The purpose of this study is to determine if optimal lead placement, guided by the largest improvement in aortic flow measured by Doppler will:

1. Improve the way the heart's left ventricle functions
2. Decrease the number of hospital admissions for heart failure related symptoms
3. Reduces uncoordinated heart contractions
4. Improve quality of life as measured by the Minnesota Living with Heart Failure Questionaire and NYHA Class assessed after six months

The hypothesis of this study determines if response to CRT therapy could be improved by optimizing LV lead position at the time of the left ventricular pacing lead implantation. This optimization (using a Doppler wire) would alter the left ventricular activation pattern and contraction mechanics. This increase in contractility may improve the likelihood of mid/long term response to therapy. This study will compare 6-month response to CRT (left ventricular ejection fraction, decrease in left ventricular end systolic and end diastolic dimensions and volumes) in heart failure patients.

The secondary objective will be to:

1. To determine if optimal lead placement, guided by the largest improvement in stroke volume, results in a greater 6-month improvement in clinical QOL and NYHA class.
2. Acutely compare and/or correlate intra-operative A-V and V-V timing optimization via invasive pressure volume data to post-operative echo optimization of these same parameters.
3. Acutely contrast changes in stroke volume during pacing from several different left ventricular lead locations.

Inclusion Criteria:

• Clinical indication for CRT-P or CRT-D
• QRS Duration>=120 MSEC
• Left Ventricular Ejection fraction<=35%
• NYHA Class III-IV
• History of Cardiomyopathy, least one month post MI, or at least six months old in case of non-ischemic cardiomyopathy
• At least 18 years of afe

Exclusion Criteria:

• Previous implanted CRT-P/CRT-D
• woman who are pregnant
• Psychological or emotional problems