Hemodynamic collapse during left ventricular lead implantation.

Hypotension as a procedural complication during cardiac resynchronization therapy (CRT) implantation was reported in the initial randomized clinical trials. However, this phenomenon is not well characterized. We reviewed our CRT implantation experience to better understand this issue. There were 105 patients who underwent left ventricular lead implantation for CRT. Four patients had marked hypotension (systolic blood pressure < or = 50 mmHg) during the procedure. All had a history of hypertension and diabetes mellitus and were pacemaker dependent. Two had normal renal function, one had moderate renal insufficiency, and one was on dialysis. Three patients had ischemic cardiomyopathy. All had left ventricular ejection fraction < or =20% and were in New York Heart Association class III. Propofol and midazolam were used for sedation as standard protocol. Two patients had sudden hypotension when the coronary sinus was being cannulated, and two patients experienced sudden hypotension during left ventricular pacing. Cardiac tamponade as a possible cause was ruled out by echocardiography. We discuss possible mechanisms of sudden hemodynamic collapse during CRT implantation.