Download A Case of Verapamil-Sensitive Left Ventricular Tachycardia

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A Case of Verapamil-Sensitive Left Ventricular
Tachycardia
Misbahuddin Syed MD
Lehigh Valley Health Network, [email protected]
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Published In/Presented At
Syed, M., (2015, October 24). A Case of Verapamil-Sensitive Left Ventricular Tachycardia. Poster presented at: ACP (Eastern PA)
Associates’ and Medical Students’ Annual Competition, Hershey, PA.
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A Case of Verapamil-Sensitive Left Ventricular Tachycardia
Misbahuddin Syed, MD
Lehigh Valley Health Network, Allentown, Pennsylvania
Case
A 54-year-old male presented to the hospital with a sudden onset of palpitations,
dyspnea, and lightheadedness. On presentation, the patient was hemodynamically stable.
However, his initial electrocardiogram displayed a wide-complex tachycardia with QRS
durations of 150milliseconds, a ventricular rate of 193beats/minute, a right bundle branch
morphology, and a right-axis deviation. Unsuccessful attempts were made to convert the
patient to sinus rhythm with amiodarone and lidocaine infusions. Laboratory evaluation
revealed normal cardiac markers. A transthoracic echocardiogram revealed an ejection
fraction of 55% and no wall motion or significant structural abnormalities. He was then
begun on verapamil on suspicion that his clinical presentation and electrocardiogram
was suggestive of a left anterior fascicular ventricular tachycardia. The patient converted
to normal sinus rhythm, and had resolution of his symptoms. Subsequent myocardial
perfusion imaging was negative for any signs of ischemic heart disease, further
supporting the diagnosis of verapamil-sensitive fascicular ventricular tachycardia.
Laboratory Evaluation
Laboratory Evaluation
left anterior fascicular block. Approximately 10% of cases are consistent with left anterior
fascicular VT, which involves a QRS complex with a RBBB morphology and right-axis
deviation, consistent with a left posterior fascicular block. Less than 1% of cases are
3
septal, with a narrow QRS complex and normal or right-axis deviation.
Acute management in terminating the rhythm is usually successful with intravenous
calcium channel blockers, such as verapamil. In mild cases, the patient is transitioned
to oral verapamil for the prevention of recurrent symptoms. Radiofrequency ablation is
successful for those with severe or recurrent symptoms, with rates approaching 90%.
The patient’s initial EKG revealed a widecomplex tachycardia with a QRS duration of
150ms, a ventricular rate of 193bpm, a RBBB
morphology, and right-axis deviation. The
pattern is suggestive of a left anterior fascicular
block, which occurs in approximately 10% of
cases of idiopathic fascicular VT.
Diagnostic Imaging
White Blood Cell
6.8
Troponin #1
<0.02
Hemoglobin
14.3
Troponin #2
<0.02
Hematocrit
42.7
Troponin #3
<0.02
Platelets
166
D-Dimer
<0.27
Sodium
141
Urine Drug Screen
Potassium
3.9
Thyroid Stimulating Hormone
Chloride
105
PT/INR
CO2
29
PTT
36.9
BUN
20
LDL
109
Creatinine
0.74
HDL
38
Glucose
109
Triglycerides
131
Magnesium
2.1
Cholesterol
173
Negative
• E jection fraction 55%
• M
ildly elevated septal
wall and posterior wall
thickness
2D Echocardiogram
• N
ormal diastolic function
• T race aortic regurgitation
• A ortic sclerosis
3.24
15.0/1.2
Myocardial
Perfusion Imaging
(1-Day ExerciseGated SPECT
99mTc Cardiolite
Protocol)
The patient’s ECG after treatment with
verapamil revealed a normal sinus rhythm.
Subsequent electrocardiograms also revealed
a similar pattern.
• N
ormal clinical response
to exercise
• N
ormal ECG response
• M
yocardial perfusion
normal
• L eft ventricular ejection
fraction of 59%
• N
o wall motion
abnormalities
Key Points
•Fascicular ventricular tachycardia can easily be misdiagnosed and over-treated with
antiarrhythmic agents or cardioversion. Fascicular Ventricular Tachycardia
•Symptoms are paroxysmal and occur in younger individuals, manifesting most
commonly as palpitations. However, patients can present with syncope and tachycardiainduced cardiomyopathy.
Idiopathic fascicular ventricular tachycardia is a type of monomorphic idiopathic
ventricular tachycardia arising from the fascicles of the left bundle branch in a structurally
1
normal heart. It occurs in both genders with a median age of about 40 years. Symptoms
are usually paroxysmal and typically manifest with palpitations, but patients can present
with syncope and tachycardia-induced cardiomyopathy. The diagnosis of idiopathic
fascicular tachycardia requires induction with atrial pacing, right bundle branch
morphology with left or right axis deviation, a structurally normal heart, and sensitivity
to calcium channel blockers. A documented negative evaluation for cardiac ischemia is
crucial in its diagnosis.
•The diagnosis includes ECG evidence of a widened QRS, and a RBBB morphology with
a left or right axis deviation. The absence of ischemia and structural heart disease by
diagnostic testing is important in its diagnosis.
Idiopathic fascicular VT is further subdivided into left posterior, left anterior, and left upper
septal fascicular VT. The most common among the three is left posterior fascicular VT.
The mechanism is thought to involve a macroreentry circuit, with origins in the Purkinje
2
network of the left posterior fascicle. The circuit appears to primarily be dependent on
slow inward calcium channels. Alternatively, false tendons or fibromuscular bands that
extend from the posterior inferior left ventricle to the basal septum have been implicated.
90% of cases involve ECG characteristics of left posterior fascicular VT, which includes a
right bundle branch block (RBBB) morphology with left axis deviation, consistent with a
1. H
offmayer KS, and Gerstenfeld EP. Diagnosis and Management of Idiopathic Ventricular Tachycardia. Curr Probl Cardiol 2013;38:131-158.
2. Nakagawa H, Beckman KJ, McClelland JH, et al. Radiofrequency Catheter Ablation of Idiopathic Left Ventricular Tachycardia Guided by a Purkinje Potential.
Circulation 1993;88:2607-2617.
•Sensitivity to verapamil is the hallmark of the arrhythmia, and is the treatment of choice
in the acute and chronic setting. Radiofrequency ablation can be used for those with
refractory symptoms.
References:
3. Canan T, Vaseghi M, et al. A Complex Rhythm Treated Simply: Fascicular Ventricular Tachycardia. The American Journal of Medicine 2014;127:601-604.
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