心电图P波宽度在优化双腔起搏器房室间期中的价值

目的:探索以心电图P波宽度优化双腔起搏器房室间期(AV间期)的方法,以期获得良好的血流动力学效果。方法:选择63例因Ⅲ度或高度房室传导阻滞植入Medtronic双腔起搏器的患者,测量其心电图自身P波宽度,或从心房起搏脉冲至起搏P波末端的宽度,在此测量值上加100ms,设定为双腔起搏器的感知AV间期(SAV)和起搏AV间期(PAV)。每例患者分别在出厂常规设置的AV间期和根据心电图优化的AV间期设定值下进行超声心动图检查,比较即刻血流动力学参数。结果:经心电图优化AV间期后,患者左室舒张末容积(LVEDV)、左室收缩末期容积(LVESV)和左室射血分数(LVEF)均较常规出厂设置的AV间期有显著改善(69.5±11.2比72.3±12.7;29.5±9.5比27.88±10.07;63.6±5.3比67.2±6.2,P<0.05)。结论:根据心电图P波宽度优化双腔起搏器AV间期,可获得良好的血流动力学效果,左室充盈改善,LVEF上升;且该法简单易行,具广泛的临床实用价值。     

A perspective on atrioventricular delay optimization in patients with a dual chamber pacemaker

Atrioventricular delay (AVD) is critical in patients with DDD pacemakers (PM). Echo/Doppler evaluation of AVD providing the longest left ventricular filling time (FT) or the highest cardiac output (CO) is used for AVD optimization. Recently myocardial performance index (MPI) has been shown to improve by optimizing AVD. The aim was to compare the CO, FT, MPI derived optimal AVD, and to analyze systolic and diastolic performance at every optimal AVD. Twenty-five patients, 16 men 68 +/- 11 years, ejection fraction >or= 50%, with a DDD PM for third-degree AV block, without other major cardiomyopathies, underwent echo/Doppler AVD optimization. CO, FT, and MPI derived optimal AVDs were identified as the AVDs providing the highest CO, the longest FT, and the minimum MPI, respectively. Isovolumic contraction and relaxation time (ICT, IRT), ejection time (ET), ICT/ET, and IRT/ET ratios were also evaluated at every optimal AVD. CO, FT, and MPI derived optimal AVDs were significantly different (148 +/- 36 ms, 116 +/- 34 ms, and 127 +/- 33 ms, respectively). ICT/ET was similar at CO, FT, and MPI derived optimal AVD (0.22 +/- 0.10, 0.23 +/- 0.11, and 0.21 +/- 0.10, respectively). IRT/ET ratio was similar at FT and MPI derived optimal AVDs (0.34 +/- 0.15 and 0.33 +/- 0.15, respectively) and significantly shorter (P < 0.02) than at CO derived optimal AVD (0.40 +/- 0.15). Different methods indicate different optimal AVDs. However analysis of systolic and diastolic performance shows that different AVDs result in similar systolic or diastolic performance. At MPI optimized AVD, a high CO combined with the most advantageous conditions of both isovolumic contraction and relaxation phases is achieved.     

What Range of Programmable AV Delays is Necessary in Antibradycardia DDD Stimulation?

DDD pacemakers differ considerably in device specific extents of AV delay (AVD) programmability. To demonstrate the requirements of a mean DDD pacemaker patient population optimal AVDs in 200 DDD pacemaker patients (age 8 to 91 years) were estimated by left atrial electrography. The results should help to define an AVD programmability standard. Left atrial electrograms were recorded via a bipolar filtered esophageal lead. The method aims on adjusting the left atrial electrogram to 70 ms prior to the ventricular spike, both during VDD and DDD operation of the pacemaker. In atrial sensed stimulation the optimal AVD varied from 40 to 205 ms (100.5 ± 24.5 ms) and in atrial paced stimulation from 85 to 245 ms (169.1 ±24.5 ms). The difference of the mean values is statistically significant (p < 0.001). The difference between both values in the individual patient, the individual AVD correction time, varied from 0 to 170 ms (68.7 ± 26.6 ms). Thus, from our findings requirements on AV delay programmability standard can be derived: AVDs (1) should have a range from 40 to 250 ms, (2) should be independently programmable during atrial sensed and atrial paced operation, ami (3) should provide as nominal settings 100 ms for atrial sensed and 170 ms for atrial paced stimulation.     

Doppler index and plasma level of atrial natriuretic hormone are improved by optimizing atrioventricular delay in atrioventricular block patients with implanted DDD pacemakers

Doppler index is the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and has clinical value as an index of combined systolic and diastolic myocardial performance. This crossover study compared the Doppler index and atrial natriuretic hormone (atrial natriuretic peptide) [ANP] between optimal (AV) delay and prolonged AV delay in patients with DDD pacemakers. The study included 14 patients (6 men, 8 women, age 78.4+/-9.3 [SD] years) with AV block with an implanted DDD pacemaker. AV delay was prolonged in a 25-ms, stepwise fashion starting from 125 ms to 250 ms. Pacing rate was set at 70 beats/min. Cardiac output (CO) was assessed by pulsed Doppler echocardiography, and optimal AV delay was defined as the AV delay at which CO was maximum, and an AV delay setting of 250 ms as prolonged AV delay. Plasma level of ANP and Doppler index determined by echocardiography were measured 1 week after programming. AV delay was switched to another AV delay and measurements were repeated after 1 week. Optimal AV delay was 159+/-19 ms. Doppler index was significantly lower at optimal AV delay than at prolonged AV delay (0.68+/-0.26 vs 0.92+/-0.30, P < 0.05). The plasma ANP level was significantly lower at optimal AV delay than at prolonged AV delay (29.0+/-30.7 vs 52.6+/-44.9 pg/mL, P < 0.05). In conclusion, the Doppler index and the plasma ANP level were significantly lower at optimal AV delay than at prolonged AV delay. This study shows the importance of the optimal AV delay setting in patients with an implanted DDD pacemaker, the Doppler index and plasma ANP levels are good indicators for optimizing AV delay.     

永久性心脏起搏器植入对左心室重构影响研究

目的:分析心脏起搏器植入后不同起搏方式对左心室重构的影响。方法:共入选34例患者,其中VVI起搏器20例,DDD起搏器14例,分别在术前及术后5~12个月,用超声心动图观测左室舒张末期内径、左室收缩末期内径、左室射血分数。结果:34例起搏器植入患者均出现左心室重构,VVI组观测指标植入前后比较差异有统计学意义,DDD组观测指标差异无统计学意义。结论:起搏器植入后均可出现左心室重构,提示右室心尖部起搏对左心室的收缩、舒张功能产生不利影响;起搏器植入应选用生理性或接近生理性起搏方式。     

Application of Pulsed-Doppler Tissue Imaging in Patients with Dual Chamber Pacing: The Importance of Conduction Time and AV Delay on Regional Left Ventricular Wall Dynamics

Pulsed-Doppler tissue imaging (pDTI) is able to measure myocardial wall velocities (systolic: S; early diastolic: E; late diastolic: A) and their timings. Relationships have been demonstrated between the preelection period and indexes of left ventricular systolic function. This study was designed to examine with pDTI the effects of variations in atrioventricular delay (A VD) (100 ms, 150 ms, 200 ms) on myocardial dynamics and on their timings at the basal interventricular septum (IVS) from an apical approach and at the posterior wall (PW) from the parasternal view. These data were compared with stroke volume measurements recorded from the left ventricular outflow tract. Seventeen patients with dual chamber pacemakers (7 because of complete heart block, 10 with sick sinus syndrome and first-degree AV block) were studied; full atrial and ventricular capture was present at any AVD. These data were also compared with those obtained in 10 age-matched healthy volunteers with comparable heart rates. Results: Optimal atrial contribution to left ventricular filling and, consequently, best systolic performance were achieved when AVD was programmed such that a mean interval of 77 ms was allowed between the end of the A wave and the beginning of the S wave, similar to what was measured in the healthy control group by pDTI. Conclusion: The noninvasive measurement of timings of the cardiac cycle by pDTI is helpful to determine the optimal AVD in individual patients.     

Left ventricular diastolic filling prior to cardiac resynchronization therapy: implications for atrioventricular delay programming

Background: The programmed atrioventricular delay (AVD) is an important determinant of the response in left ventricular (LV) systolic performance during cardiac resynchronization therapy (CRT). It is not well established if the optimal AVD for CRT may be influenced by the LV diastolic filling pattern.
Methods: Thirty patients were studied pre- and post-CRT at programmed AVD of 60–160 ms. Doppler measurements included the aortic and mitral velocity time integral (VTI), mitral early (E) and late diastolic filling (A) wave velocities, E- and A-wave VTI, and diastolic filling time (DFT). The optimal AVD for each of the Doppler variables was defined by the maximal improvement compared to pre-CRT. Patients were grouped by the pre-CRT mitral inflow pattern as impaired relaxation (IR, mitral E/A ≤1, n = 15) or pseudonormalized/restrictive filling (PNF/RF, mitral E/A >1, n = 15).
Results: The percentage of improvement in aortic VTI was greater in the PNF/RF group (P = 0.03). Mitral E-wave velocity decreased in the PNF/RF group (P < 0 .001), E-wave VTI increased in both groups (P < 0 .05) and A-wave VTI increased in the PNF/RF group. DFT increased in both groups. The optimal AVD that maximized aortic VTI was longer than the AVD that improved DFT.
Conclusions: The effects of various programmed AVD during CRT on the response in LV stroke volume and diastolic filling are influenced by the pre-CRT LV filling characteristics. AVD optimization based on maximizing DFT is shorter compared to the aortic VTI method.     

Correlation of the M-mode atrioventricular plane early diastolic downward slope and systolic parameters

BACKGROUND: The early diastolic downward slope (EDS) of the left atrioventricular plane displacement (AVPD) is a parameter of early left ventricular (LV) diastolic filling, particularly useful in revealing pseudonormalisation of the transmitral Doppler early to atrial (E/A) ratio. In recent studies LV early diastolic function seems to be closely linked to LV systolic function. In order to further examine this relationship we studied the correlation between EDS and traditional Doppler parameters of LV diastolic function as well as between EDS and systolic parameters. METHODS: LV diastolic function was assessed by echocardiography/Doppler in 62 consecutive patients by measurement of EDS and using a traditional four-grade scale based on a combination of the E/A ratio, the E-wave deceleration time (Edt), and the systolic/diastolic ratio of the pulmonary venous inflow (S/D). LV systolic function was evaluated by ejection fraction (LVEF) and AVPD. EDS was assessed from AVPD registrations. RESULTS: In univariate analysis of variance (ANOVA), EDS was not significantly related to overall diastolic function, but highly significantly related to both LVEF (p = 0.001) and AVPD (p < 0.0001). CONCLUSIONS: EDS was more closely related to LV systolic parameters than to LV diastolic function assessed traditionally by Doppler, using a combination of E/A, Edt and S/D. This relationship between the early filling of the LV and the LV systolic function is in line with some earlier findings. It is suggestive of a relationship between the systolic and early diastolic performance of the LV.     

Method of atrioventricular programming in atrial flutter in patients with biventricular pacemaker

BACKGROUND: Atrial flutter is a common cause of exacerbation of congestive heart failure (CHF). Typically, during atrial tachycardia, pacemakers, both dual and biventricular, are programmed to ignore atrial tracking. Virtually all current pacemakers and defibrillators use a programmable mode switch algorithm to switch between atrial tracking modes (DDD, DDDR) to nontracking modes (DDIR, DDI, VVI) during episodes of atrial tachycardia. METHODS: In this report, we describe a novel method of atrioventricular (AV) pacemaker programming in four patients with atrial flutter and CHF who remained symptomatic postbiventricular pacemaker implantation. All patients had chronic atrial flutter upon interrogation; adjustment of AV delay and postventricular atrial refractory period (PVARP) was performed to enable sensing of every second to fourth atrial flutter beat by the atrial lead. Mode switch was turned "OFF" in all points, and lower and upper rate limits were set to 50 and 100 bpm. Once sequential early and late diastolic filling was seen on mitral inflow pulsed-wave (PW) Doppler, further adjustment of AV delay and PVARP was performed until the highest and broadest atrial velocity occurred on mitral inflow PW Doppler. RESULTS: All patients developed improvement in aortic ejection duration and peak ejection velocity during AV optimization. Repeat ECG in these patients at 8 months, 7 days, 2 days, and 2 months postoptimization showed no change in P and QRS relationship. All patients developed improvement in CHF symptoms postbiv pacemaker optimization. CONCLUSION: In symptomatic patients with CHF and stable atrial flutter who have a biventricular pacemaker, atrial mechanical contribution to cardiac output can be achieved by adjusting PVARP and AV delay during echo-guided pacemaker programming.     

The spectrum of left ventricular filling in severe aortic stenosis

To assess left ventricular diastolic filling in valvular aortic stenosis, pulsed Doppler echocardiography was used prospectively in 35 patients with severe aortic stenosis (valve area < 1 cm²) and in 38 age-matched normal subjects. Twenty-seven patients had a normal left ventricular systolic function at rest (ejection fraction > 0.50) and a normal or only slightly increased mean pulmonary capillary wedge pressure (mean 11±4 mm Hg). Eight patients had a poor left ventricular systolic function (ejection fraction: 0.28±0.10) and an elevated mean pulmonary capillary wedge pressure (mean: 36±9 mm Hg). The Doppler derived filling parameters were correlated with hemodynamic data, left ventricular wall thickness derived from M-mode echocardiograms, heart rate and atrio-ventricular (A-V) conduction delay using stepwise multiple correlation. The data of this study suggest that left ventricular filling is significantly impaired in patients with severe aortic stenosis and left ventricular hypertrophy with an increase in late diastolic (A-wave) velocity, an increase in the A/E ratio, a decrease in the first one-half filling fraction and a prolongation of early diastolic deceleration time. These changes in filling hemodynamics are associated with alterations in mean pulmonary capillary wedge pressure, left ventricular wall thickness, heart rate and A-V conduction delay. When heart failure develops as a result of impaired left ventricular systolic function, an increase in left atrial filling pressure is associated with a shift of left ventricular filling towards early diastole with a ‘normalisation’ of the transmitral flow velocity curve. In extreme cases, a progression towards a ‘restrictive’ filling pattern is found with a marked shortening of the left ventricular early diastolic deceleration time. In the presence of high filling pressures, increased left atrial driving pressure (derived from the mean pulmonary capillary wedge pressure) is associated with changes in the left ventricular filling pattern irrespective of the presence and the degree of myocardial hypertrophy.     

Optimizing the AV Delay in DDD Pacemaker Patients with High Degree AV Block: Mitral Valve Doppler Versus Impedance Cardiography

In DDD-pacemaker patients with high degree A V block, Doppler echocardiography of transmitral blood flow can be used to find the individually optimal AV delay (AVO) for left heart AV synchronization. This study tried to validate a Doppler method (ECHO) recently proposed to optimize left ventricular filling by comparing it to stroke volume data derived from impedance cardiography (ICG). It should be further elucidated if optimizing the AV delay (AVD) by means of this method is superior to fixed AVD settings and which differential AVD (pace-sense-offset) should be programmed for atrially triggered (A TP) and A V sequential (A VP) pacing, respectively. A VO as measured in 53 patients showed a linear correlation between ECHO and ICC for both ATP (r = 0.66, P < 0,00001) and AVP (r = 0.53, P < 0.005). The mean deviation in AVO between ECHO and ICC was ± 26 ms (ATP) and ± 30 ms (AVP), respectively, with a tendency to longer AVDs with the Doppler method. ECHO limitations could mainly be attributed to: (1) restrictions of AVD programming options (which may be compensated for by slight modification of the proposal); and (2) to pathophysiological mechanisms that alter mitral valve dynamics. Optimization of the AVD by Doppler produced a stroke volume that was significantly higher (19%) than with a fixed AVD (150 ms in ATP; 200 ms in AVP). There was a wide scatter in pace-sense-offsets between -7 and 134 ms, which was reflected by both methods. It is concluded that AVO determinations by ECHO are valid provided that methodological pitfalls and limitations caused by the disease are recognized. Tailoring AVD with respect to diastolic filling improves systolic function and is superior to nominal AVD settings. Fixed differential AVDs as offered by some manufacturers are far from being physiological. Thus modern pulse generators should offer free programmability over a wide range of AV delays.     

Strain rate imaging in normal and reduced diastolic function: comparison with pulsed Doppler tissue imaging of the mitral annulus.

OBJECTIVES: The pixel velocity values obtained by color Doppler tissue imaging (DTI) can be processed to velocity gradients as a measure of longitudinal strain rate with a technique termed strain rate imaging (SRI). Color mapping of strain rate does show the spatial-temporal relations of the diastolic phases. The phases of early filling and late filling during atrial systole can be seen to consist of a stretch wave in the myocardium, propagating from the base to the apex. Diastolic function is characterized by both peak strain rate and propagation velocity of this wave. The goals of this study were to establish normal values for these measurements and to study the changes with minimal diastolic dysfunction. METHODS: Twenty-eight healthy control subjects and 26 patients with hypertension and normal systolic function were studied. The patients had normal blood pressure on treatment, normal ejection fraction, minimal hypertrophy, and moderately prolonged deceleration and isovolumic relaxation times. Real-time SRI color cineloops, ordinary echocardiography and Doppler recordings, and pulsed wave DTI from the mitral ring were acquired and processed. RESULTS: Patients showed a reduction of systolic and early diastolic tissue velocities and strain rates and no significant increase in late diastolic tissue velocity and strain rate. Propagation velocity of diastolic strain during both early and late filling phases was reduced in the patients. The combination of changes in peak strain rate and propagation velocity of strain rate corresponded with changes in DTI. CONCLUSION: Diastolic deformation of the ventricle can be shown as a complex series of events, with temporal sequences in the ventricle. The peak strain rate and the propagation velocities of strain rate can describe the two main diastolic events: early and late filling. In reduced diastolic function, both are reduced during early filling. The velocities of the mitral ring are the result of this combination. This adds information about the physiology and pathophysiology of diastole.     

Rate-dependent AV delay optimization in cardiac resynchronization therapy

BACKGROUND: During cardiac resynchronization therapy (CRT), cardiac performance is dependent on an optimized atrioventricular delay (AVD). However, the optimal AVD at different heart rates has not been defined yet during CRT. METHOD: The effects of an increase in heart rate by pacing or physical exercise on optimal AVD were studied in 36 patients with biventricular pacemakers/defibrillators. The velocity time integral (VTI) in the left ventricular outflow tract (LVOT) was measured with pulsed Doppler either at three different paced heart rates in the supine position or in seated position before and after physical exercise. RESULTS: The baseline AVD was optimized to 99 +/- 19 ms in the supine and 84 +/- 22 ms in the seated position. When the heart rate was increased by DDD pacing, there was a positive linear relationship between an increase in heart rate, in AVD and in VTI (LVOT-VTI + 0.047 cm/s per 10 beats per minute (bpm) heart rate increase per 20 ms increase in AVD, P = 0.007). A similar but more pronounced relationship was found after physical exercise in the seated position (LVOT-VTI + 0.146 cm/s per 10 bpm heart rate increase per 20 ms increase of AVD, P = 0.013). This effect was observed in patients with and without AV block and mitral regurgitation. CONCLUSIONS: In conclusion, the systolic performance of the dilated ventricle, which depends on an elevated preload, is critically affected by the appropriate timing of the AVD during exercise. In contrast to normal pacemaker patients, in CRT the relatively short baseline AVD should be prolonged at increased heart rates. Further studies with other means of measuring exercise cardiac performance are needed to confirm these unexpected findings.     

Ventricular Endocardial Right Bifocal Stimulation in the Treatment of Severe Dilated Cardiomyopathy Heart Failure with Wide QRS

PACHÓN, J.C., et al. : Ventricular Endocardial Right Bifocal Stimulation in the Treatment of the Severe Dilated Cardiomyopathy Heart Failure with Wide QRS. The QRS widening by ventricular conventional pacing impairs the systolic and diastolic functions and increases mitral regurgitation. The aim of this study was to compare conventional pacing to an alternative stimulation mode with a narrower QRS using two leads in the RV. Thirty‐nine (25 men, 14 women; mean age 60.1 ± 15.1 years ) dilated cardiomyopathy patients (Chagas' disease [n = 17], coronariopathy [n = 9], AV ablation for tachycardiomyopathy [n = 3], and other [n = 10] ) with cardiac failure (NYHA 3.1 ± 0.8 ), pacemaker indication, and chronic AV block (22 AF) had endocardial pacemaker implantations (27 Biotronik, 12 Guidant). Two RV leads (one septal, one conventional [RV apex] were connected, respectively, to the atrial and ventricular pacemaker plugs. After clinical stabilization they were studied under three stimulation modes in the same session: AAI (septal), VVI (conventional), and ventricular endocardial right bifocal stimulation (VERBS) (DDT/DVI/DDD = AV interval = 15/10 ms). In comparison to conventional pacing, VERBS increased ejection fraction (0.124), cardiac output (19.5%), and peak filling rate (31.0%), and decreased QRS duration (24.7%), left atrium area (11.9%), mitral regurgitation area (32.3%), the diastolic transmitral flow (E/A relation) (19.3%), and the propagation flow time (18.0%) from the mitral valve to the left ventricular apex (tE_col), (P < 0.05). The quality‐of‐life showed an impressive score reduction of 50.4%. The septal stimulation alone showed a less expressive benefit. In severe dilated cardiomyopathy with classic pacemaker indication, VERBS showed significantly better performance than the septal or the conventional stimulation alone. There was a good systolic and a remarkable diastolic improvement causing an important reduction in the quality‐of‐life score.     

AV Delay Optimization and Management of DDD Paced Patients with Dilated Cardiomyopathy

Ten DDD paced patients, suffering front dilated cardiomyopathy in the NYHA functional classes III or IV were studied by means of Doppler ecbocardiography at different programmed values of atrioventricular (AV) delay (200, 150, 120, 100, and 80 msec). The following variables were evaluated: LV diameter, ejection fraction, mitral and aortic flow velocity integrals, and stroke volume. During VDD pacing, a resting AV delay associated with the best diastolic filling and systolic function was identified and programmed individually. Shortening of the AV delay to about 100 msec was associated with a gradual and progressive improvement. Further decrease caused an impairment of systolic function. The patients were clinically and beinodynamically reevaluated after 2 months of follow-up. A reduction of NYHA class and an improvement of LV function were consistently found. The reported data suggest that programming of an optimal A V delay may improve myocardial function in DDD paced patients with congestive heart failure. This result may be the consequence of an optimization of left ventricular filling and a better use of the Frank-Starling law.     

C-AMP and ANP Levels in VVI and DDD Pacing with Different AV Delays During Daily Activity and Exercise

THEODORAKIS, G., ET AL.: C-AMP and ANP Levels in VVI and DDD Pacing with Different AV Delays During Daily Activity and Exercise. Nine patients (three males) mean age 68 ± 8 years, having complete heart block, and paced in the DDD mode were examined in VVI and DDD pacing with 100 and 150 ms atrioventricular delays (AVD) during rest and exercise. Plasma atrial natriuretic peptide (ANP) and cyclic AMP (c-AMP) were measured at rest and at peak exercise test. ANP plasma levels at rest were significantly higher in VVI pacing compared to 150 AVD (p < 0.03). On exercise, ANP release was statistically increased only in DDD with 150 ms AVD, while in WI it remained in high levels at exercise but no significant change was found (p:ns). c-AMP during rest was unchanged in any pacing mode or AVD, but on exercise DDD pacing with short AVD (100 ms) released lower c-AMP plasma levels, than at rest (p:ns). DDD pacing with long AVD (150 ms) during exercise produced statistically higher c-AMP plasma levels (p < 0.05) than at rest. Also in VVI pacing the c-AMP plasma levels were statistically higher than at rest (p < 0.02). Adrenergic activity seems to be lower during exercise in DDD pacing with shorter AVD (100 ms) than in DDD with 150 ms AVD or VVI pacing. No difference was found in c-AMP plasma levels at rest. ANP release was also found to be lower at exercise in DDD pacing with short AVD (100 ms) than in DDD with 150 ms AVD. ANP plasma levels at rest were statistically higher in VVI pacing. (PACE, Vol. 13, December, Part II 1990)     

Early changes in left ventricular volume and function are predictors for long-term remodeling in patients with acute transmural myocardial infarction and preserved systolic function.

BACKGROUND: We sought to describe the degree of long-term left ventricular (LV) remodeling after acute transmural myocardial infarction with preserved LV systolic function, and to evaluate whether Doppler echocardiographic parameters in the early phase could predict this process. METHODS: A total of 60 patients without heart failure and with LV ejection fraction > or = 0.40 (mean 0.48 +/- 0.054), were followed up with Doppler echocardiographic examinations at baseline, 3 months, and 1 and 2 years. RESULTS: There was a significant increase in LV end-diastolic volume index of 7% (P =.006) and LV end-systolic volume index of 8% (P =.03), and no change in ejection fraction. This remodeling was confined to 7 patients (12%) with a significant increase in LV end-diastolic volume index above 20 mL/m(2). There was also a significant increase in the deceleration time of both the early mitral filling wave (Delta early mitral filling wave = 58 milliseconds, P <.0005) and the diastolic forward component of pulmonary venous flow (Delta diastolic forward component of pulmonary venous flow = 61 milliseconds, P <.0005), and a shift in filling pattern with increasing prevalence of abnormal relaxation. Changes in end-diastolic volume index were predicted by baseline early mitral filling wave less than 100 milliseconds, but the most powerful predictors of 2-year remodeling were volume changes at 3 months. CONCLUSION: Twelve percent of patients with Q-wave infarction and ejection fraction > or = 0.40 experienced significant LV dilatation at 2 years, and this late remodeling was partly related to baseline filling characteristics.     

The role of apically directed intraventricular isovolumic relaxation flow in speeding early diastolic left ventricular filling

Left ventricular (LV) systolic performance has been acknowledged to have a close relation to LV early diastolic filling and LV relaxation. However, the mechanism showing how good LV systolic function enhances the LV early diastolic filling has not been fully elucidated from the viewpoint of intraventricular flow dynamics. Thus, we investigated this issue in 82 patients with suggested coronary artery disease who underwent cardiac catheterization. Apically directed intraventricular isovolumic relaxation flow (IRF) and the propagation velocity of early diastolic filling flow were measured using pulsed and color Doppler echocardiography. LV ejection fraction and LV relaxation time constant tau were obtained in cardiac catheterization. As we were not able to measure the IRF velocity less than 14 cm/s that was limited by a Doppler low-cut filter, we analyzed the data collected from 78 patients with measurable IRF velocity. The IRF velocity significantly correlated with LV ejection fraction (r = 0.74, P <.001) and with LV relaxation time constant tau (r = -0.31, P <.01). The propagation velocity of early diastolic filling flow significantly correlated with the IRF velocity (r = 0.73, P <.001) and also significantly correlated with LV ejection fraction (r = 0.70, P <.001). Good LV systolic performance augments LV early diastolic filling directly, mediated by IRF. A faster IRF velocity may play a role in delivering good LV systolic performance to LV early diastolic filling.     

多普勒组织成像在心肌梗死患者经皮冠状动脉介入术后的临床应用

目的研究多普勒组织成像（DTI）技术用于心肌梗死（MI）患者经皮冠状动脉介入术（PCI）术后心功能随访的可行性。方法选择86例MI住院患者,根据是否进行PCI术,分为PCI组45例和常规治疗组41例,术前、术后1个月、6个月、12个月行DTI及常规超声心动图检查。结果PCI术后,左室射血分数（EF）及应用DTI技术检测二尖瓣环四点（室间隔、侧壁、前壁、下壁）收缩期主峰S波速度的平均值术后1个月较术前即有明显改善,S波速度与EF之间的相关性较好,且比EF的敏感性更高。DTI二尖瓣环四点的舒张早期与晚期主峰速度e/a比值的平均值术后较术前增大;常规超声心动图二尖瓣口血流舒张早期与晚期主峰速度E/A比值无显著性差异。结论PCI术后,患者整体心脏收缩、舒张功能短期内得到改善;DTI技术观测AMI患者的心功能较常规超声心动图技术敏感性及特异性均高,可作为常规超声心动图的有力补充。     

Tei指数指导优化房室延迟对置入双腔起搏器的心力衰竭患者生活质量和预后的影响

目的评价应用Tei指数指导优化房室延迟(AVD)对置入双腔起搏器的心力衰竭患者生活质量和预后的影响。方法 2009年1月至2011年1月在我院心内科拟首次置入双腔起搏器且存在心功能不全的患者162例,按随机数字表法分为对照组(80例)和优化AVD组(82例)。对照组患者置入的起搏器按厂家初始设定的AVD进行工作,优化AVD组患者术后行超声心动图检查,以Tei指数指导优化AVD。置入起搏器12个月后,对所有患者进行6min步行距离测试、超声心动图检查及生活质量评分,并记录随访期间患者死亡、急性肺水肿、心功能恶化入院、恶性心律失常(室性心动过速、心室颤动发作)等主要心脏不良事件(MACE)发生情况。结果优化AVD组患者AVD优化后左心室充盈时间(LVFT)、左心室输出量(LVCO)较优化前改善,且差异均有统计学意义[(363.74±7.57)msvs(342.57±5.34)ms,t=-5.510,P<0.05;(3.09±0.21)L/minvs(2.99±0.19)L/min,t=-2.936,P<0.05]。置入起搏器12个月后,优化AVD组心力衰竭患者6min步行距离、LVFT、左心室射血分数(LVEF)、二尖瓣反流面积和生活质量评分均优于对照组,且差异均有统计学意义[(362.09±27.01)mvs(336.71±20.92)m,t=-6.676,P<0.01;(362.76±6.47)msvs(342.63±4.42)ms,t=-10.650,P<0.01;(48.09±2.49)%vs(46.35±2.16)%,t=-4.754,P<0.01;(1.36±0.26)cm2vs(1.52±0.35)cm2,t=3.434,P<0.05;(108.40±7.40)分vs(102.80±5.80)分,t=-5.291,P<0.01]。优化AVD组患者累积无MACE生存率为90.2%(74/82),对照组患者为77.5%(62/80),差异有统计学意义(χ2=4.628,P=0.031)。结论应用Tei指数指导优化AVD能减轻置入双腔起搏器的心力衰竭患者心功能损害程度,提高患者生活质量,并改善预后。