When interpreting waveforms, simultaneous observation of pulmonary artery waveforms with the ECG registration and with arterial waveform monitoring could be useful. Under normal conditions, the PAP upstroke precedes the arterial upstroke due to the longer duration of left ventricular isovolumetric contraction [56]. Since this lag time is small under normal conditions, the waveforms may seem to overlap. However, the presence of a bundle branch block may alter this relation between PAP and systemic arterial pressure. A left bundle branch block delays left ventricular contraction, increasing the lag time between the PAP upstroke and arterial upstroke even more (Fig. 2g). A right bundle branch block has the opposite effect; arterial upstroke now precedes PAP upstroke (Fig. 2f) [23]. Tachycardia might produce fusion of waveform components, particularly the a and c-waves, whereas bradycardia can reveal a mid-diastolic plateaus pressure wave (h) between the x-descent and v-peak [57]. In case of atrial fibrillation, the a-wave will disappear from the CVP waveform due to the loss of atrial contraction. The c-wave is more prominent compared to normal sinus rhythm due to high end-diastolic atrial volume and subsequent isovolumetric ventricular contraction, displacing the tricuspid valve toward the right atrium. Atrial fibrillation leads to variability in chamber filling, and thereby to the contractile state with concurrent changes in waveform morphologies. In addition to the c- and v-waves, small amplitude pressure waves may be superimposed to the waveform, reflecting atrial activity (Fig. 2h) [57, 58]. In case of atrioventricular dissociation (ventricular tachycardia, complete heart block, re-entry tachycardia), cannon a-waves are inscribed in the CVP waveform because of atrial contraction against a closed tricuspid valve during systole. Cannon a-waves may occur before, during, or after the c-wave. Cannon a-waves can also be noted in the wedge pressure waveform (Fig. 2i) [59].
Waves Diamond Bundle v5.2 (31
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