Alsidawi, Said

Exposure to high altitude results in hypobaric hypoxia, leading to physiological changes in the cardiovascular system that may result in limiting symptoms, including dyspnea, fatigue, and exercise intolerance. However, it is still unclear why some patients are more susceptible to high-altitude symptoms than others. Hypoxic simulation testing (HST) simulates changes in physiology that occur at a specific altitude by asking the patients to breathe a mixture of gases with decreased oxygen content. This study aimed to determine whether the use of transthoracic echocardiography (TTE) during HST can detect the rise in right-sided pressures and the impact of hypoxia on right ventricle (RV) hemodynamics and right to left shunts, thus revealing the underlying causes of high-altitude signs and symptoms. A retrospective study was performed including consecutive patients with unexplained dyspnea at high altitude. HSTs were performed by administrating reduced FiO2 to simulate altitude levels specific to patients’ history. Echocardiography images were obtained at baseline and during hypoxia. The study included 27 patients, with a mean age of 65 years, 14 patients (51.9%) were female. RV systolic pressure increased at peak hypoxia, while RV systolic function declined as shown by a significant decrease in the tricuspid annular plane systolic excursion (TAPSE), the maximum velocity achieved by the lateral tricuspid annulus during systole (S’ wave), and the RV free wall longitudinal strain. Additionally, right-to-left shunt was present in 19 (70.4%) patients as identified by bubble contrast injections. Among these, the severity of the shunt increased at peak hypoxia in eight cases (42.1%), and the shunt was only evident during hypoxia in seven patients (36.8%). In conclusion, the use of TTE during HST provides valuable information by revealing the presence of symptomatic, sustained shunts and confirming the decline in RV hemodynamics, thus potentially explaining dyspnea at high altitude. Further studies are needed to establish the optimal clinical role of this physiologic method.

Case description: A 67 year old female presented for annual review to the transplant clinic 4 years post orthotopic heart transplant for nonischemic dilated cardiomyopathy. She was asymptomatic. Her medical history included hypothyroidism, hypertension, osteoporosis, restless leg syndrome and calcineurin inhibitor related complications - CKD 3b, impaired glucose tolerance and a left partial glossectomy with neck dissection for stage 3 SCC of the left lateral tongue. Medications included aspirin, atorvastatin, prednisolone, tacrolimus, septrin and ropinirole. Family history was significant for heart failure in her father. She was a nonsmoker and did not consume alcohol. Physical examination was unremarkable. Diagnostic tests are shown below. Discussion: Apical hypertrophic cardiomyopathy (ApHCM) has rarely been described in post cardiac transplant populations. Characterized by increased left ventricular apical wall thickness, it results in a ‘spade-like’ appearance on imaging and is associated with marked T wave inversion on ECG. ApHCM is associated with progression to heart failure, apical aneurysm, ventricular arrhythmias and increased mortality rates. Patients may be asymptomatic at diagnosis. Regarding screening, criteria exist for the selection of donor hearts pre transplant with caution exercised if LVH >13mm. Causes of non HCM hypertrophy in this population include calcineurin inhibitors, hypertension, obesity and graft versus host disease. Data for treatment for ApHCM is lacking however it follows the path of classical HCM, involving the use of beta and calcium channel blockers to reduce demand ischemia and management of sequelae.

Background: Fabry's disease (FD), an X-linked lysosomal storage disorder, can present with cardiac manifestations similar to HCM. We aim to emphasize considering FD as a differential diagnosis in patients with HCM while highlighting the role of genetic testing in evaluating left ventricular hypertrophy (LVH). Cases Presentation: We present a case series of 3 patients with LVH. Despite initial clinical suspicion of primary HCM, genetic testing confirmed the diagnosis of FD. Patient 1: A 38-year-old male with no prior medical history presented with presyncope, lightheadedness, and chest tightness. EKG, Echo, and cardiac MRI suggested apical HCM. Genetic testing indicated FD. Patient 2: A 62-year-old male sought a second opinion regarding his diffuse HCM. EKG suggested RBBB. Echo showed a binary appearance of the myocardium, concentric LVH. Genetic testing confirmed FD. Patient 3: A 64-year-old male with a history of hypertension and renal disease underwent evaluation for kidney transplantation. Echo showed severely increased concentric LVH and Valsalva-induced intracavitary gradient/obstruction. Alpha-galactosidase level returned very low, suggesting FD, which was confirmed by genetic testing. Discussion: FD can be challenging to diagnose due to overlapping clinical and imaging features with HCM, leading to misdiagnosis and delayed management. Therefore, Genetic testing should be offered to all patients with suspected HCM to exclude phenocopies. Particularly, those with progressive HCM and atypical clinical features (renal disease and family history predominantly in males) and imaging features (conduction abnormalities on EKG, binary appearance on Echo). Early identification of FD enables appropriate management, including enzyme replacement therapy, potentially improving clinical outcomes. Conclusions: FD should be considered as a differential diagnosis in patients with HCM. Genetic testing plays a vital role in evaluating patients with HCM.

Introduction: Constrictive pericarditis (CP) can lead to cardiac dysfunction and a range of clinical symptoms. However, differentiating it from conditions like restrictive cardiomyopathy can be challenging due to the overlapping features. Case Presentation: We present a case of a 61-year-old female with a history of atrial flutter and subsequent atrial fibrillation, experiencing worsening dyspnea on exertion, lip cyanosis, and upper abdominal constriction. Extensive diagnostic workup, including Echo, CT scan, and cardiac MRI, revealed severe biatrial enlargement, ventricular interdependence, elevated filling pressures, reduced cardiac output, and extensive pericardial thickening and calcifications ( Figures 1.a and 1.b ). These findings supported the diagnosis of extensive CP. Discussion: CP is often missed and delayed in diagnosis due to its complex hemodynamics and the non-specific symptoms. Typically, the initial imaging modality to be performed is an Echo. Specific findings such as dilated vena cava, preserved tissue velocity with annuls paradoxus, abnormal respiratory septal shift, and respiratory variations in mitral/tricuspid inflow should be first clues for potential diagnosis. Furthermore, evaluation of the hepatic vein with diastolic flow reversal during expiration is a key finding. Lack of respiratory variation in the SVC is also important. Cardiac CT will assess pericardial thickness and calcification, while cardiac MRI is key for the diagnosis by showing the pericardial thickness and fibrosis as well as the septal respiratory shift and venous congestion. An invasive hemodynamic study might be required if imaging is inconclusive. this patient’s presentation, imaging findings, exercise test results and collectively supported considering radical pericardiectomy. Conclusions: This report highlights the diagnostic challenges related to CP and the importance employing a multimodality imaging approach for accurate diagnosis.

Introduction: Doppler mean gradient (MG) can underestimate the severity of aortic stenosis (AS) in patients with atrial fibrillation (AF) compared to patients in sinus rhythm (SR). Patients with AF and severe AS may experience delayed diagnosis and more advanced disease at time of referral for transcatheter aortic valve replacement (TAVR). Methods: Patients who underwent TAVR from 2013 to 2017 for native valve severe AS were identified from an institutional database. MG and aortic valve calcium score (AVCS) at time of referral were compared in patients in AF and SR. Retrospective theoretical AVCS in AF patients were derived assuming an average progression of 152 AU/year (published data). Results: There were 820 patients included; mean age was 81.3+/- 8.2 years and 41.6% were female. AF was present in 356 patients at time of referral. Patients in AF were older (82.2 vs. 80.5, p = 0.003), had lower MG compared to SR patients (42.0 vs. 44.9, p = 0.002) and a lower peak velocity (4.1 vs. 4.2, p = 0.010) with a similar indexed aortic valve area (0.4 vs. 0.4, p = 0.17). Stratified by sex, the median calcium score for AF patients was higher (by around 300 AU) among both males (AF 2850.0 vs. SR 2561.0, p = 0.044) and females (AF 1942.0 vs. 1610.5, p = 0.025) ( figure 1 ). A density plot of retrospective theoretical AVCS in AF patients (projected assuming referral to TAVR approximately two years prior) resulted in nearly identical median AVCS between the two cohorts ( figure 2 ). Conclusions: Older age and higher AVCS in patients with AF compared to SR suggests that AS was both underestimated and more advanced at time of referral to TAVR. Patients in AF may have severe AS as early as 2 years prior to TAVR referral.

Introduction: Exposure to high altitude results in hypobaric hypoxia, leading to physiological changes in the cardiovascular system that may result in dyspnea. Hypoxic simulation testing (HSTs) simulates changes in physiology that occur at a specific altitude. Hypothesis: The use of transthoracic echocardiography (TTE) during HST can detect the raise in right-sided pressures revealing underlying causes of high-altitude dyspnea. Methods: We performed a prospective observational study of consecutive patients with unexplained dyspnea at high altitude who were referred to an aerospace medicine program at a single institution between August 2021 and March 2023. Reduced FiO 2 was administered for 20 minutes to simulate altitude levels specific to patients’ history. TTE images were obtained at baseline and during peak hypoxia to evaluate right ventricular (RV) function, RV systolic pressure, and any possible shunts. Result: The study included 27 patients, with a mean age of 64.7 ±14.4 years and 14 (51.9%) females. No significant abnormalities were seen on baseline TTE and no significant differences in blood pressure and heart rate between baseline and hypoxia simulation were detected. Notably, RV systolic pressure increased at peak hypoxia, while RV systolic function declined as shown by a decrease in S’ wave and TAPSE ( Figure 1 ). Additionally, right to left shunts were present in 19 (70.4%) patients. Of these, four patients (21.1%) had shunts present at baseline with no changes at peak hypoxia, while the severity of shunts increased at peak hypoxia in eight cases (42.1%) and the shunts were only evident during hypoxia in seven patients (36.8%). Conclusion: TTE during HST provides valuable information by revealing the presence of symptomatic, sustained shunts and confirming the decline in RV hemodynamics explaining dyspnea at altitude. Further studies are necessary to establish the optimal clinical role of this physiologic method.

Introduction: The consequences of external cardiovascular compression and cardiac displacement from pectus excavatum (PEx) are debated. The complex geometry of the right (RV) and left ventricle (LV) along with distortion from the extrinsic chest deformity pose significant limitations to reliable assessment of LV and RV volumes and function using transthoracic 2D-echocardiography in this population. Hypothesis: A 3D-echocardiography approach can reliably assess the effects of external cardiac compression and the benefits of surgical correction on RV and LV function in PEx patients. Methods: Adult patients undergoing minimally invasive repair of PEx between Oct-2021 and Feb-2023 were included in this prospective study. Intraoperative transesophageal (TEE) 6 beat full volume video loops incorporating LV and RV were captured and compared before and after surgical correction of the PEx. TomTec Software® was used for offline 3D/4D reconstruction ( Figure 1 shows changes in 3D RV and LV shape pre- and post-surgery). Result: The study included 102 patients (mean age of 32.1 ±11.8 years; Haller index 4.9 ±2.5; 60.8% males). Post PEx repair, there was a significant (p<0.001) increase in the 3D RV volumes, RV ejection fraction (EF), RV stroke volume and RV strain ( Figure 1 ). Additionally, there was a significant improvement in 3D LVEF, 3D LV strain (longitudinal and circumferential), LV twist, and torsion ( Figure 1 ). Conclusion: In this PEx cohort, 3D/4D TEE imaging demonstrated significant increases in RV volumes and in RV and LV systolic function after surgical repair. These findings support the negative cardiovascular consequences of PEx compression and benefits of surgical repair.

Abstract Introduction Lipoprotein(a) [Lp(a)] is associated with an increased incidence of aortic stenosis. Bioprosthetic aortic valve degeneration and native aortic stenosis share similar pathological mechanisms. Evidence regarding the role of serum Lp(a) concentrations in bioprosthetic aortic valve degeneration is lacking. Purpose To evaluate the association between serum Lp(a) concentrations and bioprosthetic aortic valve degeneration. Methods In this retrospective multicenter study, consecutive patients who underwent a bioprosthetic aortic valve replacement between Jan-2010 and Dec-2020 and had a preoperatory serum Lp(a) measurement were included. A baseline transthoracic echocardiography (TTE) was performed following the aortic valve replacement and a follow-up TTE was performed at least 24 months after the baseline study to determine the presence of bioprosthetic valve degeneration. Significant degeneration was defined as: (a) an increase &gt;10 mmHg in mean bioprosthetic aortic valve gradient from baseline status + a decrease in effective orifice area + a decrease in Doppler velocity index + exclusion of clinically thrombotic leaflet thickening, OR (b) new moderate or severe prosthetic aortic regurgitation (if the main component was periprosthetic, then it was not considered). Lp(a) concentrations were compared between patients with and without degeneration and regression analysis was conducted to investigate the association between bioprosthetic valve degeneration and Lp(a) levels. Results In total, 211 cases were included (mean age 74.1 ±9.4 years, 72.0% males, 29.9% transcatheter aortic valve replacements) (Figure 1). Median time between baseline and follow-up TTE was 5.0 (IQR 3.7) years. Bioprostheses degeneration was observed in 33 (15.6%) patients at follow-up. Median serum levels of Lp(a) were significantly higher in the patients affected by degeneration versus non-affected cases (50.0 vs 15.7 mg/dl, p=0.003). In the regression analysis, high Lp(a) levels (≥30 mg/dl) were associated with degeneration both in a univariate analysis (OR 4.8, 95%CI 2.2-10.9, p&lt;0.001) and multivariate analysis adjusted by other risk factors for bioprostheses degeneration (age, sex, hypertension, smoking, patient prosthesis mismatch, creatinine levels, and body surface area) (OR 5.2, 95%CI 2.1-12.8, p&lt;0.001). Conclusion Serum Lp(a) concentrations seem to be a risk factor for bioprosthetic aortic valve degeneration (Figure 2). There is an increasing need to accurately predict bioprosthetic aortic valve degeneration and to develop novel methods and treatments to increase their durability. Prospective studies are needed to confirm these findings and to investigate whether lowering Lp(a) could slow bioprostheses degradation.Population characteristicsLp(a) and bioprostheses degeneration

Abstract Background Cardiac masses encompass a wide differential including primary and secondary malignancies and can present with a variety of symptoms, many of which are non-specific. Early identification and classification are important, particularly for cardiac malignancies such as sarcomas as these are aggressive tumours with exceptionally poor prognoses when metastases are present at diagnosis. Case summary We report two cases of patients who presented with dyspnoea and were diagnosed with cardiac sarcomas; the former a primary sarcoma (undifferentiated pleomorphic subtype) and the latter a secondary sarcoma (round cell myxoid liposarcoma) that serve as comparisons for presentation and management of different types of this disease. Computed Tomography (CT) and echocardiography imaging findings are demonstrated showing the typical location and morphology of each subtype. Discussion Cardiac sarcomas are the most common primary cardiac malignancy, of which undifferentiated pleomorphic sarcoma is a common subtype. Undifferentiated pleomorphic sarcomas are aggressive, have a tendency to arise in the left atrium, and can appear similar to benign cardiac masses. Round cell myxoid liposarcomas by contrast are rare causes of secondary cardiac malignancies, metastasizing to the heart from soft tissues. Both diagnoses carry poor prognoses and although rare, are important to recognize as timely intervention with surgery, radiotherapy, and consideration of chemotherapy is key to maximizing survival.