Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_43 (heat INTEGER, lane VARCHAR, country VARCHAR, mark VARCHAR)
### Question:
What is the lowest heat for the United states with a mark of 51.85 pb and lane higher than 6?
### Answer:
SELECT MIN(heat) FROM table_name_43 WHERE country = "united states" AND mark = "51.85 pb" AND lane > 6