Detection of Atrial Fusion Systole in Patients with Dual Chamber Pacemakers by 24-Hour Esophagus ECG

We performed ambulatory 24-hour esophagus ECG in nine patients with dual chamber pacemakers suspect of transient arrhythnias in order to achieve correct and reliable P wave identification during daily life activities. In all patients episodes were observed with varying atrial artifact to left atrial depolarization sequences. These episodes probably reflected presence of atrial fusion systole, an ECG phenomenon which should be taken into account when analyzing ambulatory esophagus ECC. Thus, the ambulatory esophagus ECG revealed its ability to detect spontaneous atrial depolarization in the presence of pacemaker artifact in patients with DDD(R) pacemakers.     

Use of Color Kinesis for Evaluation of Left Ventricular Filling in Patients With Dilated Cardiomyopathy and Mitral Regurgitation

Objectives. We tested the feasibility of using analysis of color kinesis images to objectively assess global and regional left ventricular (LV) diastolic function in patients with dilated cardiomyopathy (DCM). In addition, the ability of this technique to track drug-induced changes on LV diastolic properties was studied.

Background. Diastolic dysfunction contributes to symptomatology in patients with DCM. The assessment of LV diastolic function using conventional Doppler echocardiography is indirect and is confounded by multiple variables. Moreover, the noninvasive evaluation of regional diastolic properties is difficult. In contrast, color kinesis directly tracks and color-encodes regional diastolic endocardial motion.

Methods. We studied 24 patients with DCM and mitral regurgitation (MR) and 24 age-matched normal subjects. Transmitral and pulmonary vein flow velocities were measured using pulsed Doppler echocardiography. Diastolic color kinesis images were used to calculate indexes of magnitude and timing of global and regional diastolic function. Diastolic asynchrony was evaluated in different subgroups of patients with DCM. The effects of drug infusions (nitroprusside and dobutamine) were also studied.

Results. Color kinesis indexes of global diastolic function showed significant differences between patients with DCM and normal subjects. Compared with Doppler indexes, color kinesis was less confounded by MR and was capable of differentiating between drug-induced lusitropic and vasodilator effects. Diastolic asynchrony was increased in patients with DCM and severe MR.

Conclusions. Quantitative analysis of global and regional LV diastolic function in patients with DCM using color kinesis is feasible.     

New insights into septal anterior wall motion velocities at end-systole in normal and hypertrophied left ventricles.

AIMS: It was two-fold (1) to define tissue Doppler echocardiographic characteristics of the end-systolic septal anterior motion: passive due to heart translation, or active motion free of translational effects, substantiated by a myocardial velocity gradient. (2) to specify the temporal features of this septal anterior motion on normal and hypertrophied left ventricles since it occurs while the posterior wall contracts during late ejection. METHODS AND RESULTS: Myocardial velocity gradient was calculated during the anterior motion in simultaneously colour M-mode imaged septal and posterior walls of 21 controls (49+/-12 years) and 17 patients (49+/-13 years) with left ventricle hypertrophy. Timings of septal motion were compared with flow and posterior wall motion. In controls, septal anterior motion started prior to, and overlapped the end of subaortic flow and that of the posterior wall anterior motion. Myocardial velocity gradient was found, exceeding that at the posterior wall (2.5+/-1.6 vs 0.9+/-0.5s(-1), P=0.001). In patients, septal myocardial velocity gradient was lower than in controls (1.2+/-1.04 s(-1)P=0.006). The anterior motion had a longer duration than in controls (75+/-37 vs 50+/-17ms, P=0.003). Myocardial velocity gradient and duration were correlated with septal thickness (P=<0.01). CONCLUSIONS: The septal anterior motion was active. Patients showed a decreased myocardial velocity gradient, while wall asynchrony increased. Unusual higher septal than posterior wall systolic velocities at tissue Doppler echocardiography may suggest a relaxation pattern, in spite of its end-systolic onset.     

Heart–lung interactions during positive pressure ventilation: left ventricular pressure–volume momentary response to airway pressure elevation

BACKGROUND: Left ventricular (LV) pressure and volume changes are known to occur in response to positive airway pressure (PAP). We aimed to further describe the immediate LV response to increased PAP as demonstrated in successive heart cycles with LV pressure and volume alterations. We postulated that these acute systematic LV events during institution of PAP can follow a distinct pattern that would allow calculation of parameters of systolic function, including end-systolic elastance (Ees) and preload recruitable stroke work (PRSW). We also aimed to examine the relationship of PAP-derived Ees and PRSW to the same parameters derived from vascular occlusion. METHODS: Eight anesthetized adult pigs were studied with invasive circulatory measurements including LV pressure and volume (conductance). The PAP intervention was an airway pressure plateau of 15 cm H2O for 6 s (APP). Venous occlusion was performed by transient balloon inflation in the inferior vena cava (IVCO). Ees and PRSW were derived for each APP and IVCO intervention. RESULTS: Central circulatory variables during APP and IVCO are reported. LV systolic function parameters could be derived from each of the heart-lung interactions during APP sequences. Ees and PRSW derived from APP showed a significant positive bias in relation to those derived from the IVCO sequence. CONCLUSIONS: We conclude that the heart-lung interactions during APP of the magnitude and duration shown here can allow derivation of Ees and PRSW. These parameters are not interchangeable with Ees and PRSW derived from IVCO.     

Automated method for characterization of diastolic transmitral Doppler velocity contours: Late atrial filling

We develop an automated method of characterizing the late atrial filling phase of diastole by fitting a kinematic model for diastolic filling to the clinical Doppler A-wave contour. The result is a set of model parameters which completely characterizes the contour. We have previously derived a parameterized diastolic filling (PDF) model, which predicts the time-dependent transmitral blood flow velocity obtained by Doppler echocardiography. An automated method to determine the PDF model parameters for early rapid filling from the clinical Doppler E-wave has also been developed and validated. The method consists of digitizing the acoustic Doppler waveform, recreating the Doppler velocity profile, extracting the maximum velocity envelope, and fitting the PDF model for early filling to the envelope. In the current work, we apply the same general approach for PDF parameter determination for the late atrial filling phase of diastole. To assess the presence and significance of near-degeneracies in the model parameter set, numerical experiments (consisting of fitting the model to a model-generated contour to which Gaussian noise was added) were performed. These revealed a two-dimensional degeneracy in four-dimensional parameter space which could be removed by using two kinematic simplifications: critical damping and resonant forcing. We show that these degeneracy-eliminating approximations do not limit the ability of the model to predict clinical A-wave contours.     

奥昔麻黄碱治疗冠心病

本文报道25例冠心病心绞痛患者应用奥昔麻黄碱的近期疗效。wk1给安慰剂,wk2一3口服奥昔麻黄碱8mg,tid,wk4-5给安慰剂。结果,症状疗效总有效率88％,安慰剂组36％(P<0.O1),心电图总有效率80％。说明本药有一定的抗心绞痛作用,且副作用小、安全、有效,值得推广应用。     

桡动脉搏动图测量左室收缩时间间期的初步探讨

应用ＣＴＨ－Ⅱ型心功能微机检测仪和ＳＴＩ软件研究了７０例受试者桡动脉搏动图（ＲＰＴ）．用以测量ＳＴＩ参数，并与经典的ＣＰＴ法进行了比较。结果显示，两方法相关系数γ为０．５６与０，８５，Ｐ＜０．００５。在变异方面未表明ＣＰＴ优越。而ＲＰＴ曲线便于获得，故在某些情况下ＲＰＴ可以取代ＣＰＴ用于ＳＴＩ测量。但两方法测得的ＬＶＥＴ、ＰＥＰ、ＰＥＰ／ＬＶＥＴ有显著性差异，我们认为ＲＰＴ测量ＳＴＩ应另行制订正常参考值。