, anaesthesia was induced by intravenous injection of fentanyl (5 mg/kg) and pentobarbital (6.5 mg/kg) and was maintained with a continuous infusion of fentanyl (4 mg/kg/ h) and pentobarbital (10 mg/kg/h). Muscle relaxation was achieved by administration of pancuronium 0.30 mg/kg/h.…”

The Unique Heart Sound Signature of Children with Pulmonary Artery Hypertension

“…Although these are traditional clinical indicators of PAH, the analysis of the S2, particularly differentiating the aortic and pulmonary components of the S2 and the splitting interval, remains a significant challenge. [6][7][8][9]11,12 Therefore, we concentrated on using hidden information within the frequency domain and improved on previous findings by using the relative power of the frequency band 21-22 Hz. 14 We have attempted to characterize the heart sounds of subjects with and without PAH in the same manner as speech patterns and to detect the unique signature of heart sounds in subjects with an increased PAp.…”

“…4-10 However, precise demarcation, timing, and segmentation of the components of S2 remain challenging. [7][8][9][11][12][13] We have explored instead quantitative information in the frequency domain of heart sounds that distinguish between subjects with and without PAH. 14 The relative power of the frequencies between 21 and 22 Hz of the heart sounds recorded at the second left intercostal space (2LICS) was significantly reduced in subjects with PAH.…”

Estimación auscultatoria de la presiónsistólica de arteria pulmonar: ¿Es factible?. Correlación con determinación ecocardiográfica

“…Más aun, este método clínico tuvo una adecuada reproducibilidad al ser aplicado por dos examinadores distintos. Estos resultados están en consonancia con estudios previos que han logrado aproximarse con exactitud a la PSAP por medios fonocardiográficos 11,16,24 . El segundo ruido cardíaco marca el fin de la sístole ventricular.…”

“…Sin embargo, corresponde al método más utilizado en la práctica clínica para medir la PSAP y es sobre el cual se toman las decisiones clínicas habitualmente, de modo que tener una técnica clínica comparable con la ecocardiografía Doppler pa- rece ser adecuado. Además, publicaciones previas han mostrado una correlación apropiada de los métodos fonocardiográficos con las mediciones realizadas mediante un catéter de arteria pulmonar 24,25 . Finalmente, la técnica auscultatoria fue llevada a cabo por dos médicos cardiólogos con amplia experiencia y conocimiento del examen cardíaco, por lo que se desconoce la confiabilidad del examen realizado por individuos con menos experiencia.…”