Dear Marion,

Thank you for your letter, for the medical data, and for
Dr. Skarda's advice. I hesitate to comment, lest I interfere
with Dr. Skarda's proposed diagnostic measures. But I'll
report the thoughts as they run through my mind. I mustn't
masquerade as a cardiologist or pulmonologist. But I like to
understand, and the first question that arose in my mind is:
how reliable an indicator of right ventricular strain was your
echocardiogram?  Here's what I found on the Internet:

Current Opinion in Cardiology:
September 2010 - Volume 25 - Issue 5 - p 430?436
doi: 10.1097/HCO.0b013e32833b5f94
Imaging and echocardiography: Edited by Sherif F. Nagueh
Right ventricular function by strain echocardiography
La Gerche, Andre 

Purpose of review: Right ventricular (RV) function is an independent
determinant of prognosis in a number of pathologies, but its accurate
quantification by echocardiography remains a challenge. 
With the evolving clinical utility of RV strain and strain imaging,
several studies have used it to investigate normal and pathologic conditions.
However, marked shape adaptations of the RV and the wide range of possible
loading conditions complicate the interpretation of findings, 
which will be highlighted in this review.

Recent findings: RV strain and strain rate measurements have been proven
feasible and found to offer potential advantages over traditional indices.
They allow regional function estimation with less influence from the left
ventricle (LV) or overall cardiac motion. However, there are contradictions
in recent studies regarding expected values and regional patterns,
which may be attributed to differences in imaging techniques
but also to the challenging interpretation of findings.

Summary: Strain and strain rate have a great potential for a more
accurate description of RV function and a better understanding of
its pathology. The imaging techniques are ready for translation
into the clinical arena, but their greatest utility will only be
realized once diagnostic values are more clearly defined.

My tentative hypothesis: the diagnosis of (incipient) right ventricular
failure was at best an educated guess. My snide comment: maybe the 
echocardiographer had just come back from a conference where echo-
cardiographic diagnosis of right ventricular strain was advertised,
and he didn't want to be considered backward by his colleagues.
(Would your physicians be offended if you asked for a copy of the
echocardiogram. Klemens would get us second and third interpretations.)

Fifty years ago right ventricular failure was diagnosed by enlargement
of the right side of the heart on chest X-ray, confirmed by accentuation
of pulmonary vascular markings.  Was a chest X-ray obtained, and if so,
what did it show?  In advanced right sided heart failure, there is
distention of veins even above the level of the heart. One raises the
patient's arm to ascertain the height at which the veins collapse.
Is that too old fashioned? To my mind, the simplest and perhaps most
reliable test for right heart failure, which has been abandoned perhaps
because it's not reimbursed by Medicare is the question: can you sleep
flat in bed, on a single low pillow or none at all. If the answer is
"yes" then significant right heart failure seems to me (very) unlikely, 
because in the upright position, the diaphragm falls and greatly
increases ventilation. - But maybe I'm a pretentious, simplistic fool.

When I was in general practice, obstructive sleep apnea was not a common
diagnosis. I don't know if it had even been discovered. The characteristic
of obstructive sleep apnea, as I understand it, is intermittent deep
labored breathing usually with snoring, followed by periods of apnea.
Daytime somnolence, if it is present, it seems to me, is a very non-specific
sign, especially in a patient who not infrequently dispatches e-mail
at 12:22 a.m., 1:22 a.m., 1:34 a.m. ...

I find Dr. Skarda's reasoning somewhat tenuous. If the evidence for 
right ventricular strain is persuasive, should a positive sleep study
preclude the search for pulmonary emboli and their source? Indeed,
might not obstructive sleep apnea be a contributing cause to venous
thrombosis and pulmonary embolism? If the echocardiographic evidence
for right ventricular strain is marginal, should the diagnosis of
sleep apnea be pursued in the absence of (other) signs? In that case,
I'd vote for an EKG and a chest X-ray if they haven't been done. The
chest X-ray costs much less than a CT scan, and if I'm not mistaken,
delivers far fewer gamma rays.

If miserly EJM were the patient, the bottom line would rule. Before
putting more cash on the roulette wheel, I'd want to know how much
I owed for health care up to this point, I'd want to know what the
proposed tests would cost me, and specifically, for what home tests
for sleep apnea, if any, my insurance would pay. I sleep very poorly
away from home, and having to pretend to sleep under the aegis of
a sleep specialist would so roil me, that my sleep apnea test would
be a joke. But I would enjoy toying with the electronics of the
sleep apnea test at home, and, control freak that I am, would
relish the opportunity of self-diagnosis.

Do you want me to talk to Klemens, who is a professor of medicine,
and obtain for you serious, respectable advice? If you gave me
your permission, I'd just forward to him your e-mail and my response.

Jochen