A. Forshaw

Detection of Right-to-Left Atrial Communication Using Agitated Saline Contrast Imaging: Experience with 1162 Patients and Recommendations for Echocardiography

BACKGROUND Right-to-left shunting via a patent foramen ovale (PFO) has a recognized association with embolic events in younger patients. The use of agitated saline contrast injection (ASCi) for detecting atrial shunting is well documented, but the optimal technique is not well described. The purpose of this study was to assess the efficacy and safety of transthoracic echocardiographic (TTE) ASCi for the assessment of right-to-left atrial communication in a large cohort of patients. METHODS A retrospective review was undertaken of 1,162 consecutive patients who underwent TTE ASCi, of whom 195 had also undergone clinically indicated transesophageal echocardiography. ASCi shunt results were compared with color flow imaging, and the role of provocative maneuvers (PM) was assessed. RESULTS Four hundred three TTE studies (35%) had paradoxical shunting seen during ASCi. Of these, 48% were positive with PM only. There was strong agreement between TTE ASCi and reported transesophageal echocardiographic findings (99% sensitivity, 85% specificity), with six false-positive and two false-negative results. In hindsight, the latter were likely due to suboptimal right atrial opacification and the former to transpulmonary shunting. TTE color flow imaging was found to be insensitive (22%) for the detection of a PFO compared with TTE ASCi. CONCLUSIONS TTE color flow imaging is too insensitive for PFO screening. TTE ASCi, however, is simple and highly accurate for the detection of right-to-left atrial communication, on the proviso that a dedicated protocol, including correctly implemented PM, is followed. It is recommended that TTE ASCi with PM be considered the primary diagnostic tool for the detection of PFO in clinical practice.

The safety profile of perflutren microsphere contrast echocardiography during rest and stress imaging: Results from an Australian multicentre cohort

BACKGROUND Contrast enhanced echocardiography (CEE) is utilised when sub-optimal image quality results in non-diagnostic echocardiograms. However, there have been numerous safety notices issued by regulatory authorities regarding rare but potentially serious adverse reactions (AR). This multi-centre, retrospective analysis was performed to assess the short-term safety of CEE in a broad range of indications. METHODS All CEE performed over 58 months at three institutions were assessed for AR within 30 min. RESULTS A total of 5956 CEE were performed in 5576 patients. A total of 4903 were stress CEE and 1053 resting CCE. Bolus administration in 5719, infusion in 237 cases; 89.9% of CCE were outpatients. Commonest CEE indication was functional stress testing (82.3%). There were 16 AR related to CEE (0.27%). All AR were mild, transient and all patients made a full recovery. No cases of serious anaphylaxis or death within 30 min of contrast administration. Comparing those with and without an AR, there were no significant differences in age, gender, BMI, LVEF, patient location, exam type or RVSP. There was a slightly increased likelihood of an AR during infusion versus bolus dosing (p = 0.02). CONCLUSION CEE is a safe investigation in a broad range of indications and clinical scenarios. AR are very rare, mild and transient.

Estimating left atrial enlargement parameters from the electrocardiogram using wavelets.

BACKGROUND The aim of this article was to examine the utility of using the P wave of the electrocardiogram to indicate left atrial enlargement measures determined from the echocardiogram and cardiac magnetic resonance. METHOD Wavelet-based features extracted from the beat-averaged P wave were correlated to the left atrial diameter, left atrial area, and left atrial volume index measures from echocardiogram and cardiac magnetic resonance. RESULTS Significant correlations were found between several of the wavelet features and the left atrial enlargement size measures (r > 0.5, P < .01). Left atrial diameter and left atrial area correlated best to the derived Z lead, and left atrial volume index correlated best to the derived X lead. CONCLUSIONS The good correlations illustrate that it is feasible to estimate the size of the left atrium from the P wave using wavelet techniques.