diff --git a/src/Mysql/PDO.php b/src/Mysql/PDO.php
index 679e578..8d2ca85 100644
--- a/src/Mysql/PDO.php
+++ b/src/Mysql/PDO.php
@@ -239,6 +239,9 @@ class PDO
 	 */
 	public function _pdo(): \PDO
 	{
+		if ($this->_timer === -1) {
+			$this->heartbeat_check();
+		}
 		if (!($this->pdo instanceof \PDO)) {
 			$this->pdo = $this->newClient();
 		}