A 51-year-old male patient is admitted to the hospital with anasarca and progressive dyspnea and functional limitation. He has a prior history of coronary artery bypass grafting and post-pericardiotomy syndrome with relapsing pericarditis that has likely advanced to constrictive physiology (despite slow taper steroid therapy), given his presenting symptoms and physical examination findings. During the admission he is aggressively diuresed with IV diuretics with improvement in his renal and liver function, as well as symptom improvement (edema and dyspnea). He is unable to go for a magnetic resonance imaging (MRI) for further assessment (prior metallic implant in his spine for scoliosis) and his echocardiogram images are technically difficult due to his distorted spine and prior cardiac surgery. He is referred for dual transducer cardiac catheterization for hemodynamic evaluation of right- and left-sided pressures as part of his diagnostic workup. The catheterization laboratory team begins the procedure and calls you to discuss the case. They note a sinus rhythm at 90 bpm with occasional premature ventricular contraction and a central venous pressure of 4 mmHg and nonelevated end-diastolic pressures at the beginning of the study (due to recent diuresis); they are unable to elucidate diastolic equalization of pressures, significant “dip and plateau,” or respiratory discordance of the ventricular pressure waveforms.
A potential mechanism for the discordant catheterization findings would be:A. Lack of preload due to overdiuresis
Lack of preload due to overdiuresis. Volume loading is required to elucidate the diagnostic findings described above. Constrictive pericarditis is a preload-dependent condition and with overdiuresis and low central venous pressure, the hemodynamic findings of elevated and equal end-diastolic ventricular pressure waveforms as well as respiratory discordance of the LV/RV waveforms are not seen. Often in these cases, the patient is given a bolus of 1 to 2 L of normal saline to increase the RA pressure >12 to 15 mmHg and the study is performed once they are adequately volume loaded. Of note, in cases of atrial fibrillation, the patient may require a temporary venous pacemaker to regularize the rhythm for analysis purposes.