Alternating atrial electromechanical dissociation as contributing factor for pulsus alternans

Area of Science:

• Cardiology
• Cardiac Electrophysiology
• Heart Mechanics

Background:

• Pulsus alternans is characterized by alternating strong and weak ventricular contractions.
• It is often attributed to left ventricular myocardial dysfunction.
• The underlying mechanisms, particularly atrial contributions, require further elucidation.

Purpose of the Study:

• To investigate the potential role of atrial mechanisms in the development of mechanical pulsus alternans.
• To explore the relationship between atrial electromechanical dissociation and pulsus alternans in patients with congestive heart failure.

Main Methods:

• Echocardiography and mechanocardiography were employed in ten patients with mechanical pulsus alternans.
• Apexcardiograms and M-mode echocardiograms were used to analyze cardiac mechanical events.
• Patients with identified atrial mechanisms were in normal sinus rhythm.

Main Results:

• Two patients exhibited an atrial mechanism for pulsus alternans, characterized by an "a" wave preceding strong systoles only.
• This atrial contribution was documented via apexcardiography and M-mode echocardiography.
• The identified mechanism occurred in patients with primary congestive cardiomyopathy and post-aortic valve replacement.

Conclusions:

• Alternating atrial electromechanical dissociation is a viable mechanism that can cause or contribute to pulsus alternans.
• Pulsus alternans is not exclusively a consequence of left ventricular myocardial dysfunction.
• This finding expands the understanding of pulsus alternans etiology.