Complete heart block associated with noncompaction, nail-patella syndrome, and mitochondrial myopathy.

OBJECTIVES: Complete heart block has not been reported in association with left ventricular hypertrabeculation (LVHT)/noncompaction, nail-patella syndrome (NPS), and mitochondrial myopathy (MMP).

CASE REPORT: A 47-year-old man with congenital NPS from a 17-bp deletion in exon 5 of the LMX1B gene, MMP from the A3243G mitochondrial DNA transition, and LVHT was acutely admitted after a syncope followed by dizziness. Cardiological examinations revealed bradycardia. Blood pressure was 70/30 mm Hg. Blood work revealed a creatine kinase of 389 U/L (normal, <175 U/L), renal insufficiency, anemia, and reduced calcium, phosphorus, and magnesium. Electrocardiogram showed complete heart block with an escape rhythm of 30/min. A temporary pacemaker was inserted. During the procedure, the patient became asystole but was successfully resuscitated. One day later, he received a permanent pacemaker. Echocardiography showed normal systolic function and LVHT. The patient recovered without sequelae.

CONCLUSION: In single cases, LVHT may be associated with complete heart block. Most likely, complete heart block was due to MMP. Patients with NPS and MMP require multidisciplinary surveillance, including regular electrocardiograms, for indicating anticipatory intervention in time.