We have enough evidence to question the superiority of the presumably best practice in cardiac pacing namely dual chamber pacing. Apparently, the DDD failed to show gross benefits in both AV block as well as sinus node dysfunction. (UKPACE, MODE-Selection Trial) in studies done nearly two decades ago.
It is 2022. Here is one more study in the Indian heart journal, coming up from JIPMER Pondycherry,on this concept. It is an intelligently designed cross-over study. The same patients were switched between DDD and VVI modes. This study reaffirmed the lack of appreciable hemodynamic and clinical benefits with DDD mode yet again.
We have also contributed a little on this issue. It was found cardiac failure in VVI pacing was not a real big issue in the long-term follow-up. We presented and published in world congrees of cardiology Dubai 2012, and Circulation journal.
How is that? A dual chamber pacer with AV synchrony fails to show a hemodynamic benefit?
The answer is simple..VV desynchrony is a common denominator for both VVI and DDD pacers. Providing AV synchrony without VV synchrony doesn’t make real sense in the long term to overcome the altered physiology, Still, DDD pacing continues to enjoy a popular mandate by hiding behind a vague outcome measure called quality of life.
What is the physiological pacing then?
Just because, DDD and VVI pacers are equipoise, can we presume the new pacing kid LBBB pacing would be physiological? We wish so, but unless and until we replicate the entire conducting system right from SA, and the AV node which includes many miles length of delicate Purkinje cables, every pacing system we use is currently pathological. (If that sounds too harsh, let’s make it non-physiological)
Having said that, VVI pacing is one of the most remarkable Inventions in medical science since the last century, that plays God’s own function and gives a new lease of life to all those patients with critical AV blocks and trouble some SNDs.
Final message
It may be difficult to digest for true scientists. Restoring the atrial booster pump is not bringing in the desired benefits. It is clear that VVI pacing will never become obsolete. This fact was established long before. We must argue and wonder, why we need to keep proving a scientific truth again and again? There could be a good justification too. Real-time cardiologist behavioral patterns clearly tell us, as a genre, they often struggle to get detached from futile modalities even after good published evidence (PCI for CTO, Revascularisation for Ischemic DCM, are a few more examples)