Effects of acid-base imbalance on myocardial pacing thresholds

Comparison of Surgical Cut and Sew versus Radiofrequency Pulmonary Veins Isolation for Chronic Permanent Atrial Fibrillation: A Randomized Study

“…15 Changes in pH, such as alkalosis or acidosis, expressed by base excess, also change the capture threshold. 16 Despite the presence of such variables, statistical analysis showed no interference in the final result. The autonomic nervous system (ANS) is involved in the formation of AF.…”

Metabolic disturbances for the electrophysiologist

“…Acidosis also increases pacing thresholds and prolongs refractory periods. 2,6 3 | ALKALOSIS Alkalemia is defined when the serum pH is greater than 7.45. It can be due to respiratory or metabolic alkalosis and can be associated with hypokalemia.…”

“…3 Similar to acidosis, alkalosis also leads to increased pacing threshold. 6 In advanced hyperkalemia where plasma potassium concentration exceeds 7.0 mEQ/L, slower conduction in the atria leads to decrease in P wave amplitude and prolonged P wave duration. PR interval also prolongs due to slowing of conduction in the atrium, atrioventricular node, and the specialized conduction system.…”

“…Nonuniform conduction slowing in the His‐Purkinje system could lead to the various patterns of bundle branch blocks seen in the patient, from the initial development of atypical bundle branch block, typical right bundle branch block, and finally atypical right bundle branch block. Acidosis also increases pacing thresholds and prolongs refractory periods …”

“…In studies where bicarbonate was administered and electrocardiographic changes were observed, it has been shown that there can be a reduction in the amplitude of T waves . Similar to acidosis, alkalosis also leads to increased pacing threshold …”