Arrhythmogenic right ventricular cardiomyopathy: a survey of the investigations at the University of Padua

The purpose of this paper is to review the history of the clinico-pathologic investigations performed at the University of Padua on an old morbid entity ("parchment heart"), which, in the 1960s, led to the clinical description of the disease, in the 1980s to the revival of the scientific interest, and in the mid 1990s to the understanding of the genetic background. All the steps of the progressive knowledge are reviewed: necropsy of young people who died suddenly, in vivo diagnosis by ECG, echocardiography, angiocardiography, endomyocardial biopsy, nuclear magnetic resonance, and diagnostic criteria. Familial occurrence with autosomic dominant transmission and various penetrance was documented. Gene defects were recently mapped both to chromosome 14q23-q24 and 1q42-q43, thus providing evidence for genetic heterogeneity. The pathologic substrates of arrhythmogenic right ventricular cardiomyopathy pointed to an acquired progressive myocardial atrophy with fibro-fatty replacement of dying myocytes. Nowadays the disease is definitively regarded as a primary myocardial disorder and it has been included in the revised WHO classification of cardiomyopathies.

Characteristics and prognosis of patients with decompensated right ventricular failure during the course of pulmonary hypertension

BACKGROUND

New therapies for pulmonary arterial hypertension have prolonged survival but simultaneously increased the number of hospital admissions because of decompensated right heart failure (DRHF). The optimal approach in DRHF has not been established yet.

AIM

Analysis of clinical course of DRHF in a group of patients with pulmonary hypertension treated in a single referral centre.

METHODS

We retrospectively analysed 60 episodes of DRHF in 37 patients (29 females, mean age 44+/-17 years) with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension admitted to our hospital between 2005 and 2007. We assessed the cause of decompensation, vital signs at admission, functional class and laboratory values. We classified all episodes into four haemodynamic profiles using the value of systolic blood pressure together with presence of peripheral perfusion abnormalities (profile cold vs. warm) and symptoms of venous congestion (profile wet vs. dry). Primary end-point was in-hospital mortality.

RESULTS

The most common causes of DRHF were infection (27%), drug noncompliance (20%), and pulmonary embolism (3%). In 48% no causative factor was indentified. There were 19 (32%) in-hospital deaths. The highest mortality was observed among patients with connective tissue disease (61%). The haemodynamic profile 'warm-wet' was the most common (48%) and the profile 'cold-dry' was the rarest but was associated with a 100% mortality. Patients who died had higher value of functional class (3.84+/-0.38 vs. 3.51+/-0.55, p=0.01) and higher activity of aspartate transaminase (61+/-61 vs. 42+/-78 U/l, p=0.02) compared with those who survived. In multivariate analysis higher dopamine dose (RR 2.0/1 microg/kg/min, 95% CI 1.00-5.00, p <0.001) was an independent factor of in-hospital death. In contrast 'rescue therapy' with iloprost or treprostinil decreased mortality (RR 0.09, 95% CI 0.01-0.99, p=0.04). Mortality in patients receiving dopamine was higher (60 vs. 18%, p=0.001) than in patients treated without dopamine.

CONCLUSION

Mortality in patients with pulmonary hypertension and DRHF remains very high and seems to be related to haemodynamic profile on admission. The newly introduced therapy with parenteral prostanoids may be more beneficial than dopamine infusion.

A proposed functional clinical classification predicts in-hospital and long-term survival in the setting of acute right ventricular infarction

BACKGROUND

The objectives of the present investigation were to validate the prognostic role of a proposed Clinical Classification [CC], to evaluate the TIMI risk score [RS] and to establish whether the TIMI-RS should incorporate points for patients with acute right ventricular infarction [TIMI-RS-RVI].

METHODS AND RESULTS

A total of 523 RVI patients were classified on clinical and functional basis as: A, without right ventricular failure [RVF], B with RVF and C with cardiogenic shock. The CC was evaluated prospectively among 98 patients with RVI and retrospectively in 425 RVI patients. The TIMI-RS was evaluated prospectively among 622 patients with STEMI [anterior:277, inferior:247, RVI:98], and retrospectively in 425 RVI patients. The CC established differences among the 3-RVI Classes for in-hospital mortality [prospectively and retrospectively; p<0.01, p<0.001, respectively] that were maintained at 8 years [p < 0.001]. Patients with anterior and inferior STEMI, but not those with RVI revealed an association between outcome and TIMI-RS [p<0.001]. Testing for TIMI-RS-RVI did not result a good prognostic tool [ROC=0.9; excellent discrimination, but with a very poor "clinical calibration"].

CONCLUSIONS

The proposed CC allowed prediction of mortality at short- and long-term in the setting of acute RVI. The role of the TIMI-RS should be reevaluated prospectively as a prognostic tool in the scenario of RVI patients.

The Systolic to Diastolic Duration Ratio in Children with Hypoplastic Left Heart Syndrome: A Novel Doppler Index of Right Ventricular Function

BACKGROUND

Right ventricular (RV) function is an important determinant of clinical status in children with hypoplastic left heart syndrome (HLHS). However, assessment of RV function remains challenging because of its complex morphology. We investigated the S/D duration ratio in children with HLHS as a novel index of global RV function.

METHODS

We measured systolic (S) and diastolic (D) duration using tricuspid regurgitation duration from Doppler flow, to calculate the S/D ratio in 33 children with HLHS and 33 control subjects matched for age and sex. We compared the S/D ratio between patients with HLHS and control subjects, between patients with HLHS and normal and abnormal RV function, and between patients with HLHS at different stages of palliation. We further correlated the S/D ratio with catheterization data.

RESULTS

Patients and control subjects were well matched for age (3.12 +/- 4.5 vs 3 +/- 4.5 years, not significant) sex, and heart rate (cycle length 524 +/- 179 vs 575 +/- 162 milliseconds, not significant). Patients with HLHS had a significantly higher S/D ratio than control subjects (1.65 +/- 0.85 vs 0.85 +/- 0.2, P < .0001). The S/D ratio became increasingly elevated in HLHS at higher heart rates, but not in control subjects. The S/D ratio was significantly higher in patients with HLHS and decreased RV function as compared with patients with HLHS and normal RV function (2.2 +/- 0.7 vs 1.5 +/- 0.47, P = .006), and significantly increased in patients with Norwood stage 1 versus patients with Norwood stages 2 and 3 HLHS (2.16 vs 1.4 and 1.32, respectively, P < .01 and P < .001, respectively). The S/D ratio did not correlate with catheterization-derived RV end-D pressure or cardiac index.

CONCLUSIONS

Patients with HLHS have an increased S/D ratio as a result of a shortened D and prolonged S. Measurement of the S/D duration ratio using Doppler flow is a novel method to augment assessment of global RV function in HLHS.

Left and right ventricular diastolic dysfunction as predictors of difficult separation from cardiopulmonary bypass

PURPOSE

As the evaluation of diastolic function can be complex in the setting of a busy cardiac operating room, its assessment may benefit from an algorithmic approach using transesophageal echocardiography. We developed a diagnostic algorithm which was then applied in a series of cardiac surgery patients to determine whether moderate to severe left ventricular diastolic dysfunction (LVDD) and right ventricular diastolic dysfunction (RVDD) can predict difficult separation from cardiopulmonary bypass (DSB).

METHODS

An algorithm using pulsed-wave Doppler interrogation of the mitral and tricuspid valve, the pulmonary and hepatic venous flow, and tissue Doppler interrogation of the mitral and tricuspid annulus was developed. The study was divided in two phases involving two groups of patients undergoing cardiac surgery. In phase I, echocardiographic evaluations of patients (n = 74) were used to test the reproducibility of the algorithm and to evaluate inter-observer variability using Cohen's kappa values which were calculated in three specific periods. In phase II, the algorithm was applied to a second group of patients (validation group, n = 179) to explore its prognostic significance. The primary end-point in phase II was DSB.

RESULTS

In phase I, the kappa coefficients for LVDD and RVDD algorithms were 0.77 and 0.82, respectively. In phase II, moderate or severe degrees of LVDD were observed in 29 patients (16%) and moderate to severe RVDD was observed in 18 patients (10%) before cardiac surgery. Both moderate and severe LVDD (P = 0.017) and RVDD (P = 0.049) before surgery were observed more frequently in patients with DSB.

CONCLUSION

Moderate and severe LVDD and RVDD can be identified with very good reproducibility, and both degrees of diastolic dysfunction are associated with DSB.

Sequence of echocardiographic changes during development of right ventricular failure in rat

BACKGROUND

The temporal relations between the onset of echocardiographic changes and clinical diagnosis of right ventricular (RV) failure are unresolved. We have characterized such relations in a rat monocrotaline (MCT) model of RV failure.

METHODS

Eight-week-old male Wistar rats were injected with MCT (60 mg/kg) or vehicle and underwent serial echocardiography. RV free-wall thickness (RVWT), pulmonary artery acceleration time normalized to cycle length (PAAT/CL), RV end-diastolic diameter (RVEDD), and tricuspid annular plane systolic excursion (TAPSE) were measured.

RESULTS

Significant differences in echocardiographic parameters between MCT-treated and control rats were found as early as 14 days before RV failure for RVWT, 10 days for PAAT/CL, and 7 days for RVEDD and TAPSE. The time intervals between the onset of changes in RVWT, PAAT/CL, RVEDD, and TAPSE and diagnosis of RV failure were 11.3 +/- 0.8, 10.9 +/- 0.7, 6.5 +/- 0.5, and 5.4 +/- 0.7 days, respectively. The sequence of echocardiographic changes was consistent in all animals during development of RV failure.

CONCLUSIONS

Pulmonary hypertension (assessed by PAAT/CL) and RV free-wall thickening (characterized by RVWT) precede RV dilation and RV systolic dysfunction (measured by RVEDD and TAPSE, respectively). Echocardiographic analysis permits accurate determination of the stage of disease development in MCT-induced RV failure.

Quantitative Measures of Right Ventricular Dysfunction by Echocardiography in the Diagnosis of Acute Nonmassive Pulmonary Embolism

BACKGROUND

Transthoracic echocardiography (TTE) is used in the risk assessment of patients with pulmonary embolism (PE), but the incremental diagnostic information from quantitative measures of right ventricular (RV) size, pressure, and function by TTE has yet to be fully evaluated.

METHODS

In 300 consecutive patients with suspected first nonmassive PE, TTE and ventilation/perfusion scintigraphy were performed.

RESULTS

Among measures of RV anatomy, RV pressure estimates, and estimates of global and regional RV function with significant diagnostic information in a logistic regression analysis, the acceleration time of RV outflow less than 89 milliseconds, the ratio of RV to left ventricular diameter greater than 0.78, RV outflow tract fractional shortening less than 35%, and signs of RV strain on electrocardiogram had independent, incremental diagnostic information (area under the receiver operating characteristics curve = 0.81). If D-dimer greater than 4.1 mmol/L was included, the area under the curve increased to 0.88. The negative and positive predictive values if any 2 of 3 factors in the final model were present were 88% and 70%, respectively.

CONCLUSION

TTE is able to identify differential diagnoses and enhance pretest probability of PE significantly. TTE could therefore be considered as an integral part of the initial diagnostic workup of patients suspected of PE, especially if definitive diagnostic imaging has limited availability.

Right ventricular dyssynchrony in patients with pulmonary hypertension is associated with disease severity and functional class

Background

Abnormalities in right ventricular function are known to occur in patients with pulmonary arterial hypertension.

Objective

Test the hypothesis that chronic elevation in pulmonary artery systolic pressure delays mechanical activation of the right ventricle, termed dyssynchrony, and is associated with both symptoms and right ventricular dysfunction.

Methods

Fifty-two patients (mean age 46 ± 15 years, 24 patients with chronic pulmonary hypertension) were prospectively evaluated using several echocardiographic parameters to assess right ventricular size and function. In addition, tissue Doppler imaging was also obtained to assess longitudinal strain of the right ventricular wall, interventricular septum, and lateral wall of the left ventricle and examined with regards to right ventricular size and function as well as clinical variables.

Results

In this study, patients with chronic pulmonary hypertension had statistically different right ventricular fractional area change (35 ± 13 percent), right ventricular end-systolic area (21 ± 10 cm²), right ventricular Myocardial Performance Index (0.72 ± 0.34), and Eccentricity Index (1.34 ± 0.37) than individuals without pulmonary hypertension (51 ± 5 percent, 9 ± 2 cm², 0.27 ± 0.09, and 0.97 ± 0.06, p < 0.005, respectively). Furthermore, peak longitudinal right ventricular wall strain in chronic pulmonary hypertension was also different -20.8 ± 9.0 percent versus -28.0 ± 4.1 percent, p < 0.01). Right ventricular dyssynchrony correlated very well with right ventricular end-systolic area (r = 0.79, p < 0.001) and Eccentricity Index (r = 0.83, p < 0.001). Furthermore, right ventricular dyssynchrony correlates with pulmonary hypertension severity index (p < 0.0001), World Health Organization class (p < 0.0001), and number of hospitalizations (p < 0.0001).

Conclusion

Lower peak longitudinal right ventricular wall strain and significantly delayed time-to-peak strain values, consistent with right ventricular dyssynchrony, were found in a small heterogeneous group of patients with chronic pulmonary hypertension when compared to individuals without pulmonary hypertension. Furthermore, right ventricular dyssynchrony was associated with disease severity and compromised functional class.

[Right ventricle insufficiency in pulmonary arterial hypertension. Physiopathologic considerations]

The present review is focused on chronic RV pressure overload or Cor Pulmonale as it may occur in the setting of two distinct disorders: those associated with abnormal pulmonary gas exchange (hypoxemia and/or hypercapnia) where chronic obstructive pulmonary disease (COPD) is the leading cause, and those associated with pulmonary vascular obstruction where primary pulmonary hypertension (PDDH) is the representative example. The clinical curse, prognostic, implications, and therapeutic strategies differ considerably in these two clinical entities. Right ventricular failure (RVF) may adversely influence the natural history and prognosis of patients with diverse cardiopulmonary disorders. It has been long established that right ventricular (RV) ischemia, RV overload, and RV pressure overload, alone or in combination, are the main factors involved in the pathogenesis of RVF. From the pathophysiologic point of view, RVF of COPD is more a congestive type of failure, in which activation of renin-angiotensin system is involved. In PPH, a low cardiac output state is predominant and the precise mechanism of RVF remains unknown. Current evidence in favor of the pathogenetic role of ischemia, adrenergic overdrive, and genetic determination are all reviewed during the course.

[Outcome of arrhythmogenic right ventricular dysplasia. Apropos of 4 cases]

The authors propose a classification of the outcome of arrhythmogenic right ventricular dysplasia with reference to 4 selected cases with a follow-up period of over 9 years. In type I, the left ventricular ejection fraction is normal (EF > 50%) and the risk, exclusively arrhythmic, can be controlled by appropriate antiarrhythmic therapy. This is the commonest form of arrhythmogenic right ventricular dysplasia with different varieties according to the degree of dilatation of the right ventricle. In type II, there is a variable degree of left ventricular involvement (30 < EF < 50%) either by extension of a comparable disease process as observed in the right ventricle or by an isolated or superimposed phenomenon of myocarditis. This form is stable and may remain stable for many years providing the arrhythmias are correctly treated. In type III, progressive degradation of the myocardium is observed over a period of about 10 years with a clinical presentation comparable to that of certain arrhythmogenic dilated cardiomyopathies which are often hereditary. In this case, the patients have an arrhythmic risk associated with that of cardiac failure which becomes progressively irreversible. The histology shows interstitial fibrosis with biventricular lymphocytic infiltration suggesting an autoimmune phenomenon. Therefore, the classification of cases of arrhythmogenic right ventricular dysplasia depends on the potential evolutivity of the lesions. When the patient is seen in the early stages of the disease, the prognosis should be garded, especially in a hereditary form.