CF and emphysema.

Many people want to change the rules when they look at the right heart. My perception is that the very same rules should be applied perhaps more stringently when considering any method of assessment ofright heart function. The variable shape ofthe human right ventricle makes it more difficult by every method The concept advanced by Albert is a myth about gated blood pool ventriculography which has been perpetuated for over a decade. The myth is summarized in a figure from Strauss and Pitt’s textbook Cardiovascular Nuclear Medicine, What that figure purports to show is that in the conventional left anterior oblique gated blood images, the contamination of left ventricular counts by left atrial counts is trivial but the contamination of right ventricular counts by right atrial counts is insurmountable! Accordingly, the dogma has been uncritically disseminated that gated blood pool data regarding the right ventricle is inherently inaccurate. To my knowledge, the numbers in this figure are not measurements. What is clear is that the anatomy is unusual; the right atrium is usually not four times larger than the left atrium; neither is the right ventricle smaller than the left ventricle. By observing the first passage of a tracer in first pass studies, an RAO view can be used to separate right atrium from right ventricle spatially while the left and right hearts are separated temporally. The point which has never been emphasized is that first pass techniques also have potential inaccuracies! Count rates can be one major problem with first pass studies. Therefore, given the difficulty of the right ventricle, one should validate whatever method one uses. We have compared single and biplane contrast studies with first pass and blood pooi radionuclide and echocardiographic images in hundreds of patients in multiple laboratories over a ten year period. We have shown that one can obtain reasonable gated blood pool measures in a majority of patients just as in individual patients, each method can come up short. We specifically and mathematically have dealt with the issue of chamber overlap by subjecting our gated blood pool images to phase analysis, where by atrial and ventricular pixels are 180#{176} out of phase. l Most groups using first pass methods of right ventricular assessment have not validated their methods against anything! The simple fact is that much progress has been made in overcoming the greatest myth about the right heart, namely that it is dispensable,b0 In accord with that myth, there was rio reason to study the right heart at all! Having got past that myth, we next need to defeat the myth that it cannot be studied because it is too complicated. It is likely that the greatest progress will be made when we recognize that multiple different approaches each applied with the same consistency and rigor that is expected on the left side, will finally yield the truth.