Left atrial- and left ventricular-based single lead DDD pacing. 
Single lead physiological pacing with right ventricular apex stimulation is feasible in patients with normal sinus node function and is associated with lower costs and a reduced complication rate.  Left ventricular or biventricular pacing using the tributaries of the coronary sinus was reported to improve functional status and quality-of-life in patients with advanced congestive heart failure and intraventricular conduction delays.  In addition, the proximal part of the coronary sinus has been successfully used for left atrial stimulation.  The feasibility and pacing characteristics of left atrial- and left ventricular-based temporary pacing using a conventional single pass lead were studied.  The tip of the lead was advanced in a distal position of the lateral or posterolateral branches of the coronary sinus, providing a stable position of the middle and proximal electrode pair in the first 2-7 cm of the coronary sinus.  A successful stable position was achieved in 13 of 21 consecutive attempts.  Using overlapping biphasic (OLBI) stimulation, left atrial and left ventricular pacing threshold were 2.3 +/- 0.6 and 2.5 +/- 0.5 V, respectively.  Acceptable sensing values were measured for P waves (4.1 +/- 0.7 mV) and R waves (9.7 +/- 3.9 mV).  There was a good correlation between the diameter of the coronary sinus as assessed by quantitative coronary angiography at the level of the middle and proximal rings and atrial pacing threshold (r = 0.92, P < 0.0001).  Thus, single lead left atrial- and left ventricular-based pacing is feasible although further development is necessary to increase the success rate for stable stimulation at both sites.