Key result
Treating cardiac tamponade doubles QRS voltage within one week, whether via pericardiocentesis or anti-inflammatory therapy.
Why the study?
It is unclear whether low QRS voltage is a sign of cardiac tamponade or of pericardial effusion per se and how it reverses after treatment.
Do therapeutic interventions like pericardiocentesis or anti-inflammatory medication improve low QRS voltage in patients with significant pericardial effusion and cardiac tamponade?
Cohort (n=43)
No
Do therapeutic interventions like pericardiocentesis or anti-inflammatory medication improve low QRS voltage in patients with significant pericardial effusion and cardiac tamponade?
Low QRS voltage is a specific sign of cardiac tamponade rather than just pericardial effusion, and it resolves within a week following treatment with pericardiocentesis or anti-inflammatory therapy.
Answers are grounded in this paper and cite their sources.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“I do not understand the mechanism responsible for the electrocardiographic findings reported by Bruch and associates. Could it be that the definition of low amplitude (0.5 mv) used by Bruch's group was too low? During the past few years, I have used the data provided by Odom and colleagues to calculate the normal range of QRS voltage. The normal range for the QRS voltage of adults with normal hearts is calculated by the 12-lead QRS amplitude, and is 80-185 millimeters. I prefer this method because there are few studies indicating the low end of the normal range. I wonder if the use of < 0.5 mv by Bruch is appropriate?”
Low QRS voltage may indicate tamponade over effusion alone; leaves open whether serial ECGs should guide management in pericarditis.
OBJECTIVES: The goal of this study was to define the association between low QRS voltage and cardiac tamponade or pericardial effusion and to assess the reversibility of low QRS voltage after therapeutic procedures. BACKGROUND: It is unclear whether low QRS voltage is a sign of cardiac tamponade or whether it is a sign of pericardial effusion per se. METHODS: In a prospective study design, we recorded consecutive 12-lead electrocardiograms and echocardiograms in 43 patients who were referred to our institution for evaluation and therapy of a significant pericardial effusion. Cardiac tamponade was present in 23 patients (53%). Low QRS voltage (defined as maximum QRS amplitude <0.5 mV in the limb leads) was found in 14 of these 23 subjects (61%). Nine of these 14 patients were treated by pericardiocentesis (group A). Five patients received anti-inflammatory medication (group B). Group C consisted of nine patients with pericarditis and significant pericardial effusion who had no clinical evidence of tamponade. RESULTS: In group A, low QRS voltage remained largely unchanged immediately after successful pericardiocentesis (0.36 +/- 0.17 mV before vs. 0.42 +/- 0.21 mV after, p = NS), but QRS amplitude recovered within a week (0.78 +/- 0.33 mV, p < 0.001). In group B, the maximum QRS amplitude increased from 0.40 +/- 0.20 mV to 0.80 +/- 0.36 mV (p < 0.001) within six days. In group C, all patients had a normal QRS amplitude initially (1.09 +/- 0.55 mV) and during a seven-day follow-up (1.10 +/- 0.56 mV, p = NS). CONCLUSIONS: Low QRS voltage is a feature of cardiac tamponade but not of pericardial effusion per se. Our findings indicate that the presence and severity of cardiac tamponade, in addition to inflammatory mechanisms, may contribute to the development of low QRS voltage in patients with large pericardial effusions.
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Bruch et al. (2001) conducted a cohort in Cardiac tamponade and pericardial effusion (n=43). Pericardiocentesis or anti-inflammatory medication vs. Pre-treatment baseline and patients without tamponade was evaluated on Change in maximum QRS amplitude (p=<0.001). Low QRS voltage recovered within a week after pericardiocentesis or anti-inflammatory treatment in patients with cardiac tamponade.
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