aUbilla

PacienteController:

public function actionAdmin() {
        //$model = new Paciente('search');
        $model = new Usuario('searchWithRelation');
        $model->unsetAttributes();  // clear any default values
        if (isset($_GET['Usuario'])) {
            $model->attributes = $_GET['Usuario'];
        }

        $this->render('admin', array(
            'model' => $model,
        ));
    }

Modelo Usuario:

public function searchWithRelation() {
        // @todo Please modify the following code to remove attributes that should not be searched.
        $criteria = new CDbCriteria;

        $criteria->together = true;
        $criteria->with = array('paciente');

        $criteria->compare('id', $this->id);
        $criteria->compare('rut', $this->rut, true);
        $criteria->compare('nombre', $this->nombre, true);
        $criteria->compare('apellidoPaterno', $this->apellidoPaterno, true);
        $criteria->compare('apellidoMaterno', $this->apellidoMaterno, true);
        $criteria->compare('estado', 1);

        return new CActiveDataProvider($this, array(
            'pagination' => array(
                'pageSize' => 15,
            ),
            'criteria' => $criteria,
        ));
    }

CGridView de Pacientes:
'dataProvider' => $model->searchWithRelation(), //cargo modelo usuarios que son tipo paciente.