Wild type cardiac amyloidosis: is it time to order a nuclear technetium pyrophosphate SPECT imaging study?

Transthyretin (ATTR) amyloidosis is a debilitating systemic disease often associated with symptomatic cardiac involvement. Diagnosis has dramatically changed with the advent of Technetium-99 m pyrophosphate (Tc-PYP) single-photon emission computed tomography (SPECT). With the ability to diagnose ATTR amyloidosis noninvasively and offer newer therapies, it is increasingly important to identify which patients should be referred for this testing. Relative apical sparing of longitudinal strain on echocardiogram can be potentially used to screen such patients. We sought to describe electrocardiogram (ECG) and echocardiogram (TTE) findings, including relative apical sparing of longitudinal strain, in ATTR amyloidosis patients diagnosed non-invasively with 99mTc-PYP imaging. This was a single-center, retrospective study with 64 patients who underwent 99mTc-PYP imaging between June 2016 and February 2019. Relative apical longitudinal strain was calculated from left ventricular longitudinal strain (LV LS) values. No ECG parameters were meaningfully associated with of 99 m Tc-PYP positive patients. LV mass index (p = 0.001), IVSd (p < 0.001), and LVPWd (< 0.001) demonstrated a highly significant difference between positive and negative 99mTc-PYP groups. 99mTc-PYP positive patients had a higher relative apical sparing of LV LS (p < 0.001), and notably, no 99mTc-PYP negative patient had a ratio > 1.0. The finding of relative apical sparing of longitudinal strain can reliably guide clinicians in triaging which patients to consider ordering 99mTc-PYP imaging for the noninvasive diagnosis of wild type cardiac amyloidosis. A patient with clinically suggestive features and an LV LS relative apical sparing ratio > 0.8 can be considered for 99mTc-PYP imaging to evaluate for ATTR cardiac amyloidosis.

Is pocket mobile echocardiography the next-generation stethoscope? A cross-sectional comparison of rapidly acquired images with standard transthoracic echocardiography.

BACKGROUND: A pocket mobile echocardiography (PME) device is commercially available for clinical use, but public data documenting its accuracy compared with standard transthoracic echocardiography (TTE) are not available. OBJECTIVE: To compare the accuracy of rapidly acquired PME images with those acquired by standard TTE. DESIGN: Cross-sectional study. At the time of referral for TTE, ultrasonographers acquired PME images first in 5 minutes or less. Ultrasonographers were not blinded to the clinical indication for imaging or to the PME image results when obtaining standard TTE images. Two experienced echocardiographers and 2 cardiology fellows who were blinded to the indication for the study and TTE results but not to the device source interpreted the PME images. SETTING: Scripps Clinic Torrey Pines and Scripps Green Hospital, La Jolla, California. PATIENTS: Convenience sample of 97 patients consecutively referred for echocardiography. MEASUREMENTS: Visualizability and accuracy (the sum of proportions of true-positive and true-negative readings and observer variability) for ejection fraction, wall-motion abnormalities, left ventricular end-diastolic dimension, inferior vena cava size, aortic and mitral valve pathology, and pericardial effusion. RESULTS: Physician-readers could visualize some but not all echocardiographic measurements obtained with the PME device in every patient (highest proportions were for ejection fraction and left ventricular end-diastolic dimension [95% each]; the lowest proportion was for inferior vena cava size [75%]). Accuracy also varied by measurement (aortic valve was 96% [highest] and inferior vena cava size was 78% [lowest]) and decreased when nonvisualizability was accounted for (aortic valve was 91% and inferior vena cava size was 58%). Observer agreement was fair to moderate for some measurements among less-experienced readers. LIMITATION: The study was conducted at a single setting, there was no formal estimate of accuracy given the small convenience sample of patients, and few abnormal echocardiographic measurements occurred. CONCLUSION: The rapid acquisition of images by skilled ultrasonographers who use PME yields accurate assessments of ejection fraction and some but not all cardiac structures in many patients. Further testing of the device in larger patient cohorts with diverse cardiac abnormalities and with untrained clinicians obtaining and interpreting images is required before wide dissemination of its use can be recommended. PRIMARY FUNDING SOURCE: National Institutes of Health.

Utility of a Deep-Learning Algorithm to Guide Novices to Acquire Echocardiograms for Limited Diagnostic Use.

Importance: Artificial intelligence (AI) has been applied to analysis of medical imaging in recent years, but AI to guide the acquisition of ultrasonography images is a novel area of investigation. A novel deep-learning (DL) algorithm, trained on more than 5 million examples of the outcome of ultrasonographic probe movement on image quality, can provide real-time prescriptive guidance for novice operators to obtain limited diagnostic transthoracic echocardiographic images. Objective: To test whether novice users could obtain 10-view transthoracic echocardiographic studies of diagnostic quality using this DL-based software. Design, Setting, and Participants: This prospective, multicenter diagnostic study was conducted in 2 academic hospitals. A cohort of 8 nurses who had not previously conducted echocardiograms was recruited and trained with AI. Each nurse scanned 30 patients aged at least 18 years who were scheduled to undergo a clinically indicated echocardiogram at Northwestern Memorial Hospital or Minneapolis Heart Institute between March and May 2019. These scans were compared with those of sonographers using the same echocardiographic hardware but without AI guidance. Interventions: Each patient underwent paired limited echocardiograms: one from a nurse without prior echocardiography experience using the DL algorithm and the other from a sonographer without the DL algorithm. Five level 3-trained echocardiographers independently and blindly evaluated each acquisition. Main Outcomes and Measures: Four primary end points were sequentially assessed: qualitative judgement about left ventricular size and function, right ventricular size, and the presence of a pericardial effusion. Secondary end points included 6 other clinical parameters and comparison of scans by nurses vs sonographers. Results: A total of 240 patients (mean [SD] age, 61 [16] years old; 139 men [57.9%]; 79 [32.9%] with body mass indexes >30) completed the study. Eight nurses each scanned 30 patients using the DL algorithm, producing studies judged to be of diagnostic quality for left ventricular size, function, and pericardial effusion in 237 of 240 cases (98.8%) and right ventricular size in 222 of 240 cases (92.5%). For the secondary end points, nurse and sonographer scans were not significantly different for most parameters. Conclusions and Relevance: This DL algorithm allows novices without experience in ultrasonography to obtain diagnostic transthoracic echocardiographic studies for evaluation of left ventricular size and function, right ventricular size, and presence of a nontrivial pericardial effusion, expanding the reach of echocardiography to clinical settings in which immediate interrogation of anatomy and cardiac function is needed and settings with limited resources.

Utility of on-line three-dimensional transesophageal echocardiography during percutaneous atrial septal defect closure.

Key echocardiographic assessments during percutaneous atrial septal defect (ASD) closure are the maximal defect diameter, the presence or absence of tissue rims, and the spatial relationships between the implanted device and cardiac structures. These assessments drive device selection and may help identify situations that may place a patient at risk for device erosion or other complications. On-line three-dimensional (3D) transesophageal echocardiography (TEE) enables the rendering of nearly unlimited tissue planes within an acquired pyramidal-shaped volume with minimal image post-processing. We present several cases of percutaneous ASD closure guided by on-line 3D TEE imaging that highlight the potential advantages of this new imaging technology.

Imaging Assessment of the Interatrial Septum for Transcatheter Atrial Septal Defect and Patent Foramen Ovale Closure.

Transcatheter closure of atrial septal defects and patent foramen ovale has become increasingly common with advances in device and imaging technology. The percutaneous approach is now the preferred method of closure when anatomically suitable. Two-dimensional and 3-dimensional echocardiography determines anatomic suitability by characterizing the interatrial defect and its surrounding structures, and is critical for intraprocedural guidance and postprocedure follow-up. This article provides an overview of interatrial anatomy as it pertains to interventional considerations and discusses the transthoracic, transesophageal, and intracardiac echocardiographic modalities used for periprocedural and intraprocedural imaging of the interatrial septum.

Can hospital rounds with pocket ultrasound by cardiologists reduce standard echocardiography?

BACKGROUND: Frequently, hospitalized patients are referred for transthoracic echocardiograms. The availability of a pocket mobile echocardiography device that can be incorporated on bedside rounds by cardiologists may be a useful and frugal alternative. METHODS: This was a cross-sectional study designed to compare the accuracy of pocket mobile echocardiography images with those acquired by transthoracic echocardiography in a sample of hospitalized patients. Each patient referred for echocardiography underwent pocket mobile echocardiography acquisition and interpretation by a senior cardiology fellow with level II training in echocardiography. Subsequently, transthoracic echocardiography was performed by skilled ultrasonographers and interpreted by experienced echocardiographers. Both groups were blinded to the results of the alternative imaging modality. Visualizability and accuracy for all key echocardiographic parameters (ejection fraction, wall motion abnormalities, left ventricular end-diastolic dimension, inferior vena cava size, aortic and mitral valve pathology, and pericardial effusion) were determined and compared between imaging modalities. RESULTS: A total of 240 hospitalized patients underwent echocardiography with pocket mobile echocardiography and transthoracic echocardiography. The mean age was 71 ± 17 years. Pocket mobile echocardiography imaging time was 6.3 ± 1.5 minutes. Sensitivity of pocket mobile echocardiography varied by parameter and was highest for aortic stenosis (97%) and lowest for aortic insufficiency (76%). Specificity also varied by parameter and was highest for mitral regurgitation (100%) and lowest for left ventricular ejection fraction (92%). Equivalence testing revealed the pocket mobile echocardiography outcomes to be significantly equivalent to the transthoracic echocardiography outcomes with no discernible differences in image quality between pocket mobile echocardiography and transthoracic echocardiography (P = 7.22 × 10(-7)). All outcomes remain significant after correcting for multiple testing using the false discovery rate. CONCLUSIONS: The results from rapid bedside pocket mobile echocardiography examinations performed by experienced cardiology fellows compared favorably with those from formal transthoracic echocardiography studies. For hospitalized patients, this finding could shift the burden of performing and interpreting the echocardiogram to the examining physician and reduce the number and cost associated with formal echocardiography studies.

Stiff left atrial syndrome after catheter ablation for atrial fibrillation: clinical characterization, prevalence, and predictors.

BACKGROUND: There have been no studies of atrial diastolic function after catheter ablation of atrial fibrillation (AF). We encountered a few patients with symptomatic left atrial (LA) diastolic dysfunction and associated pulmonary hypertension (PH) that developed after catheter ablation for atrial fibrillation. Similar findings were described in patients after cardiac surgery and were referred to as the "stiff left atrial syndrome." OBJECTIVE: The purpose of this study was to prospectively quantify the incidence of patients developing PH associated with diastolic hemodynamic abnormalities of the LA after radiofrequency ablation of AF and to identify the possible predictors. METHODS: Between January 2009 and July 2010, data on 1,380 consecutive patients were prospectively collected. Before ablation and at follow-up, all patients had an echocardiogram to assess for the presence of PH. Patients with no echocardiographic evidence of PH but complaining of unexplained dyspnea with LA diastolic abnormalities were evaluated with right heart catheterization (RHC). Patients were included in the analysis if they developed new or worsening PH postablation with evidence of LA diastolic dysfunction by RHC or direct LA pressure measurement. All patients were evaluated for pulmonary vein stenosis and excluded if this condition was identified. RESULTS: The mean age was 62 ± 11 (75% male), and nonparoxysmal AF was the predominant arrhythmia (71%). New or worsening PH with associated LA diastolic abnormalities was detected in 19 (1.4%) patients after ablation. The prevalence of PH did not differ between AF types (P = .612). Compared with patients who did not develop PH, LA scarring (P <.001), diabetes (P = .026), and obstructive sleep apnea (OSA; P = .006) were more frequently observed among those who developed PH. In a multivariable logistic model, preprocedure LA size ≤45 mm (odds ratio [OR] = 6.13; P = .033), mean LA pressure (OR 1.14; P = .025), severe LA scarring (OR = 4.4; P = .046), diabetes mellitus (OR = 9.5; P = .004), and OSA (OR = 6.2; P = .009) were independently associated with the development of PH postablation. CONCLUSIONS: After radiofrequency catheter ablation of atrial fibrillation (RFCAF), PH with LA diastolic dysfunction or the so-called stiff LA syndrome is a rare but potentially significant complication of AF ablation. Severe LA scarring, LA ≤45 mm, diabetes mellitus, OSA, and high LA pressure are clinical variables that predict the development of this syndrome. The main clinical findings include dyspnea, congestive heart failure, PH, and large V waves on pulmonary capillary wedge pressure (PCWP) or LA pressure tracings in the absence of mitral regurgitation.