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.