To our knowledge, this is the first report of semi-urgent rescue PVI using cryoballoon for acute-phase rhythm control against amiodarone-resistant AF tachycardia storm causing LOS and LOS-induced MOF with DIC in a tachycardia-induced cardiomyopathy.
AF may cause adverse haemodynamic effects and lead to decrease in cardiac output through the loss of atrial contraction, reduction of left ventricular filling due to rapid ventricular rates and irregular RR interval, increase maximal oxygen consumption, and exacerbate mitral and tricuspid regurgitation [
1]. Therefore, restoration of sinus rhythm in AF patients can be expected to improve cardiac output and decrease maximal oxygen consumption [
3,
4]. PVI is the established treatment for the rhythm control strategy of AF even refractory to antiarrhythmic drugs [
2] because PVI has an anti-AF mechanism different from that of drugs, such as eliminating AF substrate, denervating the autonomic nerve, and most importantly eliminating AF triggers arising from PVs [
13,
14]. On the contrary, the role and significance of acute-phase rhythm control by semi-urgent PVI is not yet established. However, Morishima et al. reported a similar case. They described that the semi-urgent rescue PVI could eliminate haemodynamically unstable AF storm and contribute to the improvement of haemodynamic states in a patient with an acute myocardial infarction, although the patient died from ventricular fibrillation as a complication of acute myocardial infarction [
15]. This report also supported the benefit of semi-urgent rescue PVI on acute-phase rhythm control against haemodynamically unstable AF tachycardia. In addition, the present case had LOS-induced MOF and DIC in which organ perfusion flow was originally reduced due to left ventricular dysfunction and was additionally reduced by AF tachycardia storm [
1]. Furthermore, especially in LOS-induced shock states, the importance of cardiac output increase and the resultant increase in blood pressure by rhythm control might be emphasised because of the following pathophysiology: (1) central shift of the circulating blood and organ perfusion in contrast flow reduction due to neurohormonal response [
16], (2) change of the source of liver blood perfusion supply from the portal vein to the hepatic artery due to hepatic arterial buffer reaction [
17], and (3) dependency of renal blood perfusion on cardiac output and on blood pressure in hypotension [
18]. Together with these considerations, we thought that the acute-phase rhythm control by semi-urgent PVI would have a certain role in LOS-induced MOF due to AF tachycardia, at least in elimination as aggravation factor, and would enable focus on the intensive care of original diseases and disorders.
We chose the cryoballoon ablation for semi-urgent rescue PVI in the present case. Cryoballoon ablation is a balloon-based ablation system using cryoenergy. In recent years, cryoballoon ablation has become the most effective alternative approach to radiofrequency catheter ablation showing non-inferiority to radiofrequency catheter ablation in freedom from AF/AT recurrence and overall safety [
7‐
9]. Several clinical studies showed shorter procedure time in cryoballoon ablation than that in radiofrequency catheter ablation [
7,
9]. An animal study showed that cryoballoon ablation has lower incidence of thrombus formation than radiofrequency catheter ablation [
12]. The shorter procedure time may suppose lesser load in intensive care setting. The lower incidence of thrombus formation may be favourable in intensive care setting accompanied with DIC. Although the significance of rescue cryoballoon ablation is unknown, we considered that cryoballoon ablation could be a favourable tool when we were required to perform semi-urgent rescue PVI, like in the present case. On the contrary, balloon-based ablation including cryoballoon ablation generally uses additional amount of contrast medium. We might consider performing the balloon-based ablation including cryoballoon ablation without left atriography for the patient with acute kidney injury, like in the present case. At the same time, we would like to emphasise the importance of careful and timely assessment of the benefit and risk of semi-urgent rescue PVI using cryoballoon because semi-urgent PVI using cryoballoon could be a complex procedure for a complex case.
In conclusion, acute-phase rhythm control by semi-urgent PVI using cryoballoon might be a considerable treatment option in patients with haemodynamically unstable AF tachycardia which is refractory to cardioversion and drug therapy and accompanied with LOS and LOS-induced MOF with DIC.