DISCUSSION
In our protocol study, no patient received ICD therapy (ATP or appropriate/ inappropriate discharges) during the dental treatment under local anesthesia regardless of the use of a vasoconstrictor. No sustained arrhythmias were observed, indicating that stable or treated patients with CCh and ICD can even be sheltered when epinephrine at pattern doses is used with lidocaine.
The safety of these anesthetics could be observed in our study protocol when QTc shortened in 2 LQTS patients, suggesting a possible protective effect of lidocaine. No LTE occurred in patients with LQTS and no significant prolongation of the QT interval were observed.
Patients with BrS preserved the same electrocardiographic pattern during the studied three-time points in both conditions, with and without epinephrine, and any dynamic changes occurred in the high precordial leads.
There was no procedure-related complication in the patient with CPVT, and fortunately with no ventricular arrhythmia documented, even under epinephrine use. These results could also be in part explained by the possible protective effect of lidocaine in both periods, as well by our strict inclusion criteria (only stable patients).
In a previous study, the use of local dental anesthesia with and without epinephrine in selected stable patients with LQTS and BrS did not result in life-threatening arrhythmias, though the maximum heart rate increased after the use of vasoconstrictor during the anesthesia period25.
According to American Society of Anesthesiologists Task Force26, anesthetic techniques do not influence cardiac rhythm management devices (CRMD) function. However, anesthetic-induced physiologic changes (i.e. , cardiac rate, rhythm, or ischemia) in the patient may induce unexpected CRMD responses or adversely affect the CRMD-patient interaction.
Anesthetic drugs have not been demonstrated to affect pacing thresholds, though the physiologic consequences of anesthetic management may. Myocardial ischemia and high blood levels of local anesthetics may increase electrophysiologic thresholds, but one hardly needs to be cautioned in these areas. It is noteworthy the importance to avoid hyperventilation in these patients, which could abruptly lower serum potassium levels2.
Vital parameters could be influenced by the use of vasoconstrictors added to the stress of the dental procedure27. The findings of the present study did not show significantly changes in BP and anxiety comparing the conditions with and without epinephrine in patients with LQTS, BrS and CPVT.
However, Tom28 pointed out that anesthetics with epinephrine used in dentistry may have considerable effects upon the sensing and function of CIED. They can promote tachyarrhythmias and initiate ICD events, if there is no prior modification of anesthetic techniques and particularly with higher doses.
The insertion of an ICD can be performed under local anesthesia with sedation during induction of VF, testing of the defibrillator, and placement in the subpectoral pocket, thus avoiding general anesthesia. The total dose of local anesthetic should be minimized, and systemic absorption limited by the use of lidocaine with epinephrine. Local anesthetics, because of their sodium channel blockade, may exacerbate Brugada ECG changes. However, the class IB drugs mexilitine and lidocaine have not been shown to cause ST-segment elevation29 which, in the final analysis, also suggests a protective and safety effect.
Theodotou and Cillo16 described a case report using local anesthetic for dental treatment in 55-year-old patient with ICD, BrS and valvular heart disease. He was subjected to exodontia and abscess drainage under general anesthesia and 15 milligrams of lidocaine with 1:100 000 epinephrine was applied in the intraoral region for local anesthesia of the operated area. The patient had not adverse cardiac events or intraoperative complications.
The dental care of a seven-year-old boy with a medical history of LQTS using ICD was described by Karp, Ganoza30. After a syncope episode with development of torsades de pointes, he suffered dental trauma and had no complications in his tooth extraction under general anesthesia.
In our casuistry, it was noted that 5 out of 7 patients with LQTS were carriers of type 2 LQTS, which characteristically could have events triggered by noise and emotions31. The dental environment needs to be as calm and quiet as possible, but devices noise is inevitable. Fortunately, none of the patients with LQTS had LTE, provided that the exclusion criteria were respected.
A case report of a 13-year-old CPVT patient was described32, whose had already undergone to previous dental treatment under general anesthesia. Due to recurrence of carious lesions and the need for further intervention, the cardiologist did not contraindicate the use of local anesthetic with epinephrine. However, the dentist considered prudent the use 3% mepivacaine for local anesthesia in the amount of 3 cartridges, besides the administration of nitrous oxide to perform dental restorations in the dental chair in a hospital setting. We also had a favorable experience with one CPVT patient using lidocaine with and without epinephrine.
It is crucial to comprehend the perioperative management of these patients to avoid preventable complications, as the EMI sources should be kept in distance from CIEDs as it is possible2 and to be aware of inadvertent local anesthesia intravascular administration33. In our protocol we did not use sources that could interfere with sensing and pacing activity.
One of our limitations is the fact that this protocol can be applied only to stable patients, as mentioned in methods. Our small sample of patients also limits strong statistical power of efficacy. However, this protocol can be used for exploratory data for future large studies or meta-analyzes.
To the authors’ knowledge, this is the first study (although small) to investigate the use of local dental anesthesia in consecutive patients with CCh and ICD, without detectable adverse clinical impact.