Original post by Michael Lineaus, MD.
Myth #1: What’s the rub, you insensitive lout?
Many physicians equate the friction rub and pericarditis, though review of historical series suggest the friction rub is a relatively rare finding in acute pericarditis. One series of 300 Italian patients found a rub in 35% of patients with acute pericarditis (JACC 2004), while the recent ICAP (Investigation for Colchicine for Acute Pericarditis) trial found a similar percentage (a portion of Table 1 is below):
ECG changes are also relatively uncommon – occuring in about 1/3 of cases from several different sources (including the ICAP trial noted above). The characteristic pain (pleuritic and sharp, improved by leaning forward and worsened by lying flat), however, is present in nearly in all cases – making the patient history the KEY to making the diagnosis of acute pericarditis.
Myth #2: The story is in the ST segments
When present, the most dramatic changes in the ECG are often reported as widespread ST segment elevation:
Variations from this pattern (particularly focal, rather than diffuse changes) are common. One trick I’ve learned is to look for changes in the PR segment (particularly in aVR) as these are more specific for the diagnosis of acute pericarditis than ST segment elevation.
Evaluating the PR segment of the electrocardiogram becomes most important when try to differentiate acute pericarditis from STEMI, where PR changes are uncommon. The ECGs above are from the web, at NEJM Pericarditis Review 2004.
Myth #3: Steroids, NSAIDs, colchicine – who cares?
Two recent large, multicenter trials have looked at the usage of colchicine for acute pericarditis:
ICAP, which randomized 240 patients with “run-of-the-mill” pericarditis (no cancer, no TB, eg, along with many other exclusion criteria) to standard therapy (mostly NSAIDs, though a few patients received glucocorticoids if they had a contraindication to NSAIDs) or standard therapy + colchicine. The study was exceedingly positive for the use of colchicine in this group – demonstrating quicker relief of symptoms, fewer re-hospitalizations, and, most importantly, far less recurrent disease (RR of 0.5 approximately). ICAP trial
COPE (Colchicine in Addition to Conventional Therapy for Acute Pericarditis), which was a randomized, open-label of 120 patients randomized to conventional treatment (aspirin or corticosteroids, if intolerant of aspirin) or conventional treatment plus colchicine. This trial was also very positive for colchicine for the same reasons noted above in ICAP, though, interestingly also showed an INCREASE in poor outcomes for those patients treated with corticosteroids:
A recent Cochrane review has also been published on the subject (2014 Cochrane review)