Determinants of survival in patients with congestive cardiomyopathy: quantitative morphologic findings and left ventricular hemodynamics

Discordance in degree of right and left ventricular dilation in patients with dilated cardiomyopathy: recognition and clinical implications

OBJECTIVES

The purpose of the present study was to assess the influence of variations in the relative degree of dilation of left and right ventricular chambers on the clinical outcome of patients with dilated cardiomyopathy.

BACKGROUND

Dilated cardiomyopathy, a primary myocardial disease characterized by ventricular dilation and systolic dysfunction, is generally associated with a poor prognosis. However, considerable variability has been observed in the clinical course and the morphologic and hemodynamic features in individual patients.

METHODS

We evaluated 67 consecutive patients with dilated cardiomyopathy and without evidence of ischemic or primary valvular heart disease. On the basis of diastolic ventricular chamber area measurements obtained by echocardiography, patients were classified into two groups: 38 patients with a relatively equal degree of left and right ventricular dilation (LV congruent to RV) and 29 patients with predominant and disproportionate dilation of the left ventricle (LV > RV).

RESULTS

The 67 patients ranged in age from 19 to 81 years (mean 56); 49 (73%) were male. The two subsets of patients with dilated cardiomyopathy did not differ with regard to age, left ventricular diastolic dimension, wall thickness and mass or ejection fraction. However, patients in the LV congruent to RV group showed more severe mitral and tricuspid regurgitation by Doppler echocardiography than did those in the LV > RV group (p = 0.01 for mitral and 0.004 for tricuspid regurgitation). Over the follow-up period of 2 to 60 months (mean 28), there were 19 deaths. Survival in the LV > RV group was significantly better than in the LV congruent to RV group (p = 0.03).

CONCLUSIONS

Patients with dilated cardiomyopathy represent a heterogeneous group with regard to both clinical outcome and the relative degree of left and right ventricular chamber dilation. Patients in the LV > RV subset appear to have better overall survival and less severe mitral and tricuspid regurgitation than do patients in the LV congruent to RV subset. Longitudinal studies are needed to determine whether these morphologic subsets in fact represent a continuum within the disease spectrum of dilated cardiomyopathy.

The spectrum of left ventricular size in dilated cardiomyopathy: clinical correlates and prognostic implications. SPIC (Italian Multicenter Cardiomyopathy Study) Group

To address the issues of variability and prognostic role of left ventricular dimensions in dilated cardiomyopathy (DCM), 144 patients with DCM were studied. They were arbitrarily assigned to two groups according to an echocardiographic left ventricular end-diastolic diameter index < or = 15% (45 patients with mildly dilated cardiomyopathy) and above 15% (99 patients with typically dilated cardiomyopathy) of the upper normality range. Among the patients with mildly dilated cardiomyopathy, there were more men (89% vs 66%; p < 0.01). This group of patients also had a greater prevalence of atrial fibrillation (22% vs 3%; p < 0.001) higher left ventricular fractional shortening (15 +/- 6% vs 13 +/- 5%; p < 0.05), higher ejection fraction (28 +/- 8% vs 24 +/- 8%; p < 0.01), and a lower exercise tolerance (5 +/- 2 MET vs 6 +/- 2 MET; p < 0.05). At the time of follow-up examination (30 +/- 15 months), event-free survival was not significantly different between patients with mildly dilated cardiomyopathy and those with typically dilated cardiomyopathy. Pulmonary capillary wedge pressure (p < 0.001) and left atrial dimension index (p < 0.01) were significant predictors of prognosis as determined by Cox multivariate analysis. Minimal or mild ventricular dilatation is not uncommon in DCM, and it identifies a heterogenous group of patients--some who are in the early stages of disease and others with severe pump dysfunction and persistently small hearts. Ventricular dilatation is not an independent predictor of prognosis.

Decreased concentration of myofibrils and myofiber hypertrophy are structural determinants of impaired left ventricular function in patients with chronic heart diseases: a multiple logistic regression analysis

OBJECTIVES

The aim of this study was to perform a multiple logistic regression analysis to identify independent structural determinants of impaired left ventricular function.

BACKGROUND

The association between contractile failure and structural alterations of the myocardium has been demonstrated in several studies, and multiple interactions between myocardial structure and cardiac performance are likely.

METHODS

Morphometric data assessed from 130 left ventricular biopsy specimens were analyzed. The endomyocardial specimens were obtained from 57 patients with normal coronary arteries (17 with normal left ventricular ejection fraction and 40 with impaired left ventricular function [dilated cardiomyopathy]), 15 patients with hypertrophic cardiomyopathy and 32 patients with aortic valve disease. Transmural biopsy specimens were assessed in 6 donor hearts before heart transplantation and in 20 patients with left anterior descending coronary artery disease whose specimens were obtained from the left ventricular anterior wall during aortocoronary bypass surgery. Global or regional left ventricular function was evaluated from left cineventriculograms. The volume fraction of cardiac fibrous tissue, intracellular volume fraction of myofibrils, volume fraction of myofibrils related to myocardial tissue (including fibrosis) and myofiber diameters were determined from semithin sections of the biopsy specimens with the use of light microscopic morphometry.

RESULTS

Multiple logistic regression analysis revealed decreased volume fraction of myofibrils (p < 0.005) and increased fiber diameter (p < 0.002) as independent determinants of impaired left ventricular function.

CONCLUSIONS

These data indicate that, independent of the underlying heart disease, both decreased concentration of contractile proteins and myocyte hypertrophy are independently associated with impaired left ventricular function.

Sudden death in idiopathic dilated cardiomyopathy

Approximately 30% of deaths among patients with IDCM are sudden. Although ventricular tachyarrhythmias are responsible for many of these deaths, bradyarrhythmias may also play a significant role. Patients with a previous history of sustained ventricular arrhythmias are at high risk for sudden death. In patients without prior symptomatic ventricular arrhythmias a history of unexplained syncope, severely impaired right ventricular hemodynamics, frequent spontaneous ventricular ectopy or NSVT, and inducible SMVT may help identify those at greatest risk of dying suddenly. With the exception of angiotensin-converting enzyme inhibitor therapy, attempts at pharmacologic prevention of sudden death have had limited efficacy. The implantable defibrillator offers promising results in survivors of previous sustained ventricular arrhythmias; its prophylactic use in other high-risk subgroups is the subject of active investigation.

Beta-adrenergic contractile reserve as a predictor of clinical outcome in patients with idiopathic dilated cardiomyopathy

To examine the ability of beta-adrenergic contractile reserve assessment to predict the outcome of patients with heart failure, a prospective study was undertaken in 35 patients with idiopathic dilated cardiomyopathy and radionuclide ejection fraction below 40%. During right- and left-sided catheterization, right atrial and left ventricular (LV) pressures, peak positive LV dp/dt, cardiac index, and plasma norepinephrine and epinephrine concentrations were measured at baseline. After a left main intracoronary infusion of dobutamine (25 to 200 micrograms.min-1), beta-adrenergic contractile responsiveness was assessed as the net increase in peak positive LV dp/dt (delta LV dp/dt). After the initial examination, patients were treated with diuretics, digitalis, and angiotensin converting enzyme inhibitors and then followed-up. After a mean follow-up period of 13 +/- 7 months, two groups of patients were distinguished: those who responded to medical therapy (group A, n = 26) and those with clinical deterioration (group B, n = 9) leading to death (n = 4) or heart transplantation (n = 5). Initial peak positive LV dp/dt, LV end-diastolic pressure, cardiac index, and LV ejection fraction were better in group A than in group B (p less than 0.001). Initial plasma norepinephrine and epinephrine concentrations were significantly higher and delta LV dp/dt was lower in group B than in group A (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased cardiac parasympathetic activity in chronic heart failure and its relation to left ventricular function

BACKGROUND

Activation of the sympathetic nervous system has been extensively studied in patients with chronic heart failure, but the parasympathetic nervous system has received relatively little attention. The objective in this study was to investigate cardiac parasympathetic activity in chronic heart failure and to explore its relation to left ventricular function.

METHODS

Heart rate variability was measured from 24 hour ambulatory electrocardiograms by counting the number of times each RR interval exceeded the preceding RR interval by more than 50 ms (counts). This method provided a sensitive index of cardiac parasympathetic activity.

RESULTS

Mean (range) of counts were: waking 48 (1-275)/h, sleeping 62 (0-360)/h, and total 1310 (31-7278)/24 h. These were lower than expected, and in 26 (60%) of the 43 patients counts fell below the lower 95% confidence intervals (95% CI) for RR counts in normal subjects. A significant correlation between total 24 hour RR counts and left ventricular ejection fraction was present (r = 0.49, p less than 0.05).

CONCLUSIONS

These results indicate that most patients with chronic heart failure have reduced heart rate variability and therefore reduced cardiac parasympathetic activity. The degree of parasympathetic dysfunction is related to the severity of left ventricular dysfunction. This may be relevant to the high incidence of ventricular arrhythmias and poor prognosis of patients with chronic heart failure.

The natural history of isolated left ventricular diastolic dysfunction

STUDY OBJECTIVE

To assess the natural history of isolated left ventricular diastolic dysfunction.

PATIENTS AND METHODS

Follow-up (average duration, 68 months) was obtained in 51 patients with isolated left ventricular diastolic dysfunction at cardiac catheterization, characterized by (1) an elevated left ventricular end-diastolic pressure; (2) normal left ventricular end-diastolic and end-systolic volumes; (3) normal left ventricular ejection fraction; (4) no coronary artery disease; and (5) no valvular disease.

RESULTS

During follow-up, seven patients died, but only one died of cardiac causes. Of the 44 living subjects, 20 (45%) noted new-onset symptoms of congestive heart failure, with 11 (25%) of these requiring hospitalization, and 12 (27%) required hospitalization for recurrent chest pain.

CONCLUSIONS

Isolated left ventricular diastolic dysfunction is associated with a low cardiac mortality; at the same time, however, it is associated with substantial morbidity.

Prognostic features in patients with congestive heart failure and selection criteria for cardiac transplantation

Cardiac transplantation can be a highly successful therapeutic option for patients with end-stage congestive heart failure. Successful results, however, depend on the appropriate selection of patients for the procedure. Patients whose survival or quality of life would be compromised without cardiac transplantation and who are likely to benefit from this intensive type of treatment are potential candidates. Each patient should undergo a thorough assessment to identify any medical or psychologic contraindications to cardiac transplantation. In this review, we discuss the important predictors of survival in patients with congestive heart failure: the cause of heart failure, the patient's symptomatic and functional status, the hemodynamic and pathologic findings, the evaluation of neurohumoral activity, and the presence of cardiac arrhythmias. Once a patient with congestive heart failure has been identified as having a limited life expectancy and severely impaired quality of life, cardiac transplantation should be considered.

Long-term outcome in patients with congestive heart failure and intact systolic left ventricular performance

Congestive heart failure (CHF) is typically associated with impaired left ventricular (LV) systolic performance. Few reports exist describing the long-term outcome in patients with CHF and normal LV systolic function. Fifty-two patients initially hospitalized with CHF and intact LV function (ejection fraction greater than or equal to 45%) were followed for 7 years. Mean age when initially identified was 71 +/- 11 years (range 36 to 96), and average LV ejection fraction was 61 +/- 11%. CHF was graded by a clinicoradiographic index, with a mean of 7.0 +/- 2.3 (range 3 to 12, 13 indicates worst CHF). A third heart sound was present in 19 patients (37%), and 17 (33%) had presented with acute pulmonary edema. Principal cardiovascular diagnoses were coronary artery disease in 27 (52%), hypertensive heart disease in 16 (31%) and restrictive cardiomyopathy in 7 (13%). At 7 years, cardiovascular mortality was 46% (24 of 52), and noncardiovascular mortality was 10% (5 of 52). Survival was not correlated with age, principal diagnosis, third heart sound, pulmonary edema at presentation, LV ejection fraction, or presence or degree of LV diastolic dysfunction. Cardiovascular morbidity, consisting of nonfatal recurrent CHF, myocardial infarction, unstable angina or other cardiovascular events occurred in 29% (15 of 52). Combined cardiovascular mortality and morbidity was 75% (39 of 52). In patients with CHF, intact LV systolic function does not confer the same favorable prognosis it defines in other clinical situations. For such patients, the risk of future cardiovascular events is high, a finding that should be considered when designing therapeutic strategies in this group.

Survival of heart failure patients with preserved versus impaired systolic function: the prognostic implication of blood pressure

The impact of impaired versus preserved systolic function on survival of patients with heart failure was investigated in 78 patients with decompensated heart failure. Patients were classified on the basis of their left ventricular systolic performance, as defined by fractional shortening (FS); group I (n = 56) had impaired systolic function (FS less than 24%) and group II (n = 22) had preserved systolic function (FS greater than or equal to 24%). Mean ejection fraction was 15 +/- 5% and 40 +/- 13% for these groups, respectively. By the end of 48 months, 36 patients in group I had died compared with only 22 patients in group II (p less than 0.05). Both systolic and diastolic blood pressure were significantly lower in the deceased patients compared with the survivors in group I (p less than 0.05). There was a trend for an opposite direction in the relationship of blood pressure to mortality in group II. We conclude that the prognosis of patients with heart failure and preserved systolic function is more favorable than that of those with impaired function, and that blood pressure may have a differential prognostic meaning in the two groups.

Predictors of prognosis in severe chronic heart failure

A total of 127 patients with chronic heart failure referred to our exercise laboratory were studied retrospectively to identify parameters predictive of prognosis. Patients were followed for a mean of 14.6 months. The group as a whole had severe ventricular dysfunction with a median ejection fraction of 17% and a median peak rate of oxygen consumption of 13.7 ml/kg/min. During the follow-up period 23 patients (18%) died and 18 (14%) underwent cardiac transplantation. The effect of the following variables on outcome (death or transplantation) were examined: age, cause of heart failure, cardiothoracic ratio on chest radiography, left ventricular end-systolic dimension on echocardiography, left ventricular ejection fraction on radionuclide ventriculography, mean dose of diuretic, plasma sodium and urea concentrations, and peak oxygen consumption during exercise. Although all variables except cause of heart failure affected outcome on univariate analysis, multivariate analysis identified three variables that were statistically significant and independent predictors of outcome. In order of importance these were plasma sodium level, left ventricular ejection fraction and peak oxygen consumption. Even in this group of patients with severe heart failure, these variables were predictive of outcome.

Decreased coronary sinus oxygen content: a predictor of adverse prognosis in patients with severe congestive heart failure

Patients with congestive heart failure have abnormal coronary hemodynamics, characterized by decreased coronary sinus oxygen content, increased coronary sinus blood flow and increased myocardial oxygen consumption. To evaluate their prognostic importance, the clinical characteristics and systemic and coronary hemodynamics were related to survival in 91 patients with severe congestive heart failure and decreased ejection fraction (25.5 +/- 10% [mean +/- SD]). In 69 patients congestive heart failure was due to or secondary to coronary artery disease (group 1) and in 22 it was due to idiopathic dilated cardiomyopathy (group 2). Five patients were in functional class II, 48 in class III and 38 in class IV. The median survival time was 20.7 months. As assessed with the Cox proportional hazards model, coronary sinus oxygen content was most strongly associated with a poor prognosis. On the basis of a comparison between the lowest (coronary sinus oxygen content less than or equal to 4.44 vol%) and highest quintile (coronary sinus oxygen content greater than 4.44 vol%), a low coronary sinus oxygen content was associated with a 2.34-fold increased risk of dying (95% confidence interval, 1.31 to 4.08). A low systolic blood pressure and a high diastolic pulmonary artery pressure were also significantly associated with increased mortality. Patients in the subgroup with a low coronary sinus oxygen content had values for functional class, ejection fraction and systemic hemodynamics similar to those of patients in the subgroup with high coronary sinus oxygen content. It is concluded that a low coronary sinus oxygen content indicative of noncompensated metabolic demand suggests a poor prognosis in patients with severe congestive heart failure.

The natural history of dilated cardiomyopathy--a community study

The incidence, clinical features and natural history of dilated cardiomyopathy within a clearly defined population of Scotland was studied retrospectively. From 1982 to 1986, 57 cases were recorded in a population of 145,00, representing an annual incidence of 7.9 per 100,000 per year. This incidence rate is higher than that reported from other centres, and the overall survival rates were poorer.

Acute heart failure: determinants of outcome

We prospectively studied 69 consecutive patients hospitalized with a primary diagnosis of acute left ventricular failure so as to assess the impact of vasodilators on incidence and morbidity of acute symptomatic left ventricular failure. The determinants of duration of hospitalization, in-hospital mortality and symptomatic status 2 months after discharge were examined. There were 9 in-hospital deaths (13%), and survival at 60 days was 77%. Median duration of hospitalization was 9 days, and 33% of the surviving patients remained in New York Heart Association functional class III-IV 60 days subsequent to discharge. Of the patients, 49 (76%) had previously received treatment for left ventricular failure: 30 (61%) of these had received vasodilators, most commonly angiotensin converting enzyme inhibitors and nitrates. Ischaemic chest pain was present in 34 (49%) of the patients. Acute utilization of vasodilators (45% of patients) was largely limited to nitrate therapy associated with ischaemic chest pain (P less than 0.01). Multiple logistic regression revealed previous left ventricular failure, advanced age and hypokalaemia as significant correlates of prolonged hospitalization (greater than 9 days). Previous left ventricular failure was also predictive of persistent severe disability two months subsequent to discharge. No factor was a significant predictor of in-hospital death. Although preceding treatment with digoxin and incremental angiotensin converting enzyme inhibitor therapy tended to predict brief hospitalization, the parameter of acute ischaemia, other biochemical anomalies and modes of acute or chronic therapy were not significant correlates of any end point. We conclude that preceding disability, rather than mode of treatment, predicts an adverse outcome in acute left ventricular failure.

Prognostic indicators of chronic chagasic cardiopathy

After 104 patients with positive serology for Chagas' disease had been followed for a decade, a selection of 66 patients was made from this number and a total of 25 variables obtained from clinical and paraclinical findings were analyzed, with the purpose of knowing which of these variables may be of help, in time, in determining prognosis. The information was analyzed using the Cox regression model. The patients were classified into groups according to the results in the invasive and noninvasive studies: those with a normal electrocardiogram without heart disease (14 patients) or with early segmental abnormalities of the left ventricle (9 patients); those with an abnormal electrocardiogram and advanced myocardial damage but without signs of congestive heart failure (26 patients); and those with an abnormal electrocardiogram together with congestive heart failure (17 patients). Of these patients, those with electrocardiographic abnormalities correspond to stages of the disease where advanced myocardial damage is proven. There was a 42% mortality during the follow-up of these patients. According to the regression model, the value of the systolic blood pressure is a good predictor of mortality (P = 0.0380) in those with congestive heart failure. When we analyzed jointly the patients with an abnormal electrocardiogram, we found that several variables (systolic blood pressure, the presence of atrial fibrillation, the radiologic cardiothoracic index, and left ventricular end-diastolic volume obtained by the ventriculogram), were negatively correlated with regard to survival. This last model has a chi-square of 11.36 (P = 0.0228). These models allow us to predict the prognosis in this group of patients with Chagas' disease and advanced myocardial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of thallium-201 perfusion defects in idiopathic dilated cardiomyopathy

To assess the prognostic significance of thallium-201 perfusion defects in patients with idiopathic dilated cardiomyopathy (IDC), 43 patients underwent thallium scintigraphy in addition to clinical, echocardiographic, angiographic and hemodynamic evaluation. Eleven patients had no significant thallium perfusion abnormality, 19 had multiple small defects and 13 had a large defect. During 3.2 +/- 2.2 years, 14 patients had disease-related mortality. The patients who died had a higher incidence of ventricular tachycardia (71 vs 31%; p less than 0.02), increased cardiothoracic ratio (60 +/- 6 vs 54 +/- 6; p = 0.005), decreased fractional shortening (11 +/- 6 vs 15 +/- 5; p less than 0.05), increased pulmonary wedge pressure (15 +/- 7 vs 10 +/- 6 mm Hg; p = 0.05), increased left ventricular end-diastolic pressure (21 +/- 8 vs 14 +/- 6 mm Hg; p = 0.02) and abnormal thallium perfusion defects (13 of 14 vs 16 of 26; p less than 0.05) compared with survivors. Age, gender, left ventricular end-systolic and end-diastolic dimensions, cardiac index and ejection fraction were not statistically different in the survivors versus the patients who died. Kaplan-Meier survival estimates at 1, 3 and 5 years were 100% in patients without significant perfusion abnormality; 89, 77 and 64%, respectively, in patients with multiple small defects; and 84, 76 and 30%, respectively, in patients with a large defect (p less than 0.025 by log rank test).(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated pulmonary artery pressure. An independent predictor of mortality

Analyses in this study were based on hemodynamic and angiographic data obtained in a cohort of 1,371 predominantly black patients during right and left heart catheterization. All patients were followed up prospectively for a mean of 117 weeks, and 103 fatal events were recorded. In Cox survival analysis, three variables were found to be independently related to survival: pulmonary artery mean pressure (PAMP), number of stenosed vessels, and left ventricular (LV) ejection fraction (p less than 0.01); in multivariate stepwise analysis, PAMP entered the model first with the largest chi 2 value of the three prognostic variables (chi 2 = 33.4; p less than 0.0001). The PAMP was 32 percent higher in decedents compared with survivors (25 + 11 mm Hg vs 19 + 8 mm Hg, p less than 0.01 [mean, SD]) and a 10 mm Hg increase in PAMP was associated with a more than fourfold increase in the relative risk of dying; this finding was independent of pulmonary vascular resistance and therefore could not be attributed to primary pulmonary vascular or parenchymal disease. In both the subgroup of 1,118 patients with a normal LV ejection fraction (greater than 50 percent) and the 253 patients with a reduced ejection fraction (less than 50 percent), PAMP emerged as an independent predictor of mortality (p less than 0.0001 and 0.01, respectively), and is therefore a marker of cardiac disease beyond impairment of systolic contractile function. Among patients without obstructive coronary artery disease, PAMP alone provided prognostic information in the multivariate survival analysis.

Atrioventricular plane displacement in severe congestive heart failure following dilated cardiomyopathy or myocardial infarction

Echocardiographic recording of the atrioventricular (AV) plane displacement during the cardiac cycle was used to assess left ventricular (LV) global function in patients with congestive heart failure (CHF). The study population consisted of 70 patients with chronic CHF (NYHA functional groups III and IV) following dilated cardiomyopathy (DCM) or myocardial infarction (MI), and 35 age-matched healthy subjects. The AV plane displacement was recorded from the apical 4- and 2-chamber views at four LV sites located about 90 degrees apart and representing the septal, anterior, lateral and posterior parts of the LV wall. A mean value was calculated from the above sites (AV-mean). Patients with CHF showed a significant generalized reduction of AV plane displacement compared to healthy subjects (5.6 mm vs. 14.5 mm, P less than 0.001). Thirty CHF patients also underwent radionuclide angiography in order to determine the ejection fraction (EF). The correlation between AV-mean and EF was good (r = 0.82, P less than 0.001). The selection of an AV-mean of less than 7 mm to define a severely depressed LV function (EF less than 30%) gave a sensitivity of 92% and a specificity of 67%. It is concluded that the AV plane displacement can be used to estimate LV systolic function in patients with CHF.

Interstudy reproducibility of dimensional and functional measurements between cine magnetic resonance studies in the morphologically abnormal left ventricle

The validity of geometric formulas to derive mass and volumes in the morphologically abnormal left ventricle is problematic. Imaging techniques that are tomographic and therefore inherently three-dimensional should be more reliable and reproducible between studies in such ventricles. Determination of reproducibility between studies is essential to define the limits of an imaging technique for evaluating the response to therapy. Sequential cine magnetic resonance (MR) studies were performed on patients with dilated cardiomyopathy (n = 11) and left ventricular hypertrophy (n = 8) within a short interval in order to assess interstudy reproducibility. Left ventricular mass, volumes, ejection fraction, and end-systolic wall stress were determined by two independent observers. Between studies, left ventricular mass was highly reproducible for hypertrophied and dilated ventricles, with percent variability less than 6%. Ejection fraction and end-diastolic volume showed close reproducibility between studies, with percent variability less than 5% End-systolic volume varied by 4.3% and 4.5% in dilated cardiomyopathy and 8.4% and 7.2% in left ventricular hypertrophy for the two observers. End-systolic wall stress, which is derived from multiple measurements, varied the greatest, with percent variability of 17.2% and 15.7% in dilated cardiomyopathy and 14.8% and 13% in left ventricular hypertrophy, respectively. The results of this study demonstrate that mass, volume, and functional measurements are reproducible in morphologically abnormal ventricles.

Mechanical pathophysiology of some heart diseases: a theoretical model study

Sarcomere dynamics are related to the global left ventricular (LV) function in some representative pathological states, by using a theoretical model which combines sarcomere function, LV fibrous structure and geometry with the haemodynamic loading conditions. The analysis shows that pressure (concentric) hypertrophy due to hypertension or aortic stenosis is associated with an increase of the normal endocardial-to-epicardial gradient(s) of oxygen demand, which may be one of the causes for the development of endocardial fibrosis. The analysis also indicates that sarcomere shortening is relatively normal in compensated volume (eccentric) hypertrophy. Mitral stenosis demonstrates a case of decreased LV function, secondary to a chronic decrease in LV end diastolic volume, with sarcomeres that operate at their lowest length range. Conversely, the sarcomere function is depressed in cardiomyopathy; the heart's pumping function is maintained by appropriate adjustment mechanisms. However, the sarcomeres show minimal shortening and function at their highest length range with low (or zero) functional reserve. The study thus provides a quantitative tool that relates global LV function to local sarcomere dynamics in various pathological states.

Application of new two-sample tests to data from a randomized placebo-controlled heart-failure trial

In a randomized placebo-controlled double-blind trial of 230 congestive heart failure patients, four treatments were evaluated for efficacy, with exercise tolerance time (ETT) as the primary outcome. Various two-sample tests were applied to the analysis of ETT data. It is shown in this paper that the conventional two-sample tests (t and rank-sum) are insensitive to situations where the effect of the experimental therapy is not consistent across a patient population. Tests recommended by O'Brien are more appropriate for these data. It is also shown that the application of the O'Brien tests led to the identification of sub-groups where the observed effect of the experimental therapy was most pronounced.

Mildly dilated congestive cardiomyopathy. Use of prospective diagnostic criteria and description of the clinical course without heart transplantation

Prognosis in classically described dilated congestive cardiomyopathy has been reported to be related to ventricular size. Mildly dilated congestive cardiomyopathy (MDCM) has been defined as end-stage heart failure of unknown etiology (New York Heart Association class IV, left ventricular ejection fraction less than 30%), occurring with neither typical hemodynamic signs of restrictive myopathy nor significant ventricular dilatation (less than 15% above normal range). The present study includes follow-up in 12 nontransplant patients. In the first 4 months after diagnosis, two patients improved and are living, and two showed cardiac dilation and clinical deterioration and died. Six of the remaining eight with persistent MDCM died (four with intractable heart failure and two, sudden deaths) without change in ventricular size before death, despite medical therapy over 20 +/- 8 months. Eight comparable transplanted patients with persistent MDCM demonstrated improved total survival by life table analysis (p less than 0.05). A family history of congestive cardiomyopathy was found in nine of 16 patients (56%) with persistent MDCM. Nontransplant patients were older (p less than 0.02), but other findings were similar in the two groups. Endomyocardial biopsies available in 14 of 16 cases showed little or no myofibrillar loss in spite of severe hemodynamic impairment. The degree of myofibrillar loss did not correlate with hemodynamic parameters but showed good correlation with left ventricular size, that is, five of six patients with no myofibrillar loss had normal ventricular size, whereas all eight patients with mild myofibrillar loss had mild cardiomegaly (p less than 0.002). Our current experience suggests a somewhat variable but negative prognosis after prospective diagnosis of MDCM, with poor survival in patients with persistence of the original diagnostic features during follow-up. Preservation of heart size in MDCM is probably related to lack of significant myofibrillar loss. Thus, irrespective of heart size or myofibrillar preservation on biopsy, heart transplantation should be strongly considered in MDCM if signs of severe cardiac dysfunction persist despite therapy.

Long-term predictors of sudden and low output death in chronic congestive heart failure secondary to coronary artery disease

Clinical, hemodynamic and neurohumoral variables in 238 patients with chronic congestive heart failure (CHF) secondary to coronary artery disease were analyzed to determine potential predictors of mortality in a large population and to allow analysis according to mode of death (sudden or low output death). All variables were assessed before initiation of treatment with vasodilators (converting enzyme inhibitors, direct acting vasodilators) or with the nonglycoside, noncatecholamine class of inotropic agents. Survival outcome was determined as alive, sudden death or low output death. When all variables except ejection fraction were analyzed by Cox multiple regression analysis, the most important independent predictor of all deaths was the baseline plasma renin activity (p less than 0.001). When subdivided by cause of cardiovascular death, baseline plasma renin activity was retained as the most important determinant of low output death (p less than 0.001), whereas baseline left ventricular stroke work index (p less than 0.001), pulmonary capillary wedge pressure (p less than 0.002) and absence of sinus rhythm (p less than 0.006) were the most powerful independent predictors of sudden death. Plasma norepinephrine was markedly elevated in the group dying of low output, but only modestly elevated in the group of survivors and the group dying suddenly. However, baseline norepinephrine was not found to be an important independent predictor of mortality in any of the subgroups. Plasma renin activity, but not plasma norepinephrine, is a powerful independent prognostic determinant of mortality in this group of patients with CHF.

Correlation between histomorphometric findings on endomyocardial biopsy and clinical findings in idiopathic dilated cardiomyopathy

Multivariate analysis was used to analyze the morphometric data of endomyocardial biopsies (area, perimeter and minor diameter) of myocardial cells obtained at light microscopy by a computerized approach with 16 clinical parameters and prognosis in 52 patients with idiopathic dilated cardiomyopathy. The best morphometric parameter was "area" (R2 = 0.47). A positive correlation was found with age (p less than 0.02), interval between first symptoms and diagnosis (p less than 0.02), left ventricular end-diastolic volume (p less than 0.02), cardiac index (p less than 0.05) and echocardiographic end-diastolic diameter (p less than 0.1). A negative correlation was found with prognosis (p less than 0.02), ejection fraction (p less than 0.02), shortening fraction (p less than 0.05), echocardiographic end-systolic diameter (p less than 0.06) and mitral regurgitation presence (p less than 0.1). The parameters that provided no correlation were New York Heart Association class, left ventricular end-diastolic pressure, right atrial pressure, cardiothoracic ratio, presence or absence of heart failure, fever or alcohol intake. These findings suggest that endomyocardial biopsy may provide prognostic information and confirm clinical diagnosis.

Predictors of total mortality and sudden death in mild to moderate heart failure. Captopril-Digoxin Study Group

The relation between baseline clinical variables and subsequent mortality was examined in 295 patients with mild to moderate heart failure who participated in a multicenter trial comparing the effect on treadmill exercise tolerance of captopril, digoxin and placebo given in addition to a diuretic drug. At baseline study, all patients had a left ventricular ejection fraction less than or equal to 40%; 81% were in New York Heart Association functional class II. The etiology of heart failure was ischemic in 62% and nonischemic in 38%. During an average follow-up period of 16 months, 47 patients (16%) died and 24 deaths were classified as sudden. By univariate analysis, left ventricular ejection fraction, ventricular premature beat frequency, couplet frequency, ventricular tachycardia frequency, functional class, treadmill exercise time and nonischemic heart disease were statistically associated with mortality. With multiple logistic regression analysis, left ventricular ejection fraction was identified as the variable most closely associated with total mortality (p = 0.006). Twenty-seven percent of patients with an ejection fraction less than or equal to 20% died compared with 7% with an ejection fraction greater than or equal to 30%. Ventricular tachycardia frequency on Holter monitoring was independently associated with both total mortality (p = 0.008) and sudden death (p = 0.003). Patients with a ventricular tachycardia frequency of greater than 0.088 events/h had a mortality rate of 34% compared with 12% in those without ventricular tachycardia. In the multivariate model, functional class (p = 0.02) and etiology of nonischemic heart disease (p = 0.04) remained as independent predictors of mortality, whereas treadmill exercise duration did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of end-stage idiopathic dilated cardiomyopathy: a multivariate analysis of 104 patients

Our purpose in this study was to investigate the correlation of clinical, electrocardiographic, hemodynamic, and histopathologic features at diagnosis with the long-term prognosis in 104 patients with idiopathic dilated cardiomyopathy to determine which factors are the independent determinants of the end-stage disease. During a mean follow-up of 3.8 +/- 3.5 years, 35 patients (33%) died, 14 (13%) suddenly and 21 (20%) from congestive heart failure. Univariate analysis of survival curves disclosed that clinical and electrocardiographic variables at diagnosis were similar in survivors and non-survivors. On the contrary, patients who subsequently died had higher mean right atrial pressure (p = 0.0001), right ventricular end-diastolic pressure (p = 0.0061), mean pulmonary artery pressure (p = 0.0001), and left ventricular systolic (p = 0.0049) and end-diastolic (p = 0.0021) pressure than survivors. They also exhibited larger left ventricular end-diastolic (p = 0.0046) and end-systolic (p = 0.0027) volumes, lower ejection fraction (p = 0.0001), and a greater proportion had severe mitral regurgitation (p = 0.0095). Univariate analysis of histologic findings collected in a subgroup of patients referred since 1984 revealed a mild degree of myocellular hypertrophy to be associated with a poor prognosis (p = 0.0217). Multivariate analysis selected only mean right atrial pressure (p = 0.0022), ejection fraction (p = 0.0089), and end-systolic volume (p = 0.0265) as independent determinants of cardiac death. Our results suggest that cardiac catheterization is mandatory for risk stratification of patients with idiopathic dilated cardiomyopathy, since it allows the assessment of hemodynamic, angiographic, and histopathologic features helpful in identifying patients with a poor prognosis.

Diagnostic and prognostic utility of right-sided catheterization and endomyocardial biopsy in idiopathic dilated cardiomyopathy

To determine the value of cardiac catheterization and endomyocardial biopsy in patients with heart failure and dilated cardiomyopathy, the records of 61 patients (36 men, 25 women, ages 13 to 65 years) with this disorder were reviewed. Myocardial lymphocytic infiltration was present in 8 (13%). Three had myocyte degeneration and necrosis ("definite" myocarditis), whereas the other 5 had no degeneration or necrosis ("equivocal" myocarditis). Compared with the 53 without lymphocytic infiltration, these 8 patients more often had symptoms of a preceding viral illness (88 vs 30%, p = 0.002) and had a shorter duration of cardiac symptoms (18 +/- 18 vs 109 +/- 132 days [mean +/- standard deviation], p less than 0.001). Histologic features of the biopsy did not relate to survival, but right- and left-sided intracardiac pressures were higher (p less than 0.05) in nonsurvivors. Thus, (1) endomyocardial biopsy is most likely to show lymphocytic infiltration in patients with symptoms of a preceding viral illness and a short duration of cardiac symptoms, and (2) right- and left-sided hemodynamic variables at the time of biopsy may offer insight into prognosis.

Recently diagnosed idiopathic dilated cardiomyopathy: incidence of myocarditis and efficacy of prednisone therapy

Fifty-two patients with recently diagnosed idiopathic dilated cardiomyopathy were studied to determine the incidence of myocarditis; patients were randomly assigned to receive either conventional therapy alone or conventional therapy plus prednisone to assess possible therapeutic efficacy with regard to survival. Inflammatory criteria were present in 23% of the population studied with 13% having overt myocarditis according to the Dallas criteria. The addition of prednisone to conventional therapy did not improve survival in a homogeneous population with new-onset dilated cardiomyopathy. Furthermore, the diagnosis of myocarditis by endomyocardial biopsy did not influence 2-year survival once dilated cardiomyopathy had developed. Biopsy-documented myocarditis resolved in all patients, according to results of 3-month follow-up endomyocardial biopsies, regardless of treatment group. There was a trend for patients with a left ventricular ejection fraction less than 20% to show reduced survival at 2 years compared to the group with a higher ejection fraction (p = 0.07). Right ventricular dysfunction determined at catheterization was present in 20 of 52 patients and was the most significant predictor of survival. Patients with preserved right ventricular function had a 95% 24-month survival rate compared to 47% for patients with right ventricular diastolic dysfunction (right ventricular end-diastolic pressure greater than or equal to 11 mm Hg) (p = 0.005).

Left ventricular shape, afterload and survival in idiopathic dilated cardiomyopathy

Because idiopathic dilated cardiomyopathy is characterized by elevated wall stress and a more spherical left ventricle, the relations among shape, afterload and survival were examined. Thirty-six patients with cardiomyopathy were prospectively studied by two-dimensional echocardiography. Data included echocardiographic short- and long-axis cavity dimensions, their ratio and, with cuff systolic blood pressure, meridional and circumferential end-systolic stress and their ratios. Survivors (n = 16) were followed up for 52 months (range 40 to 76); nonsurvivors (n = 20) died an average of 11 months after study. Survivors had a smaller left ventricular end-diastolic short-axis dimension (6.4 versus 7.1 cm, p less than 0.03) but a similar long-axis length (8.6 versus 8.3 cm). However, overall cavity shape or the ratio of short- to long-axis end-diastolic dimensions was more spherical in those with poorer survival (ratio 0.76 versus 0.68, p less than 0.02). Meridional and circumferential end-systolic stresses were similar in the two groups, but stress was more evenly distributed in the long- and short-axis planes in nonsurvivors (meridional/circumferential stress ratio 0.57 versus 0.52 in survivors, p less than 0.05). Improved survival was associated with an end-diastolic short-axis dimension less than 7.63 cm, a short- to long-axis ratio less than 0.76 and a meridional to circumferential stress ratio less than 0.54. Life table analysis revealed a 28% mortality rate in patients with all three of these characteristics compared with 100% in patients with none. Survivors and nonsurvivors did not differ in systolic cavity dimension, wall thickness, relative wall thickness, cavity volume, percent posterior wall thickening or fractional shortening.(ABSTRACT TRUNCATED AT 250 WORDS)

Descent of the base of the left ventricle: an echocardiographic index of left ventricular function

Mitral annular apical systolic excursion or descent of the base (DB) of the left ventricle has been qualitatively observed by two-dimensional echocardiography studies to decrease as left ventricular systolic function deteriorates. On the basis of this observation a quantitative assessment of DB was examined as a means to estimate left ventricular ejection fraction (LVEF). Two-dimensional echocardiographic apical images were obtained in 100 subjects, 26 normal individuals and 74 clinical patients. Major diagnoses in the clinical patients were dilated cardiomyopathy in 24, coronary artery disease in 13, valvular disease in 16, left ventricular hypertrophy in 8, and no evident heart disease in 12. Wall motion was visually assessed; 22 subjects had a segmental wall motion abnormality, and 21 had a diffuse wall motion abnormality. All patients had a complete Doppler examination, and 31 had mitral and/or aortic regurgitation judged to be 2+ (moderate) or greater in severity. To quantitate DB the difference of the distance from the apex of the sector fan to the middle-mitral annular plane between end-diastole and end-systole in both two- and four-chamber views was calculated. Left ventricular end-diastolic volume and LVEF were calculated with a modified Simpson's rule algorithm applied to planimetered apical two- and four-chamber images. The mean DB of the normal subjects was 12 +/- 2 mm with both two- and four-chamber images. All normal subjects had a DB of 8 mm or greater. LVEF in percentage was linearly related to DB (millimeters) as follows. Two-chamber view, LVEF = 3.8 DB + 21; r = 0.78; standard error of the estimate = 14% Four-chamber view, LVEF = 4.1 DB + 17; r = 0.84; standard error of the estimate = 12% A four-chamber DB of less than 8 mm was associated with a depressed LVEF (less than 50%) with 82% specificity and 98% sensitivity. DB for a given LVEF was slightly increased in patients with 2+ or greater mitral and/or aortic regurgitation (p less than 0.001). Similarly, DB for a given LVEF in patients with a diffuse wall motion abnormality was slightly increased compared with those patients with a segmental wall motion abnormality (p less than 0.001). Comparison of left ventricular end-diastolic volume to DB showed a poor linear correlation. In conclusion, DB quantitation provides a useful, noninvasive method to estimate LVEF.

Prognosis of congestive heart failure and predictors of mortality

The interaction of physiologic variables that appear to be predictive of prognosis in patients with severe congestive heart failure was examined in a series of 139 patients referred to a heart failure service. Left ventricular ejection fraction, peak oxygen consumption during a progressive maximal exercise test and resting plasma norepinephrine concentration were identified as the strongest univariate predictors of prognosis. Examination of their interaction was accomplished by stratifying each variable into quartiles and then pooling quartiles for bivariate analysis. The data demonstrate that ejection fraction has the most profound effect on survival calculated from maximal oxygen consumption and norepinephrine concentration, but that each of the variables provides additional independent prognostic information when added to survival estimated from any of the other variables. Therefore, ventricular function, exercise tolerance and sympathetic nervous system activation appear to provide independent insight into the prognosis of patients with heart failure.

Lack of tolerance development during chronic ibopamine administration to patients with congestive heart failure

Beta-adrenergic agonists can progressively lose their efficacy during chronic therapy in patients with heart failure. Ibopamine is a new dopamine derivative, active on dopaminergic and beta-adrenergic receptors, whose hemodynamic activity has been acutely demonstrated. To assess whether any attenuation of its efficacy occurs, the variations of the cardiac output induced during chronic therapy were monitored by impedance cardiography in 15 patients with dilated cardiomyopathy who showed a significant increase of the cardiac output (20.7 +/- 10.0%) after acute ibopamine administration. The efficacy of ibopamine was also assessed after 6 and 12 months of therapy by echocardiography, exercise testing, and 24-hour dynamic electrocardiogram (EKG) monitoring. The cardiac output response to ibopamine did not show any significant attenuation (range 15% to 19%) in the evaluations at 1, 2, 3, 4, 8, and 12 months of therapy. No significant change, was noted, after 6 and 12 months, in the exercise capacity (505 vs. 602 and 604 seconds) and the fractional shortening (16.2 vs. 18.3 and 18.5) without any change of the diastolic diameter. Ventricular arrhythmias were significantly reduced after 6, but not 12, months of therapy. No significant change in the New York Association (NYHA) functional class was noted at 6 and 12 months of therapy (2.4 +/- 5 vs. 2.3 +/- 7 and 2.4 +/-0.6, respectively). Our results show that ibopamine can maintain its hemodynamic activity even during chronic therapy.

Fontan hemodynamics

Right atrial-pulmonary artery connection places the pulmonary circulation in series with the systemic circulation rather than the single ventricular "parallel" circulatory arrangement that usually is present prior to repair. The accompanying central cardiac shunt and volume overload physiology are eliminated. Favorable changes in ventricular dimension, ventricular wall stress, cardiovascular efficiency, relative systemic perfusion, and arterial oxygen saturation should result. The ongoing myocardial injury associated with the single-ventricle volume overload is presumably arrested and repair is initiated to a variable degree. Some candidates for right atrial-pulmonary artery connection may not benefit from repair because of irreversible ventricular injury. More accurate indices of systolic and diastolic ventricular function should be applied to this difficult group of borderline patients to further define potential for myocardial recovery and, therefore, candidacy for Fontan repair.

Idiopathic dilated cardiomyopathy. Role of programmed electrical stimulation and Holter monitoring in predicting those at risk of sudden death

The prognostic role of programmed electrical stimulation and Holter monitoring was evaluated in 21 patients with idiopathic dilated cardiomyopathy who had no prior history of ventricular tachyarrhythmias. During a mean follow-up period of 23 months, sudden death or ventricular fibrillation occurred in four (20 percent). One patient died of complications of sepsis, and one underwent cardiac transplantation. Programmed electrical stimulation (PES) resulted in five or more beats of induced ventricular tachycardia in seven patients (33 percent), but was a poor predictor of sudden death (sensitivity = 20 percent). Thirteen patients (62 percent) had complex ventricular ectopy (Lown class 4A or 4B) by ambulatory monitoring. This was a sensitive (80 percent) but not specific (31 percent) marker for sudden death. The predictive value of a negative Holter monitor study was high (80 percent) for identifying those at low risk of sudden death. The results of this prospective study suggest that programmed ventricular stimulation and routine ambulatory monitoring are poor predictors of sudden death in this population.

Long-term prognostic significance of ventricular arrhythmias in idiopathic dilated cardiomyopathy

The prognostic significance of ventricular arrhythmias in idiopathic dilated cardiomyopathy is controversial. Thus, 73 patients with idiopathic dilated cardiomyopathy who had both 24-hour Holter monitoring and angiography were followed for greater than or equal to 3 years. Twenty-eight patients (38%) died, 14 patients (19%) due to pump failure and 14 patients (19%) due to sudden death. Univariate analysis revealed ventricular tachycardias as a major risk indicator, among others. However, multivariate analysis determined the major independent risk factors in the following order: patients who died from pump failure, left ventricular filling pressure, left bundle branch block, the number of beats in the longest episode of ventricular tachycardia and left ventricular ejection fraction; patients who died from sudden death, left bundle branch block and left ventricular ejection fraction, but not any form of ventricular arrhythmias. Reclassification by means of the risk factors resulted in a meaningful identification of patients who died from pump failure; however, patients who died from sudden death could not be separated from survivors. Thus, in the present study Holter monitoring was unable to distinguish between patients who died from subsequent pump failure and patients who died from subsequent sudden death.

Predictive value of immunofluorescence and electron microscopic evaluation of endomyocardial biopsies in the diagnosis and prognosis of myocarditis and idiopathic dilated cardiomyopathy

The distinction between idiopathic dilated cardiomyopathy and myocarditis is controversial, both clinically and pathologically. To increase diagnostic accuracy and provide prognostic information, we prospectively tested the routine application of immunofluorescence and electron microscopy in endomyocardial biopsy evaluation. Biopsy samples from a consecutive series of 79 patients with cardiomyopathy and possible myocarditis were thus evaluated by light (LM), immunofluorescence (IF), and electron microscopy (EM). Patient course was followed prospectively to determine prognostic factors. Immunoglobulin (IgG) and complement (C) in biopsy tissue were graded 0 to 3+ and an IF score was derived as 2 (IgG) grade + C grade. A highly significant association was found between IF score greater than or equal to 2 and the presence of mononuclear cells (lymphocytes plus macrophages) greater than 5/high-power field, confirmed by EM; 12 of 15 (80%) with IF score greater than or equal to 2 had inflammatory cells, vs only 2 of 64 (3%) with IF score less than 2 (p less than 0.000001). EM was used to confirm the identity of infiltrating cells and to grade myofilament loss (0 to 3+) and 11 other ultrastructural features. EM did not provide important predictive information in myocarditis, but confirmed the presence of inflammatory cells. However, the EM finding of myofilament loss provided prognostic information both in patients with and without myocarditis (p less than 0.03). Mortality at 18 months was 37% for patients with 2 to 3+ myofilament loss, vs 10% in those with 0 to 1+ loss. Moreover, myofilament loss was prognostically independent of clinical class and ejection fraction. EM determination of myofilament loss is valuable as a prognostic indicator, whether or not myocarditis is present. Routine IF and EM increase the diagnostic accuracy and prognostic information in endomyocardial biopsies from patients with suspected myocarditis or cardiomyopathy.

Dilated cardiomyopathy and myocarditis: natural history, etiology, clinical manifestations, and management

This monograph begins and ends with a statement of uncertainty regarding many aspects of dilated cardiomyopathy. Natural history studies identify patients with widely differing outcomes. A host of prognostic factors have emerged, yet it would appear that the major determinants of survival are as yet unrecognized. The diagnosis remains primarily one of exclusion, and management is largely nonspecific and supportive. The frequency of sudden cardiac death is well documented, but the ability to accurately identify patients at risk and the efficacy of antiarrhythmic therapy is unestablished. The emerging success of cardiac transplantation is a source of encouragement. The causes of dilated cardiomyopathy remain a source of intense investigation. Accumulating evidence (much of it circumstantial) does, however, implicate a viral etiology and perhaps altered function of the immunoregulatory system. However, the disparity between the severity of functional disturbance with the relative lack of histologic markers of cellular necrosis implies a disturbance at a cellular level. The etiology or etiologies remain elusive. Future investigation directed at fundamental aspects of cardiac cellular biology may provide the answers.

Predictors of antiarrhythmic drug efficacy in patients with malignant ventricular tachyarrhythmias

The relationship between arrhythmia density observed during ambulatory monitoring, left ventricular ejection fraction (EF), and response to antiarrhythmic drug therapy was evaluated in 94 patients presenting with ventricular fibrillation (VF) (n = 20) or ventricular tachycardia (VT) (n = 74). Following baseline studies, an average of 4.9 antiarrhythmic drugs were tested singly in each patient. Univariate and multivariate analyses revealed that the density of VT on baseline ambulatory monitoring and initial left ventricular EF were independent predictors of drug efficacy. The 45 patients with an EF less than or equal to 35% responded to 34 +/- 29% of drugs tested, whereas the 49 with an EF greater than 35% had arrhythmia suppression with 46 +/- 28% of agents (p less than 0.038). Patients exhibiting VT during greater than or equal to 50% of monitoring hours responded to 32 +/- 26% of drugs, whereas those with VT during less than 50% of hours showed arrhythmia suppression with 48 +/- 29% of antiarrhythmic agents tested (p = 0.009). During a mean follow-up period of 12.9 months, the annual sudden death mortality for all patients was 9.3%. However, 8 of the 55 patients responding to less than 50% of drugs tested died suddenly and 17 had recurrent VT. By contrast, only 1 of the 39 patients responding to greater than or equal to 50% of the antiarrhythmic drugs tested died suddenly and two experienced recurrent VT (p = 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)

The course of idiopathic dilated cardiomyopathy in New Zealand

The course of dilated cardiomyopathy in New Zealand was studied in 72 cases that were followed up for less than or equal to 10 years after cardiac catheterisation and coronary angiography. Eighty one per cent were male and 86% were white; the remainder were Maori. The mean age of patients at the time of investigation was 50 X 15 years. Most patients were unskilled labourers. The commonest presenting symptom was dyspnoea and the commonest physical sign was cardiomegaly. Mean survival time from first hospital presentation was 85 months; half the deaths were sudden. Factors predicting a poor survival included cardiomegaly, age, arrhythmias, cigarette smoking, and subclinical thiamine deficiency. The syndrome of dilated cardiomyopathy in New Zealand appears to be identical with that seen in other European populations.

Clinical determinants of mortality in chronic congestive heart failure secondary to idiopathic dilated or to ischemic cardiomyopathy

To determine which of the many clinical parameters routinely collected influence mortality in patients with congestive heart failure (CHF), 201 patients with idiopathic or ischemic dilated cardiomyopathy were prospectively followed for a 28-month study period. Mean age of the study group was 62 +/- 10 years, 60% had ischemic cardiomyopathy, and two-thirds were in New York Heart Association functional class II or III. Fifteen clinical variables were analyzed using a Cox proportional hazards model, while individual variables also were calculated for independent prognostic significance. There were 85 deaths, 26 (31%) of which were sudden cardiac deaths. Three characteristics at the study entry independently predicted an increased mortality risk: left ventricular ejection fraction, maximal oxygen uptake and ischemic cardiomyopathy. A Cox proportional hazards model showed that the combination of VO2max, S3 and the diagnosis of ischemic cardiomyopathy provided the best estimates of risk for an early death. Mortality for the low-risk group was only 5% at 6 months and 10% at 1 year. In contrast, in patients with an S3, ischemic cardiomyopathy and low maximal oxygen uptake, 6-month mortality was 24% and 36% at 1 year (p less than 0.001). Thus, these patients at high risk with left ventricular dysfunction associated with ischemic heart disease, a decreasing exercise tolerance and the development of an S3 should be strongly considered for an interventional trial with the aim of decreasing mortality.

Prognostic significance of 24-hour ambulatory electrocardiographic monitoring in patients with dilative cardiomyopathy: a prospective study

We studied 33 patients with dilative cardiomyopathy to evaluate the predicting factors for sudden death occurring within one year. The information on each of the patients included history, physical examinations, two-dimensional echocardiograms, 24-h ambulatory electrocardiograms, and cardiac catheterization or autopsy. Patients were followed up for one year. Univariate analysis showed maximum number of premature ventricular complexes per hour (PVCs/h) (p = .0012), maximum beats per episode of ventricular tachycardia (VTmax) (p = .0012), and left ventricular end-diastolic pressure (p = .046) to be significant prognostic risk indicators of sudden death within one year. To select the best combination of factors that predict sudden death, multivariate stepwise logistic regression analysis was performed. By this method, only PVCs/h and VTmax were selected as the best combination. Probability of sudden cardiac death within 1 year = 1/(1 + exp[6.65-1.78 (log PVCs/h)-0.71 (VTmax)]). The equation showed 85.7% sensitivity and 69.2% specificity at a probability cutoff point of p = .124, with accuracy of 72.7%. The incidence of sudden death was 80% in patients showing both frequent (greater than 100/h) PVCs and presence of VT (VTmax greater than or equal to 3), and 6% in patients with neither or both. We concluded that PVCs/h and VTmax are independent and significant prognostic factors in patients with dilative cardiomyopathy.

Predictive value of M-mode echocardiography in patients with congestive heart failure

The M-mode echocardiogram (ECHO) is widely used to follow patients with congestive heart failure (CHF), but the value of ECHO for this purpose is unclear. In 49 patients with symptomatic CHF, we obtained ECHO during baseline evaluation to determine the value of ECHO for predicting 1-year survival or maximal oxygen uptake during exercise (VOmax). The cause of CHF was coronary artery disease in 12 patients and idiopathic dilated cardiomyopathy in 37 patients. Overall mortality at 1 year was 10 of 49 (20%), but was higher in patients with coronary artery disease (42%) compared to those with idiopathic dilated cardiomyopathy (14%), p less than 0.001. ECHO indices of left ventricular contractility were greater in survivors (S) in whom shortening fraction averaged 16 +/- 8 (SD)% vs 10 +/- 4% in nonsurvivors (NOS), p less than 0.025. Velocity of circumferential fiber shortening averaged 0.53 +/- 0.25 Hz in S vs 0.35 +/- 0.15 Hz in NOS, p less than 0.05. No left ventricular dimensions, including systolic and diastolic diameters, volume, wall thickness, and mass differed significantly between S and NOS. No ECHO measure of left ventricular dimensions or contractility correlated significantly with VOmax. Thus, ECHO may be useful to predict survival but not functional capacity in patients with CHF.

Tachycardia-induced cardiomyopathy: a reversible form of left ventricular dysfunction

Eight patients, aged 5 to 57 years, with uncontrolled symptomatic tachycardia for 2.5 to 41 years (mean 15) and significant left ventricular (LV) dysfunction in the absence of any other apparent underlying cardiac disease underwent evaluation. Incessant tachycardia was present for 0.5 to 6.0 years (mean 2.1) in 7 patients. One patient had an ectopic atrial tachycardia and 7 patients had an accessory atrioventricular pathway that participated in reciprocating tachycardia. Six patients underwent surgery; the ectopic focus was ablated in 1 patient and an accessory pathway was divided in 5 patients. One patient underwent open ablation of the His bundle and 1 patient underwent closed-chest ablation of the atrioventricular conduction system. Myocardial biopsy specimens were obtained from 5 patients, none of which yielded a specific diagnosis. Pretreatment radionuclide angiography demonstrated a mean ejection fraction (EF) of 19 +/- 9% (range 10 to 35%). Following tachycardia control a marked improvement in LV function was noted in 6 of 8 patients at rest and in 1 additional patient during exercise. The EF increased to 33 +/- 17% (range 16 to 56%) an average of 8 days after treatment and to 45 +/- 15% (range 22 to 67%) at late follow-up 3.5 +/- 40 months (mean 17) later (p less than 0.005). Seven patients remain asymptomatic 11 to 40 months (mean 22) after the corrective procedure and have resumed normal activities. These findings suggest that chronic uncontrolled tachycardia may result in significant LV dysfunction, which is reversible in some cases after control of the arrhythmia.