A 32-year-old male presents to the ER with sudden-onset heart palpitations. His blood pressure is 100/70 mmHg, and his heart rate is 160/min with regular rhythm. The physician instructs the patient to do the "Valsalva maneuver" to relieve these symptoms. Which of the following structures indicated on the pelvic CT image below is most important in performing the Valsalva maneuver?

Question

A 32-year-old male presents to the ER with sudden-onset heart palpitations.  His blood pressure is 100/70 mmHg, and his heart rate is 160/min with regular rhythm.  The physician instructs the patient to do the "Valsalva maneuver" to relieve these symptoms.  Which of the following structures indicated on the pelvic CT image below is most important in performing the Valsalva maneuver?

Quizplus · Accepted Answer

The patient described in the question stem is experiencing paroxysmal supraventricular tachycardia. Treatment can be with vagal stimulation, such as carotid sinus massage or the Valsalva maneuver. Maneuvers that increase vagal tone increase the refractory period in the AV node and help prevent a reentrant circuit from conducting. If Valsalva measures fail, intravenous administration of adenosine is recommended. The Valsalva maneuver is executed by forcibly exhaling against a closed glottis. This is done by taking a full inhalation, closing the glottis (i.e. holding one's breath), and subsequently bearing down-without exhaling-as one would during a bowel movement. The rectus muscles are recruited in this process, and they (Choice A) play the largest role in the development of the resultant elevated intraabdominal and intrathoracic pressure during this maneuver. (Choice B) This structure is the iliacus muscle, a flexor of the hip that lies over the iliac fossa. (Choice C) This structure is the gluteus minimus muscle. This muscle is innervated by the superior gluteal nerve and has the subtle, but important function of preventing the contralateral (non-weight-bearing) side of the pelvis from dipping when that leg is elevated off of the ground, as when one walks. (Choice D) This structure is the gluteus medius muscle. This muscle has the same innervation and function as the gluteus minimus. (Choice E) This structure is the gluteus maximus muscle. This muscle is innervated by the inferior gluteal nerve and is the major extensor of the thigh at the hip. Educational Objective: The Valsalva maneuver increases vagal tone and can be used to abolish paroxysmal supraventricular tachycardia. The rectus abdominis is the most important muscle in achieving the increased intraabdominal and intrathoracic pressure of the Valsalva maneuver.

A 32-Year-Old Male Presents to the ER with Sudden-Onset Heart