Right Ventricular Fatty Infiltration With an Abnormal ECG

Two middle-aged women had evidence suggesting right ventricular hypertrophy on routine electrocardiograms. Their echocardiograms showed right ventricular thickening and cardiac magnetic resonance imaging revealed right ventricular fatty infiltration. Neither patient fulfilled the criteria for arrhythmogenic right ventricular cardiomyopathy, and both had a benign clinical course. (Level of Difficulty: Intermediate.)

Treatment Targets for Right Ventricular Dysfunction in Pulmonary Arterial Hypertension

Right ventricle (RV) dysfunction is the strongest predictor of mortality in pulmonary arterial hypertension (PAH), but, at present, there are no therapies directly targeting the failing RV. Although there are shared molecular mechanisms in both RV and left ventricle (LV) dysfunction, there are important differences between the 2 ventricles that may allow for the development of RV-enhancing or RV-directed therapies. In this review, we discuss the current understandings of the dysregulated pathways that promote RV dysfunction, highlight RV-enriched or RV-specific pathways that may be of particular therapeutic value, and summarize recent and ongoing clinical trials that are investigating RV function in PAH. It is hoped that development of RV-targeted therapies will improve quality of life and enhance survival for this deadly disease.

Pathogenic Role of mTORC1 and mTORC2 in Pulmonary Hypertension

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G protein-coupled receptors and tyrosine kinase receptors signal through the phosphoinositide 3-kinase/Akt/mTOR pathway to induce cell proliferation, survival, and growth. mTOR is a kinase present in 2 functionally distinct complexes, mTORC1 and mTORC2.

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Functional disruption of mTORC1 by knockout of Raptor (regulatory associated protein of mammalian target of rapamycin) in smooth muscle cells ameliorated the development of experimental PH.

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Functional disruption of mTORC2 by knockout of Rictor (rapamycin insensitive companion of mammalian target of rapamycin) caused spontaneous PH by up-regulating platelet-derived growth factor receptors.

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Use of mTOR inhibitors (e.g., rapamycin) to treat PH should be accompanied by inhibitors of platelet-derived growth factor receptors (e.g., imatinib).

Concentric lung vascular wall thickening due to enhanced proliferation of pulmonary arterial smooth muscle cells is an important pathological cause for the elevated pulmonary vascular resistance reported in patients with pulmonary arterial hypertension. We identified a differential role of mammalian target of rapamycin (mTOR) complex 1 and complex 2, two functionally distinct mTOR complexes, in the development of pulmonary hypertension (PH). Inhibition of mTOR complex 1 attenuated the development of PH; however, inhibition of mTOR complex 2 caused spontaneous PH, potentially due to up-regulation of platelet-derived growth factor receptors in pulmonary arterial smooth muscle cells, and compromised the therapeutic effect of the mTOR inhibitors on PH. In addition, we describe a promising therapeutic strategy using combination treatment with the mTOR inhibitors and the platelet-derived growth factor receptor inhibitors on PH and right ventricular hypertrophy. The data from this study provide an important mechanism-based perspective for developing novel therapies for patients with pulmonary arterial hypertension and right heart failure.

Electrocardiogram signs of right ventricular hypertrophy may help identify pulmonary hypertension in patients with dilated cardiomyopathy

Objective

To the authors' knowledge, limited data are available regarding the association between Electrocardiogram (ECG) signs of right ventricular hypertrophy (RVH) and pulmonary hypertension (PH) in patients with dilated cardiomyopathy (DCM). We aimed to assess the accuracy of the recommended ECG criteria of RVH for predicting PH in patients with DCM.

Methods

According to the definition of PH (mPAP ≥ 25 mm Hg), 35 patients with DCM were divided into 2 groups: DCM with PH (n = 22) and DCM without PH (n = 13). Right heart catheterization was performed in all patients. Seventeen parameters of RVH recommended by the AHA/ACCF/HRS for diagnosis of RVH on ECG were determinded.

Results

The following parameters were correlated with mPAP: R_V1 > 6 mm, S_V5 > 10 mm, R:S_V6 < 0.4, R_V1 + S_{V5 or V6} > 10.5 mm and P_II amplitude. The following parameters were significantly different between DCM patients with and without PH: S in V₅ (S_V5) > 10 mm, S in V₆ (S_V6) > 3 mm, R:S ratio in V₅ (R:S_V5) < 0.75, R_V1 + S_{V5 or V6} > 10.5 mm, S > R inI, S > R inII and R:S _V1 > R:S _V3, although results were no longer significant after correcting for multiple comparisons. High specificity (92.3-100%), lowsensitivity (31.8-50%), high positive predictive value, and low negative predictive value of established parameters of RVH were noted for predicting PH in patients with DCM.

Conclusion

Several ECG signs of RVH may be useful for in the diagnosis PH in patients with DCM.

Combined uphill and downhill varices as a consequence of rheumatic heart disease: a unique presentation

Hemorrhage from downhill varices is a rare manifestation. The etiology of downhill varices is due to superior vena cava obstruction while uphill varices are secondary to portal hypertension. We report a rare case of 55-year-old female with bleeding downhill varices not associated with obstruction or compression of superior vena cava, but was due to severe pulmonary artery hypertension secondary to chronic rheumatic heart disease.