Effects of abnormal activation on the time course of the left ventricular pressure pulse in dilated cardiomyopathy

Objective—To investigate the effects of QRS duration on characteristics of the left ventricular pressure pulse derived from the time course of functional mitral regurgitation by continuous wave Doppler.Design—Retrospective and prospective study of 50 patients with dilated cardiomyopathy, by electrocardiography, echocardiography, and Doppler cardiography.Setting—Tertiary cardiac referral centre.Patients—50 patients (mean age (SD) 58 (16)) with dilated cardiomyopathy, all with functional mitral regurgitation.Results—The values of QRS duration ranged widely, from 70 to 190 ms with a mean value of 110 ms, and were unimodally distributed. The overall duration of mitral regurgitation correlated positively with QRS time (r=0·65) over the entire range of values. When the duration of mitral regurgitation was divided into contraction, aortic ejection, and relaxation times, increased QRS duration prolonged contraction (r=0·51) and relaxation (r=0·52) times. Aortic ejection time was affected by RR interval (r=0·74). Duration of QRS correlated negatively with peak rate of rise in left ventricular pressure (+dP/dt) (r=−0·48), and positively with the time intervals from Q to peak pressure (r=0·49) and to peak +dP/dt (r=0·72), and also with those from the start of mitral regurgitation to peak pressure (r=0·49) and to peak +dP/dt (r=0·76). Duration of QRS did not directly affect the peak rate of left ventricular pressure fall (−dP/dt), or the isovolumic relaxation period.Conclusions—Values of QRS duration are unimodally distributed in patients with dilated cardiomyopathy, without evidence of a discrete group of patients with left bundle branch block. Prolonged QRS duration reduces peak +dP/dt, prolongs overall duration of the pressure pulse, the time to peak +dP/dt, and relaxation time. Duration of QRS must therefore be taken into account in assessing standard measurements of myocardial function in patients with dilated cardiomyopathy.     

Effects of abnormal activation on the time course of the left ventricular pressure pulse in dilated cardiomyopathy

Objective—To investigate the effects of QRS duration on characteristics of the left ventricular pressure pulse derived from the time course of functional mitral regurgitation by continuous wave Doppler.

Design—Retrospective and prospective study of 50 patients with dilated cardiomyopathy, by electrocardiography, echocardiography, and Doppler cardiography.

Setting—Tertiary cardiac referral centre.

Patients—50 patients (mean age (SD) 58 (16)) with dilated cardiomyopathy, all with functional mitral regurgitation.

Results—The values of QRS duration ranged widely, from 70 to 190 ms with a mean value of 110 ms, and were unimodally distributed. The overall duration of mitral regurgitation correlated positively with QRS time (r=0·65) over the entire range of values. When the duration of mitral regurgitation was divided into contraction, aortic ejection, and relaxation times, increased QRS duration prolonged contraction (r=0·51) and relaxation (r=0·52) times. Aortic ejection time was affected by RR interval (r=0·74). Duration of QRS correlated negatively with peak rate of rise in left ventricular pressure (+dP/dt) (r=−0·48), and positively with the time intervals from Q to peak pressure (r=0·49) and to peak +dP/dt (r=0·72), and also with those from the start of mitral regurgitation to peak pressure (r=0·49) and to peak +dP/dt (r=0·76). Duration of QRS did not directly affect the peak rate of left ventricular pressure fall (−dP/dt), or the isovolumic relaxation period.

Conclusions—Values of QRS duration are unimodally distributed in patients with dilated cardiomyopathy, without evidence of a discrete group of patients with left bundle branch block. Prolonged QRS duration reduces peak +dP/dt, prolongs overall duration of the pressure pulse, the time to peak +dP/dt, and relaxation time. Duration of QRS must therefore be taken into account in assessing standard measurements of myocardial function in patients with dilated cardiomyopathy.

     

扩张型心肌病左室容积变化对左室射血分数的影响

目的 :探讨扩张型心肌病 (DCM)左室腔容积 (L VCV)等参数变化对左室射血分数 (L VEF)的影响。方法 :DCM组 4 2例 ,按 L VEF降低程度又分为 :轻度异常组 12例 ,LVEF4 4 .5± 2 .39;中度异常组 2 4例 ,L VEF32 .8± 3.80 ;重度异常组 6例 ,LVEF17± 3.2 8。用超声心动图及 Simpson法测定并算出 LVCV、L VEF等参数。结果 :4 2例 DCM患者与健康人比较 ,LVCV明显增加 (P<0 .0 1) ;而在 DCM组内不同 L VEF组间 ,LVCV在中、重度异常组比轻度异常组明显增高 (P<0 .0 1) ;重度异常组与中度异常组比较也有明显增高 (P<0 .0 1)。结论 :测定结果表明 LVCV越大对 LVEF负面影响越大。在康复心脏病学中 LVCV可作为心功能指标之一     

Importance of the left ventricular filling pressure on diastolic filling in idiopathic dilated cardiomyopathy

Both mitral regurgitation and elevated left ventricular (LV) filling pressures may normalize or enhance rapid filling in patients with idiopathic dilated cardiomyopathy. To assess the individual effects of the LV filling pressure and mitral regurgitation, 33 normal subjects, 14 patients with cardiomyopathy and normal LV filling pressures (measured as mean pulmonary capillary pressure) and 26 patients with elevated LV filling pressures (greater than 15 mm Hg) were studied with transmitral spectral tracings derived from pulsed Doppler echocardiography. Both cardiomyopathy groups demonstrated similarly dilated left ventricles with reduced systolic dysfunction. Patients with cardiomyopathy and normal LV filling pressures had prolonged isovolumic relaxation periods and a reduced ratio of the rapid filling to atrial filling integrals. Patients with cardiomyopathy and elevated LV pressures demonstrated an increased peak rapid filling velocity (97 +/- 21 cm/s) and rapid filling fraction (74.8 +/- 16.2%) compared with normal subjects (80 +/- 16 cm/s, p less than 0.01; 62.4 +/- 12.5%, p less than 0.05) and patients with cardiomyopathy and normal LV filling pressures (81 +/- 27 cm/s, p less than 0.05; 59.3 +/- 8.8%, p less than 0.05). Conversely, the atrial filling fraction was decreased in the cardiomyopathy group with elevated LV filling pressures compared with normal subjects and patients with cardiomyopathy and normal LV filling pressures. Mitral regurgitation increased the peak rapid filling velocity in both cardiomyopathy groups without altering the distribution of diastolic filling. In conclusion, elevated LV filling pressures appear to affect the distribution of diastolic filling, whereas mitral regurgitation affects the peak rate of rapid filling.     

Effects of partial left ventriculectomy on left ventricular performance in patients with nonischemic dilated cardiomyopathy

Objectives. This study sought to assess the effects of partial left ventriculectomy (PLV) on left ventricular (LV) performance in a series of consecutive patients with nonischemic dilated cardiomyopathy.

Background. Reduction of LV systolic function in patients with heart failure is associated with an increase of LV volume and alteration of its shape. Recently, PLV, a novel surgical procedure, was proposed as a treatment option to alter this process in patients with dilated cardiomyopathy.

Methods. We studied 19 patients with severely symptomatic nonischemic dilated cardiomyopathy, before and 13 ± 3 days after surgery, and 12 controls. Single-plane left ventriculography with simultaneous measurements of femoral artery pressure was performed during right heart pacing.

Results. The LV end-diastolic and end-systolic volume indexes decreased after PLV (from 169 to 102 ml/m², and from 127 to 60 ml/m², respectively, p < 0.0001 for both). Despite a decrease in LV mass index (from 162 to 137 g/m², p < 0.0001), there was a significant decrease in LV circumferential end-systolic and end-diastolic stresses (from 277 to 159 g/cm², p < 0.0001 and from 79 to 39 g/cm², p = 0.0014, respectively). Ejection fraction improved (from 24% to 41%, p < 0.0001); the stroke work index remained unchanged.

Conclusions. The PLV improves LV performance by a dramatic reduction of ventricular end-systolic and end-diastolic stresses. Further studies are needed to assess whether this effect is sustained during long-term follow-up and to define the role of PLV in the treatment of patients with dilated cardiomyopathy.     

Dissimilar course in the right and left ventricular function in a patient with dilated cardiomyopathy

The case of a patient with severe dilative cardiomyopathy and cardiomegaly demonstrates that M-mode echocardiography and planar chest radiographs are not always sufficient to follow up the disease correctly. Using other non-invasive imaging modalities, in this case radionuclide ventriculography and NMR tomography, which provide more precise information with regard to morphology and function of both the right and the left heart, allows a more reliable follow-up of the disease.     

Cardiac thrombus in dilated cardiomyopathy. Relationship between left ventricular pathophysiology and left ventricular thrombus

The relationship between left ventricular thrombus and left ventricular dynamics in dilated cardiomyopathy (DCM) was studied by echocardiography and postmortem examination. The subjects were 57 patients with DCM, 40 were survival patients examined by echocardiography and 17 were autopsy patients. Systemic or pulmonary embolism occurred in 10 of 57 patients, 4 of 40 survival patients and 6 of 17 autopsy patients. Intracardiac thrombus was detected in 11 of 40 survival patients and was found in 8 of 17 autopsy patients. Left ventricular segmental wall motion abnormalities were observed in all 40 patients examined by two-dimensional echocardiography and apical dyskinesis or akinesis was observed more frequently in patients with left ventricular thrombus than in patients without left ventricular thrombus. Of 33 patients examined by pulsed Doppler echocardiography, Doppler ejection flow signals in the apical long axis view were recorded in 9% at the apex, in 17% at the middle portion and in 57% at the portion near the interventricular septal center. The signals at the portion near the interventricular septal center were recorded in only 2 patients with left ventricular thrombus but in 66% of patients without left ventricular thrombus. Systemic or pulmonary embolism and intracardiac thrombus occurred less frequently in patients treated with warfarin than in patients without warfarin. These results indicate that endomyocardial and blood flow disorders of the left ventricle play important roles in the occurrence of left ventricular thrombus and that anticoagulant therapy is useful for the prevention of systemic or pulmonary embolism and cardiac thrombus.     

Pathophysiologic significance of left ventricular hypertrophy in dilated cardiomyopathy

Background and hypothesis: Patients with dilated cardiomyopathy (DCM) with left ventricular hypertrophy (LVH) have been found to have a better prognosis than patients without LVH. However, the pathophysiologic mechanism for that has not been investigated. We sought to clarify the pathophysiologic significance of LVH in DCM. Methods: We performed isoproterenol infusion echocar-diography (0.02 m?g/kg/min) in 17 patients with DCM, and measured plasma epinephrine and norepinephrine levels at rest and at the end of ergometer exercise in 14 of the 17 patients. Patients were classified into groups according to the presence (9 patients) (LVH+) or absence (8 patients) (LVH-) of LVH. Left ventricular hypertrophy was defined as an inter-ventricular thickness or posterior wall thickness ≥13 mm. Results: Although there was no significant difference between groups in fractional shortening at rest during isoproterenol infusion, fractional shortening was significantly higher in the LVH (+) group than in the LVH (-) group (29 ± 9 vs. 17 ± 8%;p<0.025). Although there was no significant difference in plasma norepinephrine level, it was significantly lower in the LVH (+) group than in the LVH (-) group (233 ± 169 vs. 519 ± 258 pg/ml;p<0.05) at the end point of the exercise. Conclusion: Systolic reserve, represented by the response to isoproterenol, is greater in patients with DCM with LVH than in those without LVH, and a lower plasma level of norepinephrine is needed to activate the myocardium during ex ercise in patients with DCM with LVH. This pathophysiologic characteristic could be one of the mechanisms which explain a better prognosis in patients with DCM with LVH.     

Effects of exercise and nitroprusside on left ventricular ejection dynamics in idiopathic dilated cardiomyopathy

To characterize the abnormal pattern of instantaneous left ventricular (LV) ejection in heart failure, proximal aortic pressure, flow, acceleration, power and dW/dt were measured at rest and during supine bicycle exercise using high-fidelity, catheter-mounted pressure and velocity sensors in 16 patients with idiopathic dilated cardiomyopathy (IDC) and 11 normal control subjects. In patients with IDC, peak flow was lower than normal both at rest (454 +/- 155 vs 649 +/- 168 ml/s, p less than 0.01) and during exercise (569 +/- 213 vs 916 +/- 329 ml/s, p less than 0.01). Peak acceleration, power and dW/dt were also significantly reduced in patients with IDC at rest and during exercise. Time to peak flow (as a fraction of LV ejection time) was consistently prolonged in patients with IDC (rest, 0.40 +/- 0.08 vs 0.29 +/- 0.04; exercise, 0.36 +/- 0.06 vs 0.28 +/- 0.04, both p less than 0.01). Exercise-induced increments in peak flow, power and dW/dt were significantly blunted in patients with IDC. Studies during pacing tachycardia and nitroprusside administration failed to reproduce the abnormalities during exercise in patients with IDC. Thus, the instantaneous flow pulse in heart failure is both diminished in magnitude (decreased stroke volume and peak flow) and abnormal in shape (decrease peak acceleration and delayed time to peak flow). Exercise stress in IDC results in abnormalities of LV performance that can be detected using instantaneous ejection information. These abnormalities are unlikely to be explained by changes in heart rate or loading conditions.     

Familial dilated cardiomyopathy complicated by left ventricular aneurysm

Two siblings presented with symptoms of left ventricular dysfunction and ventricular arrhythmias. Echocardiography and left ventriculography revealed dilatation, diffuse hypokinesis and apical aneurysm of the left ventricle in both cases. Myocardial infarction was unlikely by history and examinations. We diagnosed them as cases of familial dilated cardiomyopathy complicated by left ventricular aneurysm.     

Shortened left ventricular filling time in dilated cardiomyopathy: additional effects on heart rate variability?

OBJECTIVE--To assess possible mechanical influences underlying the reduced heart rate variability in patients with dilated cardiomyopathy. DESIGN--Comparison of standard non-spectral indices of heart rate variability with echocardiographic Doppler measures of left ventricular function in patients and normal controls. PATIENTS--20 patients with dilated cardiomyopathy and 15 normal subjects of similar ages were studied. METHODS--Standard non-spectral indices of heart rate variability were measured over 24 hours. These were correlated with left ventricular cavity size, shortening fraction, and isovolumic relaxation time measured by M mode echocardiography, and the duration of functional mitral regurgitation and left ventricular filling time assessed by continuous wave Doppler. RESULTS--Mean RR interval and estimates of short term variability (root mean square difference of successive RR intervals, proportion of adjacent RR intervals > 50 ms different, and SD indices) were not different from normal. The overall mean (SD) of the RR interval (65 (35)), and SD of five minute mean RR intervals (55 (30)), however, were reduced compared with normal values (115 (40) and 105 (45); p < 0.01 for both). Neither correlated with left ventricular cavity size or shortening fraction, but both were strongly related to left ventricular filling time (coefficient of variation, r = 0.82 and r = 0.81 respectively). Correlation persisted when the SD was corrected for RR interval (r = 0.69) although this correlation was not found in the controls. In individual patients, the difference between RR interval at the time of echo and minimum value during the 24 hours, a measure of ability to increase heart rate, also correlated closely with filling time (r = 0.92). CONCLUSION--As the duration of functional mitral regurgitation is effectively fixed, its presence can limit the time available for left ventricular filling in dilated cardiomyopathy when heart rate is high. This may become the mechanism by which maximum heart rate is set, becoming fixed to optimise cardiac output. This manifestation of dilated cardiomyopathy may be an important factor in reduction of heart rate variability in these patients.     

Right ventricular dilated cardiomyopathy.

Fourteen patients with predominantly right sided dilated cardiomyopathy were studied, of whom five died suddenly. The condition is characterised by male preponderance, syncope, ventricular tachycardia, which typically has a left bundle branch block pattern on the surface electrocardiogram, and right heart failure. The diagnosis should be considered in patients presenting with otherwise unexplained ventricular tachycardia or syncope; the diagnosis may be readily missed because of the nonspecific nature or absence of signs.     

美托洛尔治疗扩张型心肌病及高血压对左心室重构的影响

目的观察扩张型心肌病患者对β受体阻断药的耐受性及治疗后左心室重构与高血压的关系。方法扩张型心肌病26例,高血压组12例,血压正常组14例。在常规治疗基础上开始口服美托洛尔6．25mg／d,逐渐加大剂量直至目标剂量250mg／d或最大耐受量,然后维持此剂量并随访1年。所有患者均于治疗前及治疗后1年采用超声心动图检测其左心室舒张末期内径（left ventricular end-diastolic dimension,LVEDd）、左心房舒张末期内径（left atrial end-diastolic dimension,LAEDd）及左心室射血分数（left ventricular ejection fraction,LVEF）。结果高血压组患者对美托洛尔的平均耐受量明显高于血压正常组患者（P〈0.05）;治疗前,两组患者LVEDd、LAEDd及LVEF组间差异无统计学意义（P〉0．05）;美托洛尔治疗1年后,两组患者LVEDd、LAED的及LVEF均有明显改善,但高血压组LVEDd明显小于血压正常组患者,而LVEF明显高于血压正常组（P〈0.05）。结论伴发高血压的扩张型心肌病患者对美托洛尔的耐受性较好,治疗后改善左心室重构更显著。     

Cardiac fibrosis detected by magnetic resonance imaging on predicting time course diversity of left ventricular reverse remodeling in patients with idiopathic dilated cardiomyopathy

This study aimed to identify the association between the time course of left ventricular reverse remodeling (LVRR) and late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-cMRI) in patients with idiopathic dilated cardiomyopathy (IDCM). We identified 214 IDCM patients treated by optimal pharmacotherapies. LVRR was defined as ≥10 % increment in LV ejection fraction along with ≥10 % reduction in LV end-diastolic dimension. Findings of LGE-cMRI focusing on presence and extent of LGE were evaluated at baseline. Echocardiographic evaluation for detecting LVRR was performed in all patients for 3 years. The primary endpoint was defined as composite events (CEs) including readmission for heart failure, detection of major ventricular arrhythmia, and all-cause mortality. LVRR was found at <1 year in 59 patients (28 %, early responder), ≥1 year in 56 patients (26 %, late responder), and was absent in 99 patients (46 %, non-responder). Multivariate Cox-proportional hazards analysis revealed that both early responders (P = 0.02) and late responders (P < 0.001) had lower incidence of CEs than non-responders. Among 66 subjects (23 %) with complete cMRI evaluation, LGE was detected more often in late and non- than early responders (65, 83 vs. 23 % P < 0.001, respectively), whereas the LGE area was smaller in both early and late than non-responders (2 ± 3, 4 ± 3 vs. 12 ± 10 %, P < 0.001, respectively). In conclusion, evaluating the presence and the extent of LGE is useful for predicting the clinical differences of LVRR time course and subsequent long-term outcomes.     

Elevated left ventricular myocardial dopamine in preterminal idiopathic dilated cardiomyopathy

The adrenergic nervous system is chronically activated in patients with congestive heart failure (CHF). One consequence of this is depletion of the normally high levels of myocardial norepinephrine. In this study, myocardial norepinephrine and dopamine concentrations from the left ventricular walls of 3 patients undergoing cardiac transplantation for severe refractory CHF are reported. The dopamine/norepinephrine ratios were high in all 3 patients (29, 58 and 26%). This finding supports data from animal studies suggesting a change in the rate-limiting step for myocardial norepinephrine synthesis in CHF. Conversion of tyrosine to dopa by tyrosine hydroxylase is replaced as the rate-limiting step by inability to hydroxylate dopamine to norepinephrine. Thus, dopamine accumulates while norepinephrine is depleted.     

Electrocardiographic correlates with left ventricular morphology in idiopathic dilated cardiomyopathy

The purpose of the present study was to verify whether the electrocardiographic pattern of patients with idiopathic dilated cardiomyopathy (IDC) might be useful in predicting measurements of left ventricular (LV) morphology. A total of 12 electrocardiographic criteria for LV enlargement were evaluated in 67 patients with IDC, aged 14 to 68 years (mean 48), and were correlated to LV wall thickness, volume and mass, as assessed at angiography (all patients) and echocardiography (50 patients). Linear regression analysis showed weak correlations between multiple electrocardiographic criteria and LV wall thickness, volume and mass. Multiple logistic regression analysis showed that total 12-lead QRS amplitude, voltage criteria of Sokolow and Lyon, overshoot and U-wave inversion were the variables significantly related to LV wall thickness, as assessed by angiography (r = 0.55, p less than 0.005) and echocardiography (r = 0.43, p less than 0.025). The sum of T/R-wave ratios, the RV6/RV5 ratio and the Romhilt-Estes score were predictors of LV end-diastolic volume, as determined by angiography (r = 0.83, p less than 0.001) and echocardiography (r = 0.77, p less than 0.005). Total 12-lead QRS amplitude and the sum of T/R-wave ratios were the only independent predictors of LV mass, either angiographically (r = 0.81, p less than 0.001) or echocardiographically measured (r = 0.71, p less than 0.025). It is concluded that a single electrocardiographic criterion for prediction of LV morphology in patients with IDC is barely effective. Multiple electrocardiographic criteria should be utilized to better predict LV mass and distinguish reliably between LV wall thickening and dilatation.     

Regional left ventricular wall motion abnormalities in idiopathic dilated cardiomyopathy

An evaluation and a comparison of left ventricular regional wall motion were performed in 32 patients with idiopathic dilated cardiomyopathy, none of whom had coronary artery diameter stenosis exceeding 20% in any major artery, and 17 control subjects, using frame by frame video intensity analysis of digitized ventriculograms. This technique evaluates the whole cardiac cycle in short overlapping intervals and yields information for systolic and diastolic events, without assumptions regarding the position and orientation of the ventricle. Diastolic regional wall motion abnormalities were found in 31 of 32 patients and systolic abnormalities were present in 16 patients. Asynchronous regions most commonly detected during diastole were anteroapical and apical; they were found in 19 of 32 patients. Regional contraction abnormality was observed in the apical and the anteroapical regions in 6 of 16 patients. Dilatation-induced changes in left ventricular shape exaggerate the phenomenon of higher wall stress at the apex of the normal ventricle. Basal wall motion is thus relatively preserved in dilated cardiomyopathy.     

Prognostic significance of Doppler-derived left ventricular diastolic filling variables in dilated cardiomyopathy.

To determine the prognostic significance of pulsed wave Doppler-derived left ventricular diastolic filling velocity profiles and the relationship between Doppler variables and clinical functional status, the follow-up outcomes of 62 consecutive patients with dilated cardiomyopathy and symptoms of left ventricular dysfunction were analyzed. All patients had echocardiographic left ventricular end-diastolic dimension > or = 6.0 cm, fractional shortening < 25%, increased E pointseptal separation, and diffuse hypokinesia or akinesia. During a mean follow-up period of 30.5 +/- 13.9 months, 27 patients experienced cardiac events: 23 died of either progressive pump failure or an episode of sudden death and four required cardiac transplantation because of refractory heart failure. Peak early filling velocity (78 +/- 23 cm/sec vs 65 +/- 25 cm/sec; p < 0.03) was higher and late atrial filing velocity (34 +/- 13 cm/sec vs 55 +/- 19 cm/sec; p < 0.001) was lower in patients with cardiac events than in cardiac event-free survivors. The ratio of early to late transmitral filling velocities was higher (2.6 +/- 1.2 vs 1.5 +/- 1.3; p < 0.001), and the deceleration time of early diastole was shorter (133 +/- 48 msec vs 175 +/- 71 msec; p < 0.001) in patients with cardiac events. The cardiac event rate was significantly higher in patients with an early to late filling velocity ratio greater than 2 (77% vs 19%; p < 0.001) or a deceleration time less than 150 msec (58% vs 23%; p < 0.05) than in those without. Stepwise multivariate regression analysis revealed that the pattern of transmitral early to late filling velocity ratio was the only significant independent Doppler echocardiographic predictor of outcome for these patients. Repeat Doppler echocardiographic examinations, which were performed in 31 survivors after intensive treatment (mean, 38.6 +/- 6.5 months), showed that early filling velocity was decreased (55 +/- 20 cm/sec vs 75 +/- 25 cm/sec; p < 0.02), late atrial filling velocity was increased (74 +/- 27 cm/sec vs 57 +/- 21 cm/sec; p < 0.01), early to late filling velocity ratio was reduced (0.8 +/- 0.3 vs 1.7 +/- 1.3; p < 0.001), and deceleration time was prolonged (227 +/- 60 msec vs 167 +/- 82 msec; p < 0.01) in 18 patients with clinical functional improvement, whereas these measurements were unaltered in the remaining 13 patients whose functional status was unchanged or had deteriorated.(ABSTRACT TRUNCATED AT 400 WORDS)