The ECG Characteristics of Patients With Isolated Hypomagnesemia

Abstract

BackgroundElectrocardiographic (ECG) characteristics of patients with isolated hypomagnesemia are not well defined. We aimed to investigate these ECG characteristics in order to define clearly the features of isolated hypomagnesemia.HypothesisLower serum magnesium could affect ECG parameters after excluding potential confounders.MethodsThis retrospective study was of patients with low serum magnesium <0.65 mmol/L compared with the same patients after restoration to normal serum magnesium. Patients with hypokalemia, hypocalcemia and other electrolyte disturbances were excluded. ECG parameters manually determined and analyzed were P wave dispersion, PR interval, QRS duration, ST-T changes, T wave amplitude, T peak-to-end interval (Tpe), corrected Tpe (Tpec), QT, corrected QT (QTc), QT peak corrected (QTpc) and Tpe dispersion, Tpe/QT ratio.ResultsTwo-hundred-and-fourteen patients with isolated hypomagnesemia were identified with 50 of them (56.9 ± 13.6 years; 25 males) being eligible for final analysis from 270,997 patients presenting April 2011–October 2017. In the period of isolated hypomagnesemia, P wave duration was found prolonged (p ≤ 0.02); as was QTc (439 ± 27 vs. 433 ± 22, p = 0.01). Tpec (122 ± 24vs. 111 ± 22, p = 0.000) and Tpe/QT ratio (0.29 ± 0.05 vs. 0.27 ± 0.05, p = 0.000) were increased. QTpc decreased during hypomagnesemia (334 ± 28 vs. 342 ± 21, p = 0.02). However, no significant differences were found in PR interval, QRS duration (85 ± 12 ms vs. 86 ± 12 ms, p = 0.122) and ST-T segments between the patients and their own controls.ConclusionsIn patients with isolated hypomagnesemia, P wave duration, QTc, Tpec, and Tpe/QT ratio suggesting atrial depolarization and ventricular repolarization dispersion were significantly increased compared with normal magnesium levels in the same patients after restoration to normal levels.

Electrocardiogram Features in Non-Cardiac Diseases: From Mechanisms to Practical Aspects

“…Patients with lower serum magnesium concentrations (≤1.9 mg/dL) have a higher risk of developing atrial fibrillation compared to those with magnesium levels in the upper normal limit. 150 , 151 …”

The Role of Hypomagnesemia in Cardiac Arrhythmias: A Clinical Perspective

“…Changes in the surface electrocardiograms (ECG) associated with hypomagnesemia have been described over time, dependent and varying according to magnesium levels: ST segment depression, peaked and tall or flattened T waves, shortening of the PR interval and QTc, lowering of the QRS voltage, increasing in the QRS duration and the presence of U waves. In a study by Yang et al, isolated hypomagnesemia was found to be associated with increased dispersion of ventricular repolarization evaluated by Tpe /QT ratio (T peak-to-end interval (Tpe), QT-peak interval standard measurement from the beginning of the QRS complex to the peak of the T-wave (QTp)) [ 24 ].…”

Magnesium (Mg2+) Deficiency, Not Well-Recognized Non-Infectious Pandemic: Origin and Consequence of Chronic Inflammatory and Oxidative Stress-Associated Diseases

“…Patients with isolated hypomagnesemia (without other electrolyte disturbance) frequently present electrocardiogram disturbances with a P wave, corrected QT, and corrected T peak-to-endinterval duration prolonged, suggesting atrial depolarization and ventricular repolarization dispersion increased [176]. Even though the electrophysiologic action on cellular function is unclear, it suggests that these disturbances may have importance in the relationship between hypomagnesemia and sudden death [176]. Mg 2+ deficiency has been implicated in sudden death, and it is suspected that the electrophysiological changes induced by calcium are involved [177,178].…”