McConnell's sign is an echocardiographic finding characterized by regional right ventricular (RV) dysfunction with akinesia of the mid-free wall but preserved contractility of the apex. This pattern is highly specific for acute pulmonary embolism (PE).
In acute PE, sudden obstruction of the pulmonary artery leads to acute right ventricular pressure overload, causing regional wall motion abnormalities. The sparing of the apex differentiates it from other causes of RV dysfunction such as myocardial infarction.
This sign is considered a useful bedside clue in the echocardiographic diagnosis of PE, especially when combined with clinical findings and Doppler evidence of elevated pulmonary pressures.
The sign is described in the "Textbook of Clinical Echocardiography, 6e", Chapter on Acute Right Heart Dysfunction, with reference to McConnell's original description and its clinical significance in acute pulmonary embolism diagnosis#20:340-345Textbook of Clinical Echocardiography#.

Mitral valve prolapse (MVP) occurs during ventricular contraction (systole). Specifically, during systole, the increased pressure in the left ventricle causes the mitral valve leaflets to billow or prolapse back into the left atrium. This abnormal systolic displacement of the mitral leaflets beyond the annular plane leads to mitral regurgitation in many cases.
The echocardiographic hallmark of MVP is systolic bowing or displacement of the mitral leaflets into the left atrium, best visualized in parasternal long-axis or apical views during ventricular contraction. MVP is not seen during ventricular filling phases such as early filling, atrial systole, or diastasis because the leaflets are normally open or positioned differently.
This is well-documented in the "Textbook of Clinical Echocardiography, 6e", Chapter on Mitral Valve Disease, explaining the pathophysiology of MVP and its timing during the cardiac cycle#20:390-
395Textbook of Clinical Echocardiography#.

A heterograft (also called xenograft) cardiac valve is derived from an animal species, commonly porcine or bovine, and implanted into a human. These bioprosthetic valves are treated to reduce immunogenicity.
Option A describes an allograft (homograft). Option B refers to bioprosthetic valves but does not specify species. Option C describes an autograft, such as the Ross procedure.
This classification is standard in cardiac surgery and echocardiography literature#16:Textbook of Clinical Echocardiography, 6ep.450-455##12:ASE Valve Prosthesis Guidelinesp.200-205#.

Comprehensive and Detailed Explanation From Exact Extract:
Pulmonary vein Doppler signals have low velocity and low frequency components that can be filtered out by standard Doppler wall filters. To obtain a good quality spectral Doppler waveform for diastolic function evaluation, the wall filter settings should be lowered or adjusted to allow low frequency signals to be detected and displayed clearly.
Non-imaging transducers and continuous wave Doppler are not appropriate for pulmonary vein Doppler because spatial resolution and site localization are required. Filtering out low frequency signals would degrade the quality of the pulmonary vein waveform.
This is detailed in ASE Doppler imaging and diastolic function assessment protocols#12:ASE Diastolic Function Guidelinesp.85-90##16:Textbook of Clinical Echocardiography, 6ep.125-130#.

A respirometer monitors the respiratory cycle and is essential when evaluating diseases in which respiratory variation affects echocardiographic measurements, such as pericardial effusion and cardiac tamponade. In tamponade, respiratory changes in mitral and tricuspid inflows, as well as variations in inferior vena cava size, are key diagnostic features.
Congestive heart failure, ischemic cardiomyopathy, and mitral valve diseases do not require synchronization with respiration for diagnosis or quantification and are not reliant on respirometer use.
This recommendation is outlined in ASE pericardial disease guidelines and echocardiography procedural protocols#16:Textbook of Clinical Echocardiography, 6ep.280-285##12:ASE Pericardial Disease Guidelinesp.300-305#.