Primary hyperparathyroidism presenting as torsades de pointes

Arrhythmia Resolution After Successful Parathyroidectomy for Primary Hyperparathyroidism

The prevalence of primary hyperparathyroidism (PHPT) is increasing as routine laboratory testing for calcium and parathyroid hormone becomes more prevalent due to heightened awareness of the disease. PHPT affects multiple organ systems including the cardiovascular system. This case report highlights a patient with first degree atrio-ventricular block pre-operatively that resolved after resection of her parathyroid adenoma. This case emphasizes the importance of treating asymptomatic hyperparathyroidism to optimize cardiac function.

Primary hyperparathyroidism associated with acquired long QT interval and ventricular tachycardia

SUMMARY

We present a 54-year-old patient admitted to the emergency department due to loss of consciousness. The initial ECG registered monomorphic ventricular extrasystoles and prolonged QT interval (QT corrected (QTc) >500 ms). Sustained ventricular tachycardia (VT) was registered on 24-h Holter ECG monitoring, which clinically was presented as a crisis of consciousness. Coronary angiography and other visualization methods were normal. Implantable cardioverter-defibrillator (ICD) implantation was planned for the purpose of secondary prevention of sudden cardiac death (SCD). Laboratory and hormonal analyzes revealed primary hyperparathyroidism (PHPT), chronic kidney disease, and hypokalemia. Neck ultrasound showed a 25 mm, sharply outlined homogenous tumor mass which was separated from thyroid gland (TG) and exerted a mild impression on lower parts of the left lobe. Dual wash technetium-99m sestamibi parathyroid scintigraphy with single-photon emission CT (SPECT)/CT also showed the uptake of tracer behind the lower half of the left lobe of the TG. Surgical treatment, lower left parathyroidectomy, was performed, and pathohistological analysis verified parathyroid adenoma. The patient was rhythmically and hemodynamically stable for 7 days after surgery, without additional complaints, and was discharged from the hospital. Timely diagnosis of PHPT, correct assessment and surgical treatment, did not lead our patient to unnecessary ICD implantation. Our case suggests an additional intertwining of electrolyte disorders and ventricular arrhythmias in PHPT and more importantly emphasizes the need for caution when indicating ICD, even in patients with the most serious life-threatening arrhythmias.

LEARNING POINTS

Electrolyte abnormalities in PHPT can have highly malignant consequences, and the occurrence of hypokalemia in the presence of hypercalcemia is underestimated in PHPT, and the consequences can be life-threatening. Although hypercalcemia causes shortened QT interval, concomitant severe hypokalemia may overcome hypercalcemia and prolong QT interval, even in the absence of structural heart disease or LQTS. Timely diagnosis of PHPT, correct assessment and surgical treatment, do not lead to unnecessary ICD implantation.

Primary hyperparathyroidism and recurrent ventricular tachyarrhythmia in a patient with novel RyR2 variant but without structural heart disease

It is important to consider calcium and parathyroid hormone levels in patients with recurrent VT/VF without any obvious cause of arrhythmia. In similar cases to gain rhythm control using isoprenaline and do comprehensive molecular-genetic. Diagnosis and surgery in case of parathyroid adenoma may be needed to obtain definite arrhythmia control.

Hypercalcemic crisis and primary hyperparathyroidism: Cause of an unusual electrical storm

Hypercalcemia is a known cause of heart rhythm disorders, however its association with ventricular arrhythmias is rare. The authors present a case of a fifty-three years old male patient with a ischemic and ethanolic dilated cardiomyopathy, and severely reduced ejection fraction, carrier of cardiac resynchronization therapy (CRT) with cardioverter defibrillator (ICD), admitted in the emergency department with an electrical storm, with multiple appropriated ICD shocks, refractory to antiarrhythmic therapy. In the etiological investigation was documented severe hypercalcemia secondary to primary hyperparathyroidism undiagnosed until then. Only after the serum calcium level reduction ventricular tachycardia was stopped.

HYPERPARATIROSIS AND CARDIOVASCULAR SYSTEM PATHOLOGY

For many years, hyperparathyroidism, including primary, primarily associated with severe pathology of the osseous system and kidneys, was considered a rare disease. The widespread introduction into the clinical practice of the determination in the blood of calcium, and then parathyroid hormone, and osteodensitometry made it possible to recognize this disease more often and at earlier stages and to treat it more successfully. By now, the specific gravity of mild and asymptomatic forms of hyperparathyroidism has increased from 10-15% in the 1980s to 80%. Conservative management of these forms of hyperparathyroidism requires more thorough research on the prognosis of survival, duration and quality of life, and the risk of developing associated diseases in these patients.

Torsade de pointes: the clinical considerations

Torsade de pointes is a form of polymorphic ventricular tachycardia occurring in a setting of prolonged QT interval on surface electrocardiogram. Congenital causes of prolonged QT interval occur in individuals with genetic mutations in genes that control expression of potassium and sodium channels and acquired causes are numerous, predominantly drugs causing prolonged QT interval by blockade of potassium channels. Among the drugs, antiarrhythmic agents most notably quinidine, sotalol, dofetilide and ibutilide have the potential to induce the fatal torsade de pointes. Many non-antiarrhythmic drugs can also cause torsade de pointes. Although it is important to distinguish between the congenital and the acquired forms of long QT syndrome as the later can often be reversed by correction of the underlying disorder or discontinuation of the offending drug, both forms are not mutually exclusive. Clinical considerations and management of torsade de pointes are described.

Ventricular tachycardia in a patient with primary hyperparathyroidism

We present a case of primary hyperparathyroidism with hypercalcemia in a patient who had spontaneous attacks of ventricular tachycardia. Right ventricular burst pacing reproducibly induced ventricular tachycardia in the electrophysiological laboratory after intravenous administration of calcium-gluconate, and verapamil could terminate the tachycardia. After resection of the parathyroid adenoma, the calcium level was restored to normal, and ventricular tachycardia did not occur again during the follow-up period.

Primary Hyperparathyroidism and Polymorphic Ventricular Tachycardia

BACKGROUND: Primary hyperparathyroidism is a rare but important cause of ventricular arrhythmias. METHODS AND RESULTS: The medical records of a patient with primary hyperparathyroidism and polymorphic ventricular tachycardia was reviewed. The patient was serially interviewed and examined before and after parathyroidectomy. A literature search was performed. The association of primary hyperparathyroidism and polymorphic ventricular tachycardia is rare. Hypokalemia and hypomagnesemia occur infrequently in primary hyperparathyroidism. CONCLUSIONS: The potential for malignant ventricular arrhythmias in the setting of primary hyperparathyroidism must be recognized.

Electrophysiologic mechanisms of the long QT interval syndromes and torsade de pointes

PURPOSE

To review the current understanding of the mechanisms and treatment of the long QT interval syndromes and torsade de pointes.

DATA SOURCES

Personal databases of the authors and a search of the MEDLINE database from 1966 to 1994.

STUDY SELECTION

Experimental and clinical studies and topical reviews on the electrophysiologic mechanisms and treatment of torsade de pointes were analyzed.

RESULTS

The long QT interval syndromes have been classified into acquired and hereditary forms, both of which are associated with a characteristic type of life-threatening polymorphic ventricular tachycardia called torsade de pointes. The acquired form is caused by various agents and conditions that reduce the magnitude of outward repolarizing K+ currents, enhance inward depolarizing Na+ or Ca2+ currents, or both, thereby triggering the development of early afterdepolarizations that initiate the tachyarrhythmia. The hereditary form appears to result from an abnormal response to adrenergic or sympathetic nervous system stimulation. At least some cases of the hereditary long QT interval syndromes may result from a single gene defect that alters the intracellular regulatory proteins responsible for the modulation of K+ channel function. Treatment of the acquired form is primarily directed at identifying and withdrawing the offending agent, although emergent therapy using maneuvers and agents that favorably modulate transmembrane ion currents can be lifesaving. In torsade de pointes associated with the hereditary long QT interval syndromes, early diagnosis leading to treatments designed to both shorten the QT interval and block the beta-adrenergic-induced instability of the QT interval is essential.

CONCLUSIONS

The long QT interval syndromes and torsade de pointes are potentially life-threatening conditions caused by various agents, conditions, and genetic defects. The mechanisms responsible for these conditions and available treatment options for them are reviewed.