private function getExistingVisitFieldsToUpdate($visitIsConverted)
    {
        $valuesToUpdate = array();

        $valuesToUpdate = $this->setIdVisitorForExistingVisit($valuesToUpdate);

        $dimensions = $this->getAllVisitDimensions();
        $valuesToUpdate = $this->triggerHookOnDimensions($dimensions, 'onExistingVisit', $valuesToUpdate);

        if ($visitIsConverted) {
            $valuesToUpdate = $this->triggerHookOnDimensions($dimensions, 'onConvertedVisit', $valuesToUpdate);
        }

        // Custom Variables overwrite previous values on each page view
        return $valuesToUpdate;
    }